583 FXUS66 KSEW 240947 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 247 AM PDT Thu Apr 24 2025 .SYNOPSIS...High pressure will maintain warm and dry conditions through Thursday. Split flow aloft will keep conditions mostly dry and mild through Saturday. Chances for precipitation increase by the end of the weekend as a system moves over the Pacific Northwest, with dry and warmer conditions returning by mid-week. && .SHORT TERM /TODAY THROUGH SATURDAY/...A high pressure ridge will continue to amplify and shift inland today, allowing for continued dry conditions and high temperatures in the 70s across much of western Washington. A weak trough approaching the northern California coast will advect some moisture into the region, resulting in little more than some passing high clouds today. Forecast models remain in good agreement over the trough moving inland over California on Friday, keeping any precipitation chances to our south. Conditions Friday will be similar to today, with partly cloudy skies and highs in the 70s once again for much of the lowlands. Split flow aloft will be in place by Saturday, allowing for continued dry conditions and mostly sunny skies. Temperatures will cool a few degrees but will stay mild in the mid to upper 60s across most western Washington lowlands. The exception will be along the Pacific Coast, where high temperatures will be limited to the 50s due to the development of marine stratus. .LONG TERM /SUNDAY THROUGH WEDNESDAY/...Split flow aloft will shift eastward on Sunday as a high pressure ridge moves towards the Pacific Coast. Ensembles have continued to decrease chances for showers on Sunday, with a slight chance along the Cascade Foothills and over the Chehalis Basin. Much of the region will see little more than cloudy skies, with mild temperatures once again on Sunday. Moisture ahead of an approaching weak trough will spread towards western Washington on Monday, though forecast models continue to show uncertainty over the timing and amount of rainfall that will move into the region with this approaching system. Chances for showers will increase into Tuesday before a cold front crosses the region and a drier air mass fills in behind. Models have come into better agreement over high pressure rebounding by mid-week, with dry and warmer conditions on track to return by Wednesday. 15 && .AVIATION...Upper level ridge over the area early this morning will shift east while an upper level trough digs offshore today. A closed low will develop in the bottom of the trough and move towards Northern California tonight into Friday. Flow aloft becoming southerly this morning and will remain southerly for the remainder of today. Flow aloft becoming southeast Friday morning. Light flow in the lower levels. Clear skies into Friday. LIFR stratus along the South Coast will approach KHQM this morning and could nick the airport between 13z-15z. KSEA...Clear skies. Northeast wind 4 to 8 knots becoming northerly 8 to 12 knots early afternoon. Winds returning to northeast 4 to 8 knots after 04z tonight. Felton && .MARINE...A surface ridge centered offshore will weaken today. A broad area of weak surface low pressure will develop tonight and Friday over the Pacific Northwest while high pressure remains centered well offshore. This will lead to an overall increase in onshore flow into the weekend. High pressure will build over the waters later Sunday into the first part of next week. Small craft advisory winds developing over the outer coastal waters tonight will continue into at least Saturday and possibly Saturday night for the northern outer waters. Small craft advisory westerlies in the Central and Eastern Strait of Juan de Fuca Friday night with the increasing onshore flow. Seas building tonight into Friday peaking in the 8 to 11 foot range Friday night into Saturday night. Seas subsiding Sunday and be in the 3 to 6 foot range by early next week. Felton && .HYDROLOGY...No river flooding is expected over the next 7 days. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory from 8 PM Friday to 5 AM PDT Saturday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory from 8 PM Friday to 6 PM PDT Saturday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm. && $$

203 FXUS66 KPQR 241008 AFDPQR Area Forecast Discussion National Weather Service Portland OR 308 AM PDT Thu Apr 24 2025 .SYNOPSIS...High pressure will maintain warm temperatures and dry weather across most of the area today. An approaching system will bring a 15 to 20 percent chance of thunderstorms this evening across the Linn and Lane County Cascades as well as the southern Willamette Valley. Linger showers over the central Oregon Cascades through Saturday, with warm and dry conditions persisting across the rest of the area. Cooler weather expected for Sunday and Monday. && .SHORT TERM...Now through Saturday Night...Clear skies persist across the region early this morning as high pressure remains overhead. Expect today to be the warmest day of the week as 850 mb temperatures climb a few more degrees to 9-10 C this afternoon, yielding highs well into the 70s across the interior lowlands. The warmest spot will be across the Portland Metro area, where the NBM shows about a 60% chance to reach 80 degrees this afternoon. Meanwhile, coastal areas will remain more mild today as the marine layer maintains its influence along the coast. Aside from the warm temperatures, the primary forecast concern for today remains the potential for a few elevated thunderstorms across the southern part of our area this afternoon and evening as an upper level trough approaches offshore. The trough will take on a slight negative tilt as it digs southward along the coast. This will induce southerly or even slightly southeasterly flow aloft and drawing mid level moisture northward into our area, contributing to MUCAPE values of 200-400 J/kg across Lane County and vicinity by late afternoon. Will therefore maintain a slight chance of thunderstorms across primarily the Lane and Linn County Cascades but also portions of the south Willamette Valley and Coast Range through late this evening. Expect any thunderstorms that do develop to remain well below severe thresholds given lack of vertical wind shear, will frequent lightning, small hail, and gusty and erratic winds being the primary threats. Warm and mostly dry conditions persist across the area Friday and Saturday as the upper trough evolves into a closed low and drops south towards the San Francisco Bay Area. Wrap around moisture on the northern periphery of this feature will maintain a chance of showers across the southern extent of the area into the weekend, with the best precipitation chances confined to the Lane County Cascades through Saturday. Will need to continue to monitor