014 FXUS66 KSEW 290924 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 224 AM PDT Wed Apr 29 2026 .SYNOPSIS... High pressure will resume today for warmer temperatures and sunnier skies today. A weak, dry front will progress through the region late Thursday into Friday for another round of cloud cover and reduced temperatures, but high pressure amplifies over the weekend and into early next week. && .SHORT TERM /TODAY THROUGH FRIDAY/... Expect a much sunnier day with temperatures climbing into the upper 60s as high pressure returns to the region. Winds will be light and generally out of the north. A break in the high pressure pattern is in store for late Thursday into Friday as a weak front moves through the region. This will bring an increase in cloud cover and a few degrees cooler on Friday. Temperatures on Thursday will be in the low 70s, approaching the upper 70s in the Chehalis Valley. This corresponds to minor HeatRisk through Friday. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Clouds will stick around through Friday night, though the temperatures will still be pleasant in the upper 60s and low 70s. High pressure developing along the west coast will continue to amplify late in the week and into the weekend. Clearing skies and thermal trough developing along the coast are increasing confidence in temperatures climbing to the 80s by Sunday. The locations with the highest likelihood of seeing the upper 80s will be the Chehalis Valley and some of the Cascade valleys. This is also suggesting a 30-40% chance of moderate HeatRisk in areas generally south of the Seattle Metro area, and above 50% in the aforementioned warmer locations. In addition to the temperatures climbing, afternoon relative humidity values will be decreasing. Right now, the forecast calls for minimums on Sunday afternoon of 28-38%. While not in the peak of our dry season, it`s never too early to start taking extra precautions around sources of ignition and mitigating those. Temperatures will remain warmer through Monday before decreasing a few degrees on Tuesday as onshore flow returns and the ridge begins to flatten. 21 && .AVIATION... High pressure will shift inland today with a dry and stable air mass over western WA. Skies are mostly clear along the coast with a BKN-OVC layer around 6000 ft in the interior. This layer will scatter out this afternoon for VFR conditions across the board. Low clouds may return to the coast overnight and into Thursday morning. 33 KSEA...VFR today with a cloud layer around 6000 ft this morning. Skies becoming mostly clear this afternoon. Light N wind around 5 kt this morning and 5-8 kt this afternoon/evening. 33 && .MARINE... High pressure is offshore with lower pressure inland, maintaining onshore flow across western WA. A stronger push down the strait is expected Thursday afternoon and evening with a weak front. The flow turns more N to NE (and offshore) over the weekend with low pressure to our south. 33 && .HYDROLOGY... No river flooding is expected in the next seven days. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$

567 FXUS66 KPQR 291101 AFDPQR Area Forecast Discussion National Weather Service Portland OR 401 AM PDT Wed Apr 29 2026 .SYNOPSIS...High pressure strengthens over the region Wednesday and Thursday, delivering the warmest weather of the week. A weak, moisture-limited trough brushes the Pacific Northwest Friday into Saturday, bringing a slight cool-down and low-end Cascade shower chances. With warm and dry conditions returning Sunday and Monday, continue to keep cold water safety in mind as local rivers remain cold enough for cold water shock. && .DISCUSSION...Today through Tuesday... Satellite imagery as of early Wednesday morning depicts a few/scattered clouds across northwest Oregon and southwest Washington as skies slowly begin to clear out. These clearing skies are supporting efficient radiational cooling, especially across the Upper Hood River Valley. This morning`s low temperature forecast for the Upper Hood River Valley was adjusted slightly colder to the low to mid 30s based on current observations. A Frost Advisory remains in effect for the Upper Hood River Valley through 8 AM this morning, with the highest threat for frost being above 1000 feet elevation where temperatures are coldest. Warm and sunny weather returns today and Thursday as an upper- level ridge builds overhead and a drier airmass settles in. There is high confidence (80-90% chance) that afternoon temperatures reach the upper 60s to low 70s today, then climb into the upper 70s to near 80 on Thursday. The Greater Portland/Vancouver Metro down to Aurora have the best chances of exceeding 80 degrees on Thursday (about 80-90%), while the remainder of the I-5 corridor is lower (roughly 30-50%). Winds remain light and generally northerly. Overnight lows should continue to drop comfortably, keeping heat-related impacts limited. Friday into Saturday, ensemble guidance remains