540 FXUS66 KSEW 271028 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 328 AM PDT Mon Apr 27 2026 .SYNOPSIS... Upper level ridge along British Columbia coast with low level onshore flow through Tuesday giving Western Washington mostly cloudy and cooler weather. Upper level ridge moves over the area Wednesday then slides east Thursday. Weak upper level trough moving through Thursday night. Upper level ridge building to the northwest with an upper level low developing well west of California Friday through the weekend with temperatures warming into Sunday. && .SHORT TERM /TODAY THROUGH WEDNESDAY/... Satellite imagery shows stratus west of the Olympics, over the Southwest Interior and at 3 am/10z starting to fill up the Central Puget Sound area. Mostly clear skies elsewhere. Temperatures with the cloud cover were warmer than the previous mornings, in the 40s and lower 50s. Marine push ongoing this morning. Stratus will continue to fill in over the Central Puget Sound through sunrise with the stratus getting as far north as Skagit county. No top reports yet this morning but the Black Hills in Southwest Washington are covered so tops at least 3000 feet and probably a little higher. Continuing onshore flow through the day combined with the thickness of the marine layer will keep skies cloudy this morning before somewhat of an afternoon breakout over the interior. Skies remaining cloudy along the coast with light showers or drizzle possible this morning. Cooler today with highs in the mid 50s to lower 60s. Little change in the pattern tonight into Tuesday with low level onshore flow. Marine layer returning to the interior overnight for another cloudy start to the day. Low level flow going light in the afternoon but cross Cascade gradients still around plus 6 mb late in the afternoon. This will make it hard for a complete clear out of the stratus over the interior. Will word the forecast mostly cloudy. Highs again in the mid 50s to lower 60s. Lows Tuesday morning in the 40s. Upper level ridge along the British Columbia coast today into Tuesday morning moving over Western Washington Tuesday night into Wednesday. Low level flow going light northerly Wednesday with cross Cascade gradient trending towards zero. This will thin out the marine layer. Plenty of sunshine Wednesday with highs back into the lower to mid 60s. Lows Wednesday morning in the mid 30s to mid 40s. Felton && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Upper level ridge over the area Wednesday night moving east Thursday. Weak upper level trough sliding through Thursday night with another upper level ridge rebuilding Friday. Models continuing to have trouble latching on to a solution for Friday night through the weekend. Latest solution has an upper level block forming offshore over the weekend with north northeasterly flow aloft and the low level flow turning offshore. Highs Thursday in the 60s and lower 70s, cooling a little Friday into the 60s then warming over the weekend to the mid 60s to mid and upper 70s by Sunday. Current model blend has a high of 74 for Seattle Sunday. About a quarter of the solutions have the high in the upper 70s. Normally in May a high in the upper 70s would not be a record in Seattle. 30 out of the 31 days in May have a record high of 82 degrees or warmer. The one day that does not, May 3rd with a record high of 77. Outside chance of setting a record Sunday. The average first 80 degree plus day in Seattle is May 20th. The earliest April 1st, 1987 ( 82 degrees ) and the latest July 21, 1980 ( 85 degrees. Something happened in 1980 that caused this late date ). Felton && .AVIATION...North to northwesterly flow aloft continues through the TAF period with troughing over the interior West and upper ridge offshore. Onshore flow this morning is resulting in stratus spreading into the interior. Predominantly MVFR (areas of IFR) cigs has been observed this morning. Cigs will slowly improve into VFR around 18-22z Monday afternoon for interior locations, with MVFR continuing along the coast. More widespread MVFR cigs are in the forecast overnight Monday into Tuesday. Southerly winds 8-12 kt with gusts around 20 kt for interior terminals. KSEA...MVFR ceilings have developed this morning and will remain through 18-20z before improvements to VFR in the afternoon. There also remains approximately a 30% probability of IFR cigs, peaking between 10 to 15z Monday. S/SW surface winds through the TAF period ranging between 5 to 10 kts with gusts near 20 kt possible this morning and during the afternoon. More MVFR cigs likely to develop overnight into Tuesday. 41 && .MARINE... High pressure continues over the coastal waters, with lower pressure inland. Onshore this week with weak pushes through the Strait of Juan de Fuca. The strongest push in the guidance is Monday evening, but the probability of winds exceeding 20 kt remains low. Low ceilings in the coastal waters Monday morning (with pockets of fog) may lower visibilities at times to mariners. The next potential system may bring breezy winds over the coastal waters around Friday. Seas for Sunday hold around 4-6 ft, and increase to 6-9 ft for the remainder of the week. 41 && .HYDROLOGY... No river flooding in the next 7 days. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$

