829 FXUS66 KSEW 220307 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 807 PM PDT Thu May 21 2026 .SYNOPSIS... Upper level ridge centered offshore through Friday will weaken Friday night and Saturday. Surface high pressure building ahead of the next weather system with increasing low level onshore flow Saturday night into Sunday. System arriving Memorial Day with a trailing upper level trough over the area Tuesday. Weak upper level ridge trying to build Wednesday. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... No updates to forecast or discussion anticipated this evening. 27 Satellite imagery shows a few small buildups over the Cascades along with some high clouds otherwise clear skies over Western Washington this afternoon. Temperatures at 3 pm/22z were in the mid 60s to mid 70s. Upper level ridge centered offshore remaining in place through Friday. Light flow in the lower levels. Friday looks to be a repeat of today with just patchy fog near sunrise otherwise mostly clear skies. Onshore flow increasing late in the day will put a cap on the high temperatures with mid 60s to upper 70s in the forecast. Lows tonight in the 40s and lower 50s. Ridge flattens out Friday night into Saturday. Low level onshore flow remaining intact with the marine layer getting inland Saturday morning. The layer will be shallow and dissipate in the afternoon. A little cooler Saturday, about 5 degrees versus Friday, with highs in the 60s to lower 70s. Lows in the 40s. Surface ridge out ahead of an approaching system building over the coastal waters increasing the low level onshore flow Saturday night. Possible gale force westerlies down the Strait of Juan de Fuca. Increasing cloud cover will keep lows a little warmer, in the mid 40s to lower 50s. Felton && .LONG TERM /SUNDAY THROUGH THURSDAY/... Low level onshore flow Sunday combined with high clouds out ahead of the approaching weather system will give Western Washington a mostly cloudy/partly sunny day. Temperatures a little cooler again Sunday with highs mostly in the 60s. Operational run solutions now trending towards the ensemble solutions yesterday with rain arriving Memorial Day as a front reaches the coast late in the day. Highs only in the 50s. Front moving through Monday evening with cool upper level trough trailing the front keeping at least a chance of showers in the forecast Tuesday. Lows in the 40s and highs in the upper 50s to mid 60s. Weak upper level ridge moving into the area Wednesday for a dry forecast. Ensembles not real confident in the strength of the ridge Thursday. Weak system riding by to the north for now producing slight chance pops across the area. Highs near normal, mostly in the 60s. Lows in the 40s and lower 50s. && .AVIATION... High pressure offshore will keep the weather pattern consistent tonight into Friday. VFR conditions will prevail through the TAF period for most. The exception will be the Pacific coast once again, where stratus and patchy fog is expected to redevelop and bring IFR conditions overnight into Friday morning. The stratus looks to make it slightly further inland compared to this morning, but still remain short of the Puget Sound interior. Probabilities hover around 30-50% for terminals including OLM, PWT, and CLM for seeing low ceilings. Ceilings should clear quickly aoa 17-19Z Fri. N/NW winds 5- 8 kt becoming light and variable tonight. Winds resume tomorrow again N/NW 5-10 kt. KSEA...VFR conditions through the period. Probability of seeing stratus is around 25-30%, but confidence is higher on remaining mostly clear overnight. Winds N/variable 5-8 kt becoming light overnight. NW winds 5-10 kt during the day Friday. 62 && .MARINE... The pattern continues to remain steady with high pressure offshore and lower pressure inland through the rest of the week and into this weekend. Northwesterly winds persist over the coastal waters, with the outer-most areas out to 60 NM experiencing winds up to 20 to 25 kt, thus allowing for a small craft advisory from this afternoon through Friday morning. Winds will ease Friday morning as the gradient decreases as the high shifts westward. Another round of small craft winds is likely Friday night into Saturday with more robust onshore flow from the high moving back eastward closer to shore. Winds look to ease once again Sunday. A low pressure system will traverse the area on Monday, bringing widespread small craft conditions across much of the area waters. Diurnally driven westerly pushes down the Strait of Juan de Fuca will occur each afternoon and evening through Monday, which will also bring Small Craft conditions to the central and eastern Strait. Saturday look to be the strongest day, with a 40-60% chance of gale force winds through the Strait. Seas remain 6-11 ft through the rest of the week and this weekend, with the largest and steepest waves over the offshore waters. Dominant periods will be around 8 seconds through Friday, and then once again on Saturday as waves become driven more by the local wind. Waves increase to 10-13 ft Monday into Tuesday as a low pressure system moves through the area. 62 && .HYDROLOGY... The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated during this time as needed. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory until 5 AM PDT Friday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory until 11 AM PDT Friday 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. && $$

368 FXUS66 KPQR 220525 AFDPQR Area Forecast Discussion National Weather Service Portland OR 1025 PM PDT Thu May 21 2026 Updated aviation discussion. && .SYNOPSIS...Dry and warm weather is expected across the region through the weekend with high pressure over the NE Pacific spreading east over the Pacific NW. Rain, cooler temperatures, and slightly elevated winds return to the area late Sunday into early next week, which could impact any outdoor Memorial Day plans. && .DISCUSSION...Today through Wednesday...There has been very little change in the forecast since the previous package. Today is still shaping up to be the warmest day of the week. Temperature observations at noon were around 70-74 degrees for most interior lowland locations, which is right on track for high temperatures to peak in the low to mid 80s. The daily normal temperature for today is around 69-71 degrees across the Willamette Valley, so today`s high temperatures are forecast to be around 10-15 degrees warmer than normal. However, no record high temperatures