706 FXUS66 KSEW 211610 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 910 AM PDT Thu May 21 2026 .UPDATE... Satellite imagery shows a little fog left along the Chehalis river going into Grays Harbor otherwise mostly clear skies over Western Washington this morning. Temperatures with the sunny skies are already in the 50s with a few locations near 60 at 9 am/16z. Forecast on track with a pair of sunny and warm days in store today and Friday. Highs in the mid to upper 60s along the coast and upper 60s to upper 70s inland. Transition to onshore flow over the weekend will cool things down with the next system due into Western Washington Memorial Day. No update this morning. Previous discussion follows with updated aviation and marine sections. Felton && .SHORT TERM /TODAY THROUGH SATURDAY/... Broad upper-level troughing resides over western CONUS while an upper-ridge is nosing into BC and W WA. Mostly clear skies across the CWA this morning aside from marine stratus along sections of the coast and southwest interior. This activity along with patchy river valley fog will continue before burning off as the morning progress. Mostly sunny skies today as large- scale subsidence ensues. High temperatures are forecast to be above average - in the 70s across the interior with near 80 F throughout the Chehalis River valley. Coastal areas to remain in the 60s. Overnight lows will fall into the 40s and lower 50s. Upper-ridging will flatten on Friday as zonal flow switches into gear on Saturday. Temperatures will warm into into the 70s again for both Friday and Saturday but low-level onshore flow will also begin to strengthen. Coastal areas will see afternoon highs in the 60s with lows in the 40s and lower 50s area-wide. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Deterministic guidance continue to hold off rain over the interior until late Monday. However, ensembles are more progressive with an earlier arrival of the front late Sunday. This is in the current forecast with a chance of rain Sunday night and rain spreading over the area on Memorial Day. Upper- troughing on Monday/Tuesday before another ridge noses into the region towards midweek. 41 && .AVIATION... High pressure will bring dry and stable conditions to western WA today. The flow aloft is northerly. Fog/stratus is dissipating at HQM this morning should lift before 18Z this morning. VFR conditions should prevail for most through the rest of the TAF period. Another round of stratus along the coast will likely bring IFR conditions to the coast and may push a bit farther inland, but it should stay west of the Puget Sound interior terminals. Higher likelihood of occurrence at terminals such as OLM, PWT, and CLM (30- 50% probabilities). Winds remain N/NW 5-10 kt today, becoming light NE overnight. KSEA...VFR conditions prevail through the TAF period. Winds N/NW 5- 10 kt today, becoming light (<5 kt) NE overnight. 62 && .MARINE... Onshore flow will prevail this week with high pressure offshore and lower pressure inland. Expect diurnal westerly pushes through the Strait of Juan de Fuca with highest wind and waves during the late afternoon and evening hours. Stronger onshore flow Saturday evening does have the potential to produce gales through the Strait. A low pressure system Monday will likely produce widespread Small Craft conditions through the area waters. 33/62 && .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 from 5 PM this afternoon to 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 from 2 PM this afternoon to 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. && $$

729 FXUS66 KPQR 211759 AAA AFDPQR Area Forecast Discussion...UPDATED National Weather Service Portland OR 1059 AM 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 and cooler temperatures return to the area late Sunday into early next week, which could impact any outdoor Memorial Day plans. && .DISCUSSION...Today through Wednesday...The upper level ridge that has been persistent over the NE Pacific will slide across the Pacific NW today as shortwave trough over the Gulf of Alaska sends a weak impulse toward the region. 850 mb temps rise to around 12-13C this afternoon while a weak surface thermal trough pushing into the Willamette Valley this morning shifts over the Cascades. With drier, offshore flow in the foothills, there are lower chances for morning stratus developing. This should allow mostly sunny skies to help warm surface temperatures into at least the lower 80s for inland areas today, which is around 10-15 degrees above normal for today. Record high temps are generally in the upper 80s to mid-90s through the Memorial Day Weekend, so we are not expecting any record high temps to be broken at this time. Conditions are expected to remain dry through the end of the week and into the weekend as high pressure continues across the region. The upper level ridge re-amplifies over the NE Pacific tonight and sags back over the PacNW region on Friday. 