thunder potential over the next few days, but chances generally remain below 10% for Friday and Saturday as increasing cloud cover helps to limit instability. Meanwhile, expect areas from Salem northward to remain dry through the weekend as the low drops farther south. The increased cloud cover and shower potential over Lane County will also contribute to a fairly sizable temperature gradient from south to north, with the Eugen area likely to be in the mid 60s on Friday while the Portland area remains in the mid to upper 70s. /CB .LONG TERM...Sunday through Wednesday...Temperatures will drop off more substantially Sunday and MOnday as the upper low moves into the Great Basin and ushers in broad onshore flow across the Pacific Northwest. This will bring daytime highs closer to seasonal norms in the low to mid 60s through the early part of next week. A passing shortwave trough may bring a few showers to to the area on Tuesday, but do not see any indications of meaningful precipitation at this time. Beyond Tuesday, WPC ensemble clusters favor a return of upper level ridging over the region mid to late next week, resulting in another warming trend as daytime highs potentially climb back up into the 70s for the latter half of next week. /CB && .AVIATION...Expect VFR conditions at most terminals through the TAF period. Coastal terminals will be the exception, with a 40-50% chance of MVFR conditions, 20-30% chance of IFR conditions, and a 10-20% chance of LIFR conditions between 12-17Z Thursday. Conditions along the coast will likely return to VFR thereafter, with the exception of KONP possibly (30-50% chance) staying MVFR through most of the TAF period. Winds will generally stay light and variable for most terminals. Terminals along the Columbia River Gorge will see increased easterly winds around 8-10 kt between 18-23Z Thursday. It`s also worth noting right around 21-23Z Thursday, there is potential for isolated shower and thunderstorm development in the Lane County Cascades/foothills southward. Have refrained from mentioning in the KEUG TAF due to low confidence at this time. PDX AND APPROACHES...VFR conditions and clear skies continue through the TAF period with light northwest winds turning more easterly and increasing to 5-8 kt after 18Z Thursday. ~Hall && .MARINE...Strong high pressure offshore will maintain northerly to northwesterly winds across the coastal waters through the upcoming weekend. Current increased winds continue to ease this morning as a thermal trough breaks down. North to northwesterly winds will begin to increase Friday night, with gusts up to 25 kt. As a result, have issued a Small Craft Advisory for the outer coastal waters between Cape Shoalwater WA and Cape Falcon OR. Otherwise, expect seas to persist around 5 to 7 ft and increase to around 9 ft on Saturday, with periods around 12 seconds decreasing to 9 to 10 seconds through the weekend. ~Hall/TK && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory from 8 PM Friday to 5 AM PDT Saturday for PZZ271. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

405 FXUS66 KMFR 241149 AFDMFR Area Forecast Discussion National Weather Service Medford OR 449 AM PDT Thu Apr 24 2025 .Updated Aviation Discussion. .DISCUSSION...Satellite image shows marine stratus along the coast and just offshore. At the same time a thin layer of cirrus is moving in from the west ahead of an approaching upper trough. The upper trough will move towards the forecast area resulting in a chance for showers and isolated storms along and west of the Cascades. The CAMS (convective allowing models) which shows radar reflectivity shows convective showers and thunderstorms developing from late Thursday morning and lasting into Thursday afternoon with most of the action along and west of the Cascades. Additionally, the HREF calibrated thunderstorms also shows the highest vales along and west of the Cascades mid to late Thursday afternoon into Thursday evening. Friday and Saturday are likely to be cool and unsettled with isolated to scattered showers, with showers most frequent in the afternoon and early evening hours due to daytime heating. Guidance shows marginal instability in portions of Klamath, Lake, and Modoc County Friday afternoon and evening, and again Saturday afternoon and evening. Therefore we`ll maintain a slight chance of thunderstorms there. The upper trough will begin to shift east Sunday with showers diminishing and becoming more isolated. Most of next week should be dry and mild weather for most of next week. However, the operational ECMWF and some of the individual ensemble members show an upper trough moving into the area Tuesday with light precipitation west of the Cascades. The GFS and ensemble members and clusters maintain the upper ridging and dry conditions. -Petrucelli && .AVIATION...24/12Z TAFs...Along the coast and just offshore. Satellite image shows marine stratus with MVFR/IFR ceilings and reduced visibility. This will continue for most ofthe morning, then ceilings ans visibility will improve as instability increases as an upper level system approaches. Confidence on the timing of improvement is low to medium, but conditions should improve by the afternoon. Stable conditions return this evening with ceilings lowering to IFR until the end of the TAF period. Inland, west of the Cascades. The main concern will be convective showers increasing this afternoon and lasting into this evening along with isolated thunderstorms. Guidance suggest an increasing concern for isolated storms this afternoon and lasting into early this evening, therefore PROB30 for thunderstorms has been added to the Medford and Roseburg TAFs. Because we`ll be in a convective environment in the afternoon and early evening hours, there is concern for turbulence, and gusty and erratic winds. This will need to be monitored closely. The concern for storms ends around 3z this evening, but convective showers will continue tonight. The concern for convective showers and isolated storms are low east of the Cascades, but cannot be ruled out in the vicinity of Klamath Falls towards 0z. Should any storms develop in the vicinity of or at Klamath Falls, it could result in gusty and erratic winds, along with some turbulence. Ceilings will remain VFR through the TAF period. -Petrucelli && .MARINE...Updated 200 AM Thursday, April 24, 2025...Winds will remain below small craft levels, but seas will remain just elevated enough for Small Craft conditions to continue through this morning. Calmer conditions are likely this afternoon through Friday as low pressure moves to the south. Showers are likely during this time period, then stronger north winds and steep seas are possible again by Saturday afternoon. -Spilde/Petrucelli && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 11 AM PDT this morning for PZZ350-356-370-376. && $$

