414 FXUS66 KSEW 210237 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 737 PM PDT Wed May 20 2026 .SYNOPSIS...Upper level ridge centered offshore building tonight and remaining in place into Friday. The ridge will weaken Saturday. Surface high pressure out ahead of an approaching front will increase the low level onshore flow Sunday for cloudier and cooler weather. Next system arriving Memorial Day. Another upper level ridge will build into British Columbia Tuesday or Wednesday. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... No updates to forecast are anticipated this evening. Previous discussion follows with update to aviation portion. 27 Satellite imagery shows some strato cumulus banked up again the Central and Southern cascades this afternoon. Another area of stratus over the Olympics with mostly clear skies elsewhere. Temperatures at 3 pm/22z were in the mid 50s to mid 60s. Low level onshore flow decreasing overnight with upper level ridge building offshore. By sunrise light flow in the lower levels with patchy fog developing in the fog prone locations like the Lower Chehalis and Snohomish river valleys. The fog will be shallow and dissipate soon after sunrise. Lows in the 40s. Upper level ridge building offshore, temperatures warming aloft and light flow in the lower levels will give Western Washington a warmer day Thursday. Patchy morning fog and stratus will be gone by mid morning. Highs in the mid to upper 60s coast and 70s to lower 80s inland. Not much change in the pattern Thursday night into Friday. Low level onshore flow a little stronger with stratus developing along the coast spreading inland in the early morning hours. The marine layer will be shallow and not get east of Puget Sound. Under sunny skies highs again in the 70s to lower 80s inland. Morning clouds keeping highs in the 60s along the coast. Lows Thursday night in the mid 40s to lower 50s. Upper level ridge offshore weakening Friday night with increasing low level onshore flow. Stratus making it into the interior around 12z. Lows in the mid 40s to lower 50s. Minor HeatRisk both Thursday and Friday. Felton && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... First two days of the holiday weekend look dry. Stratus dissipating back to the coast Saturday. Minor HeatRisk continues. Upper level ridge out ahead of an approaching front will increase the onshore flow Sunday for more cloud cover and cooler temperatures. Models having a hard time with the timing of the next system. Operational runs hold off rain over the interior until late Monday. Ensembles show this solution is in the minority with a majority of the ensembles with a faster eastward progress of the front. This is in the current forecast with a chance of rain Sunday night and rain spreading over the area on Memorial Day. Highs in the 60s and lower 70s Saturday lowering to the mid 50s to lower 60s Monday. && .AVIATION... VFR conditions in place over W WA this evening with scattered high clouds in place. These conditions are expected to prevail for most through the TAF period. The exception will be the Pacific coast where the marine layer will reform overnight into Thursday morning. Latest satellite imagery is already starting to show a bank of stratus just off the coast. These stratus should remain mostly confined to the coastline, through there`s a low chance it could get as far east as SHN and CLM (15-25% chance). Elsewhere should remain clear (less than 15% chance of MVFR or lower). Mostly clear skies will continue tomorrow with cirrus clouds streaming overhead. Surface winds NW 5-10 kt will ease after sunset, becoming light NE or variable overnight. Winds once again switch to NW 5-10 kt during the day Thursday. KSEA...VFR conditions through the TAF period with high clouds overhead. Winds NW 8-10 kt becoming NE around 5 kt overnight. Winds Thursday return to NW 5-10 kt. 62/18 && .MARINE... High pressure will remain situated offshore through the rest of the week, keeping north/northwest winds prevailing across the coastal waters. Diurnally driven pushes through the Strait of Juan de Fuca each afternoon are expected, though the weakest day looks to be Thursday before the winds reach back up to small craft advisory thresholds. The strongest winds will remain farther offshore, but out near the 60 NM border winds may reach up to 20-25 kt at times. Small Craft conditions look more probable for the outer coastal waters Friday night into Saturday as high pressure edges closer onshore. This will also allow for stronger onshore flow, with the strongest being Saturday which has the potential (30-50%) to reach gale force through the Strait of Juan de Fuca. A frontal system remains on track to traverse the area on Monday, which will bring more widespread small craft conditions to most of the coastal and interior waters. Seas remain around 6 to 8 ft through Friday. Seas look to pick up and steepen with the winds late Friday into Saturday and reach near 10 ft through the outer coastal waters. Seas then ease on Sunday before the incoming low pushes seas up to 10 to 13 ft Monday into Tuesday. 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 11 PM PDT this evening for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. && $$