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. Coastal locations will experience a brief warmup today into the 60s to lower 70s before onshore flow brings typical temperatures there. 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. About 90% of ensemble members indicate 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. 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 norms by the middle of next week, though some uncertainty remains due to low chances of precipitation. DH/03 && .AVIATION...High pressure over the area will maintain VFR conditions with clear skies for Willamette Valley terminals through the entire TAF period. Along the coast, marine stratus has burned off and will briefly maintain VFR conditions with clear skies through this evening. Tonight, marine stratus re-develops along the coast and will lead to a 40-60% chance for IFR/MVFR CIGs or lower at any given hour for KAST/KONP between 09-17z Fri. Northerly to northwesterly winds today with gusts up to 20-25 kt along the coast and central/southern Willamette Valley. Elsewhere, winds generally under 10 kt. Winds weaken overnight as pressure gradients ease. KPDX AND APPROACHES...VFR with clear skies through the TAF period. Northwesterly winds 5-10 kt. No impacts expected. -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 tonight 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 water and northern outer water zones before increasing again this afternoon. Gusty northerlies are again likely south of Cape Falcon on Friday. 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 and returns southwesterly winds by Monday. -10/DH && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory from 7 AM this morning to noon PDT today for PZZ210. Small Craft Advisory until 5 AM PDT Friday for PZZ252-253- 271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

623 FXUS66 KMFR 212010 AFDMFR Area Forecast Discussion National Weather Service Medford OR 110 PM PDT Thu May 21 2026 .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 isoalted 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 (18Z TAFs)... Marine stratus is along the coast and is into Charleston, and it will continue burning off through the morning. Otherwise, VFR prevails. Northwest winds will strengthen this afternoon with 20-30 kt gusts at the coast, and 15-20 kt gusts at Roseburg. Sustained winds will go to the 9-12 kt range for other areas near the Rogue Valley and east of the Cascades. Marine low clouds/fog will develop tonight along the coast north of Cape Blanco and also the coastal valleys (Coquille, Umpqua). This will result in IFR/MVFR ceilings through the early morning hours at North Bend. Some clouds could also form in the Umpqua Basin around Roseburg, but these will be patchy and may avoid the terminal. -Spilde/Hermansen && .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 critcal 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. && $$

264 FXUS66 KEKA 210818 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 118 AM PDT Thu May 21 2026 .SYNOPSIS...Heat peak today with Minor to localized Moderate HeatRisk. There is a chance of isolated mountain showers on Friday. A weak and shallow marine layer will hang along shore. Temperatures will trend lower this weekend weekend. Chances of rainfall returns on Monday as a cold front approaches the forecast area. && .KEY MESSAGES... - Minor to localized Moderate HeatRisk Today, with interior highs peakings into mid 90s. - Chance (10-25%) of isolated mountain showers across the interior on Friday. - Gradual cool trend and lighter winds this weekend and into early next week. - Chance for morning coastal stratus and fog will persist, with increasing opportunity for longer duration stratus and fog through the weekend. - Increasing chance (25-50%) of rainfall Monday night and Tuesday, especially for areas farther north of northern Mendocino County. &&& .DISCUSSION...High clouds continue to stream across the area overnight, while low clouds and patchy fog has developed around the Humboldt Bay and vicinity, and extended along the Eel River Valley. Expect any low clouds and fog to lift and clear out this afternoon. A broad upper level ridge with above normal 500 mb heights continue to builds into the Pacific Nortwest today, dominating the weathern pattern for Northwest California. Heat peak today across the interior with Minor to localized Moderate HeatRisk as high temperatures climb into mid 90s. The heat will have impacts on anyone without effective cooling and/or adequate hydration. Coastal areas will remain generally in the upper 50s to mid 60s with the breezy northwest winds. 