Scattered damaging winds from severe thunderstorms will be possible across parts of the Northeast and Mid-Atlantic States Sunday. Excessive heat will continue over the southern U.S. Sunday before another round of heat arrives Monday through the central and southern U.S. spreading into the East by Independence Day. California will see excessive heat starting Tuesday. Read More >
Seattle, WA
Center Weather Service Unit
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679 FXUS66 KSEW 301101 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 401 AM PDT Sun Jun 30 2024 .SYNOPSIS...Weak upper level trough over Western Washington today with a convergence zone over mainly Snohomish county. Trough moves east tonight and convergence zone dissipates Monday morning. Upper level ridge building offshore Monday will slowly move east for the remainder of the week ending up near Western Washington by late in the week. && .SHORT TERM /TODAY THROUGH TUESDAY/...Satellite imagery shows cloudy skies over Western Washington early this morning. Doppler radar indicating showers over the Central and Northern Cascades as well as over Whatcom county. With the cloud cover temperatures were on the mild side at 3 am/10z, in the upper 50s to mid 60s. Weak upper level trough over Western Washington today. Convergence zone developing over Snohomish county this morning with the convergence zone continuing into the afternoon hours. Main story today will be the cloud cover. With the weak trough will have a slight chance of showers for most of the lowlands in the morning. By afternoon showers chances becoming confined to the convergence zone and the Cascades. Air mass unstable enough over the North Cascades for a slight chance of a thunderstorm this afternoon. Highs today in the mid 60s along the coast and upper 60s to mid 70s inland. Upper level trough moving east tonight but the weak convergence zone will remain intact into the early morning hours. Showers chances pretty much confined to the convergence zone into early Monday morning. Some clearing early but with increasing low level onshore flow cloud cover increasing again overnight. Lows in the 50s. Upper level ridge building offshore Monday. Weak shortwave rippling down the back side of the ridge nicking the Northern portion of the Cascades keeping a chance of showers in the forecast for that location. For the remainder of the area morning clouds will give way to afternoon sunshine. Highs in the mid 60s coast and upper 60s to mid 70s inland. Upper level ridge slowly starting to move east Monday night into Tuesday. Low level onshore flow continuing through Tuesday keeping the late night and morning clouds with afternoon sunshine forecast going through Tuesday. With the onshore flow highs Tuesday will be similar to Monday, mid 60s coast and upper 60s to mid 70s inland. Lows Tuesday morning in the 50s. .LONG TERM /WEDNESDAY THROUGH SATURDAY/...Extended models in good agreement with the upper level ridge continuing to move east Wednesday. The ECMWF brings the ridge over Western Washington Thursday with the ridge remaining over the area into Saturday. The GFS keeps the ridge offshore Thursday through Saturday. Both models do not turn the low level flow offshore going to more flat gradients beginning Thursday. Slow warming trend through the period with highs Wednesday in the mid 60s along the coast and 70s inland warming to the mid 70s to lower 80s along the coast and upper 70s to near 90 inland Saturday. Ensembles show a big spread in the solutions for the high temperature Saturday. Model blend puts highs in the mid 70s along the coast and mid 70s to upper 80s inland. Ensemble means off both the GFS and ECMWF were a few degrees warmer then the blend. Given the possible HeatRisk issues have gone with the warmer ensemble mean highs for Saturday. Felton && .AVIATION...A weak upper level trough remains over the region today with west to northwest flow aloft. The air mass is moist with widespread IFR and low MVFR ceilings this morning. Ceilings are expected to gradually lift by afternoon with most areas returning to VFR near or after 22Z. Areas of MVFR will redevelop by early Monday A.M. KSEA...IFR or occasional LIFR ceilings are expected to linger through mid-morning before gradually lifting to VFR 20Z-22Z. Surface winds S/SW 5 to 10 knots becoming light and variable late this evening. 27 && .MARINE...Broad surface ridging will rebuild over the coastal and offshore waters through Monday with lower pressure continuing east of the Cascades. This will lead to an increase in onshore flow with small craft advisory westerlies likely in the central/east strait this evening. A somewhat stronger onshore gradient will lead to the potential for a few hours of gales in the strait Monday evening. Thermally induced low pressure is expected to expand northward across the interior midweek onward. This will lead to lighter winds across interior waters, but will likely produce small craft advisory strength N/NW winds for portions of the coastal waters at times Tuesday through late week as a more typical summer synoptic pattern takes hold. 27 && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory from 5 PM this afternoon to 3 AM PDT Monday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. Gale Watch from Monday afternoon through late Monday night for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. && $$ 757 FXUS66 KPQR 300935 AFDPQR Area Forecast Discussion National Weather Service Portland OR 235 AM PDT Sun Jun 30 2024 .SYNOPSIS...Light shower chances continue across the northern portions of the CWA today. Onshore flow will maintain near average temperatures into early next week. There is 50-60% chance that stronger high pressure offshore will shift over the region towards the end of next week and bring the hottest temperatures of the Summer so far. && .SHORT TERM...Sunday through Tuesday...Upper level trough continues moving over the PacNW today. Scattered showers dissipated by late last night but are expected to return later this morning into the afternoon as surface heating produces enough localized instability. Showers will mainly be located over the Coast Range and Cascades as orographic forcing will be the main lifting mechanism for showers, but a few could meander into the valley. NAM soundings show significantly less instability for today than yesterday, so thunderstorm or heavy shower chances are very limited with today`s scattered showers. As the upper trough moves east Monday into Tuesday, ensemble guidance continues to indicate strong ridging building over the eastern Pacific with lower heights over the PacNW. This will bring dry weather but will keep temperatures stable at right around normal. Expect high temperatures for inland valleys in the upper 70s to low 80s today through Tuesday with 60s along the coast. -HEC .LONG TERM...Wednesday through Saturday...The overall pattern remains the same on Wednesday, according to the WPC 500 mb cluster analysis, though the ridge axis looks to shift slightly east over the Pacific which would allow widespread 80s for inland valleys. Thursday into Saturday remain a little uncertain as ensemble members continue to struggle to handle the specifics of the pattern. However, consensus in the WPC clusters is increasing on either the upper ridge moving over the region or remaining close enough to the region to warm temperatures into the 90s, though the timing of the ridge moving inland remains uncertain. NBM and LREF also agree with this scenario as both indicate around a 50-60% chance of temperatures reaching or exceeding 95F Friday and Saturday for inland valleys, which would be the warmest temperatures of the summer so far. NBM also indicates a 30-40% chance of inland valleys reaching 100F at least one of those days. It still needs to be mentioned that there`s a 5-15% chance of a shortwave trough