996 FXUS66 KPQR 202118 AFDPQR Area Forecast Discussion National Weather Service Portland OR 218 PM PDT Wed May 20 2026 .SYNOPSIS...Dry and warm weather is expected across the region through the weekend with high pressure over the Northeast Pacific spreading east over the Pacific NW. Rain and cooler temperatures return to the area late Sunday into early next week, which could impact any outdoor Memorial Day plans. && .DISCUSSION...Wednesday afternoon through Tuesday...Visible satellite imagery early Wednesday afternoon shows mostly clear skies across NW OR with dissipating stratus across SW WA as high pressure over the eastern Pacific expands east over the West Coast. Temperatures today will be similar to yesterday with inland highs in the low 70s and mid 50s to low 60s along the coast. Dry weather continues through the weekend as the area generally remains under high pressure. Winds turn weakly offshore by Thursday morning as the high pressure peaks over the area and a weak surface thermal trough builds along the N CA and S OR coast. Some locations in the Willamette Valley may see stratus again Thursday morning, but drier air from the offshore winds will limit widespread expansion. This pattern continues into Friday, allowing temperatures to warm to around 10-15 degrees above daily normals for Thursday and Friday. Expect daytime temperatures to peak in the low to mid 80s for inland valleys and 60s along the coast. There is a 35-45% chance for Moderate Heat Risk in the Portland metro area and Tualatin Valley and a 10-25% chance in the rest of the interior valleys on Thursday. These chances fall to 5-15% on Friday. A weather system pushing through Canada over the weekend will break down the high pressure over the PacNW and lead to more zonal flow. Temperatures will fall a few degrees but still remain above normal, peaking in the mid to upper 70s both Saturday and Sunday for inland valleys. There is much higher agreement that Sunday will remain mainly dry and warm, though could begin to see increasing cloud cover ahead of an approaching weather system. About 85-90% of ensemble members from the GFS, Euro, and Canadian ensembles indicate the weather system will push into the PacNW sometime late Sunday night into Monday bringing shower chances through Tuesday. Some uncertainty still remains in 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. The NBM 90th percentile (only 10% chance of occurring) for 48 hour rain totals through 5 AM Wednesday indicates 0.5-0.95 inch for the Willamette Valley, 0.8-1.6 inches along the coast and Coast Range, and 1-1.5 inches along the Cascades. When looking at the probability of reaching or exceeding 0.5 inch for the same time period, there`s a 10-20% chance for the Willamette Valley, 20-40% for the Portland and Vancouver metro area and SW WA lowlands, 30-60% for the coast and Coast Range, and 45-60% for the Cascades. Temperatures will also drop substantially for Monday and Tuesday with high temperatures in the mid 60s for the interior lowlands. -03 && .AVIATION...Satellite imagery as of late Wednesday morning depicts MVFR stratus continuing to break out across the region. By 22-23z Wed, an upper level ridge offshore will support a return of northerly winds and VFR conditions with a FEW/SCT high clouds across the region, lasting through the end of the TAF period. North-northwesterly gusts up to 20-25 kt along the coast (strongest near KONP) through 03-04z Thu. For the Willamette Valley, north winds generally 10-15 kt except under 10 kt across the Portland/Vancouver Metro Area. Winds ease overnight. There remains a 15-30% chance for MVFR stratus returning along the coast at any given hour between 12-18z Thu. Otherwise, VFR conditions prevail. KPDX AND APPROACHES...VFR conditions through the TAF period. Northwesterly winds 5-10 kt this afternoon, weakening below 5 kt tonight. -10 && .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 remain in effect for the waters south of Cape Falcon through early Friday morning for northerly wind gusts up to 25 kt. Will note that there may be a brief lull in the winds between 5-11 AM Thursday for the inner waters zones (from the coast to 10 NM offshore) before increasing again tomorrow afternoon. For the outer waters north of Cape Falcon, Small Craft Advisories remain are in effect through tonight, and again Thursday evening. A Small Craft Advisory has also been issued for the Columbia River Bar between 7 AM-12 PM Thursday for a strong ebb current bringing seas up to 7 ft along the Main Channel. Seas 6 to 9 feet expected across all waters through this weekend. The summer-like pattern is likely to break down Sunday night as a front approaches the waters and returns southwesterly winds. -10/DH && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory from 7 AM to noon PDT Thursday for PZZ210. Small Craft Advisory until 5 AM PDT Friday for PZZ252-272. Small Craft Advisory until 5 AM PDT Friday for PZZ253-273. Small Craft Advisory until 5 AM PDT Thursday for PZZ271. Small Craft Advisory from 5 PM Thursday to 5 AM PDT Friday for PZZ271. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