are expected to break as record high temperatures are generally in the upper 80s to mid-90s through the Memorial Day Weekend. Temperatures at noon along the immediate coast were much cooler, in the mid 50s to low 60s due to lingering marine stratus. As that dissipates through the early afternoon, coastal temperatures are expected to peak in the mid to upper 60s. Conditions are expected to remain dry through the end of the week and into the weekend as high pressure continues across the region. High temperatures on Friday will be just a few degrees cooler than today, generally right around 80 degrees for the inland valleys. The broad upper level ridging on Friday becomes more zonal aloft Saturday into Sunday. Expect a slight cooling trend in temperatures through the weekend, but still likely to remain above seasonable averages in the mid to upper 70s. There remains good agreement that Sunday will remain mainly dry and warm, though could begin to see increasing cloud cover ahead of an approaching weather system. There high confidence in the ensemble members that a frontal system will push into the PacNW sometime late Sunday night into Monday, with chances of rain increasing for Monday, followed by showers into Tuesday. Some uncertainty still remains in the general timing of rain as well as rain totals, but latest consensus is that rain will hold off until at least late Sunday night along the far N OR and SW WA coast, then spread southeast Monday morning. Confidence is high that this will be non-impactful rain. When looking at the probability of reaching or exceeding 0.5 inch for 48 hour rain totals through 5 AM Wednesday, there`s a 10-20% chance for the Willamette Valley, 20-40% for the Portland and Vancouver metro area and SW WA lowlands, 45-65% for the coast and Coast Range, and 50-70% for the Cascades. However, some elevated winds are possible on Monday as the front sweeps through the area. There`s a 60-80% chance of peak gusts of at least 25 mph and about a 20-40% chance of peak gusts of at least 30 mph. These aren`t high enough gusts for any wind advisory concerns, but they could cause impacts to any tents that might be in place for outdoor holiday activities. Temperatures will also drop substantially Monday and Tuesday with high temperatures in the lower to mid 60s for the interior lowlands. Conditions are likely to rebound back to seasonable normals by the middle of next week, though some uncertainty remains due to continued low chances of precipitation. -03/DH && .AVIATION...Latest satellite imagery depicts regions of low marine stratus beginning to redevelop along the coast, while largely clear skies otherwise remain in place. Inland, clear skies and VFR flying conditions will prevail through the period with diurnal winds rising to 5-10 kt out of the north to northwest by 17-19z Fri. Patchy low stratus will initially result in intermittent VFR/IFR flying conditions along the coast through 09z Fri, when coverage is expected to increase, pushing chances for IFR/LIFR to 50-80%, with highest chances along the central Oregon coast at KONP. Cigs will most likely lift to low- end MVFR after 18z Fri, however there are 20-50% chances IFR cigs persist through much of the day. Any improvement will be temporary as cigs are again favored to fall below IFR threshold by 03z Sat. Gusty diurnal winds continue, with north to northwest flow easing to around 5 kt through the 12z Fri, then rising to 10-15 kt with gusts reaching 20-25 kt after 18z Fri. KPDX AND APPROACHES...VFR conditions continue through the period with only a 15-20% chance of low marine stratus reaching far enough inland along the Columbia to yield MVFR cigs. Any low clouds will quickly mix out by 16-18z Fri. Diurnal northwest winds will ease below 5 kt by 09z Fri, then rise to 5-10 kt by 18z Fri. -36 && .MARINE... High pressure offshore will maintain breezy northerly winds through the end of the week. The strongest winds are expected during the afternoon and evening periods as the surface thermal trough strengthens over the northern CA/southern OR coast. Small Craft Advisories for northerly wind gusts up to 25-30 kt remain in effect for the waters south of Cape Falcon through 11 PM Friday, and through 5 AM Friday for the waters north of Cape Falcon and beyond 10 NM offshore. Seas 6 to 9 feet are expected across all waters through this weekend. The summer-like pattern is expected to break down Sunday night as a front approaches the waters. This system will return breezy southwesterly winds and a westerly swell that will likely (60-80% chance) build seas above 10 ft by Monday. -10/DH && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory until 11 PM PDT Friday for PZZ252-253-272- 273. Small Craft Advisory until 5 AM PDT Friday for PZZ271. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

741 FXUS66 KMFR 220551 AFDMFR Area Forecast Discussion National Weather Service Medford OR 1051 PM PDT Thu May 21 2026 ...Updated Aviation Discussion... .DISCUSSION (Today through Wednesday)... Key Points: * Minor/low impacts continue the next several days * Well above normal temperatures through Sunday - Cooler temperatures early next week - Below normal on Tuesday * No strong signal for precipitation until early next week - Small (10%-25%) indications for isolated showers Fri-Sun - Mainly for northern California and eastside areas - Could have isolated thunder if anything develops - More widespread rainfall chances (30%-90%) Mon-Wed * Elevated fire weather concerns this week - Combination of low RH and breezy winds - Isolated areas of both critical RH & wind Monday afternoon - Fuels fortunately keeping the overall fire threat low/moderate Further Details: A ridge of high pressure remains over the Pacific Ocean through Friday night/Saturday morning, which will result in an overall dry and stable airmass. As the high shifts west, this will allow for more of a zonal flow to set up over the PacNW with weak embedded PVA. There is at least some semblance of a potential for isolated convection each afternoon Friday and Saturday as we reach convective temperatures. Saturday may see more isolated to scattered coverage. Upper level features are less than desirable both days resulting in low confidence, but there is enough overlap of parameters to warrant at least a mention of showers/thunderstorms during peak heating. MUCAPE values vary but are generally around 200-500 J/kg. CAMs are indicating this potential as well each