breaking through the ridge and approaching the region Friday or Saturday, bringing stronger onshore flow and lowering temperatures back to near normal. -HEC && .AVIATION...VFR prevails inland as a weak upper level disturbances tracks across the region. Marine stratus has begun to settle into the coast with a mix of IFR to LIFR cigs/vis already in place a KAST and KONP. These should see gradual improvement through the day Sunday with MVFR to low VFR conditions prevailing come the mid to late afternoon hours. Inland VFR conditions with CIGs around 4000-6000 ft will deteriorate as winds shift west/southwest at low and mid levels to spread marine clouds with MVFR cigs inland roughly after 10-13Z Sun, then gradually improving to VFR after 18-19Z Sun. The HREF projects a 60-80% chance for CIGS at or below 3kft between 12-18z before the aforementioned improvement finally takes place. PDX AND APPROACHES...VFR conditions will begin to deteriorate around 10Z with increasing chances for MVFR cigs 2000-3000 ft to develop. Chances for MVFR peak at around ~70-80% 12-18Z Sun, then rapidly decrease by 18Z Sun for high chances of VFR. -Batz && .MARINE...Weak high pressure over the northeast Pacific with lower surface pressure over California and the Great Basin will more or less maintain itself into next week. A weak area of surface low pressure will pass over the area today, supporting initially southwest winds before turning to the west in its wake. Otherwise, expect north to northwest winds across the waters as high pressure strengthens toward the middle of next week, with the strongest winds generally off the central coast of Oregon and lighter winds farther north. Winds will generally peak in the afternoon and evening hours each day. A thermal low develops along the northern California/southwest Oregon coast on Tuesday and strengthening/spreading north into Wednesday and thereafter. This will increase the pressure gradient along the coast and over the waters with a >90% chance that northerly wind gusts of 20-30 kt spread northward across the waters by mid week. This will in return develop steep wind driven seas of 5-8 ft with a dominant period of 7-8 seconds by late Tuesday or Wednesday. -Batz && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...None. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland 913 FXUS66 KMFR 301115 AFDMFR Area Forecast Discussion National Weather Service Medford OR 415 AM PDT Sun Jun 30 2024 .UPDATE...Updated aviation discussion for 12z TAFs. && DISCUSSION (Today through Saturday)... Overview: Potential impacts from both heat and fire weather are at the forefront of the forecast for the next week, but early indications suggest we could be in for a rather dry and hot first half of July. By middle of next week, the heat will be ramping up across the forecast area, and there is a high likelihood for some sort of heat risk. In fact, there is the potential for some records to be broken as well. Unfortunately, with the heat comes low RH values that could be coupled with breezy winds, so there is at least some risk for elevated to perhaps critical fire weather conditions next week. Lastly, there will be a small chance for thunderstorms today for mainly areas on the eastside. Not expecting severe weather, but the threat for lightning will exist. Further Details: Pieces of energy are expected to round the base of a passing trough today. This may result in a chance for thunderstorms today, but the problem is we have weak variables, especially the moisture aspect. There is some indication the vorticity field might phase with some limited moisture today, and this could kick off some showers/thunderstorms over parts of Klamath and Lake counties. Not a great chance, but also not a zero chance. Models are suggesting upwards around a few hundred J/kg of MUCAPE could be present today. Again, not expecting severe weather, but lightning may disrupt outdoor activities this afternoon and early evening on the eastside. The heat is coming! The probabilities for 100 degrees or more have gone up (again) for some of the westside valleys with some areas sitting around a 70-80 percent chance for 100 degrees or more on the holiday (July 4th). In fact, by July 5th the probability for 110 or greater is around 30% for both the Rogue Valley and Shasta Valley. In other words, there is a high probability for some sort of heat related headline come next week to account for this threat as the Rogue Valley could go about 7 days or more with 95+ degrees starting Wednesday. Overnight low temperatures might be in the mid 60s for some areas on the westside Fri-Sun, which would not allow for much relief from the heat overnight. Some Potential Records: -------- July 4th -------- Medford: 103 in 2015 (Forecast: 101) Roseburg: 98 in 2023 (Forecast: 95) Brookings: 96 in 1931 (Forecast: 78) Klamath Falls: 98 in 1981 (Forecast: 94) Mount Shasta: 97 in 2007 (Forecast: 99) -------- July 5th -------- Medford: 102 in 1926 (Forecast: 103) Roseburg: 98 in 2023 (Forecast: 98) Brookings: 84 in 1993 (Forecast: 77) Klamath Falls: 98 in 2007 (Forecast: 96) Mount Shasta: 100 in 2007 (Forecast: 100) -------- July 6th -------- Medford: 104 in 1922 (Forecast: 105) Roseburg: 102 in 1960 (Forecast: 100) Brookings: 84 in 1998 (Forecast: 74) Klamath Falls: 96 in 2021 (Forecast: 97) Mount Shasta: 99 in 2007 (Forecast: 101) Unfortunately, the heat (above normal temperatures) may continue into parts of mid July as the Climate Prediction Center is forecasting the chance for above normal temperatures to continue with below normal precipitation chances. This doesn`t bode well for our fire weather conditions as a prolong drying period appears slated for much of the area through at least mid July. -Guerrero AVIATION... 30/12Z TAFS...Low clouds and fog will will impact areas along the coast this morning, clearing to VFR in the afternoon. Low clouds with IFR and MVFR are likely to return to the coast Sunday evening. Inland, areas of MVFR are expected to spread into the Umpqua Basin to Roseburg early this morning. These clouds will clear in the late morning to VFR. Elsewhere, expect VFR across the area. Smoke from a few wildfires could produce some locally low visibility near those fires, otherwise the smoke will not be an issue near terminals. There is a low chance for an isolated thunderstorm east of the Cascades this afternoon. -Miles MARINE...Updated 200 AM Sunday, June 30, 2024...Winds and seas will remain low today. However, areas from Brookings south within about 15 NM of shore could observe brief and isolated advisory level seas as winds peak in the afternoon, generating a steep wind wave. If in this area, watch Buoy 27 to monitor conditions to be safe before heading out. A very strong thermal trough is expected to develop next week beginning Monday afternoon and lingering towards the end of the week. A Gale Watch and other headlines have been put in place for this event this morning. The peak should be either Tuesday or Wednesday evening, and the guidance is trending towards Tuesday; although very little drop off in intensity is expected Wednesday. As for the wind speeds expected during the peak of the thermal trough, the gale force gusts of 35 to 45 kt are expected south of Cape Blanco, but there is a 20-40% chance that gusts reach or exceed 50 kt Tuesday or Wednesday evening. With the chance for gale force gusts remaining below 50% between Cape Blanco and Cape Arago, a Hazardous Seas Watch was put in place instead of something for the infrequent gale force gusts. Comparing this event to the past, this is getting into the top end of events, standing out against climatology. And to summarize, this occurrence of the thermal trough northerlies will not be one to mess with. -Miles FIRE WEATHER (Updated 300 AM Sunday, June 30th)... ..Elevated to critical fire weather possible Tuesday through the weekend... As