506 FXUS66 KMFR 202339 AFDMFR Area Forecast Discussion National Weather Service Medford OR 439 PM PDT Wed May 20 2026 .Updated AVIATION Discussion... && .AVIATION...21/00Z TAFs...VFR prevails area wide currently. Aside from gusty N-NW winds closer to the coast (20-30 kt), excellent flying conditions will continue this afternoon/evening. Then, expect marine low clouds/fog to develop along the coast north of Cape Blanco and also the coastal valleys (Coquille, Umpqua). This will result in IFR/MVFR ceilings through early Thursday morning at North Bend. Some clouds could also form in the Umpqua Basin around Roseburg, but these will be patchy and may avoid the terminal. Right now, probability of an MVFR ceiling at Roseburg is 15-20%. For Medford and Klamath Falls (and elsewhere), expect VFR to prevail for the next 24 hours. -Spilde && .PREV DISCUSSION... /Issued 211 PM PDT Wed May 20 2026/ DISCUSSION (Today through Tuesday)... Key Points: * Minor/low impacts continue the next several days - Well above normal temperatures start tomorrow - Temperatures closer to normal through early next week * No strong signal for precipitation until early next week - Small indications for isolated showers this weekend - Mainly for northern California - Could have isolated thunder if anything develops * Elevated fire weather concerns this week - Combination of dry, breezy, and warm temperatures - Fuels fortunately keeping the overall fire threat low/moderate Further Details: A ridge of high pressure continues its position over the Pacific Ocean through the next several days. As a result, an overall dry and stable airmass is likely to persist through Friday night/Saturday morning. However, this does start to break down/move west by Saturday. 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 convection starting Saturday afternoon as we reach convective temperatures. Upper level features are less than desirable for high confidence, but there is enough overlap of parameters to warrant at least a mention of showers/thunderstorms. CAMs are indicating this potential as well Saturday afternoon for northern California and eastside areas. Currently, the NBM has no mention of this potential (<10%), and therefore the current forecast does not reflect this potential. As CAMs start to get weighted into the NBM, we may see these chances reflected in PoPs and subsequent forecast. With the ridge of high pressure displaced out of the region, a 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, overall height fields, and hence coverage of precipitation chances. The takeaway here is there is at least a better signal for widespread precipitation than we have seen in recent weeks. Confidence is increasing for precipitation between Monday and Wednesday but details are still unclear. As we maintain the dry airmass and breezy afternoons, there will be at least an elevated threat for fire weather conditions each day. However, fuel conditions per fire agencies reveal the overall fire weather threat will remain 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. 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 MARINE...Updated 200 PM PDT Wednesday, May 20, 2026...A thermal trough will bring 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 && .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. && $$

685 FXUS66 KEKA 202043 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 143 PM PDT Wed May 20 2026 .SYNOPSIS...Clear and dry conditions will remain through the week with a warming trend through Thursday. A weak and shallow marine layer will hang along shore. Temperatures will trend lower this weekend weekend. .KEY MESSAGES... - Winds will trend lighter Thursday and much lighter through the holiday weekend -A brief chance for very light rainfall or light drizzle early next week -Chance for morning coastal stratus and fog will persist, with increasing opportunity for longer duration stratus and fog through the weekend -Conditions will warm through Thursday with highs in the interior peaking near 90. && .DISCUSSION...The stratus quickly cleared out through midday. Expecting a similar evolution Thursday, with shallow stratus and fog giving way to ample sunshine. A ridge of high pressure is building in over the region. This will increase daytime highs Thursday, creating some minor heatrisk for the interior, with temperatures getting into the low to mid 90s. Winds will trend lower Thursday and especially through the weekend. A weak shortwave disturbance will push through from the north late Thursday and Friday. Some ensembles are generating shower activity over east Trinity Friday afternoon. These types of setups usually bare watching for thunderstorm development; however, The mid to lower level environment will be very dry and this will inhibit convective development. There is up to a 10% chance for a thunderstorm over the Yolla Bolly area Friday afternoon. A couple light showers may form otherwise, but no precipitation would likely reach the ground. .EXTENDED DISCUSSION...(Saturday through Tuesday)...High pressure weakens over the weekend, and daytime highs will trend cooler. The combination of light northwesterly flow and a shallow marine layer will present a setup for more persistent coastal stratus with some fog likely through the weekend. Most ensemble members continue to show a trough dipping across the Pacific Northwest early next week. Very light showers to light drizzle will be possible. There is currently 20 to 35% chance for 0.1 (wetting rainfall) over northern Humboldt through Del Norte. This will be dependent of how far south the low tracks, and if it ends up farther north, little to no rainfall will fall through the already dry antecedent environment. && .AVIATION...A thin band of stratus in between Patrick`s Point and the Eel River Delta is slowly eroding away. These IFR conditions are expected to become VFR like the rest of the the forecast area. Gusty NW winds along the coast are expected, increasing the likelihood for some bumps due to weak Low Level Turbulence. There are growing chances for low, IFR ceilings returning to the North Coast tonight from 06Z through 15Z. Forecast confidence in FG is growing as high pressure build, compressing the marine layer. Clearing to VFR is expected again tomorrow by 19Z (+/-1hr). Inland