afternoon for northern California, but Saturday could see these chances spreading to eastside areas as well. The NBM has started to show this potential (10%-25%) in the PoP field. May continue to see these chances increase for Saturday in subsequent runs. By Monday, as the ridge of high pressure becomes displaced out of the region, a strong trough is progged to develop and dig south over the west coast early next week. This is a much stronger signal for precipitation across our entire forecast area than we have seen in well over a week (outside of isolated rainfall). That said, there are discrepancies between global models on the timing/location of said trough (height fields out of phase from one another) and hence coverage of precipitation chances Mon-Wed. The takeaway here is we have a better signal for widespread precipitation compared to what we`ve seen in recent weeks. In other words, confidence is increasing for potential widespread precipitation Monday through Wednesday, but exact details on amounts and timing are still unclear. -Guerrero && .AVIATION...22/06Z TAFs...Along the coast, areas of IFR ceilings will continue overnight into Friday morning north of Cape Blanco. Stratus will clear by late Friday morning as gusty winds develop along the coast. Areas of IFR are then expected to redevelop Friday evening for areas north of Cape Blanco. Inland, expect VFR levels with clear skies through the TAF period. && .MARINE...Updated 100 PM PDT Thursday, May 21, 2026...A thermal trough is bringing gusty north winds and steep to very steep seas over the coastal waters through Friday night. Winds will be strongest and seas will be highest during the afternoons/evenings. Through this stretch, very steep seas of 10-13 ft are most likely south of Cape Blanco with steep seas (6-9 ft) north of Cape Blanco. Gale force gusts (~40 kt) are possible across portions of the southern waters, especially from around Gold Beach south. The pattern will ease some this weekend as an upper trough pushes in from the NW. This should bring lighter winds and lower seas (still at least Small Craft Advisory), especially by Sunday. Could be a brief break Sunday night, but models continue to show another trough moving through on Monday (Memorial Day). The strength and timing of this trough are still somewhat uncertain, but it could bring periods of rain, gusty W winds that shift back to N and steep seas. This one should be followed by a larger WNW swell. -Spilde/Hermansen && .FIRE WEATHER... As we maintain the dry airmass and breezy afternoons, there will be at least an elevated threat for fire weather conditions each day. Monday in particular will see the strongest winds. In fact, wind speeds may reach wind advisory criteria for eastside areas. Lake County in particular could see isolated areas of critical wind and critical RH, but timing of precipitation could alter the RH field leading to uncertainty. With that said, fuel conditions per fire agencies reveal the overall fire weather threat remains low to moderate. Given the low RH values each afternoon and breezy winds, people should exercise caution with any outdoor activities that could cause sparks or flames, especially eastside areas with Lake County in particular. Bottom line is that fire season was declared early this year, so these precautionary actions should already be in place, but its especially important when we have these elevated concerns. -Guerrero && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Hazardous Seas Warning until 11 PM PDT Friday for PZZ356-376. Small Craft Advisory until 11 PM PDT Friday for PZZ350-370. && $$

833 FXUS66 KEKA 212106 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 206 PM PDT Thu May 21 2026 .SYNOPSIS...Temperatures trend slightly lower through the weekend, remaining pleasant, with light winds. Isolated thunderstorms may form in Trinity County Friday afternoon. A clipping storm system will bring chances for light rain and drizzle early next week. Northerly winds will begin turning strong again by Monday afternoon, and likely remaining breezy through mid next week. .KEY MESSAGES... - Winds remain light through the holiday weekend, but trend much stronger Monday afternoon. -Chances for light rainfall or light drizzle increase early next week. -Isolated thunderstorms possible in Trinity County Friday afternoon, which would bring a lightning risk to early holiday weekend outdoor activities. -Morning coastal stratus and fog will persist, with increasing chances for longer duration coastal stratus and possibly fog through the weekend. && .DISCUSSION...Coastal stratus was clinging along the immediate coast for the afternoon, with full sunshine elsewhere. This pattern will continue through the weekend, with light north- westerly winds and coastal eddies locking in the coastal low clouds more effectively. Interior temperatures will slower moderate through the weekend as high pressure ridging is flattened from troughing to the north. A weak upper disturbance is passing through from the north. There are big questions in available moisture/instability in regards to potential subsequent afternoon thunderstorm activity for Trinity County Friday. There will be a strong capping inversion in place, but convective allowing models have in more recent runs depicted breaking of the cap and thunderstorms over Trinity County. With run- to-run deterministic and ensemble congruity, have increased thunderstorm chances for Trinty Friday afternoon. There is a small, low confidence chance a lone storm may form out there this afternoon. A lingering chance for convective activity may carry into Saturday afternoon for far northern Trinity County if the cap can break. A deeper trough will work farther south Monday. A late season, weak front off the low has been forecast to clip the area and deliver some light rainfall or drizzle to the northern portion of the region Monday and possibly Tuesday. With a slightly more southerly track modeled, chances for a wetting rainfall (over 0.1 inch) have increased to 30-50%; however, these types of systems usually underperform when arriving into such dry antecedent conditions. Ensemble spread is still quite high, ranging form nothing to 0.4 inches for Del Norte, and this is typical modeling for late season systems. The deep trough will progress SE through the Pacific Northwest/Great Basin region later Monday through Wednesday. With Northern Pacific high pressure strengthening against