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. 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. / ZVS & JJW && .AVIATION...(06Z TAFs)...MVFR ceilings around 1200 feet at KACV, while VFR conditions at KCEC and KUKI with high-level clouds streaming across the area. Well offshore, a shallow marine layer will continue to slowly approach the nearshore through this morning. Nearshore southerly winds should push the low clouds into KCEC overnight and into early morning. Expect MVFR to IFR conditions for the coastal terminals overnight, lowering to LIFR conditions after 12Z. Low clouds and fog/mist are expected to gradually lift and scatter out with the diurnal heating and increasing NW winds, first at CEC after 15Z and after 19Z for KACV. Short-term model guidance suggests low clouds redeveloping after 22/01Z around Humboldt Bay and vicinity. This should promote MVFR ceiling impacting KACV again. Meanwhile, VFR conditions are expected to prevail at KUKI. Winds will be lighter compared with the last couple of days, but expect NW winds around 10 kts with highest gusts developing during the afternoon, especially at KCEC. /ZVS && .MARINE...Northerly winds begin to slowly diminish across the waters as the pressure gradient will shift slightly during the next few days. However, strong to gale-force gusty winds persist across the outer waters through Friday night, with the strongest winds in the northern outer waters. Gale-force gusts are anticipated to redevelop closer to the coast each afternoon in the lee of Pt St George and Cape Mendocino. These winds will continue to generate steep to very steep, hazardous seas across the waters into the weekend. Northerly winds are expected to diminish this weekend as the high pressure shifts eastward and the pressure gradient relaxes. Seas will also subside this weekend and into early next week, and could be below 5 feet across the waters by Sunday night. Monday, winds shift to west-northwest as a cold front from the Northeastern Pacific (NEPAC) moves through. Wind shifts to northerly and increase in the wake of the front Monday night through Tuesday. There is a 50-70% chance of gale-force gust winds across the waters on Tuesday, with the highest chances for south of Cape Mendocino. /ZVS && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 11 PM PDT Friday for PZZ450. Small Craft Advisory until 10 AM PDT Thursday for PZZ455. Gale Warning until 11 PM PDT Friday for PZZ470. Gale Warning until 10 AM PDT Thursday for PZZ475. Hazardous Seas Warning from 10 AM Thursday to 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

175 FXUS66 KMTR 211935 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1235 PM PDT Thu May 21 2026 ...New SHORT TERM, LONG TERM... .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 && .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 extend 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... (18Z TAFS) Issued at 1107 AM PDT Thu May 21 2026 Clear skies across the interior with an expansive stratus deck along the coast. Kept HAF overcast throughout the day but a brief period of clearing is likely for MRY and SNS. Current thinking is that the marine layer will deepen to around 1000 ft tonight with a mix of IFR to MVFR stratus across the interior. LIFR and fog is expected directly along the coastline with fog potential increasing by early tomorrow morning. Clearing is expected by late tomorrow morning/early afternoon. Vicinity of SFO...Winds strengthen to around 17 knots this afternoon/evening before easing overnight. Moderate confidence that MVFR CIGs will reach SFO around 10Z with some potential for CIGs to briefly drop below 1000 ft. It is worth noting that the HRRR shows a "donut hole" developing over SFO this morning stratus filters in through the Golden Gate Gap and fills into the East Bay/SF Bay but does not reach SFO. Confidence is slightly higher that a CIG will reach SFO overnight but it is worth noting their is some potential for conditions to remain VFR overnight. SFO Bridge Approach...MVFR to IFR CIGs are likely to develop over the SF Bay overnight with clearing by late tomorrow morning. Monterey Bay Terminals...CIGs have cleared from MRY and SNS with a brief period of VFR expected through 01/02Z. Given the expansive stratus deck just offshore, opted to push the arrival of stratus