491 FXUS66 KEKA 241156 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 456 AM PDT Thu Apr 24 2025 .SYNOPSIS...An upper level trough approaching the area will bring cooler temperatures across the interior through Saturday. There is a slight chance for thunderstorms over the mountains for the next few days as well as widespread showers in most areas by Friday. Cool nights and pleasant sunny afternoons will return Sunday and into next week. && .DISCUSSION...The approach of a deep upper level trough is evident as high level clouds encroach on the CWA. The trough axis is currently at the -140W Longitude with a trajectory that will place the vorticity max somewhere south of the SF Bay area. This open wave pattern trough will deepen and form a split flow low by Friday afternoon, with the leading edge bringing southerly winds and instability as cold air advects/overruns the warm air mass. Leaning more towards a positive tilt with this system, there will be less chance of a severe storm outbreak yet localized convection is expected for the interior mountains. PWAT values increase by the weekend to around 0.8 inches. This afternoon inland areas are expected to see a number of showers and possibly some thunderstorms as well. CAPE varies quite a bit of model to model, but the HREF mean is showing around 200 j/kg. Shear is only around 20 kt and mid level lapse rates are generally around 6.5 to 7c/km. This will likely be enough to generate a few thunderstorms this afternoon and well into the evening. Tonight into Friday, showers are expected to become more widespread as the upper level trough moves in. There is the potential for some thunderstorms again Friday afternoon. Saturday the upper level low starts to move out of the area, but there is expected to be a resurgence of showers in the afternoon with the daytime heating. High temperatures across the area expected to struggle to break 60 degrees even in the warmer areas. Overnight lows are not expected to drop too much due to the moisture and clouds around. Any areas that do remain clear Saturday night could see some frost. Sunday clearing skies are expected and temperatures will start to warm back up again. Inland areas are expected to see highs in the 60s. Sunday night into Monday morning is expected to be the coldest night and frost is possible in the colder valleys. High pressure continues to build in through the week with highs around 80 for the inland areas by Wednesday. /MKK /EYS && .AVIATION...High level clouds are forecast to cover the CWA as a low pressure system advances. MVFR flight conditions are expected through the TAF period as ceilings drop to around 1500-2000ft. Both KCEC and KACV will probably see light rain tonight. KACV has already received light rain as of 11z as vertically integrated moisture condenses. Coastal stratus is prevalent this morning but confidence is low for this to effect conditions at KUKI. && .MARINE...Seas are dropping early this morning but remaining steep waves keep advisory levels into midday Thursday. There is a pronounced and persistent wind eddy for the far northern inner zone and around Point St George starting tonight around 8 pm. The resulting localized southerly flow will generate southerly winds through most of Thursday. A weak cold frontal system will move into the area Thursday and weaken the pressure gradient. As a result, winds Thursday afternoon will be lighter than yesterday, with even lower winds and seas of 5 ft on Friday. In the wake of the frontal system, northerly winds will begin to increasing Friday night through Saturday. Winds of up to 25 kts are forecast Saturday evening, and can be expected to persist into next week. There is currently a low probability for gale force gusts over 34 kts (25-35%) through that period, and mainly for the afternoons south of Cape Mendocino and Point St. George. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 5 AM PDT early this morning for PZZ450-455. Small Craft Advisory until 11 AM PDT this morning for PZZ470-475. && $$ 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

988 FXUS66 KMTR 241149 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 449 AM PDT Thu Apr 24 2025 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 1239 AM PDT Thu Apr 24 2025 Cooler trend continues today into the weekend. Patchy drizzle and fog are possible within the marine layer clouds. Light rain, drizzle, and isolated thunderstorms are possible throughout the region Friday and Saturday. && .SHORT TERM... (Today and tonight) Issued at 1239 AM PDT Thu Apr 24 2025 Marine layer stratus has developed across the Bay Area and Central Coast. The latest data from the Point Sur profiler suggests that the marine layer has thickened to around 2500-3000 feet, a depth that would support stratus intrusion well into the interior. Some of the far interior locations could see some transitory sunshine for a few hours in the afternoon, but the coastal region and the coastal valleys should remain socked in through the day. A cooling trend continues across the region with a strengthening upper level trough approaching California. High temperatures range from the lower to middle 60s in the inland valleys, with southern Monterey County seeing temperatures up to the lower 70s, while the coasts and the bays see temperatures reach the middle 50s to the lower 60s. Onshore winds this afternoon will be breezy and gusty, with gusts of 20-30 mph at the coast and through the gaps and passes. In some favored regions, particularly Altamont Pass, Pacheco Pass, and the Mayacamas, the gusty winds could last well into the evening. && .LONG TERM... (Friday through Wednesday) Issued at 1239 AM PDT Thu Apr 24 2025 An upper level low should impact the state on Friday and Saturday, with the trends for a stronger and more southerly low continuing as of the latest model outputs. The ensemble model clusters are finally coming into agreement on the location of the low coming in, if not the exact strength. As a result, while we`re more confident in where the rain will fall, there`s still some variation in the exact rain amount. The current forecast calls for around 0.10-0.25" of rain in the Monterey Bay region, the Santa Cruz Mountains, and the Salinas Valley, with rainfall totals as high as 0.5-0.7" in the Santa Lucia mountains. Elsewhere, rain totals across the Bay Area will be very light, especially across the North Bay where upper level offshore flow will limit the precipitation chances, and outside of the southern and eastern mountains of Santa Clara County, wetting rains (over 0.1" of rain) are not likely. We`re also noting an steady increase in the likelihood of convection across the region. While still slight, the probabilities of