it, the northerly to westerly winds will once again begin turning strong by Monday afternoon. The strongest winds will initially be focused over the eastern portion of the area, through Trinity and Lake Counties. Chances for gusts over 35 mph are notably high for Lake County Monday afternoon and evening, at 60-75%. Wind gusts over 40 mph are also looking probable (40 to 50%) for the ridges and locations around Clearlake. On Tuesday, these strong northerlies expand westward over the coastal regions. Chances for wind gusts over 30 mph are pretty solid for the exposed coastal headlands Tuesday afternoon, at 40 to 60%. This pattern will not likely quickly breakdown through Wednesday, but chances for stronger gusts are much lower Thursday. JJW && .AVIATION...Stubborn stratus is keeping IFR ceilings at the North Coast with periods of VFR at KCEC and KACV. IFR is forecasted to return tonight around 03Z as ceilings reform and drop with ~70% confidence. After 12Z, North Coast ceilings are more likely than not to be LIFR if they do form. The daily clearing pattern is forecasted to repeat again Friday. VFR elsewhere through the TAF period. && .MARINE...Buoys in the inner waters report slightly calmer winds off the NW CA coastline today. However, near gale force gusts off SW Oregon and in the outer waters are creating steep, short period seas for our waters. Sea heights are much higher in the southern waters as the northern winds continue and fetch grows. A Gale Warning is active for the northern outer waters through tomorrow evening as is a Hazardous Seas Warming for the southern outer waters. Inner waters are reporting large, steep waves with dangerous conditions for small crafts through tomorrow as well. Into the weekend, the synoptic weather pattern changes as a weak frontal system passes overhead. This front will do two things for the coast waters. Firstly, expect light winds as the surface pressure gradient weakens over the area. Gusts up to 20kts are expected, which is a nice chance after multiple days of gales. Secondly, a large swell will build Sunday into next week with the storm travelling across the Northern Pacific. This NW swell is forecasted to be up to 14ft@12s at its peak on Tuesday. Seas for this holiday weekend will be calm before this swell builds in with seas of 5-7ft expected. DS && .FIRE WEATHER...There is a small, low confidence 5-10% chance for an isolated thunderstorm over far eastern Trinity County this afternoon. Chances for isolated thunderstorms increase Friday afternoon for Trinity County (10-20%). There will be a strong capping inversion in place, but convective allowing models have in more recent runs depicted breaking of the cap and thunderstorms over Trinity County. With run-to-run deterministic and ensemble congruity, have increased thunderstorm chances for Trinty Friday afternoon. A lingering chance for convective activity may carry into Saturday afternoon for far northern Trinity County if the cap can break. After some light rain/drizzle chances Monday for mainly Humboldt and Del Norte counties, northerly to westerly winds will quickly increase Monday afternoon. Winds will initially be strongest in east Trinity through Lake County, with moderate to high chances for gusts over 35 mph (60-75%) Monday afternoon and evening. Wind gusts over 40 mph are probable (40-50%) for the ridges of Lake County and around Clearlake. Winds will then increase across the entire region Tuesday, and will likely remain breezy through Wednesday. Minimum RH is currently forecast to drop to the mid to low 20s with these winds. JJW && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 11 PM PDT Friday for PZZ450-455. Gale Warning until 11 PM PDT Friday for PZZ470. Hazardous Seas Warning until 11 PM PDT Friday for PZZ475. && $$ NOTE: The full forecast discussion is now regularly issued between 10 am/pm and 1 pm/am. Additional updates will be issued as needed. 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

567 FXUS66 KMTR 220440 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 940 PM PDT Thu May 21 2026 ...New AVIATION, MARINE... .KEY MESSAGES... Updated at 1234 PM PDT Thu May 21 2026 - Diurnally driven onshore winds during the afternoon and early evening - Warm and dry weather through Friday leads to elevated fire weather concerns for the interior Bay Area and Central Coast - Gradual cooling trend begins Friday with seasonal temperatures for the upcoming weekend && .UPDATE... Issued at 643 PM PDT Thu May 21 2026 Stratus continues to impact the immediate coast with some inland expansion across the Monterey Bay region, and a finger of stratus coming through the Golden Gate into the Berkeley area. The Bodega Bay profiler is reporting a marine layer depth of around 1000 to 1500 ft, which is conducive to expanded stratus development into the inland valleys through the early hours of Friday morning. DialH && .SHORT TERM... Issued at 1234 PM PDT Thu May 21 2026 (This evening through Friday) Today we continue to see dry conditions across the interior and with afternoon maximum temperatures reaching the lower 80s to lower 90s under sunny skies. Meanwhile, the coast will stay cooler thanks the ~1000 ft marine layer where we are expecting the upper 50s to middle 60s. With the large scale pattern aloft is defined by a through over the northern Rocky Mountains and a building ridge over the northeastern Pacific. This pattern largely supports onshore winds at the surface with coastal breezes developing each afternoon and evening. Tonight, expect the marine layer to remain steady, yet the inland extent is likely to increase into the coastal adjacent valleys early Friday morning. However, similar to today, these low clouds will quickly retreat to the coastline by late morning. Friday we are expecting a slight cool down in afternoon temperatures as the trough shifts eastward allowing for a deeper marine layer to return. Coastal areas are likely to remain in the upper 50s to middle 60s with the interior warming into the upper 70s to middle 80s. The only far interior areas like Pinnacles National Park, King City, San Lucas, and San Ardo have the potential to reach 90 deg F. && .LONG TERM... Issued at 1234 PM PDT Thu May 21 2026 (Friday night through next Wednesday) The cooling trend will continue into this upcoming weekend with temperatures returning to near seasonal averages. This is as the marine layer is forecast to deepen to ~1500 ft. Cannot rule out late evening and early