mentioned above in the discussion, we have a small chance for thunderstorms today mainly on the eastside. Not expecting widespread thunder or severe weather, but isolated strikes could occur late this afternoon and early evening. A strong warming and drying trend will begin Monday night as high pressure builds into the region. This will bring moderate to locally poor humidity recoveries to ridges. The poorest recoveries and hottest temperatures are expected from Wednesday morning into the weekend. Western Siskiyou County in particular could experience critical fire weather conditions starting as early as Tuesday afternoon, but much of the forecast area will have at least elevated concerns through the weekend. Additionally, there is concern for both critically poor night-time ridge top humidity recoveries (higher terrain of Curry and western Josephine counties), and also gusty afternoon winds accompanying a very dry airmass. The limiting factor is likely to be wind speeds, while the hot and dry aspect looks like a "slam dunk" to occur. -Guerrero && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Gale Watch from Monday afternoon through late Wednesday night for PZZ356-376. Small Craft Advisory from 5 PM Monday to 5 AM PDT Thursday for PZZ350-370. Hazardous Seas Watch from Monday afternoon through late Wednesday night for PZZ370. && $$ 475 FXUS66 KEKA 292200 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 300 PM PDT Sat Jun 29 2024 .SYNOPSIS...Dry and seasonable conditions will continue through weekend along with gusty northwest wind in the afternoon. A strong heatwave will build early through at least mid week. && .DISCUSSION...Seasonable weather will continue through the weekend with interior highs around 90. The coastal pressure gradient will peak this afternoon and Sunday afternoon as an upper trough moves east and high pressure quickly builds on its heels. This will bring gusty northwest wind this afternoon gusting between 20 and 30 mph on exposed ridges and in channeled terrain. There is high confidence that very strong high pressure will build early this week, generating significantly warmer than normal temperatures by Tuesday. By Wednesday, NBM shows a 90 to 100% chance of highs in excess of 100 throughout inland valleys of Lake, Mendocino, and Trinity Counties. Focused on the Russian River Valley, there is even a 60 to 80% chance of highs above 110 just in time for the 4th of July. Such values will rival the daily high record for Ukiah. Overnight lows will bring little relief, especially along midslope areas and ridges of Mendocino and Lake counties where lows are likely to stay above 70. Such high temperatures are expected to bring Major to isolated Extreme HeatRisk around Clear Lake and in the Russian River Valley. where and excessive heat watch has been issued. Widespread Moderate HeatRisk is expected throughout the rest of the interior. Despite similar high temperatures, much cooler overnight lows in the 50s for Trinity and northern Mendocino County will help lower the overall HeatRisk. Though there are flagged areas of Major or even Extreme HeatRisk beyond Lake and southern Mendocino, the vast majority of the populated areas show only Moderate HeatRisk. These areas will need to be watched closely in the coming days as the need for further heat products may increase. Above average temperatures are most likely to persist late into the week. That said, the presence of a surface low pressure off the coast late in the week may disrupt the heat depending on how efficiently it can break up larger scale high pressure and pull in marine influence. It is possible its impact will be negligible, with about 50% of model ensemble members showing Major to Extreme HeatRisk continuing even late into the week. /JHW && .AVIATION...Pics from the sky shows high altitude cirrus sweeping across our area today ahead of a weak frontal passage. As of right now, VFR conditions are stable at all terminals. This is forecasted to change this afternoon/evening as a marine stratus push should lower ceiling heights between 1000-500ft (probabilities at these heights at 90% & 50% respectively). Model guidance even suggests possible ceiling heights of only a couple hundred feet AGL late tonight into early tomorrow morning for coastal terminals. Fog coverage and lowered visibilities will possibly be allowing LIFR conditions to reform. AT KUKI, when the winds eventually pick up, they are forecasted to stay from the north with no low cloud coverage expected. Thus, KUKI should remain in VFR conditions for the next 24 hours. && .MARINE...Northerly winds will continue to ease across the waters today into tomorrow, especially north of Cape Mendocino as a weak frontal system moves through. Strong breezes will continue across the southern waters today, with locally near-gale to gale force gusts downwind of Cape Mendocino. NDBC buoys observations are reporting WNW seas around 4-6 feet @ 5-7 seconds. A WNW swell should enter our waters tonight bringing an additional wave group of 5ft @ 12s to the sea state. Tomorrow morning will show Steep seas around 7- 9 feet will remain across the southern water zones over the weekend. Monday, winds are forecast to strengthen again as a high pressure offshore begin to builds in quickly in the wake of the trough. A thermal trough is then expected to develop near the coast Monday night/early Tuesday and favor moderate to strong pressure gradient. Widespread strong to near gale force winds and very steep, hazardous seas (12-16 ft @ 10 s) are forecasted for early to mid next week. Confidence is high for high for gale force gusts up to 40 kt over the outer waters, with locally gales downwind of Cape Mendocino. && .FIRE WEATHER...Seasonable warm and dry conditions will persist through the weekend. A tightening pressure gradient will continue to enhance northwest winds today with gusts of 20 to 30 mph most likely on exposed ridges and in channeled terrain. This is especially true in southern Mendocino and Lake Counties. Onshore flow will slightly increase humidity, but interior valleys will still be dry with minimum RH down to 20%. In combination, wind and RH will create locally critical fire weather conditions in the afternoon, especially in fine fuels below 2000 feet in elevation. Thankfully, such conditions will be short lived during the late afternoon and evening. /JHW && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Excessive Heat Watch from Tuesday morning through late Thursday night for CAZ113-115. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 AM PDT Monday for PZZ455-475. Small Craft Advisory until 9 AM PDT Sunday for PZZ470. && $$ Visit us at https://www.weather.gov/eureka Follow us on Facebook and Twitter at: https://www.facebook.com/NWSEureka https://www.twitter.com/NWSEureka For forecast zone information see the forecast zone map online: https://www.weather.gov/images/eka/zonemap.png 223 FXUS66 KMTR 301133 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 433 AM PDT Sun Jun 30 2024 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 129 AM PDT Sun Jun 30 2024 Significant warm up still on the way for next week after near normal temperatures this weekend. Increased fire danger next week as well with temperatures well above normal and dry conditions through next weekend. && .SHORT TERM... (Today and tonight) Issued at 129 AM PDT Sun Jun 30 2024 An upper level trough is currently impacting the region and will result in near to slightly above seasonal average temperatures this afternoon. Mostly sunny conditions are expected once any low clouds that do develop dissipate. Tonight, expecting temperatures to cool into the 50`s across much of the region while the higher elevations remain in the 60`s to lower 70`s. If you live in the interior, now is the time for any outdoor chores you may need to get done before the warm up begins