thunderstorms have risen to 10-20%, mainly across the Central Coast, extending from Friday night through Saturday. From the previous forecaster: Forecast soundings show a few hundred J/kg of CAPE across the Central Coast overnight Friday into Saturday with forecasted CAPE values to peak Saturday morning. To have a thunderstorm you need four main ingredients: moisture, instability, lift, and wind shear (speed or directional). With this system incoming, we have a source of moisture, a source of lift (cold frontal passage), and some instability forecast. The questionable ingredient is wind shear. As of right now during the time of the highest thunderstorm probabilities (5AM-5PM Saturday), forecast soundings show some directional wind shear (winds veering with height indicating some warm air advection is occurring) but not very much speed wind shear. The surface to 500 mb bulk shear shows much higher speed shear values located just to our south in San Luis Obispo County (NWS Los Angeles` CWA). While the current trend for this cut-off low has been to shift southwards, if the low were to shift just slightly northward we could potentially see those higher bulk speed shear values shift into Monterey County. If this were to occur, it would increase confidence that we may see some thunderstorms across southern Monterey County given the alignment of wind shear with our area of moisture, lift, and instability. It`s worth watching over the next few days to see where this cut- off low tracks (further south or further north) and how our thunderstorm risk along the Central Coast changes this weekend. Ridging should return after the trough moves out, with daytime highs rebounding to near to slightly above the seasonal averages in the early and middle part of next week. && .AVIATION... (12Z TAFS) Issued at 448 AM PDT Thu Apr 24 2025 Widespread MVFR CIGS are affecting the region with IFR CIGs for STS. Winds stay light to moderate through the morning and increase slightly into the afternoon. Cloud cover snuggles to erode in the late morning and into the afternoon, with CIGs scattering in most areas, but mid level clouds continue to build. MVFR CIGs become widespread into Thursday evening, with slight reductions in wind. The next approaching rain system will cause some coastal drizzle and some shower chances into early Friday. Vicinity of SFO...MVFR CIGS rise into the afternoon to around 2300 ft AGL before scattering into the late afternoon but mid-level cloud cover remains. MVFR CIGS return into the evening and last through much of Friday before some slight lifting as the low pressure system and light rain chances approach. Expect moderate west winds through the TAF period. SFO Bridge Approach...Similar to SFO Monterey Bay Terminals...MVFR CIGs last through the late morning before scattering. West winds increase into the afternoon but reduce in the early evening and MVFR CIGs re-fill over the terminals. && .MARINE... (Today through Tuesday) Issued at 448 AM PDT Thu Apr 24 2025 Winds and seas continue to abate. Expect quiet into the late work week with some light rain moving across the waters starting Friday morning and lingering into that night. Strong northwesterly breezes and rough seas return late Saturday. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ SHORT TERM...DialH LONG TERM....DialH AVIATION...Murdock MARINE...Murdock Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, X, and YouTube at: www.facebook.com/nwsbayarea x.com/nwsbayarea www.youtube.com/nwsbayarea

002 FXUS66 KOTX 240936 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 236 AM PDT Thu Apr 24 2025 .KEY MESSAGES... - No significant weather impacts expected for the remainder of this week into the weekend. - Dry weather through Thursday with chances for showers Friday into early next week - Breezy Saturday and Sunday, especially over central WA and near the Blue Mountains. && .SYNOPSIS... Warm and dry weather is expected through at least Friday with high temperatures in the upper 60s and 70s. The arrival of a frontal system Saturday and Sunday will produce locally gusty winds for central Washington and the chance for showers across southeast Washington and north Idaho. Mountain showers and seasonably breezy conditions are expected early next week. && .DISCUSSION... Today and Friday: After a chilly start this morning, temperatures will rebound into the upper 60s and low 70s this afternoon. Our resident air mass remains quite dry. Not only will clouds be few and far between today, but relative humidity values this afternoon will dip into the upper teens and low 20s. With surface high pressure over Montana and low pressure off the coast today and tomorrow, the easterly surface pressure gradient will induce sustained winds of 10 to 15 mph with gusts of 20 mph or more across the Upper Columbia Basin, Waterville Plateau, and West Plains. The Inland Northwest is far from peak wildfire season, but dead grasses from last year will be capable of carrying fire with above average temperatures and dry breezes. If an ignition occurs in dry grass the next couple of days, it will have the potential to spread. Saturday: The ensembles continue to trend further south with a low pressure system this weekend. Of the four main ensemble clusters for Saturday, they all forecast the track of the incoming upper low to track across central California into Nevada Friday night into Saturday. This solution keeps the Evergreen state dry with the exception of the far southeast corner of Washington with a 20 percent chance showers Pomeroy, Clarkston, Asotin. The ensembles have trended drier across north Idaho as well with just a 20 to 30 percent chance of showers Saturday afternoon/night across the Camas Prairie up to Shoshone county. Saturday should be the warmest day for the next 7 days with highs well into the 70s. Winds will become westerly by the afternoon and evening as the low track into the Great Basin. Cascade gap winds will become breezy late in the day with places like Wenatchee, Chelan, and Vantage likely experiencing sustained 10 to 15 mph winds with gusts to 25 mph. /GKoch Sunday to Wednesday: The Inland NW will be in a progressive pattern, with periodic precipitation and breezy to locally windy conditions. One wave will be shifting out of the region Sunday, leaving some shower chances around far eastern WA and the ID Panhandle. Models are painting at least a couple hundred J/kg of CAPE over these areas, so I did push PoPs higher than most guidance but only a bit. There is instability but not much strong lift, yet models tend to under do the shower coverage in these set-ups, even if they are just isolated. There will also be a slight chance of afternoon/early evening t-storms, but any that develop look weak with the main impact brief downpour and