areas remain VFR with breezy afternoon winds. Cumulus is forecasted to build near higher terrain in Trinity and Mendcino counties; no rain showers are forecasted. DS && .MARINE...Buoy observations are reporting nearshore gusts near 20kts and steep, short period waves dominating the sea state. In the outer waters, Gale Force gusts are forecasted and model data is upholding is claim with a 4mb pressure differential modeled between 10nm to 60nm out to sea. While the pressure gradient driving these winds will shift slightly over the next few days, strong winds with near-gale force gusts and short period seas will persist. High resolution ensemble model data is showing high (>80%) confidence for gale force winds in the northern outer waters. The chance for Gale force winds in the southern waters are slightly less likely at 30 - 50%. The synoptic weather pattern shifts this weekend as a storm in the gulf of alaska weakens the pacific high pressure center. This shift will result in a weakening of the surface pressure gradient and therefore, weaker winds. Significant wave heights will lower as a result, possibly under 5ft by Monday afternoon. Looking into next week, winds remain calm and a westerly mid-period swell enters the waters. DS && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 10 AM PDT Thursday for PZZ450- 455. Gale Warning until 9 PM PDT Friday for PZZ470. Gale Warning until 10 AM PDT Thursday 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

106 FXUS66 KMTR 202342 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 442 PM PDT Wed May 20 2026 ...New AVIATION, MARINE... .KEY MESSAGES... Updated at 256 PM PDT Wed May 20 2026 - Diurnally driven winds, with onshore winds during the afternoon and early evening. - Warm and dry weather through Thursday leads to elevated fire weather concerns for the interior Bay Area and Central Coast. - Above normal temperatures continue through midweek with seasonal temperatures returning by the upcoming weekend. && .SHORT TERM... Issued at 256 PM PDT Wed May 20 2026 (This evening through Thursday) A deeper marine layer, ~750 ft in depth, and stratus has resulted in cooler conditions near the coast so far this afternoon. Temperatures there are in the upper 50s to mid 60s. However, inland areas are well on their way to the upper 80s to lower 90s. Breezy onshore winds are likely to increase this afternoon and peak early in the evening with gusts up to 30 mph before easing overnight. With low clouds hovering near and along the coast, expecting a greater potential for stratus to spread inland through the Golden Gate and into the Salinas Valley tonight and into Thursday morning. For Thursday afternoon, expecting little change compared to today with mostly sunny sky conditions across the interior. The higher elevations above 1000 feet will remain critically dry (10-20%) with poor overnight (less than 30% in spots) humidity recoveries. && .LONG TERM... Issued at 256 PM PDT Wed May 20 2026 (Thursday night through next Tuesday) Temperatures on Friday will heavily depend on how deep the marine layer becomes as the Bay Area and Central Coast remains between the high pressure to the west and troughing to the east. The stronger the marine layer, the less time there is for daytime heating (especially where the stratus hangs around for much of the day). Temperatures gradually cool over the weekend as troughing develops to the north. Then, cooler and potentially unsettled weather returns for early next week as the aforementioned trough drops southward across the West Coast. As such, the 6-10 Day Temperature Outlook from the CPC indicates temperatures leaning below average with the same outlook for precipitation leaning above. Again, above average for this time of year may bring either drizzle and/or very light rain to the region as we go deeper into our "dry season". All that said, please keep up to date with the latest forecast information over the next few days. && .AVIATION... (00Z TAFS) Issued at 441 PM PDT Wed May 20 2026 Currently VFR at all terminals with the exception of IFR at HAF. Moderate to high confidence on IFR conditions at HAF, MRY, and SNS with VFR elsewhere tonight. Diurnal winds will prevail. Vicinity of SFO...Currently MVFR with gusty northwesterly flow and haze. High confidence in VFR and diurnal winds prevailing through the TAF period; however, FEW/SCT IFR clouds will be possible on the north side of the terminal if stratus sneaks through the Golden Gate Gap. SFO Bridge Approach...The San Mateo Bridge Approach has a lower probability of IFR conditions. Monterey Bay Terminals...Currently VFR with northwesterly flow at MRY and MVFR with northwesterly flow and haze at SNS. Moderate confidence on IFR conditions developing at the terminals tonight. VFR is expected by late morning with IFR stratus sticking close to the coast during the day. && .MARINE... (Tonight through next Monday) Issued at 441 PM PDT Wed May 20 2026 Hazardous conditions for small craft will continue through Thursday for the northern outers due to rough seas and strong northerly breezes. Elsewhere, moderate northwesterly breezes and moderate seas will prevail. Conditions improve into the weekend as seas and northwesterly breezes become moderate. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 3 PM PDT Thursday 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