consistent in showing the ridge weakening and shifting eastward as a weak trough drops in from Canada. Moisture with this trough appears limited, so most areas should stay dry. The only location with a meaningful precipitation signal remains the Cascades (including the Cascade foothills), where orographic lift will support a 15-30% chance for light showers; elsewhere probabilities remain below 10%. Temperatures will cool a few degrees with the passage of this weak trough, but remain seasonably warm. Sunday into Monday, the majority of ensemble members depict the aforementioned trough shifting southeast and becoming a closed low towards California while upper-level ridging rebuilds over the Pacific Northwest (rex block pattern). This will favor another warm-up with dry weather prevailing for most lower elevations; the Cascades could still see occasional light showers due to wrap-around moisture from the south. Guidance continues to show very high confidence (>95%) for temperatures exceeding 80 degrees across interior valleys on Sunday, with a 50-70% chance for exceeding 90 degrees across the Portland/Vancouver Metro Area. If KPDX (Portland Int`l Airport) reaches 90 degrees on Sunday, May 3rd, not only would this break the daily record of 89 degrees set back in 1992, it would also be the second earliest day of the year where the airport reached 90 degrees. The earliest KPDX reached 90 degrees was April 30, 1998. The upper-level ridge breaks down Monday to Tuesday, gradually cooling temperatures back down into the 70s. During this late-week warmth, those recreating on area rivers should remain aware of water temperatures, which remain cold enough for cold water shock, even on hot afternoons. Wear a personal floatation device and use extra caution around fast, cold water. -10/12 && .AVIATION...Satellite imagery as of early Wednesday morning depicts FEW/SCT clouds across northwest Oregon as conditions gradually clear up. High confidence for predominately VFR conditions through the TAF period, as chances for MVFR CIGs are only 10-20% for all terminals through 16-17z Wed. High pressure will build today, leading to sunny skies by this afternoon. Northerly winds under 5 kt across the region through 17-18z Wed, then strengthening in the afternoon as pressure gradients tighten. Northerly winds for inland terminals remain under 10 kt this afternoon, while the coast remains breezier with gusts up to 20 kt between 21z Tue-02 Wed. KPDX AND APPROACHES...VFR conditions through the TAF period with mostly clear skies. 10-20% chance for MVFR CIGs this morning through 16-17z Wed. Northerly winds under 10 kt today. -10 && .MARINE...High pressure offshore will maintain northerly winds across the waters through the end of the week. Northerlies strengthen each afternoon and evening as pressure gradients tighten over the coastal waters due to strengthening surface thermal trough near the southern Oregon coast. Wind gusts are expected to remain below 20 kt through this afternoon. This evening through at least Friday, there is high confidence (70-90% chance) for at least occasional small craft wind gusts up to 20-25 kt. The strongest gusts would mainly be south of Cape Falcon. A Small Craft Advisory has been issued for the waters south of Cape Falcon beginning 2 PM this afternoon and lasting through 11 PM for the inner waters (from shore to 10 NM) and through early Friday morning for the outer waters (beyond 10 NM offshore). A Small Craft Advisory has also been issued for the Columbia River Bar due to a strong ebb current between 2-7 AM Thursday. Seas of 6 to 8 ft are expected to persist through the week with a northwesterly swell. Mid-period swells of 12-15 seconds will also result in a moderate sneaker wave threat at beaches Wednesday and Thursday. Those participating in razor clam digs should take extra precaution. -10/DH && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Frost Advisory until 8 AM PDT this morning for ORZ121. WA...None. PZ...Small Craft Advisory from 2 AM to 7 AM PDT Thursday for PZZ210. Small Craft Advisory from 2 PM this afternoon to 11 PM PDT this evening for PZZ252-253. Small Craft Advisory from 2 PM this afternoon to 5 AM PDT Friday for PZZ272-273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