gusty winds. The other feature of this set-up, with a trough shifting east and jet across the region and modest gradient, will be the general gusty winds. These will be strongest near the Cascades and western basin and near the and downwind of the Blue Mountains. Gusts of 20 to 30 mph will be possible, with locally higher gusts near 40 near the Waterville Plateau and near the Blue Mountains. Heading into Sunday night and Monday brief ridging develops, shifting the primary precipitation potential into ID/MT border mountains. Another system moves in from the west later Monday and especially into Tuesday. This one has a bit better lift and deeper moisture. This will bring expanding precipitation chances around the mountains late Monday night and then throughout much of the region into Tuesday, save for the lee of the Cascades/deeper Columbia Basin. Ensembles show a modest risk for measurable precipitation (>=0.01") through Tuesday afternoon, with 24-hour probabilities near 40-90%. The best risk will be in the mountains. However the risk for wetting rains is low at 10-30%, locally higher near the Cascade crest. The potential for precipitation retreats to the mountains Tuesday night into Wednesday and wanes by early Wednesday evening. It will remain breezy Monday and Tuesday, with gusts near 15-30 mph. Lighter winds are expected Wednesday. Temperatures will be slightly above normal, except on Tuesday when they will be closer to normal with the wetter pattern. This means highs in the 60s to mid-70s, except Tuesday when highs will be in the upper 50s and 60s with some lower 60s in the deeper basin and L-C valley. Lows will largely be in the upper 30s and 40s. /Solveig && .AVIATION... 12Z TAFS: With high pressure in control of our weather, mainly clear skies and good visibility are expected through Thursday night. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in VFR conditions at TAF sites through the period. && .Preliminary Point Temps/PoPs... Spokane 43 72 45 73 46 68 / 0 0 10 10 10 10 Coeur d`Alene 42 71 43 72 44 66 / 0 0 10 10 20 20 Pullman 43 71 45 68 46 60 / 0 0 10 20 30 20 Lewiston 45 77 51 74 51 68 / 0 0 10 20 30 20 Colville 38 74 40 75 42 71 / 0 0 10 10 10 10 Sandpoint 40 70 41 70 44 66 / 0 0 10 10 20 30 Kellogg 43 68 46 69 47 61 / 0 0 10 30 30 40 Moses Lake 45 78 47 78 47 73 / 0 0 10 10 0 0 Wenatchee 47 75 51 77 48 69 / 0 0 10 10 0 0 Omak 43 76 45 78 46 73 / 0 0 10 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...Frost Advisory until 9 AM PDT this morning for Moses Lake Area. ID...None. && $$

565 FXUS66 KPDT 240956 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 256 AM PDT Thu Apr 24 2025 .SHORT TERM...Today through Saturday... 1. Pattern shift today will bring precipitation across the OR Cascades 2. Isolated thunderstorms both Friday and Saturday afternoon Current satellite shows very clear skies over the region this morning. With the lack of clouds, temperatures will decrease hedging into some isolated areas of freezing. Especially along the foothills of the Blues and portions of the Columbia Basin. A freeze warning has been issued for the freeze through 9 AM. Models show the upper level ridge to remain over the region through much of the day today. Temperatures will remain warm under the influence of the ridge with temperatures cresting the 70s across much of the CWAs mid and lower elevations. By this afternoon and through the evening and upper level low will continue to move southeast and begin to undercut the region bringing with it a minute amount of precipitation to the far corner of Deschutes County. Models show the upper level low to continue to move southeast and by tomorrow being just offshore of California. The wrap around from the upper level low will continue to bring in warm air advection as well as instability and moisture. Beginning at or near 11 AM, 10-20% of the NBM raw ensembles show probabilities of thunderstorms along the eastern mountains. CAMs sounding data also shows the areas along the eastern mountains to be a bit unstable as the day warms up with MUCAPE values ranging between 250-300 J/kg, LIs of -2 to -3, Lapse rates well above normal at 9-9.5 C/km. This is enough to allow for some isolated thunderstorms to pop up along the eastern mountains through the afternoon and evening on Friday. This set up continues through to Saturday with NBM raw ensembles increasing slightly in probabilities of thunder to 20-30%, with the CAMs soundings showing an increase in MUCAPE values to 300-450 J/kg, LIs of -3 to -4 and lapse rates 8.5-9 C/km. With that said, cannot rule out the likelihood of isolated thunderstorms popping up along the eastern mountains both Friday and Saturday afternoon. Bennese/90 .LONG TERM...Sunday through Thursday...Sensible weather concerns through the extended forecast will revolve around the passage of an upper low pressure system to the south and east of the forecast area Sunday, followed by an upper shortwave trough passage Tuesday. Otherwise, upper level ridging will develop between and after the systems Monday and again Wednesday through Thursday next week. An upper level low south of the forecast area will continue to push east across the Great Basin and towards the Rockies Sunday. While the brunt of the precipitation and best instability will stay south and east of the forecast area, there is a 40-70% chance that surface CAPE will increase to and above 150 J/kg Sunday afternoon across Wallowa county. The increased surface instability, combined with modest mid-level lapse rates (7-8C/km) will allow for a few isolated thunderstorms to develop amongst the shower activity across Wallowa county in the afternoon. The showers/thunderstorms will push east of Wallowa county in the evening Sunday with the eastward push of the upper low to our south. Ensemble guidance is in great agreement that dry conditions will develop across the area as upper level ridging attempts to build to into the PacNW late Sunday through Monday afternoon. By Monday afternoon, there is mod-high confidence (60-80%) that the upper ridge will flatten as a shortwave trough approaches the PacNW. The upper shortwave will glide across the PacNW Tuesday, resulting in increasing rain and high mountain snow showers across the Cascades, Blues, and eastern mountains. A few showers may also develop along the Blues Mountain foothills, though 12 hour probabilities of at least 0.01 inches of precip are between 20% and 40% ending late Tuesday evening. Overall, there is great agreement that upper level ridging will build back over the PacNW with dry conditions overnight Tuesday through Wednesday. However, ensemble cluster solutions Wednesday into Thursday depict uncertainty in the strength of the ridge and the location of the ridge axis as it passes over the region. Namely, 