114 FXUS66 KOTX 210022 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 522 PM PDT Wed May 20 2026 .KEY MESSAGES... - 10-30% chance of pop up showers and isolated thunderstorms northeastern WA and north Idaho Wednesday afternoon. - Conditions trend drier and warmer through the workweek regionwide, with periodic breezy winds for the Cascades and central WA. - 90% chance for a cooling trend into early next week with chances for precipitation and breezy conditions. && .SYNOPSIS... Showers with isolated thunderstorms will continue Wednesday afternoon in east Washington and north Idaho. Precipitation chances decrease and afternoon highs trend warmer through the workweek, climbing into the high 70s and 80s by Friday and continuing through the weekend. Breezy winds are expected at times through the Cascade gaps and across the western Columbia Basin. There is high confidence for cooler and unsettled conditions to return early next week. && .DISCUSSION... This afternoon through Sunday: The Inland NW will remain in a northerly flow through the next couple days, before a ridge builds in and a more zonal flow develops. For the rest of today into this evening a shortwave disturbance will continue to drop south across the eastern WA and ID. It will encounter some instability, with CAPE values between 100-200 J/kg focused especially over Idaho and southeast WA, along with lapse rates between 8.5-9.0 C/km in the 700-500mb layer. A cumulus field has built up over with the heating of the day. There have been some isolated showers/t-storms around Idaho, but the shortwave and instability interact these are projected allow them to increase in coverage. The best chances will remain over Idaho and southeast WA, but some could also develop over northeast WA. A few ridge-top showers are possible in the higher Cascades. All of this activity will migrate toward the southeastern CWA through the evening and wane heading into the overnight. A breezy northerly flow will continue this afternoon to early evening before starting to abate after 8-10 PM. Strongest winds will be near the Cascades and central WA with gusts of 15-30 mph possible. Lows tonight will be largely be in the 40s to low 50s, but some middle to upper 30s are forecast in the northern valleys where some localized frost pockets are possible. Heading into Thursday to Sunday, the forecast is dry with variable cloud cover. The more notable cloud cover will be Thursday afternoon/early evening when a secondary upper shortwave moves by, but at this time it is not expected to produce precipitation. That will be monitored. Any precipitation chances Friday into Sunday are forecast to be around the fringes of the CWA. Wind will start to increase again later Saturday into Sunday as the next system approaches, with the strongest winds near the Cascades to central WA in a westerly flow. Gusts of 15 to 30 mph are possible, strongest toward the Cascades to Upper Columbia Basin. Temperatures warm into the upper 60s and 70s Thursday, with some low 80s in the deeper basin; Friday to Sunday will see more 70s and 80s. Saturday looks like the warmest day with some areas pushing near 90 in the deeper basin on Saturday. Lows will be in the 40s and 50s. Sunday night through Wednesday: A low pressure system moves toward the region and migrates inland through the middle of next week. Ensembles are still coming together on the precise evolution of the low, with some bringing a more progressive low into the area and others that are slower; they also vary on precise track. What does have confidence is increase clouds and at least a chance of rain. The first rain chances come to the Cascade crest Sunday night, then the risk expands out over much of the area Monday to Wednesday. It is possible there could be some moderate rain amounts, but with the model uncertainty confidence in that is low. Right now the best chance of wetting rain is around the mountains on Monday at around 30-50%, while the lowlands have around at 10-30% chance. So rain is in the forecast for Memorial Day. There is some risk for t-storms each day, but right now the risk around 10%; so not high enough to show up in the official forecast yet. Winds will remain breezy through this period, with the strong winds right now forecast for Monday with gusts of 15-30 mph, once again strongest near the Cascades and central WA. As for temperatures, a general cooling trend if forecast but precise numbers have low confidence. Ensembles show at 10-15 degree spread between the 25th and 75th percentiles Monday to Wednesday (up to 25 degree difference between the 5th and 95th percentiles). The forecast calls for highs in the 60s and 70s, with Tuesday being the coolest day with mostly 60s. Lows are forecast to be in the 40s, with a few lower 50s Monday morning and some upper 30s in the northern valleys Tuesday and Wednesday morning. Expect these numbers to be fine-tuned as we get closer. /Solveig && .AVIATION... 00Z TAFs: VFR conditions expected through the period. Showers and isolated thunderstorms will spark across eastern Washington and Idaho through the early evening with breezy outflow gusts 20 to 30 knots. Any thunderstorm chances will wane be 02Z. Winds will be calming overnight. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in VFR conditions the next 24 hours. There is low confidence in any showers or thunderstorms moving over a TAF sites. ----------------------- 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 43 71 46 76 48 79 / 0 0 0 0 0 0 Coeur d`Alene 41 70 46 74 48 77 / 10 0 0 0 0 0 Pullman 40 68 44 73 46 76 / 20 0 0 0 0 0 Lewiston 46 74 48 79 50 83 / 10 0 0 0 0 0 Colville 36 75 42 79 44 81 / 0 0 0 0 0 0 Sandpoint 40 69 45 74 47 76 / 10 0 0 0 0 0 Kellogg 40 71 45 75 47 78 / 30 0 0 0 0 0 Moses Lake 47 78 48 82 52 85 / 0 0 0 0 0 0 Wenatchee 52 78 54 82 57 83 / 0 0 0 0 0 0 Omak 46 78 49 82 53 85 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...None. ID...None. && $$