007 FXUS66 KMFR 291149 AFDMFR Area Forecast Discussion National Weather Service Medford OR 449 AM PDT Wed Apr 29 2026 .DISCUSSION...Updated aviation discussion. && .AVIATION...29/12Z TAFs...Areas of low clouds and/or fog along the coast and in portions of the Umpqua Basin through around 17Z; otherwise, VFR will prevail across the forecast area through this evening. Some cumulus will develop over the East Side this afternoon and evening, but precip chances are low. Marine stratus and fog probably returns to the coast tonight into Thursday morning, especially north of Cape Blanco. -Spilde && .PREV DISCUSSION... /Issued 333 AM PDT Wed Apr 29 2026/ KEY MESSAGES... -Upper ridging builds into the area today resulting in above normal warmth through late week. -Above normal temps likely continue this weekend. -Upper trough forms into a closed low offshore Friday. -Shower and t-storm chances increase Friday/Saturday, peak Sunday/Monday as the low moves onshore into California. -Cooler temperatures Monday/Tuesday; showers/storms linger, especially Cascades eastward Tuesday. -Upper ridge rebuilds by mid next week. DISCUSSION...High pressure aloft will build into the area today. There is still a weak trough that will swing down east of the Cascades and this could lead to some cumulus over the East Side along with some virga, but precipitation chances are low (10% or less). Other than some low clouds for coastal valleys and the Umpqua Basin this morning, expect mainly sunny skies elsewhere today. For the area as a whole, high temperatures will be a few to several degrees higher than yesterday. With a thermal trough setting up in NorCal, we expect some breezy north winds along the coast in the afternoon/evening. The ridge will move in overhead on Thursday and then push inland into the Intermountain West and the Great Basin on Friday. This will maintain the warmth in our area with high temps generally 5-15F above normal. We`d like to remind everyone that even when the air is warm, area waterways are still quite cold this time of year. Water temperatures are only in the upper 40s and 50s! So, always wear a life jacket, don`t swim alone and have a flotation device ready just in case. Meanwhile, an upper trough in the northeast Pacific will be "squeezed" southeastward along 130W as another strong ridge amplifies out near 140W. This will cause the trough to develop into a closed low off the PacNW Friday, which will settle southward and be offshore of the California coast this weekend. This will set up a "Rex block" (high over low) that will linger over the West into next week. Movement of weather systems in this type of regime will be slow. Areas farther to the north and closer to the upper high (northern Oregon and Washington) will largely maintain a warm, dry pattern. However, areas farther south and closer to the closed low offshore, will see a surge in moisture and instability. This could lead to a relatively active weather pattern down here with increasing chances for showers and thunderstorms. This could begin as early as Friday afternoon/evening. Models are showing weak instability near the Cascades then, so there is a slight chance of late afternoon/evening showers and thunderstorms there and also perhaps an isolated shower/t-storm near the coast range mountains. Moisture and forcing gradually increase this weekend, and peak Sunday into Monday as the low eventually moves onshore into California to our south. Currently, it still looks like Sunday and Monday feature the most widespread chances, including along the coast. Temperatures will cool down by Monday since we`ll generally be in the cloudier, showery pattern. The focus for shower/t-storm activity shifts to east of the Cascades on Tuesday as the cut off low gradually shifts eastward. Models then show upper ridging returning toward the middle of next week with the air mass warming again. -Spilde AVIATION...28/06Z TAFs...Some low clouds and patchy MVFR is possible in the Umpqua Valley and along the coast tonight and early Wednesday. Otherwise, VFR conditions will prevail across the forecast area for most of Wednesday. -Smith MARINE...Updated 300 AM PDT Wednesday, April 29, 2026....A thermal trough pattern will bring strong north winds through Saturday. North winds will reach peak strength during Thursday and Friday afternoons. The strongest winds and very steep seas are expected south of Port Orford this afternoon and evening, and are likely again Thursday afternoon through at least Friday evening. Meantime, seas will be steep elsewhere. Steep, fresh swell may linger while winds diminish and turn southerly Saturday night into Sunday. && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 8 PM PDT Friday for PZZ350-356-370-376. Hazardous Seas Warning from 2 PM this afternoon to 11 PM PDT this evening for PZZ356-376. Hazardous Seas Watch from Thursday afternoon through Friday evening for PZZ356-376. && $$