48% percent of the ensemble members (from the GFS, ECMWF, and Canadian) depict the upper ridge axis exiting into the norther Rockies, allowing deep southwest flow to develop over the PacNW and for light showers to develop at least over the Cascade crest Thursday. Though guidance has difficulty this far out with depicting convection, if these members do validate for Thursday next week, would expect increasing instability at the surface and for at least one or two isolated thunderstorms to develop in areas of showers (confidence 10-20%). Otherwise, there is fairly good agreement amongst ensemble members that surface pressure gradients will remain tightened through Tuesday, with Sunday having the strongest gradients through the extended forecast. This will result in breezy to locally gusty winds (gusts 35-45mph) developing through the Cascade gaps Sunday, with the strongest gusts of 40-50mph through the Kittitas valley (confidence 70-90%). Monday through Tuesday, wind gusts will mainly be between 30-40mph through the Cascade gap areas each afternoon (confidence 55-70%). The lower Columbia Basin will also see breezy conditions(gusts 25-35mph) through this period (confidence 60-80%). Lawhorn/82 && .AVIATION...12Z TAFs...VFR conditions to prevail through the period. Winds will generally be light, less than 12kts, through the period with wind directions diurnally driven. Lawhorn/82 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Freeze Warning until 9 AM PDT this morning for ORZ507. WA...Freeze Warning until 9 AM PDT this morning for WAZ028-029. && $$ SHORT TERM...90 LONG TERM....82 AVIATION...82

512 FXUS65 KREV 240930 AFDREV Area Forecast Discussion National Weather Service Reno NV 230 AM PDT Thu Apr 24 2025 KEY MESSAGES... * Warm weather continues today with a slight chance of showers for northeast California. * Light mountain snow and valley rain, thunderstorms, increased winds, and cooler weather for Friday into the weekend. * Warmer and drier weather by early next week with low chance of afternoon showers and thunderstorms by mid week. && .DISCUSSION... High over the region will ensure today remains warm and spring- like. Daytime highs will top near the upper 50s and 60s for Sierra valley locations, and mostly 70s for western Nevada communities. As long as the ongoing warm weather continues, regional streamflows will run fast and very cold for the time being. A few light showers are still possible across northeast CA near the OR border. Mono County into Mineral should also see cumulus fields maturing into the afternoon as well. Otherwise, a very nice day indeed. Well, at least until a cooler and wetter pattern begins early Friday. An approaching pattern change to more active weather features an area of low pressure and closed low tracking across central CA into the Sierra by early Friday. This low pressure system will bring periods of valley rain showers, high elevation mountain snowfall, and breezy winds to the Sierra and western region before exiting the region by Sunday. * Blended guidance projects on Friday a 10-15% chance for isolated thunder Friday across portions of northeast CA and far northwest NV, and a 15-20% for isolated thunderstorms from the the Lake Tahoe Basin south along the eastern Sierra across Mono-southern Lyon-Mineral counties. Look for brief periods of heavy rain, localized erratic and gusty surface winds, and dangerous lightning. If thunder roars-go indoors! * Based on current storm timing and trajectory, and multi-model ensemble liquid precipitation guidance, liquid amounts are trending with better agreement. But liquid amounts are looking a little more impressive to say the least. But most areas from northeast CA south to the Lake Tahoe Basin could see a 40-60% chance for liquid amounts ranging from 0.25 to something just short 1.00. Taking into consideration the more southern track of the low into the Sierra, the eastern Sierra to include Mono County, the White Mountains, and higher elevations east across Mineral County will see higher liquid precipitation amounts. * Blended simulations show snow levels across much of the region today starting around 7500- 8500 then dropping to 6500- 7000 by Friday morning. Eventually, snow levels by Saturday morning will fall to around 5000-5500 across western NV, the eastern Sierra, to include Mono County. Although snow levels will drop as a cooler air mass filters into the region, longer daytime hours, as well as storm timing and trajectory are still limiting factors for snow accumulations amounts. This storm systems more southern track will favor higher snowfall amounts from the Lake Tahoe basin south along the eastern Sierra with higher mountains across Mono and Mineral counties seeing higher accumulation totals. Still, higher mountain passes (Donner, Echo, and Carson) have at least a 50-70% chance for 1.0 - 3.0 of accumulating snow. Higher snow totals of up to 6 could fall across the Carson Range, Mount Rose Summit, Mammoth areas, and the White Mountains through Sunday morning. * Breezy west-southwest winds over the Sierra ridgetops peaking at 40-50 mph with breezy south-southwest mixing down into western NV with gusts to 20-30 mph as well as 35 mph across higher foothill areas Fri and Sat. Look for choppy surface conditions across larger area lakes especially friday afternoon for Pyramid Lake, and periods of moderate mountain wave turbulence and low level wind shear for aviation concerns. Unseasonably cooler temperatures will occur across Sierra valleys from northeast CA, south to the Lake Tahoe basin, and Mono County with overnight lows still projected to drop below freezing into the mid-high 20s for a brief few hours before day break early Saturday, Sunday, and Monday mornings. If you have already started a garden, you still have time to take those precautionary steps to protect your plants. As the upper low exits into the eastern areas of NV on Sunday, any drying will still be limited as a slight chance for a few lingering showers remain across the high Sierra. Blended simulations continue to project higher pressure building into the region to bring a robust warming trend. This will be complemented with drier conditions as daytime highs rising 5-10 degrees above seasonal average. Stay tuned for further updates for any changes to forecast details. This was a worthwhile journey with the National Weather Service to finalize almost 45 years of government service. Please, always Support Your Local Meteorologist! Amanda signing off..... && .AVIATION... * A brief period of patchy FZFG and IFR/LIFR conditions, however, is possible around the Martis valley to include KTRK through 15Z this morning. A rapid return to VFR will occur afterwards. * Otherwise, VFR conditions with light west to southwest winds will prevail for all main terminals today. Sierra terminals (KSVE-KTRK- KTVL) could see wind gusts 10-20 kts during the afternoon and early evening hours. Starting overnight Thursday through Saturday, look for increasing shower and isolated thunderstorm chances and breezy southwest winds. * Winds aloft across the Sierra at FL100 will increase from the south-southwest 20-25 kts between 00-06Z Friday, and further intensify to 25-35 kts by 21-03Z Saturday. Look for increasing turbulence and LLWS from Friday afternoon through Saturday morning. - Amanda sends-LAST NO AMD && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$