027 FXUS66 KPDT 202314 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 414 PM PDT Wed May 20 2026 .KEY MESSAGES... - Dry conditions will continue through early next week. - Warming trend continues through the weekend. - Breezier/wetter conditions early next week with a cold frontal passage. && .DISCUSSION... A ridge will be situated just off the coast of the PacNW, bringing subsidence across the region. Temperatures will continue to trend warmer as a result through the weekend, where highs will warm to the mid to high 80s by Saturday afternoon. HeatRisk values are limited to 1 across the region which will have a chance to affect the most susceptible population who have no access to cooling or hydration. A pattern change will emerge going into Monday & Tuesday as the upper level ridge moves east. At the same time, a trough will dig down from British Colombia into the PacNW, bringing unstable wetter conditions and ending the warm trend we will see through this week. Majority of the clusters (86 percent of members) paint a similar pattern of broad light to moderate showers across the region through days 5-7. The biggest struggle the clusters are facing is the timing of the trough approaching the area. An accompanied cold front will pass through Monday, bringing tight pressure gradients across the region. This will result in stronger, breezier winds across the region with no anticipated wind highlights out of this system. However, strong westerly winds will return just preceding the cold front bringing strong, breezy conditions across places like the Kittitas Valley (60 to 80 percent chance). && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... VFR conditions will persist through the forecast period. CIGs remain FEW/SCT to SKC through the period with mostly light winds under 10 kts. DLS/BDN is gusting to near 15 kts and will decrease after 6Z and 9Z respectively. 90 && .Preliminary Point Temps/PoPs... PDT 45 75 47 80 / 0 0 0 0 ALW 48 76 50 80 / 0 0 0 0 PSC 50 80 49 85 / 0 0 0 0 YKM 49 80 51 85 / 0 0 0 0 HRI 48 79 48 83 / 0 0 0 0 ELN 44 75 47 79 / 0 0 0 0 RDM 39 77 41 82 / 0 0 0 0 LGD 41 73 42 78 / 0 0 0 0 GCD 39 75 39 81 / 0 0 0 0 DLS 50 82 53 86 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...None. OR...None. && $$ DISCUSSION...95 AVIATION...90

444 FXUS65 KREV 202016 AFDREV Area Forecast Discussion National Weather Service Reno NV 116 PM PDT Wed May 20 2026 .KEY MESSAGES... * Warmer than normal weather prevails through the weekend with breezy north winds Thursday. * Potential for showers and thunderstorms increases Thursday into the holiday weekend. * A Pacific storm may result in a period of cooler, more unsettled weather early next week. && .DISCUSSION... A warm and dry pattern remains in place today with temperatures warming to near 70F and 80F this afternoon. Further warming is expected through the weekend when daytime highs reach the upper 70s and 80s for Sierra communities and NE/W NV valleys, respectively. Increased north breezes are also possible Thursday in the wake of a dry frontal passage, but impacts should be minimal. Shower and thunderstorm potential increases Thursday into the weekend as Pacific moisture overspreads warming surface temperatures each afternoon. Weak instability and subsident flow should limit spatial coverage during this sequence, favoring the higher Sierra/Sierra Front terrain and southeast-adjacent areas for showers and thunderstorms. Friday appears to be the most favorable day for thunderstorms (10-20% odds) as a weak shortwave trough passes overhead. Dry SW flow displaces Pacific moisture to the northeast, shifting best shower/t-storm potential to the OR border, the W NV Basin and Range, and Mono County for the holiday weekend. Be sure to make your holiday plans accordingly, and ensure you have ways of receiving weather alerts if recreating outdoors. Ensembles continue to hint at a stronger Pacific storm impacting the region early next week, which may result in cooler, more unsettled weather. However, confidence is low on the track and timing of this storm, so details are TBD for now. -Salas && .AVIATION... Widespread VFR conditions and light breezes prevail today. Shower and thunderstorm chances increase Thursday and Friday, with best chances (10-20%) at KTRK-KTVL-KMMH. Otherwise, expect increasing cumulus in the afternoons, which may result in mountain obscurations. -Salas && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$

113 FXUS66 KSTO 201802 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1102 AM PDT Wed May 20 2026 .KEY MESSAGES... - Well-above normal temperatures, with areas of Moderate HeatRisk today-Friday. - Chances (10-20%) for isolated mountain showers and thunderstorms Friday afternoon. - Cooler, breezier weather by the weekend; strongest west-southwest winds in the Delta and vicinity locations. && .DISCUSSION... ...Today-Friday... Heights continue to rise as ridging builds off the Pacific Northwest coast, resulting in well-above normal temperatures today through Friday. High temperatures will be 10 to 20 degrees above normal today-Thursday, with widespread Moderate HeatRisk. Warmest temperatures, into the mid to upper 90s in the Valley, are anticipated on Thursday before gradually cooling into the weekend. Delta breeze influence will aid in relief from the heat in the vicinity Delta, keeping highs in the mid 80s to