460 FXUS66 KEKA 290849 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 149 AM PDT Wed Apr 29 2026 .SYNOPSIS...The possibility of interior thunderstorms increases Friday into Sunday as an area of low pressure begins to organize by the end of the week. && .DISCUSSION...Marine stratus filling in overnight into Wednesday morning as low level inversion is further enhanced behind high pressure and subsidence, albeit a weak ridging pattern with gaps not encouraging vorticity. The gradient will not be particularly steep across isobars until a more uniformed and defined system begins to form Saturday, strengthening Sunday. That said, GFS is highlighting MUCAPE and RH with an embedded shortwave late Friday afternoon into the early evening for the interior areas of Siskiyou, western Trinity and in a linear succession down to northeastern Mendocino and western Lake county. The mean surface CAPE from NBM is highlighting most of the interior starting Friday which could be attributed to surface heating and parcel buoyancy but with increasing humidity there could be implications for thunderstorm activity. Ensembles also show a rise in PWAT values rising into the weekend for what could be thunderstorms with the chance of lightning Friday through Monday at least. NBM begins to include Del Norte Saturday early evening for 15% and greater chances of thunder which also coincides with high CAPE values in the 700-800j/kg range. /EYS && .AVIATION...00Z TAFs...Stratus expanded out from Humboldt Bay Tuesday evening. Confidence is growing on southerly return flow from a coastal eddy to advect stratus up to CEC through Wednesday morning. MVFR to IFR CIGS expected at ACV (53% chance for IFR). There is a lesser chance (20%) for LIFR in the 13-16Z Wednesday timeframe at ACV. CIGS at CEC will mainly range in MVFR levels for a chance (26%) for IFR. UKI is expected to remain VFR with very little indications for a surge push of stratus up the Russian River Valley. Chances for this occurrence and resulting MVFR CIGS are 21%. && .MARINE...Northerly winds will continue their strengthening trend through Friday. Gale to near gale conditions will be possible in the waters by Thursday. The inner water buoys are recording up to 8 ft short period seas Tuesday night, with propagation from the outer zones where the stronger northerlies continue. Small Craft advisories remain in all zones to cover the wind and steep sea threat to smaller vessels. A brief period of lower seas is possible Wednesday morning and early afternoon so the advisories end early Wednesday morning. However, winds and seas will build further by Wednesday afternoon and advisories will need to once again be issued for those areas starting as early as mid afternoon on Wednesday. Persistent winds over the outer waters will keep seas elevated and winds in small craft criteria to near gale Wednesday into Wednesday night. As the pressure gradient further strengthens, gale force gusts will become likely Thursday afternoon through Friday night in the outer zones. Gale conditions may linger into Saturday before winds begin substantially easing late Saturday afternoon. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 5 AM PDT early this morning for PZZ450. Small Craft Advisory until 6 AM PDT early this morning for PZZ455. Small Craft Advisory until 3 PM PDT Thursday for PZZ470. Gale Watch from Thursday afternoon through late Friday night for PZZ470. Small Craft Advisory until 11 PM PDT this evening for PZZ475. Gale Watch from this evening through late Friday night 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

361 FXUS66 KMTR 291123 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 423 AM PDT Wed Apr 29 2026 ...New AVIATION, MARINE... .KEY MESSAGES... Updated at 1257 AM PDT Wed Apr 29 2026 - Overnight and early morning stratus returns to the forecast - Warming and drying trend continues into the late week for areas away from the coast - Cooler conditions return this weekend with a chance of drizzle and/or light rain into early next week && .SHORT TERM... Issued at 1257 AM PDT Wed Apr 29 2026 (Today and tonight) Coastal Stratus is building along the SF Peninsula and around Point Reyes. This cloud cover will be spotty along the coast, will build further into the night, affecting the bays. This is a good indicator that the marine layer is becoming more stable, and looks to stay intact despite the ridging pattern to the north. A big player in retaining the marine layer is the cut off low to the south west which will prevent too much of a climb in pressure and keep the marine zones and immediate coast on the breezier side. While the marine influence will keep coastal and slightly inland temperatures fairly stable over the next few days, areas further inland will continue the warming trend. Wednesday offers highs in the 60s along the coast, areas inland into the mid to upper 70s and a few spots breaking 80. This looks to be a slight decrease from previous model runs, as the ridge to the north seems to have slightly weekend in the forecast update. Overnight lows will also see the opportunity to warm, but strong humidity recoveries and increasing marine influence will make the overnight warming trend much more modest. && .LONG TERM... Issued at 1257 AM PDT Wed Apr 29 2026 (Thursday through Tuesday) The warming trend continues Thursday and Friday. For areas in the North Bay and potions of the rest of the SF Bay will see fairly similar temperatures on both days with the warmest interior locations breaking into the lowers 80s. The bigger difference will be felt in the interior south bay and the more interior portions of Monterey and San Benito counties: going from the lower 80s on Thursday to the mid to upper 80s for Friday. The trend breaks on friday as the ridge pushes east and weakens. High-level clouds build through Saturday as a low pressure and trough builds along the Pacific coast. This low will also call for expanding the marine layer both in height and inland push, and along with increasing onshore flow, will allow for a strong cooling trend through the weekend. Models are in better agreement for good rain chances, but not a lot in accumulation from this low pressure moving inland. Drizzly conditions look to start Sunday morning with the chances for passing light showers building into that night and lasting into the work week. Models still need to iron out the finer details of the exit of this low, but there is good agreement that rain conditions could last into next Tuesday, before another ridge and warming trend begin. && .AVIATION... (12Z TAFS) Issued at 423 AM PDT Wed Apr 29 2026 Shallow stratus is spreading along the coast and into portions of the Bay Area. This will bring local MVFR to IFR conditions with the potential for fog to develop across the North Bay Valleys. Clearing looks to occur by 17/18Z with stratus returning again tonight as a relatively deep marine layer persists. Breezy onshore winds return during the afternoon/evening before winds ease again overnight. Moderate confidence in timing of stratus return for tonight. Kept a later arrival (07-12Z) for most sites to stay in line with LAMP guidance but some models suggest an earlier arrival is possible. Vicinity of SFO...Patchy stratus is drifting through the San Bruno Gap producing temporary MVFR CIGs at SFO. Moderate confidence that MVFR CIGs will fill in at SFO over the next hour and then persist through late morning. Gusty winds return this afternoon with gusts peaking around 24-25 knots. Stratus returns late this evening. The TAF currently has stratus returning around 07Z but LAMP guidance suggests it could occur closer to 09Z. SFO Bridge Approach...VFR this morning. Stratus is not expected to fill in over the SF Bay this morning but models do show stratus filling in over the bay tonight as a deeper marine layer develops. Monterey Bay Terminals...Currently VFR with some potential for LIFR conditions to return later this morning. Up until the last hour, MRY was reporting stratus and LIFR conditions. Satellite shows an eddy developing over the bay that pulled stratus away from land. Guidance shows a decent chance for stratus to return to MRY so have kept in a tempo for them but removed stratus chances from SNS. Breezy afternoon winds return before easing overnight. Stratus is expected to return again tonight with moderate confidence in the current timing. Current thinking is that more widespread stratus will return earlier tonight given the expected deeper marine layer. && .MARINE... (Today through Monday) Issued at 423 AM PDT Wed Apr 29 2026 Breezy, fresh to strong northerly winds continue to bring locally hazardous conditions for small crafts into the weekend. Significant wave heights, driven by the stronger winds, build late week into the weekend with fresh swell between 8 to 12 feet expected. Winds diminish and seas abate late weekend into next week. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Thursday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory from 3 PM this afternoon to 3 PM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 3 PM PDT Thursday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Murdock LONG TERM....Murdock 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

212 FXUS66 KOTX 291113 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 413 AM PDT Wed Apr 29 2026 .KEY MESSAGES... - Warmer and drier conditions Wednesday into the upcoming weekend. && .SYNOPSIS... Temperatures begin a gradual warming trend through the rest of the week. By Monday, high temperatures will be in the 80s, with some isolated areas seeing 90. && .DISCUSSION... Today through Thursday: A ridge positioned off the Canadian coast will migrate eastward through the forecast area. This northwest flow will keep things mainly dry and warming, with little to no impacts expected. A shortwave disturbance embedded within the flow will move through later today, resulting in a low chance for rain in the mountains due to orographic lift. With these higher heights moving in, temperatures continue to warm by a few degrees each day. By Thursday, maximum temperatures will reach the low 70s and minimum temperatures will reach the mid 40s. Friday through Tuesday: As the ridge moves eastward and weakens, a second, stronger ridge begins strengthening off the Canadian coast Friday into Saturday. At this point, the main forecast question becomes: how warm will it get? Earlier disagreement in previous cluster runs showed a small chance for a low pressure system off the California coast to keep the higher heights at bay; that small chance has disappeared. As the low tracks eastward, temperatures in the Inland Northwest are expected to warm into the high 70s to low 80s by the beginning of next week, which is roughly 15 degrees above normal. Some areas such as the Moses Lake, Wenatchee, Omak, Chelan, and Coulee Dam areas could hit 90 degrees. With these warming temperatures, Minor HeatRisk values are expected nearly regionwide, primarily affecting those extremely sensitive to heat. /AS && .AVIATION... 