416 FXUS66 KSTO 231946 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1246 PM PDT Wed Apr 23 2025 .Discussion... .Synopsis... Chances for afternoon and evening showers are in store into the early weekend with Friday-Saturday as the best days for widespread precipitation and thunderstorm development. A cooling trend with light mountain snow showers on Saturday is expected with minor travel impacts. && .Key Messages... * Today: Last day of warm temps and trending cooler through the rest of the week. Isolated showers and thunderstorms tonight, mainly over Shasta County. -Probability of high temperatures 75 degrees F or higher: 50-85% -10-25% chance of isolated showers or thunderstorms Wednesday and Thursday PM across northern Sacramento Valley and surrounding terrain. * Thursday-Weekend: -Cooling trend with breezy to gusty onshore winds Thursday and Friday PM -Isolated to scattered showers and thunderstorms (10-30%) possible, primarily near the Coast Range & Shasta/Tehama County, becoming widespread Friday afternoon through Saturday -High elevation snow showers possible late Friday & Saturday, with a 40-70% probability of 2 inch or more of snowfall above 5500 feet along Sierra/southern Cascades, 25-55% of 4 inches or more -Lingering mountain showers Sunday, then trending warmer and drier For additional details on weather and expected impacts over the next 7 days, please visit weather.gov/sto/briefing .Changes from previous forecast... * Isolated thunderstorm potential increasing for Thursday-Friday PM * High elevation snowfall potential continues to trend higher Friday afternoon through Saturday evening && .AVIATION... VFR conditions across interior NorCal next 24 hours. South to west winds mostly below 12 kts expected, with gusts up to 15 to 20 kts for the Central Valley after 20Z Thu. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$

784 FXUS65 KMSO 240833 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 233 AM MDT Thu Apr 24 2025 .DISCUSSION... KEY MESSAGES: - Isolated to scattered showers across southwest Montana, Lemhi County and north central Idaho through Friday. - Breezy easterly winds Today into Friday, causing choppy water on area lakes. - Gradual warming under south winds into Saturday. - Cooler with more widespread precipitation with cold front likely Sunday into Monday. Shower activity will remain in place across the southern half of western Montana and north central Idaho (generally along and south of Interstate 90) through Friday. Showers will likely become a bit more widespread in these areas Thursday afternoon as a low pressure circulation tracks along the southern Montana/ID/WY borders. Precipitation chances taper off significantly to the north, especially across northwest Montana. All areas, especially closer to the divide, will see breezy easterly winds lasting into Friday morning. Widespread gusts 20 to 30 mph will be common, with exposed terrain in northwest Montana potentially seeing gusts up to 35 mph, especially in the evening timeframe today. Those with outdoor sensitivities to wind may want to monitor the forecast, as well as outdoor recreationalists on area lakes due to expected choppy water conditions. Overall, temperatures will be trending upwards through Friday and into Saturday, with many locations seeing their warmest temperatures of the week Saturday afternoon. Shower activity will begin to increase Saturday afternoon across north central Idaho and southwest Montana ahead of an approaching trough of low pressure. For the most part, forecast models have continued to trend further south with the main low pressure system for Sunday into Monday. While wet, showery and cooler conditions look likely, the scenarios showing a very wet system are becoming less likely (15 to 20 percent chance). In fact, locations near the northwest Montana/Idaho panhandle border may see very little (if anything) in the way of precipitation. The higher terrain of southwest Montana and north central Idaho will likely see some snow showers down to roughly 6000 feet by Monday, however impacts down to mountain pass levels look minimal at this time. There is growing confidence in a more pronounced ridge of high pressure building into the region by mid-late next week. While the details of this ridge are still somewhat in question, there is a growing chance for prolonged dry and warm conditions by this timeframe. && .AVIATION...A low pressure will be tracking into Yellowstone NP today will continue to cause a few showers over Lemhi county and southwest Montana. KSMN and KBTM have the best probability of being impacted by a light shower. This system will also cause gusty easterly winds across the Northern Rockies with the strongest winds being near the Continental Divide. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$

660 FXUS65 KBOI 240857 AFDBOI Area Forecast Discussion National Weather Service Boise ID 257 AM MDT Thu Apr 24 2025 .SHORT TERM...Today through Saturday night...A weak upper level low will move through the CWA today, providing conditions for showers and a slight chance of thunderstorms in the northeast portion of the area (mainly in Valley County southeast into the Camas Prairie). As a deep low moves south along the coast, our upper flow will become SSW tonight, then SSE to SE Friday through Saturday night. Showers and thunderstorms associated with this low will move into most of the area from the southwest Friday and linger through Saturday night. The chance of measurable precipitation in any one spot varies over a considerable range, but is generally highest in the afternoons and evenings, as is usually the case. Because the low will be to our south, the highest chance of precipitation is also over roughly the southern half of the CWA, which is roughly south of Ontario. Temperatures will around 5 degrees above normal today, then warm a few more degrees as warm southerly flow arrives Friday and Saturday. Winds are expected to be less than 10 mph in most areas today, but gusty east to southeast winds southeast of Mountain Home will develop Friday. .LONG TERM...Sunday through Thursday...Showers Sunday as an upper closed low makes its way across the