on Monday. && .LONG TERM... (Monday through Saturday) Issued at 129 AM PDT Sun Jun 30 2024 On Monday ridging will begin to build over the region from the west and continue to shift eastward throughout the week. Monday kicks off the first day in a stretch of well above average temperatures with far interior areas (e.g. Pinnacles National Park and Lake Berryessa) likely to reach 100F. Tuesday and Wednesday (as currently forecast) are expected to be the warmest days of the week with afternoon highs expected to be well into the 100s for inland areas, nearing 110F for areas such as northern Napa and Sonoma counties, eastern Contra Costa and Alameda counties, and southern Monterey and San Benito counties. As such, we have upgraded the watch to an Excessive Heat Warning for interior parts of the North Bay, East Bay, South Bay, Santa Cruz Mountains, and interior portions of Monterey and San Bentio counties. Locations in and around the San Francisco Bayshore, Northern Monterey Bay, and Northern Salinas Valley are in a Heat Advisory as temperatures are expected to range from the lower 80`s to mid 90`s (especially around the San Francisco Bayshore). Coastal areas will continue to see temperatures ranging from the upper 60s to the mid 80`s. As such, coastal areas including the City of San Francisco are not included in any advisories or warnings (this is subject to change as we move through this heat event). Overnight minimum temperatures will be an issue with this event as well, with elevations above about 1000 feet struggling to cool below about 75- 80F starting Tuesday morning. Lower elevations will still see some degree of marine influence, but by Thursday morning will only cool into the 60s. There is considerable uncertainty regarding the pattern after Friday, but the possibility remains that the ridge hangs out for even longer, thus will prompt the need to extend heat- related messaging into next weekend. Heat Safety and Impacts: By now youre well aware that it is going to be extremely hot next week with well-above normal temperatures; now lets talk about the impacts of excessive heat and actions we can take to minimize those impacts: With extreme heat, and especially prolonged heat events, it is a marathon, and not a sprint. Our bodies, infrastructure, pets, and livestock will be under duress from heat over the span of days as opposed to just a day or two. Given that there is little overnight relief expected throughout this event, this is where it really becomes a marathon, and precautionary measures are necessitated in order to prevent adverse results such as heat exhaustion and stroke. This is not just for individuals sensitive to heat, but rather, the entire population. Heat for this duration and at these temperatures can be dangerous for everyone. Do your body a favor and if you can, suspend outdoors activities between the hours of 10am and 7pm on days where Heat Advisories or Excessive Heat Warnings are in effect. Remain in air conditioning if you have that available to you in your residence, or seek out air conditioned environments such as stores, movie theaters, restaurants, libraries, and cooling shelters. If you cannot access air conditioned environments, must be outside, work outdoors, or otherwise, there are other precautionary measures you can take to keep yourself and your loved ones safe (including pets!) during excessive heat. Take frequent breaks in the shade and ensure that you are drinking plenty of cool water, or other hydrating beverages such as sports drinks with electrolytes. Avoid DEHYDRATING drinks such as alcohol or caffeinated beverages. That aside, visiting your city public pool or a lake, river, or ocean can also help keep you cool, but dont forget the life jacket! If planning on swimming, stick to where there is a lifeguard, and know the ocean or river conditions before you get in. Although outside of our area, its worth repeating: rivers can run fast and cold with snowmelt in the Sierra Nevada mountains, and cold water shock can set in quickly, which can lead to loss of muscle control, and ultimately, drowning. Cold water shock can also set in for ocean- goers. Have fun at the water, but be smart, be safe, and Know Before You Go! Finally, if you do not have air conditioning or cannot access it, and also cannot access a body of water to stay cool: consider taking cold showers or baths, turn on those sprinklers or garden hose and have a fun time in your own makeshift water park, or lay a damp, cool towel across your head or body. Even just dipping your hands and feet in cool water can help to abate feelings of excessive heat. For pets and livestock, make sure they have access to shade structures or areas, and have clean water freely available to them at all times. They do not have the same resources or ability to notify of feeling heat-stressed as we do, so check in on them! If theyre permanently outdoors, consider giving them a quick rinse- down with the hose or set up misters, as the evaporation will help to keep them cool as well. && .AVIATION... (12Z TAFS) Issued at 432 AM PDT Sun Jun 30 2024 IFR-LIFR ceilings in the northern Monterey Bay have for the most part stayed away from the Monterey bay terminals, although patchy ceilings could impact the terminals through sunrise. Otherwise, generally high confidence of VFR into this evening, with breezy and gusty onshore winds developing in the afternoon. Marginal LLWS concerns continue for the rest of this morning and tonight as surface winds decouple from flow aloft, especially along the coast, but outside of STS the magnitude is not severe enough to note in the TAFs. Model output suggests stratus coming through the San Mateo peninsula into the northern SF Bay terminals late tonight and Monday morning, but confidence remains low and the immediate coast and Monterey Bay look more likely to see stratus tonight. Vicinity of SFO...VFR through at least this evening. Northwest winds remain breezy overnight before strengthening Sunday afternoon. Gusts could reach 30 knots, but low confidence that they will reach 35 knots or above. Will continue to monitor observations and further model guidance through the day. Some model output suggests some IFR- LIFR stratus will flow over the San Mateo peninsula and impact the terminal late tonight into Monday morning, but confidence is low the TAF remains VFR throughout. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...IFR-LIFR ceilings remain mostly confined to the northern Monterey Bay, and have occasionally impacted SNS but not at MRY. Confidence in stratus impacts at MRY is decreasing and as such have turned the prevailing ceiling into a TEMPO group. Breezy onshore winds develop this afternoon, and diminish into the evening as stratus returns to MRY and later SNS. && .MARINE... (Today through Friday) Issued at 432 AM PDT Sun Jun 30 2024 Surface high pressure over the Eastern Pacific Ocean will be the driving feature through the period. Northwesterly breezes with occasional gale force gusts will continue today. As the aforementioned surface high pressure builds on Monday, the pressure gradient will tighten and breezes will become northerly with gale force gusts expected over the outer waters through Wednesday. Significant wave heights build to 10-15 feet through Tuesday before beginning an abating trend towards the end of the period. && .FIRE WEATHER... Issued at 129 AM PDT Sun Jun 30 2024 ...Critically low relative humidity expected across the interior and in higher terrain this upcoming week, especially Tuesday and Wednesday... Fire weather concerns will elevate this upcoming week. A Heat Advisory and Excessive Heat Warning remains in effect for most of our area away from the coastline for Tuesday through Friday. ERCs are quickly shifting into the 70ish percentiles and higher in areas prone to grass fires. The high heat and subsequent low RH values, poor overnight RH recovery and the associated risks of fireworks with the Fourth of July - all makes for a combustible situation, please plan accordingly. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Excessive Heat Warning from 11 AM Tuesday to 11 PM PDT Friday for CAZ502>504-506-510-512>518. Heat Advisory from 11 AM Tuesday to 11 PM PDT Friday for CAZ508- 528-529. PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this evening for Mry Bay. Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena to Pt Reyes 0-10 nm. Gale Warning from 3 PM this afternoon to 9 PM PDT this evening for Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory until 3 AM PDT Monday for Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory from 9 AM this morning to 9 PM PDT this evening for Pigeon Pt to Pt Pinos 0-10 nm. Small Craft Advisory from 9 AM this morning to 9 PM PDT Monday for Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 3 PM PDT Monday for Pt Arena to Pt Reyes 10-60 NM. Gale Watch from Monday afternoon through Tuesday morning for Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory until 9 AM PDT Monday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...RGass LONG TERM....RGass/Behringer/Clouser AVIATION...DialH MARINE...DialH Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea 320 FXUS66 KOTX 301145 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 445 AM PDT Sun Jun 30 2024 .SYNOPSIS... Winds will be breezy Sunday afternoon with a renewed chance of showers and thunderstorms for northeast Washington and north Idaho. Mountain showers and seasonal temperatures continue through early next week, followed by drier and much warmer weather by the end of the work week. && .DISCUSSION... Today and tomorrow: Elevated showers have brought some rains to the Inland Northwest tonight, but a dry low level atmosphere has limited accumulations largely below 0.10". The best chances for additional rainfall through this morning are southeast Washington, the Idaho Panhandle, and the Cascades. Watching the potential for thunderstorms later today, particularly north and east of Spokane. Thunderstorms will be capable of heavy rain, frequent lightning, small hail, and gusty outflow winds. Some guidance indicates the potential for an inch of rain where thunderstorms may train in northern Pend Oreille County and northern Bonner/Boundary County. This area can handle rains better than most other places in the Inland Northwest, so flash flooding potential is fairly low. Creeks and small streams may have flashy responses with this amount of rain We`ll also have to monitor the Kootenai Complex burn scar from 2022 despite being a low risk burn scar. Temperatures today will be in the 70s and 80s. Thunderstorm potential returns Monday as we remain in an conditionally unstable airmass. Northeastern Washington and the northern Panhandle again have the best shot at additional thunderstorm activity Monday. Expecting very little changes in temperatures tomorrow. /Butler Tuesday through Saturday: Breezy winds are expected Tuesday and Tuesday evening, with gusts up to 30 mph across the Waterville Plateau and areas near Wenatchee. Lingering chances for showers and thunderstorms will also be possible over far northeastern WA and the the northern ID Panhandle Tuesday and Wednesday with near normal daytime temperatures persisting. A warming and drying trend is then anticipated for Thursday through the end of the week under strengthening high pressure. Afternoon highs for Friday and Saturday are forecast to run about 10 degrees above normal. /KD && .AVIATION... 12Z TAFS: The heavier shower activity is east of all of the TAF sites. There will be another resurgence in showers and thunderstorm chances this afternoon. The thunderstorms have the highest risk north and east of the TAF sites, but there will still be some risk over GEG/SFF/COE/PUW/LWS. Winds will also be gusty in the afternoon, gusting near 15-25 mph. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in VFR conditions at our airport through the period, with low confidence in MVFR conditions in heavier showers. If there is MVFR conditions the risk looks higher near GEG/SFF/COE. General aviation pilots will need to monitor radar for showers and thunderstorms Sunday. ----------------------- Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance For additional probabilistic information for NWS Spokane airports, please refer to the Aviation Dashboard on our webpage: https:/www.weather.gov/otx/avndashboard && .PRELIMINARY POINT TEMPS/POPS... Spokane 81 53 80 55 81 53 / 30 0 10 0 0 0 Coeur d`Alene 77 53 77 53 78 52 / 50 10 20 0 0 0 Pullman 77 52 75 51 77 50 / 30 0 10 0 0 0 Lewiston 87 61 86 59 88 58 / 40 10 0 0 0 0 Colville 75 45 78 45 80 47 / 70 30 30 0 10 0 Sandpoint 72 50 73 50 76 49 / 70 30 50 10 10 10 Kellogg 72 55 73 55 74 54 / 70 20 20 10 10 0 Moses Lake 87 55 86 55 87 53 / 0 0 0 0 0 0 Wenatchee 82 60 82 57 84 57 / 0 0 0 0 0 0 Omak 84 54 85 54 88 55 / 20 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$ 585 FXUS66 KPDT 301203 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 503 AM PDT Sun Jun 30 2024 .AVIATION...12Z TAFs...VFR conditions are very likely through the period (90-99% chance) for all sites. Light rain showers are tapering off this morning, and precipitation chances through the remainder of the period will consist of very low chances (2-8%) of isolated showers. Some diurnally driven stratocumulus (050-080) is forecast today, with otherwise mostly FEW-SCT mid- and high-level clouds. Winds will increase this morning and afternoon such that all sites have 10-15 kts sustained winds with gusts of 15-25 kts. Plunkett/86 && .PREV DISCUSSION... /issued 250 AM PDT Sun Jun 30 2024/ SHORT TERM...Today through Tuesday...Current nighttime satellite imagery and radar returns show a narrow band of showers exiting into ID, with scattered cloud cover developing behind this band. Breezy winds also developed late yesterday afternoon with the shortwave passage, and have persisted slightly through the Kittitas valley tonight. The band of showers across far eastern WA/OR will exit into ID ahead of an upper trough passage across the region today. An upper trough and surface cold front passage today will continue to bring isolated/scattered showers across the WA Cascade crest as well as Wallowa county through the afternoon. Weak instability and modest low level lapse rates will also allow for slight chances (15-25%) of isolated thunderstorms across eastern Wallowa county this afternoon. Breezy wind will also develop through the Cascade gaps and into the Columbia Basin, with generally 15-25 mph sustained winds and gusts up to 40 mph. A localized gust up to 45 mph may be possible through the Simcoe Highlands and portions of the Kittitas valley, with NBM probabilities of 55-75% through today. A marine push associated with the incoming trough/frontal passage will keep RHs above critical levels, though the anticipated breezy conditions will continue to bring elevated fire weather concerns. A secondary shortwave behind the upper trough axis exit will support breezy winds through the lower elevations Monday, with another day of 15-25 mph sustained winds and gusts up to 40 mph. That said, probabilities of 45 mph or greater gusts through Monday will increase to 70-85% through the Kittitas valley, Simcoe Highlands, eastern Gorge, and the Columbia Basin. While fire weather concerns will continue to be elevated through Monday, RHs are anticipated to remain above critical thresholds in the afternoon (confidence 70-80%). Upper level ridging will amplify across the eastern Pacific Tuesday, resulting in a dry northwest flow aloft over the PacNW. Breezy winds will continue through the Cascade gaps, with light to locally breezy winds elsewhere. Lawhorn/82 LONG TERM...Wednesday through Sunday...Warm to hot temperatures and little to no