12Z TAFS: VFR conditions with light winds are expected through the forecast period. Sky conditions will continue to clear as a ridge begins to stabilize the region. 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 66 42 72 45 74 48 / 10 0 0 0 0 0 Coeur d`Alene 64 41 70 44 73 46 / 10 0 0 0 0 0 Pullman 63 41 68 43 72 47 / 10 0 0 0 0 0 Lewiston 68 44 74 45 77 49 / 0 0 0 0 0 0 Colville 71 39 76 42 77 46 / 10 0 0 0 0 0 Sandpoint 63 40 69 42 71 46 / 20 0 0 0 0 0 Kellogg 62 40 69 44 72 48 / 30 10 0 0 0 0 Moses Lake 72 42 77 45 80 51 / 0 0 0 0 0 0 Wenatchee 71 49 76 52 77 56 / 0 0 0 0 0 0 Omak 73 45 77 47 79 51 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...None. ID...None. && $$

988 FXUS66 KPDT 291101 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 401 AM PDT Wed Apr 29 2026 .KEY MESSAGES... - Temperatures warming to above normal through early next week - Uncertainty late Friday through early next week in potential for mountain shower and thunderstorm activity && .DISCUSSION...Today through Friday: A weak shortwave exiting the area has lead to cloudy conditions across the eastern half of the forecast area tonight. Radar tonight does show very weak echo returns across portions of the Blues, though surface observations show nothing making it to the ground at this time. Across the remainder of the forecast area, winds have become light, with otherwise quiet conditions at the surface. Today, an upper level ridge will build over the PacNW and persist overhead through early Friday (confidence 80-90%). The building high pressure aloft will result in drying and warming conditions across much of the forecast area. High temperatures will warm well above normal into the upper 70s to lower 80s across the lower and mid elevations by Friday afternoon. The upper ridge will flatten and push east as an upper trough sets up offshore the PacNW the second half of Friday. Conditions will remain mostly dry across the forecast area, however increasing southerly flow with and embedded shortwave impulse will bring isolated shower chances to the Cascade crest late in the afternoon and overnight (confidence 55-65%) Saturday through Tuesday: Ensemble cluster guidance begins in good agreement of the aforementioned upper trough digging south and transitioning into a closed low off the northern CA coast late Saturday. During this time, the trough/low will place a southerly flow into OR, allowing weak instability to develop over the eastern mountains and OR Cascades. This will lead to slight chances (15-20%) of isolated showers developing with a slight chance (~15%) of isolated thunderstorms as well. Sunday through Tuesday, while overall agreement in the development of the closed low and it`s eventual push inland is high amongst ensemble members of the ECMWF, GFS, and Canadian, there is disagreement surrounding the location of the low offshore, the extent of the low, and the timing of it`s transit inland. Scenarios range from a smaller low further offshore that would keep central OR and adjacent mountain areas dry, while a larger low circulation and/or a low centered closer to northern CA would produce isolated to scattered shower chances with isolated thunderstorms for Sunday. Monday and Tuesday, there is moderate confidence (40-55%) that the low`s passage inland will bring shower and isolated thunderstorm chances across portions of central OR and the eastern mountains, however there is low confidence (15-25%) in timing and location of best chances of showers/thunderstorms owing to timing differences in the low moving inland. In addition to impacts from the closed low, ensemble cluster solutions depict upper level ridging developing poleward of the low, resulting in continued above normal temperatures for the inland PacNW. By Monday, there will be a 50-70% chance for high temperatures to exceed 90 degrees across portions of Yakima valley and the WA Columbia Basin. Across the remainder of the lower Columbia Basin, the Gorge, Kittitas valley, and the John Day basin there is a 45-70% chance of exceeding 85 degrees Monday afternoon. Lawhorn/82 && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...VFR conditions to prevail through period. Winds will be light, 12kts or less, at all sites. Lawhorn/82 && .Preliminary Point Temps/PoPs... PDT 68 42 75 45 / 0 0 0 0 ALW 69 46 75 49 / 10 0 0 0 PSC 74 44 80 45 / 0 0 0 0 YKM 73 44 77 47 / 0 0 0 0 HRI 72 42 78 44 / 0 0 0 0 ELN 68 42 73 43 / 0 0 0 0 RDM 66 34 72 37 / 0 0 0 0 LGD 66 38 71 41 / 10 0 0 0 GCD 65 37 71 42 / 20 10 0 0 DLS 73 47 80 50 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...None. OR...None. && $$ DISCUSSION...82 AVIATION...82