908 FXUS66 KPQR 271048 AFDPQR Area Forecast Discussion National Weather Service Portland OR 348 AM PDT Mon Apr 27 2026 .SYNOPSIS...Onshore flow will bringing increased cloud cover and cooler temperatures today and Tuesday, along with chances for light drizzle along the coast and light showers across the Cascades. Drier and warmer weather returns Wednesday through the weekend as high pressure builds. Weather impacts appear minimal going forward. && .DISCUSSION...Today through Sunday...Satellite imagery as of early Monday morning depicts marine stratus along the coast and mostly clear skies inland. Some of the marine stratus is beginning to filter through the Coast Range gaps as well as the Lower Columbia River into the Cowlitz Valley. Expect this marine stratus to gradually spread into the Willamette Valley this morning. Will maintain mostly cloudy skies today as onshore flow increases due to a passing shortwave trough. However, increased mixing due to daytime heating could lead to afternoon clearing along the I-5 corridor. In addition, the aforementioned shortwave will provide enough lift to result in chances for light drizzle along the coast and light showers across the Cascades. Interior valleys should remain dry. Winds will generally be light and westerly today, except for the Columbia River Gorge and Upper Hood River Valley where gusts are forecast to peak around 25-35 mph this afternoon. A similar pattern continues into Tuesday. Since we`ll have more cloud cover, temperatures today and Tuesday will be a few degrees cooler than this past weekend, with afternoon highs forecast in the low to mid 60s across interior valleys and mid to upper 50s along the coast. Wednesday to Thursday, the majority of deterministic and ensemble members show a heavily tilted upper-level ridge building over the northeast Pacific and eventually shifting into the Pacific Northwest. Most ensemble members also show above- average 500 mb heights over the area, suggesting high confidence (70-90% chance) that temperatures will rebound into the upper 60s to low 70s by Wednesday and upper 70s to near 80 by Thursday. Chances for exceeding 80 degrees on Thursday are around 50-70% for the Portland/Vancouver Metro Area, and 20-40% for the rest of the I-5 corridor. Friday through Saturday, most deterministic and ensemble guidance depicts the upper-level ridge flattening as a weak trough moves into the Pacific Northwest from Canada. It appears that there is limited moisture with this trough, so precipitation chances remain around 20-40% across the Cascades and less than 10% elsewhere. In addition, most ensemble members maintain above-average 500 mb heights over the area, meaning seasonably warm temperatures would continue through the end of the week with high temperatures forecast in the 70s for interior valleys. By Sunday, the majority of ensemble members have the trough moving southward toward California while upper-level ridging re-builds over the Pacific Northwest. Even this far out, NBM guidance is already suggesting higher confidence (60-80% chance) that temperatures exceed 80 degrees along the I-5 corridor on Sunday. -10 && .AVIATION...Satellite imagery and terminal observations as of early Monday morning depicts MVFR conditions along the coast due to marine stratus. This stratus is making its way up the Lower Columbia River and Coast Range gaps, and will gradually move into the Willamette Valley this morning. There is also some stratus already developing in the far east Portland/Vancouver Metro. High confidence for at least low-end VFR (3-4 kft) stratus across the Willamette Valley with a 40-60% chance for MVFR CIGs at any given hour between 12-18z Mon. After 18z, increased mixing from daytime heating will help lift CIGs, but remain low-end VFR. Along the coast, high confidence for MVFR stratus holding throughout the day at KAST, while there is a 40-60% chance for improvement to VFR at KONP. After 03z Tue, a renewed marine push will support CIGs dropping to MVFR again at KONP. Winds generally west-southwesterly across the region and remaining under 10 kt. An exception would be breezy west winds through the Columbia River Gorge into the Upper Hood River Valley with gusts up to 25-30 kt. KPDX AND APPROACHES...VFR through 11-12z Mon. After 12z Mon, high confidence for high-end MVFR/low-end VFR stratus. Increased mixing after 18z Mon will improve CIGs to predominately VFR. Westerly winds under 10 kt through 21z Mon, turning more northwesterly in the afternoon and evening. -10 && .MARINE...Winds remain westerly to northwesterly into Tuesday with gusts expected to remain below 15-20 kts as a weak front moves through the waters Monday. By Tuesday evening, high pressure returns over the waters, remaining through the end of the week. Winds become northerly with a 70-90% chance for at least isolated small craft northerly wind gusts up to 20-25 kt from Wednesday through Friday. Gusts will be strongest each late afternoon and evening hours when pressure gradients are tightest. Seas of 6-7 ft persist through the week with a northwesterly swell. -10 && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...None. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

293 FXUS66 KMFR 271133 AFDMFR Area Forecast Discussion National Weather Service Medford OR 433 AM PDT Mon Apr 27 2026 .DISCUSSION... Key Points: * Cooler/near normal everywhere with scattered showers east of the Cascades and in Northern California today * Coast/Coastal valleys: Overnight clouds/drizzle north of Cape Blanco, which could reach Roseburg * Ridging mid-week leading to warmer temperatures * Next low pressure system possible next weekend Satellite shows that the coast is covered with marine stratus this morning, and it is reaching portions of the Umpqua Basin near Roseburg. The main precipitation chance today will be in Northern California and east of the Cascades as scattered showers will develop this afternoon. Temperatures will be slightly below normal this afternoon. There will be typical diurnal winds as well. Tonight there will be similar conditions at the coast and into the Umpqua Basin, and lows will be in the 40s there. Elsewhere, more clearing will bring temperatures down into the upper 30s west and low 30s east. Everyone