morning coastal drizzle during this timeframe as the boundary layer remains very moist. By late Monday and early Tuesday, a frontal boundary is forecast to sweep across the region. This would bring the potential for drizzle and/or light rain as the front moves from north to south across the Bay Area and Central Coast. In wake of the frontal passage, the marine layer may mix out and allow for coastal locations slightly warmer compared to this weekend. && .AVIATION... (06Z TAFS) Issued at 938 PM PDT Thu May 21 2026 Currently a mixed bag of LIFR-VFR at the terminals. Moderate to high confidence on IFR-LIFR conditions returning to all the terminals tonight with the exception of the interior terminals of LVK and SJC. Diurnal winds will prevail. Vicinity of SFO...Currently VFR with northwesterly flow. Stratus is currently being held off just to the northwest of the terminal. Moderate confidence on this reaching the terminal, likely around 09Z. Diurnal winds will prevail. SFO Bridge Approach...Low clouds coming in through the Golden Gate Gap will continue to spread south along the East Bay Shoreline tonight with the San Mateo Bridge Approach likely to be impacted through late morning. Monterey Bay Terminals...Currently IFR with southwesterly flow at MRY and IFR with northwesterly flow at SNS. High confidence on conditions deteriorating to LIFR with fog possible. VFR is expected by late morning with IFR stratus sticking close to the coast during the day. Another early return of stratus is expected tomorrow night. && .MARINE... (Tonight through next Wednesday) Issued at 938 PM PDT Thu May 21 2026 Hazardous conditions for small craft continue tonight for the northern outer waters due to strong northerly breezes and rough seas. Moderate northwesterly breezes will back to become southwesterly tomorrow and prevail through the weekend. Rough waters are expected across the northern outer waters Friday with widespread moderate seas prevailing Saturday through Monday. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 3 AM PDT Friday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...RGass LONG TERM....RGass AVIATION...Sarment MARINE...Sarment 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

881 FXUS66 KOTX 220549 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 1049 PM PDT Thu May 21 2026 .KEY MESSAGES... - Conditions trend drier and warmer through the weekend with breezy winds especially for the Cascades and central WA. - High confidence for a cooling trend into early next week with chances for precipitation and breezy conditions. && .SYNOPSIS... Dry conditions with above normal temperatures will continue through the weekend. Breezy winds are expected at times through the Cascade gaps and across the western Columbia Basin especially Saturday and Sunday. There is high confidence for cooler and unsettled conditions to return early next week. && .DISCUSSION... This afternoon through Sunday: The Inland NW will transition from a northwest flow to a more zonal flow through the weekend. A few weak shortwaves will skim by through this period, but will have limited moisture and instability. So for the most part this will bring variable middle to high clouds with largely dry weather. One of those waves will drop through this afternoon and tonight, bringing increasing clouds. A slight chance for showers was added near the northern Cascades, near the Canadian border but this will impact very few people if any. Another wave skims by Friday afternoon and there is a bit more instability, so I added some isolated showers near the north Cascades, northern Ferry County and far northeast WA into Boundary county. A slight chance for t-storms will also be found toward northern Boundary county. Another wave pushes by later Friday night into Saturday as we transition to the zonal flow, bringing a broader area of middle to high clouds, before they decrease again Saturday afternoon into Sunday. Winds will be on the increase with that increased zonal flow, with the strongest near the Cascades gaps into the western Columbia Basin by later Saturday and into Sunday. Speeds of 15-20 mph with gusts of 25-35 mph are forecast in these areas. Farther east winds of 10 mph with gusts to 20-25 mph are possible. Temperatures push into the 70s and 80s, with some areas near 90 in the deeper basin on Saturday. With afternoon RHs in the teens and 20s, coupled with this hot and breezy conditions, fire weather will be of concern, with a risk for quickly spreading grass fires if one should develop. Sunday night through Thursday: The pattern turns more active with a low pressure trough pushing into the area, before trying to break south toward the middle to latter part of the week. This will bring increase rain chances to the Cascade crest Sunday night, with PoPs then expanding throughout the region Monday into Tuesday. Right now the highest potential for precipitation is late Monday afternoon into Monday into Tuesday morning. Thereafter shower chances continue into the end of the week, with the best risk around the mountains. Each afternoon will have some risk for t-storms, but the potential most days is around 10-15% in the afternoon and often just a tad to low to show up in the forecast. But I would expect this potential to increase some as we get closer. It will remain breezy on Monday, with gusts of 20-35 mph strongest in the lee of the Cascades and deeper basin. Locally higher gusts near 40 mph or so are possible there. So we will keep an eye out for elevated fire concerns and patchy blowing dusts. Overall, Memorial Day will not the most idea weather but it will not be a wash out by any means: shower chances and breezy. Temperatures start to cool through this period, pushing into the 70s to low 80s Monday and cooling into 60s Tuesday before some moderation afterward. There is still a lot spread among ensemble members for the precise temperatures. In fact on Monday there is a 15-20 degrees spread between the 25th and 75th percentiles (as much as 30 degrees in the 5th to 95th percentile). /Solveig && .AVIATION... 06Z TAFs: VFR, dry conditions through the period with winds generally less than 10kts. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in VFR conditions. Winds gusts of around 15 kt near MWH-EAT have less then 20 percent probability for Friday afternoon. /JDC ----------------------- 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 46 76 48 80 52 77 / 0 0 0 0 0 0 Coeur d`Alene 46 74 48 78 50 75 / 0 0 0 0 0 0 Pullman 44 73 47 77 49 75 / 0 0 0 0 0 0 Lewiston 48 78 50 84 53 83 / 0 0 0 0 0 0 Colville 42 78 44 82 45 79 / 0 10 10 0 0 0 Sandpoint 45 73 46 77 48 75 / 0 10 0 0 0 0 Kellogg 45 74 47 79 50 76 / 0 10 0 0 0 0 Moses Lake 48 82 52 86 50 82 / 0 0 0 0 0 0 Wenatchee 54 81 57 83 55 80 / 0 0 0 0 0 0 Omak 49 82 52 86 51 80 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...None. ID...None. && $$