507 FXUS65 KREV 290858 AFDREV Area Forecast Discussion National Weather Service Reno NV 158 AM PDT Wed Apr 29 2026 .KEY MESSAGES... * Patchy fog may impact this morning`s commute, especially near Truckee. * Warmer and drier weather into the weekend with low chances of afternoon showers near the Sierra crest today and Thursday. * Chances of rain and mountain snow showers, thunderstorms, and gusty winds increase this weekend and linger into early next week. && .DISCUSSION... Clear skies and minor warming above the surface should allow pockets of fog/freezing fog to redevelop overnight in NE California and the E Sierra -- especially after another afternoon of light showers. Most notably, freezing fog is favored near Truckee where the morning commute may be met by reduced visibilities and slick roads. This includes the stretch of I-80 between Boca and Donner Lake. Be sure to drive slow and leave extra space between cars if encountering fog. Exiting low pressure will allow dry, N/NW flow to overspread the region today, encouraging a warming and drying trend that lasts into the weekend. Drier air and a stable upper layer will largely suppress shower and thunderstorm potential until the weekend, but there is a low chance (10% or less) of isolated showers near the Sierra crest in the afternoon today and Thursday. Otherwise, warmer days are in store as daytime highs go from 60-70F today to upper 60s and upper 70s on Saturday. Some communities in NE CA and W NV valleys may even see highs reach 80F Saturday afternoon. Potential for unsettled weather increases over the weekend as a closed low approaches the western states. However, questions still remain on how this low will evolve next week given existing model disagreements, lending to higher uncertainty in timing and intensity of storm impacts. Generally, more isolated shower activity begins Saturday afternoon -- favoring the eastern Sierra -- before increasing in likelihood and coverage each day through Monday or Tuesday. Thunderstorm potential follows a similar trend, although Sunday stands out as a more favorable day based on the location of an upper level jet and attendant large scale ascent. Sierra snowfall will be quite sensitive to the low`s progression as snow levels remain well above mountain passes until a pocket of cold air at the low`s center moves inland. Guidance suggests this happens Monday or perhaps early Tuesday, however the window for accumulating snow at pass level (or lower) is rather brief as rising snow levels will confine snow to highest Sierra peaks on Wednesday of next week. As mentioned, forecast confidence is low at this point, and any variations in the storm`s passage can shift when what was described above occurs and how impactful it will be. -Salas && .AVIATION... The primary near-term concern will be periods of FZFG and IFR/LIFR conditions overnight at KTRK. Like yesterday, the most favorable timeframe for fog will be between 10Z and 16Z before mixing out/increasing CIGS and VIS. Minimal change in the weather pattern should allow FZFG to redevelop tonight into Thursday. Otherwise, VFR conditions and light breezes today with increasing low/mid clouds in the afternoon. Sole concern will be terrain obscuration and a 10% chance of showers at KTRK-KTVL-KMMH this afternoon. -Salas && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$

178 FXUS66 KSTO 281859 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1159 AM PDT Tue Apr 28 2026 .KEY MESSAGES... - One more afternoon and evening of mountain showers and thunderstorms today. Thunderstorms should be limited to Sierra (20-30% chance). - Dry weather and warming temperatures through Saturday. - Next system possibly late Saturday early next week with low confidence at this time. && .DISCUSSION... ...Remainder of Tuesday and evening... The upper level trough in the area will continue to bring some lift and instability to the area. Expect scattered showers and thunderstorms through this evening. Instability isn`t too bad, up to around 400 J/Kg so some isoalted stronger cells with heavy rain will be possibly this evening over the Sierra. This trough moves out of the area tonight with upper level high pressure building into the area Wednesday through Saturday. This will bring warm amd mild conditions with high temperatures in the 80s. Confidence in location and timing of the next system remains. Ensemble means have been trending to take the upper system more off shore which would mean less clouds and precipitation. Upper diffluence and forcing from this system would possibly bring chance of mountains showers later on Saturday but perhaps as late as Sunday. Still a fair amount of uncertainity at this time. This pattern would also put the valley at risk of showers and thunderstorms depending where it sets up. Stay tuned to updates but overall this doesn`t appear to be very impactful system either way. && .AVIATION... VFR conditions at TAF sites next 24 hours. Light surface winds generally 10 kts or less. Local MVFR conditions from scattered mountain showers and isolated thunderstorms this afternoon and evening until around 03z Wednesday. A few light showers may develop over the Sierra south of Highway 50 Wednesday afternoon. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$