will see warmer temperatures tomorrow by about 3-7 degrees. However, there will be a 5-15% chance for a shower in the same areas as today. After, ridging starts to build Wednesday. This will bring more locations west of the Cascades back into the 70s, and upper 60s are forecast east! This will equate to temperatures 10-15 degrees above normal. Long term: Models then show the ridge breaking down by this weekend as an upper trough just off the West Coast tries to close off offshore. An increasing number of solutions show the low closing off to our SW, which would bring an increased risk for mainly afternoon and evening showers and thunderstorms Saturday, with the potential for active weather persisting Sunday into early next week. Much will depend on the eventual track of trough/low, however. Many members, particularly from the GEFS ensembles, maintain a weaker trough moving through, which would limit the overall extent/coverage of precipitation. We`ll adjust the forecast as things come more into focus. -Spilde && .AVIATION...27/12Z TAFs...Onshore flow has brought MVFR ceilings and terrain obscurations to the Oregon coast and the coastal mountains, and this will slowly build off through this morning. These MVFR ceilings are making their way into the Umpqua Basin as well, getting closer to Roseburg. In northern California and over the East Side, showers will return this afternoon, but coverage should be more scattered. MVFR/IFR conditions with terrain obstructions are possible in any heavier showers. Otherwise and elsewhere, VFR will prevail. Another onset of MVFR ceilings will return to the coast later this evening and overnight. - Hermansen && .MARINE...Updated 145 AM PDT Monday, April 27, 2026...North winds will persist through the week with a low north west swell keeping seas around 5 to 7 feet. Northerly winds increase again Tuesday afternoon, especially south of Cape Blanco, and persist through much of the week. A Small Craft Advisory will be in effect late Tuesday morning through Wednesday morning. High and steep seas are likely in all waters Wednesday night into Saturday as a thermal trough builds in and remains along the coast. && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory from 11 AM Tuesday to 5 AM PDT Wednesday for PZZ350-356-370-376. && $$

782 FXUS66 KEKA 270815 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 115 AM PDT Mon Apr 27 2026 .SYNOPSIS...A slight chance for interior thunderstorms Monday late afternoon with probabilities even less before sunset. Chilly morning temperatures are expected Monday morning for the coldest interior valleys. Drier weather returns mid next week. && .DISCUSSION...The marine layer gets a bit shallower overnight into Monday morning. With the satellite products showing observable stratus thinning out for the interior, temperatures could dip to frost thresholds with no upper or mid-level clouds to hinder long wave radiative cooling. A frost advisory has been hoisted but is marginal as lows near interior Humboldt and Trinity will likely bottom out around 33-35F overnight into Monday morning near Dinsmore, Blocksburg, Ruth, Mad River and Hayfork. With an upper level troughing pattern passing south of the CWA, a slight risk of thunderstorms for the interior continues with less of a threat than Sunday with 13 - 15 percent chances for Trinity and Mendocino counties. Less of a chance for Humboldt and Lake counties, around 10 percent. Expect most chances of thunderstorms to ease before sunset Monday. High pressure looks to be the next trend as barometric pressure at the EKA WFO station is steadily rising overnight. Model soundings show dryer air aloft with an inversion, a prelude to seasonal warming and stability in the vertical profile. Deterministic ensembles are not in agreement over the next precipitation event for the first week of May. Stay tuned as time draws near for developments. /EYS && .AVIATION...A very deep marine layer continues to persist across the area with 3kft MVFR ceilings all along the coast and even over most of the interior. MVFR conditions will persist into Monday morning before gradually scattering off the VFR. The timing of scattering, however, has high uncertainty. Interior areas will most likely lift and scatter before 10 am where coastal locations could remain MVFR well into the afternoon. There is more uncertainty as for conditions Monday night into Tuesday. While ceilings will most likely persist, passing low pressure may be enough to lift them so high that conditions could be VFR despite the marine layer. At the very least, IFR conditions are very unlikely (less than 10% chance). /JHW && .MARINE...Gentle north winds have built across all waters. Seas have generally remained moderate up to around 7 feet at 14 seconds thanks to a combination of lingering short period seas and modest mid period swell up to 4 feet. Gentle winds will continue Monday with the swell rapidly decaying through the day. Northerly winds will begin to return to southern waters Monday night and spread into the northern waters by Tuesday. steep short period seas will build in response at least in the outer waters by Tuesday afternoon. Though strongest in the outer waters, short period wave energy will begin to impact the inner waters mid week with short period seas up to around 8 feet. Winds will continue to increase late weak with a 75% chance of near gale conditions by Thursday in the outer waters. /JHW && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Frost Advisory until 9 AM PDT this morning for CAZ106-108. NORTHWEST CALIFORNIA COASTAL WATERS... None. && $$ 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