779 FXUS66 KPDT 220529 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1029 PM PDT Thu May 21 2026 .KEY MESSAGES... 1. Dry and warm conditions will persist through the week 2. Breezy to windy through the gaps Sunday 3. Pattern shift Sunday will bring chances mountain showers becoming more widespread Monday onwards && .DISCUSSION... Current satellite shows mostly clear skies over the region with a few cumulus clouds beginning to bubble up through portions of central OR. High pressure over the region will keep the region under dry and continued warming conditions through the week with temperatures today lingering in the mid 70s and low 80s (90% probabilities). Models show the upper level ridge to remain over the region through at least Sunday morning ahead of a pattern shift. Temperatures will continue to warm through the period with temperatures peaking Saturday. Raw NBM ensembles show temperatures to be in the upper 70s to low 80s starting tomorrow with 70-90% probabilities. By Saturday temperatures will be in the low to mid 80s with 70-90% probabilities. In office difference calculations from climate shows temperatures to be 5 to 10 degrees above seasonal normal today and tomorrow before reaching 10-15 degrees above normal by Saturday. With the upper level low pressure system expected to arrive Sunday evening, in house model guidance is showing a tightening of the pressure gradients along the Cascades. This will lead to increased winds through the Cascade gaps and along the foothills of the southern Blues. NBM raw ensembles show the sustained winds of near 25 mph through these areas with 60-80% probabilities through the Gorge and Kittas Valley and 20-40% probabilities across the foothills of the southern Blues. Sunday is when the models show the next system will make its way into the PacNW. Deterministic models are in relatively form agreement with a shift in the pattern. However, ensembles clusters show there to be a deviance in the amplitude of the upper level low pressure system. 80% of the ensembles clusters are in agreement with a bit of a deeper trough coming across the region Sunday. With that said, models are showing increased chances of mountain precipitation Sunday as well as increased winds. Models show Sunday night could see some light precipitation over the Cascades before becoming more widespread Monday and Tuesday. Models show upwards of 0.15-0.20 inches of rain across the Blues with 50-60% probabilities and near 0.3-0.4 inches along the Cascades with 40-50% probabilities. With the system, temperatures are expected to drop to the low to mid 70s. 90 && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... VFR conditions and winds less than 10 kts are expected through Friday. && .FIRE WEATHER... Dry and warm conditions will persist through the weekend with a pattern shift expected Sunday evening. Daytime RHs highest over the next three days ahead of the upper level low. RHs Friday will be in the low to mid teens through central OR and the Ochco-John Day highlands. Pockets of low RHs along the southern Blues and in the Basin. Saturday RHs will become more widespread across the region with low RHs across the vast majority of the lower elevations. Sunday is the highest day of concern, especially in the Kittitas Valley where RHs will be in the low to mid 20% and winds will be between 15-25 mph. This puts this area of the region in moderate fire weather concerns. && .Preliminary Point Temps/PoPs... PDT 46 80 50 83 / 0 0 0 0 ALW 50 80 54 83 / 0 0 0 0 PSC 48 85 53 88 / 0 0 0 0 YKM 51 84 55 87 / 0 0 0 0 HRI 48 83 54 85 / 0 0 0 0 ELN 47 78 51 79 / 0 0 0 0 RDM 41 81 45 83 / 0 0 0 0 LGD 42 77 46 82 / 0 0 0 0 GCD 39 80 44 85 / 0 0 0 0 DLS 54 85 56 82 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...None. OR...None. && $$ DISCUSSION...90 AVIATION...77 FIRE WEATHER...90

274 FXUS65 KREV 212201 AFDREV Area Forecast Discussion National Weather Service Reno NV 301 PM PDT Thu May 21 2026 .KEY MESSAGES... * Warmer than normal weather prevails through the weekend with typical afternoon westerly breezes. * Showers and isolated thunderstorms are possible this afternoon with better chances Friday afternoon. * Increasing potential for stronger winds and critical fire weather conditions, showers and storms, and much cooler weather next week. && .DISCUSSION... Warm weather continues today with daytime highs reaching the low 70s and low 80s, which about 5-10F above seasonal averages. Latest satellite obs show cumulus developing along higher terrain, but are struggling to acquire much vertical growth under subsident flow. However, steepening mid-level lapse rates and low-level convergence along the zephyr breeze will support a low to moderate (10-30%) likelihood of showers and isolated thunderstorms later this afternoon across NE California, the E Sierra, and far W Nevada. Stronger showers/storms will be capable of gusty outflow winds up to 40 mph, brief heavy rain and sudden temperature drops, and occasional lightning. The potential for showers and thunderstorms peaks Friday afternoon as moisture quality improves and instability increases. Convection will focus across a similar area as today, but should begin earlier in the afternoon or perhaps in the late morning. Expect similar hazards with Friday`s bout of convection. Moisture is displaced eastward over the holiday weekend, shifting the best potential for afternoon showers and thunderstorms to the near the OR border, the W NV Basin and Range, and Mono County. Temperatures remain warmer than normal through the holiday weekend, when of which daytime highs will be in the mid to upper 70s/80s. Though tempting, be sure to avoid cooling off in lakes, rivers and creeks this holiday weekend as they are still running dangerously cold and swift (water temps in the upper 40s and 50s). A more robust Pacific low is on track to impact the region early next week, increasing the potential for strong/gusty winds, showers/t-storms, and much cooler temperatures. Critical fire weather conditions are increasingly likely