low 90s. Meanwhile Valley highs will be in the mid to upper 90s, with highs in the 80s in the foothills and mid 60s to mid 70s in the mountains. Additionally, weak troughing and attendant moisture over the mountains will lead to a 10-20% chance of isolated showers/thunderstorms Friday afternoon. Latest guidance depicts shower/thunderstorm activity setting up along the crest of both the Sierra and Coastal Range. ...The Weekend-Tuesday... Cooler temperatures are on track for this weekend and into early next week as broad troughing builds over the region, strengthening onshore flow. High temperatures cool to near-seasonal for mid to late May by Saturday. Onshore flow will steadily increase through the weekend, peaking on Monday with west to south gusts 20 to 30 mph in the Sacramento Valley/Delta. More uncertainty appears in the ensembles and clusters regarding the synoptic pattern Tuesday onward. The majority are in agreement showing a trough descending from the Pacific Northwest into the region, but diverge on it`s track and strength. This would mean the difference between increased onshore flow or north winds developing in the Valley mid next week. && .AVIATION... VFR conditions are expected over the next 24 hours. Light and variable winds less than 10 kts expected through the period. West- southwesterly winds increase through the Delta after 22Z Wednesday with gusts 15 to 20 kts at times through 06Z Thursday. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$

423 FXUS65 KMSO 202013 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 213 PM MDT Wed May 20 2026 .DISCUSSION... KEY MESSAGES: - Disturbance bringing widespread showers and thunderstorms across western Montana this afternoon and tonight. - Ridge of high pressure causing a warming and drying trend over the Northern Rockies this weekend. - Cold front expected Monday/Tuesday time frame with significant low pressure system impacting the region through much of the week. A low pressure system will be dropping southward out of central Canada this afternoon through the overnight hours. This system will push a backdoor cold front across the region. The dynamics associated with this disturbance will cause numerous showers along with scattered thunderstorms this afternoon across northwest Montana. Then the shower activity will shift southward across western Montana this afternoon through the overnight hours. These showers will be capable of producing moderate to heavy rainfall with most locations across western Montana receiving between 0.1 to 0.5 inch of rainfall by Thursday morning. North central Idaho and Lemhi county is anticipated to miss out of the majority of this precipitation. Snow levels are expected to hover around 6000 feet during the passage of this feature. McDonald and Homestake passes along with areas around Georgetown Lake could receive up to 2 inches of new snow, but impacts to area roadways will be minimal. A ridge of high pressure will be building over the region Friday into the weekend causing a warming and drying trend. The majority of the valleys will be in the 70s by Saturday with the low valleys of north central Idaho approaching the 90 mark. The long range models are showing a significant low pressure system moving into the Pacific Northwest during the first part of next week. The general consensus has a cold front pushing across the Northern Rockies sometime between Monday into Tuesday. Warm and dry conditions along with gusty winds ahead of the front could create critical fire weather conditions on Monday afternoon for southwest Montana. The low pressure system will cause cooler and active weather for the region through much of next week. && .AVIATION...Radar returns, ASOS observations, and spotter reports this afternoon indicate thunderstorms producing half-inch hail, gusty winds to about 20 knots, and frequent lightning over northwest Montana including KGPI. Convection will continue through this afternoon, with instability migrating south to include KMSO through about 21/0200Z. Expect newly developed storms to have similar characteristics as those affecting northwest Montana. Convective activity will taper off this evening, but chances for rain will continue into early Thursday morning. Showers will have the potential to decrease visibility and obscure terrain across the Northern Rockies airspace. A gradual clearing will take place on Thursday, but not before there are some chances for fog in the early hours at KGPI and KMSO. Confidence on fog was too low to include in 20/1800Z TAF issuance. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$

747 FXUS65 KBOI 210016 AFDBOI Area Forecast Discussion National Weather Service Boise ID 616 PM MDT Wed May 20 2026 .UPDATE...Updated aviation discussion. && .KEY MESSAGES... - Mostly dry with temperatures warming through Friday. Breezy conditions tonight into Thursday. - Well above normal temperatures over Memorial Day Weekend. Gusty winds and a few mountain showers on Memorial Day. - Turning cooler with gusty winds and an increasing chance of precipitation starting Tuesday. && .SHORT TERM /Through Friday Night/... Issued 239 PM MDT WED MAY 20 2026 An upper level trough will dive south across eastern Idaho tonight into Thursday. Aside from isolated to scattered showers and thunderstorms across the central Idaho mountains tonight, our area will remain dry. The trough will push a weak cold front across our area tonight into Thursday, bringing breezy conditions. Wind gusts of 25-40 mph will develop between Baker City and Ontario this evening along the