339 FXUS66 KMTR 271112 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 412 AM PDT Mon Apr 27 2026 ...New AVIATION, MARINE... .KEY MESSAGES... Updated at 1208 AM PDT Mon Apr 27 2026 - Light rain and pockets of drizzle possible today - Warming and drying trend this week - Disturbed weather returns next week && .SHORT TERM... Issued at 1208 AM PDT Mon Apr 27 2026 (Today and tonight) The radar is showing some light returns over the marine environment as well as on some of the higher peaks, indicating some lingering light rains along with the drizzle along the coast. Some of these chances will linger into the day for a few isolated spots, particularly in higher elevations on the Big Sur Coast, the North Bay Mountains, and the Santa Cruz Mountains. Rainfall totals will be fairly light, with mostly traces to a few hundredths expected. Cloud cover will be more on than off through the first part of the day, but sunnier conditions are expected for the afternoon, leading to slightly warmer conditions than previous days. The onshore flow and lingering moisture will prevent too much of a warm up, but this will be the start of our warming trend. This warming trend will be less pronounced for the coast and areas slightly inland as the marine layer rebuilds and becomes better- defined into Monday night and early Tuesday. Marine stratus will also keep things on the cooler side for the coast, but areas inland will begin to see much warmer and sunnier conditions into the work week. && .LONG TERM... Issued at 1208 AM PDT Mon Apr 27 2026 (Tuesday through Sunday) The combination of a building ridge to the north and a cutoff low to the south will set us up for an interesting gradient of temperatures through the mid-week and into the weekend. The pressure gradient caused by the low to the south looks to keep the marine environment and the coast breezy, and will help keep the marine layer intact. This will result in high on the immediate coast to stay around 60 degrees through the week, and areas slightly inland mostly staying in the 60s. The more interior areas will not benefit from the marine influence, leading to warming and drying more akin to a typical ridging pattern. Wednesday will offer widespread highs in the 70s for areas away from the coast, with a few isolated 80s. Conditions look to continue to warm for the interior through Friday with more areas breaking into the 80s and possibly the 90s in the southern Salinas Valley. Model agreement got much worse for the weekend than last night, and the movement of highs and lows through the Pacific has not become any less complicated across any of the main long-term models nor ensemble clusters. There are hints toward a Rex-Block (high pressure to the north, low pressure to the south) forming into the weekend, but the positioning vary quiet a bit across models. In most cases, it looks like the Bay Area and Central Coast will see some cooling due to the low bing closer than the high pressure. It could also include some light rain into the next work week, but confidence isn`t great. There are also some hints at the Rex-Block losing momentum and this pattern arriving and exiting at a slower pace. Be sure to keep checking back in to see if we start May with some moisture. && .AVIATION... (12Z TAFS) Issued at 412 AM PDT Mon Apr 27 2026 A mix of MVFR to VFR conditions across the region this morning will lift starting in the late morning hours, with lingering chances of isolated showers dissipating by the afternoon. Gentle to moderate onshore pattern winds develop this afternoon and evening, diminishing overnight as MVFR-low end VFR ceilings return to the terminals. Vicinity of SFO... Low end VFR ceilings will scatter out in the afternoon hours with MVFR stratus returning in the overnight period. Breezy west-northwest winds will develop this afternoon and evening before diminishing overnight. SFO Bridge Approach... Similar to SFO. Monterey Bay Terminals... VFR conditions through the day with mid- level cloud cover scattering out in the later morning. Breezy northwest winds will develop this afternoon and evening with light drainage winds overnight as MVFR ceilings return to the terminals. && .MARINE... (Today through Saturday) Issued at 412 AM PDT Mon Apr 27 2026 Moderate west to northwest breezes persist through the middle of the week, increasing to fresh to strong northwest breezes by Thursday. These stronger winds will build rough seas of 8-12 feet in exposed waters Wednesday through Friday. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 9 PM this evening to 3 AM PDT Wednesday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Murdock LONG TERM....Murdock AVIATION...DialH MARINE...DialH 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

267 FXUS66 KOTX 271117 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 417 AM PDT Mon Apr 27 2026 .KEY MESSAGES... - Afternoon showers over primarily southeast Washington and the Idaho Panhandle today and a small potential for thunderstorms. - Warmer and drier conditions Wednesday through at least Friday. && .SYNOPSIS... Afternoon showers mainly over southeast Washington and the Idaho Panhandle today. Temperatures then see a gradual warming trend through the rest of the week. Chances for showers in the mountains returns for the weekend. && .DISCUSSION... Today through Wednesday night: The Inland Northwest will remain on the back edge of a broad longwave trough of lower pressure. This places the region in a north to northwest flow pattern aloft. Very little forcing will be supplied aloft with showers primarily being driven by diurnal heating. Best chances of between a 40-60% chance for showers is expected over southeast Washington and in the southern to central Idaho Panhandle today. The atmosphere will be marginally unstable for a one hit wonder thunderstorm or two as well in the afternoon. Minimal if any lightning activity