Monday afternoon across NW Nevada where gusty winds combine with low daytime humidity (more details in the fire weather section). Still some questions about the Pacific low`s timing, but be prepared for a noticeable change in the weather next week. -Salas && .AVIATION... Showers and isolated thunderstorms will be the main concern today, focusing eastern Sierra terminals where chances are around 10-20%. Showers and storms may drift into KRNO-KCXP-KMEV, but odds are low (less than 10%). Sudden, strong wind shifts, brief heavy rain and MVFR conditions, and lightning are the primary concerns into the evening. Thunderstorm chances increase Friday afternoon across a similar area, posing renewed impacts to aviation interests. Elsewhere, cumulus build-ups may result in mountaintop obscuration in the afternoon. -Salas && .FIRE WEATHER... A critical fire weather environment is increasingly likely to develop Monday afternoon from eastern Lassen County/the Surprise Valley into NW Nevada where strong winds couple with low daytime humidity. There is still some uncertainty in the continuity of receptive fuel beds, but recent fuel intel indicates that live fuel moisture in sagebrush is at record lows and more typical of late June in west-central Nevada. As such, details need to be sorted out but certainly worth close monitoring. -Salas && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$

894 FXUS66 KSTO 211914 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1214 PM PDT Thu May 21 2026 .KEY MESSAGES... - Well-above normal temperatures and areas of Moderate HeatRisk today-Friday, with low chances for isolated mountain showers and thunderstorms. - Increased onshore flow this weekend-Monday combined with low daytime RHs will lead to elevated fire weather conditions in the Valley. - Cooler temperatures expected this weekend and into mid next week, nearing seasonal normals by Tuesday. && .DISCUSSION... ...Today-Friday... The warmest high temperatures of the week are expected today as high pressure riding remains aloft. Highs will be 10 to 20 degrees above normal resulting in areas of Moderate HeatRisk in the Valley. Increased onshore flow will aid in keeping temperatures slightly cooler around the Delta and southern Sacramento Valley. Temperatures trend slightly cooler tomorrow, but will still remain above normal. A weak shortwave develops over Northern California on Friday which will bring chances (15-20%) for isolated mountain showers and thunderstorms during the afternoon/evening hours, with northwesterly flow keeping cells along the crest. ...The Weekend-Wednesday... Cooler temperatures are on track for this weekend and into early next week as broad troughing develops over the region, strengthening onshore flow. High temperatures cool to near- seasonal for mid to late May by Saturday. West-southwesterly winds through the Valley will be breezy through the weekend with gusts 15 to 25 mph. Onshore winds peak on Monday as an upper low digs down from the Pacific Northwest into the vicinity of the Great Basin. Forecast gusts are between 25 and 40 mph, with the strongest gusts expected through the Delta, in the northeastern Sierra foothills, and over the Sierra. Gusty onshore winds combined with Valley min RHs in the teens will lead to elevated fire weather conditions Saturday-Monday, despite gradually improving overnight recoveries. This gradual cooling trend continues into early-mid next week when temperatures could fall a few degrees below normal on Tuesday. A high degree of uncertainty persists on how far east/west the aforementioned upper low will track and the amount of moisture associated with it, which could bring chances for light mountain showers midweek. Forecast confidence will continue to increase as we approach the weekend, so be sure to check back for updates. && .AVIATION... VFR conditions are expected over the next 24 hours. Onshore winds increase after 20Z Thursday, with some gusts up to 15 kts possible through 06z Friday in the Valley. Stronger west-southwest winds 10 to 15 kts with gusts up to 20 kts expected in the Delta through 18z Friday. Onshore winds will continue to be breezy tomorrow. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$

953 FXUS65 KMSO 211824 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 1224 PM MDT Thu May 21 2026 .DISCUSSION... KEY MESSAGES: - Warming and drying trend expected through the weekend. - Cold front Monday-Tuesday may usher in cooler, breezy and unsettled weather for much of next week. Through Friday: Northerly flow and weak atmospheric instability will support isolated convective showers this afternoon, primarily along the Continental Divide. Otherwise, temperatures will remain unseasonably cool across southwest Montana, with highs restricted to the 50s (roughly 10 degrees below normal for Butte). Western Montana will see highs in the 60s, while the lower elevations of north-central Idaho will approach 80 degrees. Friday will feature a warming trend, with afternoon temperatures increasing by 5 to 7 degrees across the Northern Rockies. Scattered showers are expected Friday afternoon and evening across northwest Montana and along the Divide. Impacts will remain limited to brief, localized rainfall and wind gusts up to 25 mph. However, sufficient instability may trigger an isolated thunderstorm within Glacier National Park. This Weekend/Water Safety: A significant warming trend will bring summer-like temperatures to the region by the weekend. With the warm air temperatures, outdoor recreation will likely increase around area lakes and rivers. Please be aware that local waterways continue to run extremely cold due to ongoing mountain snowmelt. Plunging into cold water without acclimatization can induce cold water shock, which drastically alters breathing, heart rate, and blood pressure, creating life- threatening conditions. Always wear a life jacket to stay afloat and exercise caution. For more information on cold water hazards, visit weather.gov/safety/coldwater. Early to Mid-Next Week: By early next week, a Pacific trough will introduce an unsettled weather pattern across the Pacific Northwest, eventually progressing into central Idaho and western Montana. Considerable spread remains among deterministic models regarding the finer synoptic details. Current ensemble cluster analysis for Monday indicates a 61% probability of a slower, milder progression, while the remaining 39% of members favor a faster, cooler, and