precipitation is forecast as an upper-level ridge dominates the region`s weather (95% chance through Saturday, and 75% chance Sunday). The main weather concern will be increasingly hot temperatures and Moderate to locally High HeatRisk for the lower elevations Friday through Sunday. On Wednesday, the 500-mb pattern will be characterized by downstream troughing over the Northern Plains and Northern Rockies, with an anomalously strong upper-level ridge in place upstream in the Pacific Ocean. This will place the forecast area under a dry northwest flow aloft. Deterministic guidance still advertises a shortwave sliding southeast across eastern WA and northeast OR during the day, but the dry air mass should preclude any significant chances of precipitation (<5% area-wide) as the shortwave traverses the region. Breezy to locally windy gap winds are likely (>90% chance) through the Kittitas Valley and eastern Columbia River Gorge. Currently, no Red Flag conditions are forecast, and NBM 24-hr probabilities of advisory-level wind gusts are 30-70% through the Kittitas Valley so wind highlights are not anticipated at this time. For the 4th of July, over 80% of ensemble members keep the offshore ridge in place. The remainder advertise a more progressive longwave pattern with the ridge axis shifting inland. The latter solution would result in the warmest temperatures east of the Cascades, though the difference would only be several degrees relative to the favored solution. Afternoon high temperatures are currently forecast to be 5-10 degrees above normal, resulting in some areas of Moderate HeatRisk for the lower elevations on the 4th of July. Friday and Saturday, ensemble clusters reveal a broader range in member solutions, though the main differences are in how members handle an upstream closed low/open wave and exactly where the axis of the ridge will be placed. Per 00Z ensembles, the upper ridge axis will likely (78% of members) remain offshore, though 17% of members place the ridge overhead, and a minority of members (4%) break the ridge down altogether and bring a trough into the PacNW. The latter solution would result in cooler temperatures, while the overhead ridge would result in the warmest weather. Sunday, guidance shows the most uncertainty in the longwave pattern. The multi-model ensemble mean places the upper-level ridge axis overhead, though individual clusters range from an anomalously strong ridge overhead (18%) to a trough passing to the north resulting in a suppressed ridge (27%) to an offshore ridge (55%). Regarding uncertainty Friday through Sunday, ~50% of ensemble variance is due to differences in the location of the upper ridge, while an additional ~25% is associated with the magnitude of the 500-mb height field over the PacNW. Despite persistent low afternoon relative humidity (upper single digits to upper teens for the lower elevations), Red Flag conditions are not anticipated to be widespread enough to warrant highlights. However, fire weather concerns will still be elevated. Precipitation chances are extremely low (<5% chance) through the period. Plunkett/86 && .PRELIMINARY POINT TEMPS/POPS... PDT 83 55 82 53 / 0 0 0 0 ALW 86 58 85 57 / 10 10 0 0 PSC 89 60 88 58 / 10 0 0 0 YKM 86 55 85 53 / 0 0 0 0 HRI 88 59 87 56 / 0 0 0 0 ELN 78 55 78 53 / 10 0 0 0 RDM 80 49 79 45 / 0 0 0 0 LGD 79 50 78 49 / 10 10 10 0 GCD 81 50 80 47 / 0 0 0 0 DLS 84 60 83 56 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...82 LONG TERM....86 AVIATION...86 413 FXUS65 KREV 300858 AFDREV Area Forecast Discussion National Weather Service Reno NV 158 AM PDT Sun Jun 30 2024 .SYNOPSIS... * Seasonably warm temperatures and breezy winds expected today with a chance of showers and storms for northeast California and far northwest Nevada this afternoon and evening. * Above normal temperatures will foster a moderate to locally major heat risk from midweek into the July 4th weekend. && .DISCUSSION... Our weather playlist is seemingly stuck on repeat as seasonable warmth with breezy afternoon winds are in store once again today. However, the main change will be a 15-25% chance of showers and thunderstorms this afternoon for portions of Lassen and N Washoe County, generally north of a Susanville-Gerlach line. Timing of afternoon convection favors the 2-8 PM PDT window with potential hazards including dry lightning, gusty outflow winds and small hail. One final note: Diluted smoke from the Basin fire may drift into southern parts of Mono County this evening, although latest Hi-Res guidance suggests smoke concentration will be lower. After today, dry weather will largely prevail throughout the upcoming week as northwest flow aloft and attendant large scale subsidence overspreads the region. The best opportunity will be Tuesday afternoon, which features a 5-10% of showers and storms from the Tahoe Basin southward. A significant warm-up remains queued up for midweek into next weekend as temperatures become 10-15 degrees above early July standards. Latest blended guidance continues to advertise daytime highs in the low 90s for Sierra communities and upper 90s to 103F for lower western Nevada valleys for Wednesday onward. Meanwhile, overnight lows will only fall into mid 60s to 70F across western Nevada during this time, providing little to no relief from the heat. As a result, a moderate to locally major heat risk will exist from midweek into next weekend for some Sierra locales and most of western Nevada. Be sure to consider the upcoming heat risk when making plans for next week, especially for Independence Day festivities, and review your safety precautions to keep yourself and loved ones safe from the heat! It does still appear that skies will be mostly clear on the night of July 4th so firework viewing should be excellent! -Salas && .AVIATION... Widespread VFR conditions and breezy surface winds in the afternoon (up to 25 kts) will prevail today. There is a 15% chance of showers and thunderstorms within 10 miles of KSVE terminals between 21Z and 03Z this afternoon. A steady warming trend may yield density altitude issues later this week. -Salas && .FIRE WEATHER... Dry, isolated thunderstorms are likely to develop along and ahead of a diffuse cold front this afternoon for portions of Lassen County into northern Washoe and Pershing counties. Widely cured fine fuel beds in this region will be receptive to lightning ignitions, especially outside of main precipitation cores. A deep, well-mixed subcloud layer will support gusty outflow winds of 40-50 mph near any mature thunderstorms. A brief 2-4 hour period of elevated to locally critical fire weather conditions will exist Monday afternoon for eastern Lassen County into western Nevada north of I-80 as gusty winds of 25-35 mph overlaps daytime humidity of 10-15%. It`s worth mentioning that Monday`s fire weather threat will spatially coincide with an area susceptible to dry thunderstorms today, which may exacerbate any holdover lightning ignitions. The remainder of the week will feature widespread warming, yielding a prolonged period of above average temperatures, very low daytime humidities, poor overnight humidities, and deep mixing heights. -Salas && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ 242 FXUS66 KSTO 300809 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 109 AM PDT Sun Jun 30 2024 .SYNOPSIS... A general warming trend begins today, culminating in dangerous heat and widespread major HeatRisk with areas of extreme HeatRisk from Tuesday into next weekend. Critical fire weather conditions are also anticipated in the Sacramento Valley from late Monday through Wednesday. && Key Points - Long-duration, major heat event expected this week impacting holiday outdoor events. - Excessive Heat Warning remains in effect for the Valley, Delta and foothills from Tuesday morning through Saturday evening. - Red Flag Warning is in