is anticipated though. Chances for showers on Tuesday will be similar as today in both intensity and location with the Idaho Panhandle seeing a 30-50% chance. Not quite as unstable as today with an even less chance for seeing thunderstorms on Tuesday. Temperatures will gradually warm to near normal over the next couple of days. Thursday through Monday: The longwave trough shifts east away from the region with a longwave ridge of higher pressure moving in to take its place over the Northwest. This will result in additional warming to above normal for the latter half of the week. Model ensembles are if fairly good agreement with a shortwave disturbance riding over the top of the ridge around Friday. Model guidance continues to show that this will largely just flatten the ridge out and bring only a 10-20% chance for showers over the Northeast Mountains and the Northern Panhandle near the Canadian border. Model ensembles are coming into better agreement with around 80% of the members showing a closed low tracking onshore off of the eastern Pacific south of the Inland Northwest. The upper level pattern does indicate a slight weakening of the higher heights under the ridge and this will introduce a slight chance (10-30%) of afternoon showers over the higher terrain of northeast Washington, the Northeast Blue Mountains and the Idaho Panhandle. Solutions with a deeper low indicate a bit more instability with at least an isolated threat for thunderstorms over the southeast portion of the forecast area. This will be something to watch as we approach the weekend for the potential of thunderstorms capable of outflow winds, small hail and brief heavy downpours. Temperatures will be warming well into the 70s by Sunday into Monday, and we will also be seeing some 80 degree weather in the Columbia Basin and in the valleys of the Cascades and Okanogan Valley. This will be warm enough for an expanding minor HeatRisk across these aforementioned areas. It`s a bit early to be seeing temperatures getting into the 80s and our bodies are still acclimate. Something to keep in mind if planning to be outside and doing strenuous activities early next week. The warmer temperatures will also result in high elevation snow melt in the Cascades and in the mountains of Canada that feeds some of our mainstem rivers. These rises will be fairly minor though. The one exception is the Stehekin River which will continue to run high and impact the Stehekin community there. /SVH && .AVIATION... 12Z TAFS: VFR conditions are expected for the TAF period. Convective showers will expand with diurnal heating on Monday. Widely scattered showers are expected over southeast Washington into the Idaho Panhandle for Monday afternoon. A few embedded thunderstorms may occur, but it is a very low probability and most likely over the higher terrain east of KLWS to KPUW. Showers around KCOE, KPUW, KLWS will be light but may produce outflows with gusty and variable wins. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence for VFR conditions. Gusty outflow winds from decaying showers on Monday may produce higher gusts than reflective in the TAFs of up to 20-25 kts for KGEG/KSFF/KCOE- KPUW/KLWS. ----------------------- 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 61 39 63 41 67 42 / 10 0 10 0 0 0 Coeur d`Alene 58 38 60 41 65 41 / 20 0 10 10 10 0 Pullman 57 37 60 40 64 41 / 30 10 10 0 0 0 Lewiston 61 41 65 44 69 44 / 30 0 10 0 0 0 Colville 63 35 66 39 71 39 / 10 0 20 10 10 0 Sandpoint 56 37 58 41 63 40 / 20 10 30 10 20 0 Kellogg 55 38 58 41 64 41 / 50 20 40 10 30 0 Moses Lake 68 39 70 41 74 46 / 0 0 0 0 0 0 Wenatchee 67 44 69 45 73 49 / 0 0 0 0 0 0 Omak 66 41 69 43 74 46 / 10 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...None. ID...None. && $$

824 FXUS66 KPDT 271110 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 410 AM PDT Mon Apr 27 2026 .KEY MESSAGES... - Chance of showers and isolated thunderstorms this afternoon in the eastern mountains - Temperatures gradually warming to above normal through the remainder of the week && .DISCUSSION... Today and Tuesday: Satellite imagery tonight shows scattered decks of mid to high level cloud cover across portions of southeast WA and northeast OR, with very little shower activity noted on regional radar. Today, a weak shortwave under a north northwest flow aloft will dive across the inland PacNW, resulting in isolated to scattered shower chances across the eastern mountains this afternoon. A weak thunderstorm or two may develop this afternoon over the eastern mountains as developing showers tap into a weak pool of instability developing into the afternoon (CAPE <500 J/kg and high low level lapse rates). Tuesday, another shortwave will move across the region, but will track across eastern WA into far northeast OR due to upper ridging pushing towards the PacNW. Shower activity will be limited the northern Blues and ridges in Wallowa county in the afternoon. Wednesday through Friday: Upper level ridging will build over the region through the latter half of the work week (confidence 70-85%). This will result in drying and warming conditions across much of the forecast area. High temperatures will warm well above normal, with mid 70s in the mid elevations (central OR) and upper 70s to lower 80s in the lower elevations. Saturday and Sunday: Ensemble cluster guidance is in good agreement that a positively tilted upper trough will slide over the PacNW through the weekend, however there is disagreement on the depth and position of the trough as it moves inland. Regardless of the position, ensemble cluster solutions indicate a southwest flow into the inland PacNW, keeping temperatures above normal over the weekend. The upper trough and southwest flow aloft will also promote shower chances