wetter solution. This trough is expected to eventually cut off and meander over the region, maintaining showery conditions through mid-week. Those with outdoor plans next week should monitor the forecast closely and be prepared with rain gear in the event the wetter solutions materialize. && .AVIATION...Predominantly VFR conditions will prevail across all regional terminals through Friday. Diurnal cumulus development will be common over the higher terrain both this afternoon and Friday afternoon, while valleys remain mostly clear to partly cloudy. Isolated showers are expected near the Continental Divide this afternoon, with shower activity expanding into northwest Montana by Friday afternoon. Sufficient instability may support an isolated thunderstorm near Glacier National Park on Friday afternoon. Expect localized wind gusts of 20-25 knots near any thunderstorm or stronger shower activity. Otherwise, light and diurnally driven winds will continue at all terminal sites. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$

133 FXUS65 KBOI 220529 CCA AFDBOI Area Forecast Discussion National Weather Service Boise ID 1052 PM MDT Thu May 21 2026 .UPDATE...Updated aviation discussion. && .KEY MESSAGES... - Mostly dry with temperatures 10 to 15 degrees above normal for Memorial Day weekend. - Gusty winds arriving on Monday ahead of a cold front, resulting in elevated fire weather conditions. - Much cooler with gusty winds and a chance of showers and thunderstorms Tuesday and Wednesday. && .SHORT TERM /Through Saturday Night/... Issued 220 PM MDT THU MAY 21 2026 A ridge of high pressure will build over the area Friday and Saturday. Temperatures Friday will be about 5 degrees warmer than today, followed by another 5-10 degrees of warming on Saturday as the ridge moves overhead. This will place high temperatures 10-15 degrees above normal, with lower elevations reaching the mid to upper 80s. Conditions will remain dry, except for a 10-20% chance of showers and thunderstorms near the Nevada border as moisture lifts north with the building ridge. Winds will mostly be light, except for breezy conditions in the higher terrain Saturday afternoon. && .LONG TERM /Sunday through Thursday/... Issued 220 PM MDT THU MAY 21 2026 Sunday and Monday see temperatures 10-15 degrees above normal as high pressure sits over the area. Afternoon minimum RHs are dry at 10-30%, increasing with elevation. The warm weather cools down Monday evening as a cold front moves through, part of a larger upper level low that sits over the area for a few days. The cold front brings wind gusts up to 45 mph Monday and Tuesday evenings. While Tuesday will be much cooler, the gusty winds, dry conditions, and warm temperatures support elevated fire weather risks Monday afternoon and evening. Making the forecast even trickier, each afternoon sees a 20-30% chance of thunderstorms through the long term as the low pressure keeps conditions unsettled. Best storm chances move from the NV border Sunday/Monday to Central ID Tuesday and most of SW ID Wednesday and Thursday. Temperatures gradually warm after Tuesday. && .AVIATION /06Z Friday through Saturday/... Issued 1052 PM MDT THU MAY 21 2026 VFR with SCT-BKN high clouds overnight through morning. Surface winds: mostly variable under 10 kt overnight through morning, then W-NW 5-15 kt in the afternoon. KBOI...VFR with scattered high clouds overnight. Surface winds: S-SE 5-10 kt or variable overnight through morning, then NW 7-12 kt in the afternoon. Weekend Outlook...VFR with mostly clear skies throughout the weekend. Winds SE or variable 5-10 kt in the night/morning and W-NW 5-15 kt in the afternoon each day. Isolated afternoon thunderstorms near the NV border each day. && .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 AVIATION.....LC SHORT TERM...ST LONG TERM....JM

468 FXUS65 KLKN 211820 AFDLKN Area Forecast Discussion National Weather Service Elko NV 1120 AM PDT Thu May 21 2026 .KEY MESSAGES... * Warming trend today and Friday * Unseasonably warm Saturday through Memorial Day * Strong, gusty winds expected Tuesday * Chance of valley rain and mountain snow Tuesday afternoon through Wednesday night && .DISCUSSION... (This afternoon through Wednesday) WEATHER PATTERN OVERVIEW: Zonal flow aloft will prevail today and Friday. A ridge of high pressure will build northwestward across the Silver State this weekend into early next week. High temperatures each afternoon Saturday through Memorial Day will be around ten degrees above normal for this time of year. A storm system will impact Northern and Central Nevada Tuesday afternoon through Wednesday night, resulting in a chance of valley rain and mountain snow. Snow levels will start at around 8,000 feet Tuesday afternoon, before dropping to about 7,000 feet Tuesday night. The majority of this precipitation will fall Wednesday. Strong, gusty southwest to west winds are anticipated, mainly in Central Nevada, from 10 AM PDT Tuesday morning until 11 PM PDT Tuesday evening. A Wind Advisory may be required. Blowing dust will reduce visibilities at times. Travel will be difficult, particularly for high profile vehicles. Here are probabilities of maximum wind gusts of 40 mph or higher for select locations in Northern and Central Nevada on Tuesday, May 26th, 2026: Ruth - 75% Eureka - 65% Lund - 60% Round Mountain - 60% Ely - 55% Ruby Lake - 55% West Wendover - 50% Elko - 45% Tonopah - 40% Spring Creek - 25% FORECAST CONFIDENCE & DEVIATIONS: High forecast confidence regarding a warming trend today and Friday. High forecast confidence in unseasonably warm temperatures each afternoon Saturday through Monday. High forecast confidence regarding strong, gusty winds Tuesday. Low forecast confidence in valley rain and mountain snow Tuesday afternoon through Wednesday night. No deviations from the NBM model output. && .AVIATION... VFR conditions will prevail at all terminals through at least the next 24 hours. Northwest to north wind gusts near 20 knots are expected this afternoon into this evening. && .FIRE WEATHER... Minimal thunderstorm chances in parts of Central Nevada both Friday afternoon and Saturday afternoon. Thunderstorm chances increase in Northern Elko County Sunday afternoon. Strong, gusty southwest to west winds anticipated Tuesday associated with the passage of a cold front. High temperatures Tuesday afternoon will be around ten degrees cooler than Monday afternoon. && .LKN Watches/Warnings/Advisories... None. && $$ 87