effect for the western side of the northern and central Sacramento Valley and adjacent elevations below 3000 feet Tuesday morning into the evening. .Discussion... A few straggling high clouds are lingering over interior NorCal early this morning as a trough moves across the Pacific Northwest, but otherwise clear skies are noted elsewhere. Some northerly downslope wind gusts are being observed throughout the northern Sacramento Valley as well, with the last gasps of onshore flow holding on from I-80 southward across the Valley and Delta. As a result, overnight low temperatures are only expected to fall into the mid 60s to low 70s throughout the Valley and foothills, with mid 40s to low 60s at higher elevations. The presence of broad troughing aloft today will allow the power struggle between onshore flow and northerly flow at the surface to continue today. High temperatures this afternoon are expected to rise a few degrees compared to yesterday. Widespread 90s to low triple digits are anticipated in the Valley and foothills, with 70s to 80s at higher elevations by this afternoon. Occasional gusts of 15 to 25 mph will remain possible through the early evening while the trough axis is overhead. A brief instance of an isolated shower or thunderstorm cannot be completely ruled out this afternoon and evening across portions of Plumas and Lassen counties, but probabilities of thunderstorm development remain around 5 to 10% at this time. Moving into the week ahead, the trough aloft is expected to gradually transition eastward as a robust ridge begins to build across the eastern Pacific. This will spur a more notable warming trend across interior NorCal through midweek, with little indication of appreciable relief on the horizon. Monday looks to be the "coolest" day of the week, with widespread high temperatures in the low to mid triple digits in the Valley and adjacent foothills, while 80s to 90s are still expected at higher elevations. Temperatures will continue to warm on Tuesday and Wednesday, with widespread mid to upper triple digits (greater than 105, less than 110) anticipated in the Valley and adjacent foothills by Tuesday afternoon and upper triple digits to low 110s likely by Wednesday afternoon. With little, if any, Delta breeze influence expected through midweek, overnight low temperatures in the mid 60s to near 80 in some areas throughout the Valley and foothills will offer little overnight relief. As a result, widespread major HeatRisk and areas of extreme HeatRisk look to arrive on Tuesday and remain in place into at least next weekend. In addition to the hot weather that looks to dominate the region this week, a period of breezy to locally gusty northerly winds is expected from late Monday night through Wednesday evening. Gusts of 20 to 30 mph will be possible throughout the Valley and adjacent foothills, with strongest winds expected along western portions of the northern and central Sacramento Valley. Given the typically dry, northerly aspect of the winds, afternoon minimum humidities into the single digits to low teens are anticipated on Tuesday and Wednesday. Overnight humidity recovery looks to remain poor as well, especially across the northern and central Sacramento Valley. As a result, elevated fire weather conditions are expected on Monday, becoming critical fire weather conditions for Tuesday and Wednesday. && .EXTENDED DISCUSSION (Thursday THROUGH Sunday)... Ensemble guidance then indicates a slight eastward transition of the eastern Pacific ridge through the late week period as the ridge axis looks to become centered over NorCal. There is some subtle uncertainty as to the exact strength of the ridge aloft as it moves inland, but the background trend of hot and dry weather continuing will remain through the end of the week and into next weekend. Resultant widespread high temperatures in the triple digits are expected from Thursday through Sunday across the Valley and adjacent foothills while 80s to upper 90s persist at higher elevations. In turn, this will lead to a continuation of widespread major HeatRisk and areas of extreme HeatRisk through much of the weekend as well. Ensemble guidance does indicate the potential for at least some semblance of Delta breeze initiation across the weekend which may introduce some modest overnight relief across the Delta and its immediate vicinity, but warm overnight lows are still expected to prevail elsewhere. && .AVIATION... VFR conditions next 24 hours. Local northwesterly surface wind gusts 15-25 kts northern Sacramento Valley thru 06Z Monday, and local southwest gusts 20-30 kts vicinity west Delta after 00Z Monday, otherwise surface wind gusts generally below 12 kts. && .STO WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from 11 PM Monday to 8 PM PDT Wednesday for Carquinez Strait and Delta-Central Sacramento Valley in Glenn, Colusa, Yuba, Northern Sutter, and Butte County Below 1000 Ft- Eastern Mendocino NF-Eastern Portion of Shasta/Trinity NF- Northern Sacramento Valley to Southern Tehama County Line Below 1000 Ft-Northern Sierra Foothills from 1000 to 3000 Ft. Includes portions of Shasta-Trinity and Butte Units-Southeast Edge Shasta- Trinity NF and Western Portions of Tehama-Glenn Unit-Southern Sacramento Valley in Yolo-Sacramento Far Western Placer, southern Sutter and Solano County Below 1000 Ft. Excessive Heat Warning from 11 AM Tuesday to 8 PM PDT Saturday for Carquinez Strait and Delta-Central Sacramento Valley- Motherlode-Mountains Southwestern Shasta County to Western Colusa County-Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-Northern San Joaquin Valley-Southern Sacramento Valley. && $$ 463 FXUS65 KMSO 300858 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 258 AM MDT Sun Jun 30 2024 .DISCUSSION...A Pacific trough of low pressure is currently moving across eastern Washington this morning, spreading light to moderate rain showers over northern Idaho. The focus of the precipitation this morning and afternoon, continues to favor Clearwater County in Idaho, and northwest Montana from Mineral, Sanders, Lincoln, Lake and Flathead counties. These locations will have around a 60% probability of picking up at least 0.25" of rainfall by sunset this evening. Isolated areas, particularly in the higher terrain may see slightly higher amounts. Later this afternoon and early evening a surface low will develop just east of the Continental Divide. This, along with increased instability from afternoon heating, is expected to allow for the development of strong thunderstorms in Deerlodge, Powell, and Sliver Bow counties. Currently, the Storm Prediction Center has these areas under a marginal risk for severe thunderstorms. High- resolution models suggest storms will develop between 3:00-7:00 PM MDT before moving east of the divide. Those planning outdoor activities should be prepared for lightning, gusty winds, and small hail. Any severe thunderstorms (5% probability) that do develop, will be capable of producing quarter to half dollar size hail, along with damaging wind gusts. The Northern Rockies will remain in a northwesterly flow pattern through mid-week, that will maintain seasonal temperatures with highs ranging from the 70s to 80s. Daily showers and thunderstorms are expected to develop, with convective activity focused along the Continental Divide. By the end of the week and upcoming weekend, 80% of ensemble guidance continues to show the return of a ridge of high pressure. This will likely lead to above-normal temperatures and below- normal precipitation for the region. && .AVIATION...A Pacific trough of low pressure will bring light to moderate rainfall to portions of north-central Idaho and northwest Montana later this morning through the afternoon. Rainshowers will periodically reduce visibility and ceilings for KGPI between the hours of 30/1400Z-30/2000Z. Currently, there is a 50% probability for thunderstorms for KGPI, KMSO, and KBTM from 30/2100Z-01/0300Z this evening, that may bring brief periods of gusty winds, small hail and heavy rainfall. High-resolution models suggests the majority of the convection will move east of the Continental Divide by 01/0300Z this evening. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$ 798 FXUS65 KBOI 300951 CCA AFDBOI Area Forecast Discussion...Corrected National Weather Service Boise ID 344 AM MDT Sun Jun 30 2024 .SHORT TERM...Today through Tuesday night...At 3 AM MDT a cold front could be clearly seen on satellite imagery extending from northern ID southward along the western ID border, then ssw-ward to near Reno, NV. The surface cold front was slightly east of the main cloud band seen on satellite. KCBX radar showed light rain echoes as far south as central Malheur County but these should retreat northward when they get into Idaho this morning. Surface winds with the front have been stronger than forecast by the models. Around midnight MDT Ontario/OR reported northwest wind 30 mph with gusts near 45 mph. Around 2 AM MDT Boise reported northwest 20 mph with gusts near 30 mph. Behind the cold front high temps today will be about ten degrees cooler than yesterday. Scattered showers and thunderstorms (30 to 60 percent areal coverage) will occur in the central ID mountains, and isolated thunderstorms (15 to 25 percent areal coverage) will develop this afternoon near the NV/ID border. Instability in the central ID mountains looks strong enough for thunderstorm wind gusts up to 50 mph and small hail. Slightly less instability is forecast near the NV/ID border. Clearing and cooler in all areas tonight, with temps holding slightly below normal through Monday as an upper trough passes through from west to east. Mostly sunny Monday, except partly cloudy in the central ID mountains. Breezy again from the west/northwest Monday afternoon. .LONG TERM...Wednesday through Sunday...Dry northwest flow will continue Wednesday and Thursday as our area remains between an upper level trough over Montana and a strong upper level ridge centered along the California coast. This will bring dry and breezy conditions with temperatures a couple degrees above normal. Forecast confidence decreases Friday through Sunday as ensembles disagree on the evolution of the pattern. Around 40% of ensembles amplify the ridge along the coast but keep our area under a weak trough, keeping temperatures from becoming too hot. However, the other 60% of ensembles move the ridge inland and bring the potential for very hot temperatures over the weekend. The current forecast is a blend between the two solutions, with lower valleys reaching the upper 90s to around 100 degrees by Saturday and Sunday, but these values are likely to change as models come into better agreement. && .AVIATION...Mainly VFR. Mid to high clouds with isolated to scattered showers and thunderstorms today, mainly across the higher terrain. Isolated showers and thunderstorms will also drift into the Magic Valley late this afternoon and evening. Surface winds: W-NW 10- 20 kt with local gusts to 30 kt. Gusts to 40 kt near thunderstorms. Winds aloft at 10kft MSL: W-SW 15-25 kt. KBOI...VFR. Increasing mid to high clouds this morning with partial clearing this afternoon. Less than a 10% chance of showers at the terminal. Surface winds NW 10-20 kt with gusts to 25 kt. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise SHORT TERM...LC LONG TERM....ST AVIATION.....ST 386 FXUS65 KLKN 300718 AFDLKN Area Forecast Discussion National Weather Service Elko NV 1218 AM PDT Sun Jun 30 2024 .SYNOPSIS... The tail end of a cold front will pass across Northern Nevada today. A few strong thunderstorms are possible in Humboldt County and northern Elko County this afternoon into this evening. A cooling trend is expected today through Tuesday. By Tuesday afternoon, high temperatures will be near normal for this time of year. Gradual warming is expected Wednesday through Saturday. && .SHORT TERM...Today through Monday night The southern extend of a cold front will pass through Northern Nevada today. Isolated showers and thunderstorms should impact Humboldt County and the northern portion of Elko County this afternoon into this evening. These showers and thunderstorms will have little rainfall associated with them. A few thunderstorms could be strong with wind gusts near 45 mph and dangerous cloud to ground lightning strikes. Southwesterly wind gusts of 30 to 35 mph are likely in most of the service area this afternoon into this evening. Ahead of and in wake of the cold front, a cooling trend is expected. High temperatures this afternoon will be around five degrees cooler than yesterday afternoon. Maximum temperatures Monday afternoon will be near normal for this time of year. .LONG TERM...Tuesday through next Sunday Northwesterly flow aloft on Tuesday across the CWA as trough energy exits to the east while at the same time high pressure begins to build in off the west coast. High temperatures under the NW flow will be near normal with mid 80s to low 90s for most valley locations. It will be most sunny on Tuesday, with relatively light northwesterly winds of 5 to 10 mph gusting to around 15 mph. High pressure approaching from the west on Wednesday will keep the skies clear and also kick off a warming trend, with highs mainly in the upper 80s to mid 90s. Winds remain northwesterly on Wednesday, but should be a few mph stronger than winds on Tuesday. Ensemble solutions diverge Thursday onward with respect to the placement of the high pressure that was progged to be just off the west coast and moving onshore into CA and western NV on Thursday. Ensembles are now favoring a halt in the eastward progression of the high pressure on Thursday, with the high then retrograding back offshore of CA and southern OR on Friday, with a more amplified ridge just off the west coast over the weekend. All ensembles keep the CWA dry through the long term, however the now favored ensemble solution would keep a northwesterly flow aloft over the CWA, with a couple embedded shortwaves (one on Saturday and one on Monday) sliding down the eastern slope of the offshore ridge, through the Pacific NW and into northern NV. Should this verify temperatures would likely cool slightly this weekend, though still remain above normal. && .AVIATION... VFR conditions are expected at all TAF sites through Sunday. Afternoon showers and thunderstorms are expected to remain north of interstate 80 through Sunday as an upper-level disturbance moves through northern Nevada although a few mid and upper-level clouds are expected through the day. A noticeable west-northwest wind will develop across northern Nevada affecting KWMC, KBAM and KEKO while southwest winds ahead of the cold front are expected at KTPH and KELY. Wind speeds of 10-15 knots with gusts up to 25 knots from the west are expected at KEKO with gusts around 30 knots from the southwest are expected at KELY. && .FIRE WEATHER... A Red Flag Warning is in effect for White Pine County and Northeastern Nye County from 12 PM PDT this afternoon until 8 PM PDT this evening due to relative humidity values as low as 5 percent and sustained southwest winds 15 to 25 mph, with gusts near 35 mph. Although dry thunderstorm probabilities have decreased (6 percent or less) in Humboldt County and northern Elko County, a few dry thunderstorms cannot be ruled out this afternoon into this evening. Elevated fire weather conditions are expected across most of Northern and Central California Tuesday afternoon due to minimum relative humidity values around 15 percent and northwest wind gusts 25 to 30 mph. && .LKN Watches/Warnings/Advisories... Red Flag Warning from noon to 8 PM PDT Sunday White Pine and Northeast Nye Counties. && $$ 87/96/93/87 |
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