over the eastern mountains both Saturday and Sunday afternoons, with a slight chance of isolated thunderstorms developing as well (confidence 30-50%). Lawhorn/82 && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...VFR conditions to prevail through the period. Only exception will be at site BDN where vsby may lower to around 3SM this morning due to smoke from a nearby fire. Showers will develop along the Blue Mountains this afternoon, though chances of showers at sites PDT/ALW (<20%) were too low to include at this time. Winds will generally be light, 12kts or less, through the period. Except at site DLS where winds will increase to around 15kts with gusts up to 25kts this afternoon and early evening. An occasional gust up to 20kts may also impact sites RDM/BDN this afternoon. Lawhorn/82 && .Preliminary Point Temps/PoPs... PDT 65 41 67 40 / 10 0 0 0 ALW 65 45 67 44 / 30 10 10 0 PSC 71 43 72 42 / 0 0 0 0 YKM 69 41 71 41 / 0 0 0 0 HRI 69 43 69 41 / 0 0 0 0 ELN 63 40 62 39 / 10 0 0 0 RDM 61 30 65 31 / 0 0 0 0 LGD 58 35 64 39 / 50 10 10 0 GCD 58 33 64 37 / 40 10 10 0 DLS 68 44 67 42 / 10 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...None. OR...None. && $$ DISCUSSION...82 AVIATION...82

592 FXUS65 KREV 270918 AFDREV Area Forecast Discussion National Weather Service Reno NV 218 AM PDT Mon Apr 27 2026 .KEY MESSAGES... * Shower and isolated thunder chances return this afternoon with temperatures remaining below average. * Shower and thunder chances decrease and shift to areas near the Sierra Tuesday-Wednesday, with a gradual warming trend. * Expect drier weather and further warming for late this week, then shower chances may return for the upcoming weekend. && .DISCUSSION... Light showers are lingering across parts of eastern CA-western NV CA early this morning as an upper level trough remains overhead through today. Another shortwave will drop southward along the CA coast Tuesday and continue its southward track through Wednesday, although a small area of upper divergence and terrain-focused convergence sets up near the Sierra. With these weak meandering weather systems slow to clear our area, shower chances will linger through midweek, although coverage is likely to decrease each day through Wednesday. Today will see a near-repeat of Sunday`s activity, with isolated to scattered showers popping up around midday and peaking between 2-5 PM. Lightning has been sparse the past few days and today looks to be similar, with only low end 15-20% chances east of US-95 in west central NV and clipping southern Mono County, with 5-15% chances elsewhere. Spotty short-lived rain with a few pellets are again expected as today`s highs remain on the cool side (near 60 degrees for lower elevations and upper 40s near the Sierra), although a majority of the region won`t receive notable rainfall amounts. For the Sierra, snow levels edge upward to near 7000 feet this afternoon and isolated mountain sites could see an inch or two of snow, but for main passes there`s only a minimal (less than 20%) chance for any accumulating snow on roads. Overall, winds today will be lighter (gusts 20 mph or less) compared to Sunday, although brief stronger gusts of 30+ mph may occur near shower activity. For Tuesday, the focus area for PM showers shifts to areas near the Sierra, based on the track of the next shortwave closer to the CA coast, while for western NV drier air with limited instability reduces the shower risk. The potential for lightning is sparse, generally around 10% near the Sierra crest northward to western Lassen County. Temperatures edge upward by about 5-8 degrees compared to today, near late April averages of mid-upper 60s in lower elevations and mid 50s for Sierra communities. The warming trend continues Wednesday-Friday, and while we can`t rule out a few PM showers near the Sierra crest of Alpine-Mono counties Wednesday and Thursday, the overall outlook for mid-late week will favor a dry pattern. Highs climb to near 80 degrees for lower elevations while Sierra valleys rebound to near 70 by Friday. While lighter winds are projected for most areas, a shallow back-door front passage may bring increased north winds Thursday afternoon for the US-95 and US-6 corridors of Mineral/southeast Mono counties. However, this warm and dry pattern isn`t expected to be long- lasting, as medium range guidance continues to advertise another trough of low pressure dropping into the western US for the first weekend of May. Showers may begin by late Saturday in far northeast CA, with increased shower/isolated thunder chances expanding to the Sierra/western NV and several degrees of cooling currently on tap for Sunday. With this trough projected to evolve to a slow-moving closed low relatively typical for spring, shower chances could carry on through the first few days of next week. Given the varied locations/tracks of this potential low among the ensemble members this far in advance, confidence remains on the lower side for precip amounts and favored locations. MJD && .AVIATION... A persistent upper trough overhead will lead to another round of shower activity starting around 19-20Z for the Sierra/Tahoe area terminals and after 21Z for the western NV terminals. Coverage will be isolated, with brief MVFR conditions in -SHRA for KTRK/KTVL/KMMH and short periods of terrain obscuration for KRNO/KCXP/KMEV. This shower activity winds down between 02-04Z. For Tuesday, isolated showers again bring similar brief MVFR potential for the Sierra/Tahoe area terminals, but western NV should remain dry with VFR conditions prevailing. Overall winds will be lighter today and Tuesday with gusts 20 kt or less, but brief gusts to 30 kt could occur near shower activity. While cloud cover should limit FZFG formation around KTRK this morning, more clearing tonight sets up a greater potential (50-70%) chance for FZFG with LIFR early Tuesday mainly between 08-15Z, especially if precip occurs at the airport today. MJD && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$