earlier in the TAF. Confidence increases in stratus returning around 01/02Z but it may return earlier if another eddy develops within the Bay. Generally expecting fog chances to increase early tomorrow morning, particularly at SNS but would not rule out patchy fog impacting MRY. Breezy onshore winds during the afternoon/evening will weaken overnight, becoming light to variable. && .MARINE... (Today through Tuesday) Issued at 945 AM PDT Thu May 21 2026 Fresh to strong northerly winds continue across the far northern outer waters, resulting in hazardous conditions and rough seas through Thursday. Moderate northwesterly breezes and moderate seas will prevail for the rest of the waters. Conditions improve into the weekend as seas and northwesterly breezes become moderate with the occasional fresh to strong breeze possible across the far northern outer waters. && .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...Kennedy MARINE...Kennedy 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

286 FXUS66 KOTX 211720 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 1020 AM 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... Today through Sunday: The next few days will be dry with increasing temperatures as high pressure lingers off the Pacific. Temperatures will steadily climb from the upper 60s to low 80s today to the upper 70s and 80s by Saturday. Sunday will be slightly cooler in the low 70s to low 80s as cloud cover approaches the region from an incoming system. There will be elevated grass fire danger Saturday afternoon and evening as a shortwave passes through British Columbia and Alberta. Surface pressure gradients will increase bringing dry and breezy westerly winds around 15-25 mph with gusts up to 35 mph for central WA. Winds for eastern WA and north ID will be weaker but still breezy around 10-15 mph. Sunday will also be breezy regionwide with sustained westerly winds 10-20 mph with gusts up to 25 mph. Monday through Thursday: Ensembles are in excellent agreement for a cooler and unsettled period Monday and Tuesday. The timing details for the onset of precipitation remain in question with 20% of the ensembles keeping conditions completely dry through Monday evening. Confidence is low on precip amounts especially if the low slows down and dives south as it moves inland which is the most likely solution as of now (80% of the ensemble). This period will need to be monitored for high elevation snow and chances for thunderstorms. The chances for at least a quarter inch of precipitation from Monday to Thursday for the lowlands look fairly promising around 20-40% for central WA, 30-60% for eastern WA, and 50-70% for north ID. Folks headed out into the backcountry of the Cascades above 5000 feet Monday and Tuesday will want to keep a close eye on the forecast as there is 30-50% chance of 1 inch or more of snow. Confidence in specifics is low at this point but the confidence of the pattern change is high. DB && .AVIATION... 18Z TAFs: VFR, dry conditions through the period with winds generally less than 10kts. Middle to high clouds increase this afternoon through evening with upper disturbance, decreasing from the west later this evening into Friday morning. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in VFR conditions. ----------------------- 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 71 46 76 48 80 52 / 0 0 0 0 0 0 Coeur d`Alene 70 46 74 47 78 50 / 0 0 0 0 0 0 Pullman 68 44 73 47 77 48 / 0 0 0 0 0 0 Lewiston 73 48 78 50 84 53 / 0 0 0 0 0 0 Colville 75 42 79 43 82 45 / 0 0 0 0 0 0 Sandpoint 69 45 73 46 77 48 / 0 0 0 0 0 0 Kellogg 71 45 74 47 79 49 / 0 0 0 0 0 0 Moses Lake 77 48 82 51 85 50 / 0 0 0 0 0 0 Wenatchee 77 54 81 56 83 55 / 0 0 0 0 0 0 Omak 78 49 82 52 85 51 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...None. ID...None. && $$

133 FXUS66 KPDT 211625 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 925 AM PDT Thu May 21 2026 .KEY MESSAGES... - Dry and Warmer conditions through Saturday - Breezy to Windy over the weekend - Increasing confidence in cooler and wetter weather early next week && .DISCUSSION... Darkening in the mid level water vapor GOES imagery showed the shortwave moving southeast through the Idaho panhandle driving the surface layer cold front southwest as seen by the NE WA observations. The weak cold front will have little impact on the PDT area and high temperatures will be similar to yesterdays and on average a couple of degrees warmer. Beyond Today, and through Saturday Afternoon temperatures will be on the rise, reaching highs in the mid 80s across the Yakima valley, central Oregon and the foothills of the Blue