front, with breezy conditions spreading into southern Idaho overnight. The strongest gusts on Thursday will be along and south of the Snake River with gusts 25-40 mph, and generally 15-25 mph elsewhere. Temperatures Thursday will remain nearly steady from today, or near normal. Temperatures will warm about 5 degrees on Friday as a ridge over the eastern Pacific starts to move inland. Winds will be much lighter on Friday. && .LONG TERM /Saturday through Wednesday/... Issued 239 PM MDT WED MAY 20 2026 Warm and dry weather will continue through Memorial Day with temperatures running 10 to 15 degrees above normal. Lower valley locations will see temperatures in the upper 80s and low 90s on Sunday and Monday. Windy conditions are likely to develop in Oregon on Monday afternoon ahead of a strong cold front that is now forecast to pass through the area on Tuesday. Very windy conditions are likely to spread into Idaho on Tuesday with much colder air moving in behind the cold front. The upper level trough driving the cold front is likely to evolve into a closed low by Wednesday over southern Idaho bringing cool and showery weather to the area with snow levels coming down to around 5000 to 6000 feet. && .AVIATION /00Z Thursday through Friday/... Issued 608 PM MDT WED MAY 20 2026 VFR, with SCT-BKN cumulus and high clouds this evening. Isolated showers and thunderstorms will continue over the central ID mountains NE of KMYL this evening. Surface winds: NW-N 10-15 kt with gusts up to 25 kt over most areas this evening, then lowering to 6-12 kt after sunset. Period of strong NW gusts 25-30 kt over KBKE and KONO this evening until midnight. Winds aloft at 10kft: NW 20 to 30 kt. KBOI...VFR with few to scattered high clouds this evening. Surface winds: NW 10-15 kt with gusts up to 25 kt this evening, lowering down to 6-11 kt after sunset. && .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.....JY SHORT TERM...ST LONG TERM....JB

140 FXUS65 KLKN 202013 AFDLKN Area Forecast Discussion National Weather Service Elko NV 113 PM PDT Wed May 20 2026 .KEY MESSAGES... * Warming trend Wednesday through Sunday * High temperatures throughout Northern and Central Nevada Sunday afternoon about ten degrees above normal for this time of year * Next round of weather expected Tuesday with a cold front from the north, bringing returning chances for precipitation and cooler temperatures * Strong winds return over Nevada Tuesday afternoon from a passing cold front && .DISCUSSION... (This afternoon through next Wednesday) WEATHER PATTERN OVERVIEW: Quiet weather conditions with some breezy afternoon winds today through Monday. Temperatures will gradually warm each day with high temperatures reaching up to 10 degrees above normal by Sunday and Monday. Models are showing a buildup of moisture across Nevada due to mid-level moisture over the state. This will cause afternoon clouds to form to give partly cloudy conditions. By Sunday, models are showing a slight buildup of moisture across northeastern Nevada that may lead to increasing clouds with the low potential for some isolated showers across Jarbidge Wilderness Area. Probabilities are low at this time as the buildup in moisture happens for a short period in the afternoon with a 30% chance of seeing up to 0.04 inches of rain. By Tuesday, models are showing the next round of weather expected to impact Nevada as a low pressure system over the northwest will push into the silver state, bringing returning chances for precipitation and much cooler temperatures. Temperatures will begin to drop by Tuesday morning over northwestern Nevada, making high temperatures reach into the 60s in areas such as Denio, while the rest of the region will be just slightly above normal in the 70s. Probabilities for precipitation is low at this time with chances between 15-25% across the region, much of the precipitation will start from the northwest moving southeast, producing light accumulations of valley rain up to 0.05-0.1 inches of rain. Snow is expected to stay in the mountains as snow levels are expected to drop below 8000 feet, and remain above 7000 feet during the event. High winds expected from the passing front in the afternoon with increasing probabilities of wind gusts reaching up to 30-45 mph across central Nevada. Winds are expected to dissipate by the evening with light showers lasting through the night and into Wednesday morning. By Wednesday afternoon, the system is expected to move east out of the state leaving calmer weather conditions behind, with cooler temperatures as highs will only be in the 60s. FORECAST CONFIDENCE & DEVIATIONS: High confidence of quiet weather conditions and temperatures warming to above normal through Monday. Moderate confidence for the next round of weather impacting Nevada on Tuesday with much cooler temperatures. Low confidence of periods of precipitation Tuesday. && .AVIATION... Look for VFR conditions with light winds across all terminals this afternoon. CIG levels across all terminals will be around FL100-FL150 (FL200 for KTPH) as scattered clouds build up across the region. Early morning hours, some breezy northerly winds up to 10-15 kts, gusts 20-25 kts will begin affecting all terminals. && .FIRE WEATHER... Look for quiet weather conditions with light winds this afternoon across all zones. Breezy northerly winds tomorrow with speeds up to 10-15 mph, gusts 20-25 mph over all zones. Temperatures will be trending warmer each day through Monday. && .LKN Watches/Warnings/Advisories... None. && $$ DISCUSSION...97 AVIATION...97 FIRE WEATHER...