506 FXUS66 KSTO 261848 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1148 AM PDT Sun Apr 26 2026 .KEY MESSAGES... - Light mountain showers and isolated thunderstorms continue today into Tuesday, with some potential into the foothills and portions of the Valley today. - Cooler than normal temperatures today, followed by drier weather and a gradual warm up throughout the week. && .DISCUSSION... ...Today-Tuesday... Latest radar imagery depicts scattered light showers over the mountains, with isolated light showers across portions of the Valley. Chances for mountain showers and isolated thunderstorms persist through early this week as a trough pattern prevails across interior northern California. Latest WPC guidance indicates additional precipitation amounts ranging from 0.25-0.50" over the mountains, with up to 0.75" over the Coast Range. Additional light snow accumulations of 1 to 3 inches are expected across northern Sierra passes and the southern Cascades above 5500-6000 feet through Monday evening. Travel impacts should be limited, with slippery roads at times. In addition, locally breezy south to southwest wind gusts up to 15-25 MPH continue today, strongest across the mountains. Hi-Res guidance shows the potential for isolated thunderstorms to develop early this afternoon and linger into the overnight hours. Main thunderstorm hazards include lightning, small hail, gusty winds, and brief heavy rain so exercise caution if commuting and find the latest road conditions at quickmap.ca.dot.gov. Lingering afternoon mountain showers and isolated thunderstorms (10-15% probability) continue on Monday and Tuesday. Elsewhere, dry conditions will prevail. Highs will warm into the upper 60s to 70s in the Valley and foothills, with 40s to low 60s across higher elevations. ...Mid to Late Week... Drier and warmer weather is likely across the area as ridging builds in from the eastern Pacific. Above normal high temperatures are expected, with mid 70s to mid 80s across the Valley and foothills and over the mountains. Ensembles hint at another trough approaching the region late week into next weekend that may bring unsettled weather and slightly cooler temperatures. && .AVIATION... MVFR to VFR conditions into 09z Monday from scattered showers and isolated thunderstorms with best chances for the Coastal Range and northern Sac. Valley. Breezy south winds with gusts up to 15-20 kts in the Valley and up to 20-30 kts over the mountains before lowering to light winds after 10z Monday. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$

465 FXUS65 KMSO 270905 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 305 AM MDT Mon Apr 27 2026 .DISCUSSION... KEY MESSAGES: - Frost possible each morning through mid week - Slow warming trend with lingering showers, especially during the afternoon and evening A broad upper level trough remains the dominant feature across the Northern Rockies, maintaining north to northwesterly flow through midweek. This regime will sustain unseasonably cool conditions and persistent shower activity across western Montana and north central Idaho. Diurnal clearing will facilitate efficient radiational cooling, pushing overnight lows below freezing for most valleys, while high-elevation terrain will likely drop into the low 20s. Within this flow, a series of subtle shortwaves will trigger isolated to scattered showers, with coverage and intensity peaking during the afternoon hours as modest instability develops. Activity should diminish rapidly after sunset each evening. The synoptic pattern shifts significantly Thursday into Friday as an amplified ridge of high pressure builds over the region. This transition will initiate a robust warming and drying trend, with Friday`s max temperatures projected to reach approximately 10 degrees above seasonal normals. While the ridge remains the primary driver, a weak disturbance traversing the Canadian border may introduce localized cloud cover and light precipitation across far northwest Montana Friday afternoon. Looking into the weekend and beyond, long-term guidance continues to advertise a significant low pressure system impacting the Western U.S., though model divergence persists regarding its exact trajectory. Current ensemble models favor a more southerly track (80% probability), keeping the primary energy and deeper moisture well south of western Montana and north-central Idaho. Under this scenario, the region would likely see increased shower activity associated with the system`s northern periphery, though high snow levels should mitigate any snow impacts. && .AVIATION...North to northwesterly flow aloft will maintain a regime of diurnally driven shower activity across western Montana and north-central Idaho through midweek. Predominant VFR conditions are expected to prevail, though localized MVFR/IFR reductions in visibility and ceilings are possible within more robust afternoon showers, particularly over terrain where mountain obscurations may occur. Any convective activity will diminish rapidly after sunset as the boundary layer stabilizes. Surface winds will see the current easterly gradient gradually relax through the remainder of the morning hours, transitioning to a light and variable or terrain-driven flow by the afternoon. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$