Mountains. Highs could hit around 90 degrees in part so The Lower Columbia and John Day Basins. Breezy to windy conditions over the weekend through onshore flow and pressure gradients across the Cascades Gaps. Looking at the NBM mean gusts, 30 to 40 mph gusts could be expected though the Kittitas valley, Eastern Columbia River Gorge and Blue Mountain Foothills/Columbia Basin of Oregon. Based on NBM members, there is about a 20 to 60% chances for advisory level wind gusts in excess of 45 mph across areas of these aforementioned zones. A look at the ensembles for the late weekend and early next week leads to high confidence in the transition to wetter, and cooler weather with also mean qpfs indicating wetting rains across the mountain zones. Mountain zone probabilities of wetting rains (greater than one tenth of an inch) are about 60-95% Monday into Tuesday. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... VFR conditions will continue with clear to FEW skies and calm to light winds continue over the next 24-hours. No VIS or CIG issues expected. && .Preliminary Point Temps/PoPs... PDT 75 46 80 49 / 0 0 0 0 ALW 76 50 80 53 / 0 0 0 0 PSC 80 48 85 52 / 0 0 0 0 YKM 80 51 84 53 / 0 0 0 0 HRI 79 48 83 52 / 0 0 0 0 ELN 74 47 78 50 / 0 0 0 0 RDM 77 41 81 44 / 0 0 0 0 LGD 72 42 77 45 / 0 0 0 0 GCD 75 39 80 43 / 0 0 0 0 DLS 82 54 85 54 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...None. OR...None. && $$ DISCUSSION...71 AVIATION...95

452 FXUS65 KREV 210854 AFDREV Area Forecast Discussion National Weather Service Reno NV 154 AM PDT Thu May 21 2026 .KEY MESSAGES... * Warmer than normal weather prevails through the weekend with typical afternoon westerly breezes. * 10-30% chances for showers along with isolated thunderstorms Thursday into the holiday weekend. * A Pacific storm may result in a period of cooler, windier, and more unsettled weather early next week. && .DISCUSSION... Warm, above average temperatures continue through the weekend. Highs will reach the lower 80s across W.Nevada through Friday, then will climb to the mid-to-upper 80s by Saturday and Sunday (70s for Sierra valleys). Moisture will increase through Friday as PWATs rise to near 0.6-0.7". Combined with daytime heating and convergence along the afternoon zephyr, weak shortwave forcing could trigger 10-20% chances for showers and 5-10% chances for isolated lightning strikes. Shower chances increase slightly Friday afternoon (20-35%), though the main limiting factor will be instability with MUCAPE values only around 100-200 J/kg. Drier air will filter in with an approaching shortwave trough on Saturday-Sunday which will shift shower and isolated thunderstorm chances eastward across the W.Nevada Basin and Range and south into Mono County. Otherwise expect dry conditions outside these areas with typical afternoon zephyr breezes with gust up to around 20 mph, then slightly breezier Saturday afternoon. We will get a reminder that we are still in spring early next as a deeper closed low drops across northern Nevada. This may result in a much cooler and unsettled pattern through mid-week. Gusty winds and low humidity in the low teens and single digits Monday afternoon could provide increasing fire weather concerns for any areas of cured fine fuels/grasses across portions of western Nevada. Timing and the trajectory of the low are still lower end confidence at this time but will have implications on how much cooling and how gusty winds become early next week. Fuentes && .AVIATION... Widespread VFR conditions and light breezes prevail today. Shower and thunderstorm chances increase Today 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/Fuentes && .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. && $$

052 FXUS65 KBOI 212020 AFDBOI Area Forecast Discussion National Weather Service Boise ID 220 PM MDT Thu May 21 2026 .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/... 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/... 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 /18Z Thursday through Friday/... Issued 1153 AM MDT THU MAY 21 2026 VFR, scattered high level clouds possible this evening. Surface winds: NW wind 10-15 kt, gusts to 25 kt, variable 5-10 kt tonight. Winds aloft at 10kft: N 10-20 kt. KBOI...VFR with mostly clear skies. Surface winds: NW 10-15 kt with gusts 20-25 kt through the afternoon, becoming S-SE up to 10 kt tonight. Weekend Outlook...VFR. Mostly clear. 5-15 kt SW-NW winds each afternoon, lighter and more variable each morning. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise SHORT TERM...ST LONG TERM....JM AVIATION.....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