Great Basin. Current ensembles show a good signal for instability. This is allowing a slight chance (10-20%) of thunderstorms nearly area wide Sunday afternoon, with the exception of Harney and western Baker counties. Chances of precipitation Sunday evening range from 20-80%, generally increasing as you move east and in higher elevations. We begin to dry out area wide through Monday morning as the closed low moves off to our east allows for ridging to build in behind it. Breezy northwest winds persist Sunday through Monday as the low vacates our area. Precipitation chances return to higher elevations Tuesday afternoon through Wednesday afternoon, as another (weaker) trough crosses over our area. The precipitation chances in higher elevations range from 20-50%. Dry area wide Thursday as ridging builds in. Temperatures follow a warming trend Sunday through Thursday, starting right around normal before warming up to 5-10 degrees above normal by Thursday. Snow levels follow suit, rising from 6-7 kft on Sunday to 8-9 kft come thursday. Snow accumulations will be minimal and confined to the highest elevations Sunday through Thursday. && .AVIATION...VFR. Chance of showers and slight chance (10-20%) of thunder Thursday afternoon over the West-Central & Boise Mtns and near KMYL. Surface Winds: Variable 5-15 kt. Winds aloft at 10kft: Variable 5-15 becoming S-SW 10-20 kt Thursday night. KBOI... VFR. Variable under 5 this morning becoming NW up to 10 kt midday. Shifting to E-SE under 10 kt overnight. Weekend Outlook...VFR. Active weather through the weekend, with chances of showers and slight chances of afternoon thunderstorms Friday-Sunday. Showers may result in areas of MVFR, mountain obscuration, and gusty outflows. Winds increasing through Sunday, with gusts up to 30 kt Sunday afternoon. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise SHORT TERM...SP LONG TERM....NF AVIATION.....NF

569 FXUS65 KLKN 240918 AFDLKN Area Forecast Discussion National Weather Service Elko NV 218 AM PDT Thu Apr 24 2025 .SYNOPSIS...Active pattern will bring periods of wind, rain and snow showers, and a few thunderstorm chances as the last week of April see a series of upper level storm system transit the Silver State. && .SHORT TERM...Thursday through Friday Unsettled weather pattern looks to continue as one weak upper level shortwave trough departs as a larger upper level low approaches the west coast. Thursday will see lingering moisture generate some isolated showers and a few isolated thunderstorms across mainly southeastern sections of Elko, and White Pine counties for Thursday afternoon. Overall chances remain similar to Wednesday, at 20% to 40% with the best chance at a shower or storm will be over eastern parts of White Pine county. Otherwise Thursday looks to be dry for most with daytime highs reaching into the middle 60s to mid 70s with partly cloudy to mostly cloudy skies. Winds will be light to breezy Thursday as south the Southwest winds of 10 MPH to 20 MPH with gusts up to 30 MPH will be possible across central Nevada, with northern NV seeing somewhat lighter winds of 5 MPH to 15 Mph with gusts up to 25 MPH possible. Lows Thursday night into Friday morning will be above normal with light SW winds and cloud cover, only dropping into the middle 30s to mid 40s. Friday will be a day of transition as a large Pacific trough and associated upper low begin to move onshore over northern California. This system will first act to enhance the southwesterly flow aloft which will mix down to the surface across central Nevada, with winds picking up to 25 MPH to 35 MPH with gusts up to 50 MPH possible, with the strongest winds occurring across northern Nye and White Pine Counties for Friday afternoon and evening. Went ahead and issued a Wind Advisory that will be valid from 11AM to 8PM PDT Friday evening for those counties listed. Will need to watch trends especially for southern Eureka and Lander counties if the advisory will need to be expanded as additional data comes in. Winds for the northwestern 2/3 of the State wont be as strong, with south to SW winds running 15 MPH to 25 MPH with gusts to 40 MPH possible. As for precipitation Friday shower chances will increase across the west first by Friday evening then overspread the rest of NV for Friday night into Saturday morning. Thunderstorms will again be possible, Friday afternoon and evening however the best environment will be constricted to a narrow strip along the Idaho/Oregon/Nevada border region. Highs Friday with the increasing cloud cover will be similar to Thursday, with temperatures in the middle 60s to middle 70s. .LONG TERM...Saturday through next Thursday. An upper level low centers along the central CA coast early Saturday morning with light showers expected to develop over parts of western NV, along with increasing southerly winds across most of central NV. Late morning and afternoon hours scattered valley rain and high elevation snow showers are expected to overspread most of the CWA, with the only dry areas over SE Elko County, the eastern two thirds of White Pine County, and the eastern third of Northern Nye County. By late Saturday afternoon the low will have progressed eastward, centering over central CA. QPF amounts through Saturday afternoon will be light, with generally less than a tenth of an inch of precipitation. Increasing instability with the approaching upper level low will however bring just enough moisture and instability to the western third of the CWA for isolated thunderstorm activity. The main impact from the approaching system on Saturday will be the strong and gusty southerly winds across east-central NV, including most of White Pine County where sustained winds of 15 to 25 mph and gust to 45 mph are expected into Saturday evening. Saturday night the low centers over NV with snow levels lowering to around 6000 feet. Not expecting any accumulations in valley areas, however higher summits could see 1-2 inches of snow by late Sunday morning especially on Pequop Summit along I-80 in Elko County, and all of the Summits along Highway 50 through Lander, Eureka and White Pine Counties. Valley rain and mountain snow showers linger Sunday into Monday. A drier and warmer pattern sets up late Monday through Thursday with highs climbing into the 60s to low 70s. && .AVIATION...VFR conditions expected at all terminals over the next 24 hour period. CIG levels begin to drop from oncoming cloud cover approaching from the west with clouds coming in around 20000 feet. Light winds at all terminals below 10 kts, with some possible gusty southerly winds at KELY in the afternoon at 10 kts, gusts 20 kts. && .LKN Watches/Warnings/Advisories... Wind Advisory from 11 AM to 8 PM PDT Friday Northeastern Nye... Northwestern Nye...White Pine. && $$ 98/96/97