053 FXUS65 KBOI 270834 AFDBOI Area Forecast Discussion National Weather Service Boise ID 234 AM MDT Mon Apr 27 2026 .KEY MESSAGES... - Afternoon rain and snow showers over higher terrain through Wednesday. - Gradual warming trend through the week. - Thunderstorms possible this weekend. && .SHORT TERM /Through Wednesday Night/... A very slow moving trough keeps conditions cool and unsettled through Wednesday. Shortwaves embedded in the trough provide sufficient forcing for afternoon showers in Eastern Oregon and Central Idaho. Modest CAPE could see a few showers become thunderstorms each day. As the trough exits, shower activity becomes limited to Central and Southern Idaho Wednesday afternoon. Temperatures rise through the forecast, starting at 5 degrees below normal today and warming to just above normal Wednesday. && .LONG TERM /Thursday through Monday/... A broad upper level ridge will move over the area Thursday and Friday, continuing a warming trend. Temperatures Thursday will increase to around 5-8 degrees above normal, then rise by another 3- 5 degrees on Friday with similar temperatures over the weekend. This translates to lower valley highs in the upper 70s to lower 80s. Dry conditions with light winds are expected Thursday and Friday. On Saturday, ensemble guidance indicates that an upper low will dive south along or near the coast and become cut off and nearly stationary Sunday and Monday, but location of the low is uncertain. A more inland track over California and the Great Basin would bring showers and thunderstorms to our area, but models also indicate the potential for the low to remain offshore, which would keep our area warmer and drier. The net result in the uncertainty is a 10-30% chance of showers and thunderstorms on Saturday, increasing to a 20- 50% chance Sunday and Monday, highest in the mountains and near the Nevada border. The forecast calls for above normal temperatures through Monday, but would trend cooler if the wetter pattern becomes more likely. && .AVIATION /06Z Monday through Tuesday/... Issued 1132 PM MDT SUN APR 26 2026 VFR with scattered mid-high clouds overnight. Snow levels 4500-5500 ft MSL. Scattered showers will return over higher terrain in the afternoon, with isolated thunderstorms over SE OR near KBKE and KONO. Surface winds: variable under 10 kt and SW 7-15 kt over Magic Valley overnight through morning, then becoming W-NW 10-15 kt with gusts 25-30 kt in the afternoon. Strongest winds east of KBOI. Winds aloft at 10kft MSL: W-NW 15-25 kt. KBOI...VFR. Surface winds: light and variable overnight through morning, then becoming NW 10-15 kt with gusts up to 20 kt in the afternoon. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise SHORT TERM...JM LONG TERM....ST AVIATION.....JY

720 FXUS65 KLKN 270701 AAA AFDLKN Area Forecast Discussion...Updated National Weather Service Elko NV 1201 AM PDT Mon Apr 27 2026 .KEY MESSAGES... * Periods of valley rain and mountain snow today * A few strong thunderstorms possible this afternoon * Unseasonably cool today * Warming trend Tuesday through Saturday && .UPDATE... Issued at 1201 AM PDT Mon Apr 27 2026 The current forecast is on track. No updates are planned. && .DISCUSSION... (Today through Sunday) WEATHER PATTERN OVERVIEW: An atmospheric impulse will move eastward across the forecast area today. There is a pesky upper level low hanging around south-central Canada and a persistent trough over northern and central Nevada. This will keep the threat for showers across the area with the highest pops centered in Central Nevada. In addition, surface based CAPE values of 100 to 250J/kg and marginal instability may bring isolated thunderstorms to portions of Northern and Central Nevada. Main threats will be wind gusts to 45 mph and cloud to ground lightning strikes. Highs will be in the 50s for the most part though locales in Central Nevada that will be seeing rain may only make it into the upper 40s. Winds will be light. During the overnight, the light precipitation is expected move off to the east and gradually end. Overnight lows will be in the 20s and 30s. Expect a brief break in the weather Tuesday morning, but the aforementioned pesky trough will hang over portions of Eastern Nevada. This could be enough to set off instability showers during the late morning and afternoon hours. Not much in the way of precipitation is expected with this feature. Highs will be a bit warmer than today with readings in the 50s and 60s. Winds are expected to remain light. Look for clouds to scatter out during the overnight hours with lows in the 30s. Northern and Central Nevada will be in between weather systems Wednesday. Some isolated showers will be possible in Eastern Nevada, but for the most part, the weather is expected to remain quiet. Little to no precipitation is expected. Highs will be warming to the mid to upper 60s. Winds will be on the light side. Quiet weather expected for Wednesday night with lows in the 30s. Thursday through next Sunday, models are hinting at a dry and quiet period through this time frame. The main story will be the warming afternoon highs, reaching the mid to upper 70s Friday and Saturday. Lows will be in the 30s and 40s with light winds. FORECAST CONFIDENCE & DEVIATIONS: Confidence is high with the current system bringing precipitation to Central and portions of Northern Nevada today. Confidence is low to moderate with isolated thunderstorms forming this afternoon. Confidence is moderate for the drying out period for the mid to late week with a warming trend by the late week. && .AVIATION... VFR conditions will be the predominant flight category across the northern TAF sites of KWMC, KBAM, KEKO, and KENV. Chances for precipitation and lower CIGS/VSBY will be greater over KTPH and KELY. In addition, will keep VCTS across the central terminals due to marginal instability with main threat from -TSRA strong wind gusts to 40KT. && .LKN Watches/Warnings/Advisories... None. && $$ DISCUSSION...86 AVIATION...86