592 FXUS65 KMSO 290913 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 313 AM MDT Wed Apr 29 2026 .DISCUSSION... KEY MESSAGES: - Showery conditions through Wednesday. - April showers are out; May flowers (and 70s!) are in. Expect a 10-degree warm up above the seasonal norm by Friday, May 1st, sticking with us through early next week. - Low probability for isolated thunderstorms this weekend over Divide and/or southern Bitterroot Mountains. A large upper-level ridge of high pressure currently centered over the Pacific coast will begin shifting eastward today. This transition will bring slightly milder, near-seasonal temperatures to our region. While dry periods are expected, scattered showers will remain possible throughout the morning, becoming more numerous during the afternoon hours. Some patchy fog has formed this morning but will largely lift by mid morning. As we move toward the end of the week, the strengthening ridge will trigger a notable warming trend, ushering in pleasant spring conditions to start May. By the weekend, high pressure will establish itself over the British Columbia coast, extending its influence across western Montana and north-central Idaho. Although a few weak atmospheric disturbances (shortwaves) tracking south could bring occasional cloud cover or an isolated shower or thunderstorm to the mountains, the overall trend remains warm. Looking ahead to next week, confidence is increasing that warm and dry weather will extend into mid week. Current ensemble models show 90 percent agreement that a low-pressure system will remain well to our south, allowing the warm ridge to persist through Monday and Tuesday. && .AVIATION...VFR conditions will generally prevail across the region today, though localized valley fog and low stratus will persist through mid-morning before lifting. KGPI remains the primary concern this morning, as variable visibilities and ceilings have resulted in conditions bouncing between MVFR and LIFR. Expect improvement to VFR at the terminal by 15Z. Shower coverage overall will be less than yesterday, but diurnal heating will trigger scattered afternoon showers, potentially leading to brief MVFR conditions due to showers and localized terrain obscurations. Surface winds will remain light, generally favoring a north to northeasterly flow across all terminals. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$

929 FXUS65 KBOI 291120 AFDBOI Area Forecast Discussion National Weather Service Boise ID 520 AM MDT Wed Apr 29 2026 .UPDATE...Updated aviation discussion. && .KEY MESSAGES... - Afternoon showers and isolated thunderstorms today and tomorrow in mountains and near the Nevada border. - Gradual warming through Saturday. - 20% chance of afternoon thunderstorms early next week. && .SHORT TERM /Through Friday Night/... Issued 332 AM MDT WED APR 29 2026 A cool upper level trough continues to bring unsettled conditions to the area. Showers will develop this afternoon across high terrain and near the Nevada border. A few showers could develop into weak thunderstorms, but may still produce small hail and locally gusty winds. Thursday is largely the same story, with showers and storms relegated almost entirely to central and southern Idaho. Temperatures will continue their steady climb, reaching the low 70s in the lower valleys by Thursday afternoon. && .LONG TERM /Saturday through Wednesday/... Issued 332 AM MDT WED APR 29 2026 The warming trend peaks Saturday at 10 degrees above normal, with lower elevations seeing afternoon highs right around 80 degrees. Temperatures hold steady at this mark through the long term forecast. This weekend, a trough amplifies into a cut off low and holds itself off the West Coast this weekend. There is still a 10% chance for precipitation in Southeast and East Oregon over the weekend, but model runs have held firm on a drier solution at this time due to the low being too far west. As the low moves inland, Sunday presents a slightly better chance of precipitation before the more significant chance Monday and Tuesday. 6 hour precipitation chances increase to 20-30% Monday and Tuesday, with a showery precipitation mode. In the afternoon, the chance of thunder increases to near 20%. Thunderstorms will produce heavy rainfall and strong wind gusts. && .AVIATION /12Z Wednesday through Thursday/... Issued 513 AM MDT WED APR 29 2026 VFR and overcast this morning. This afternoon, scattered showers will develop over highlands and mountains. There is a 10% chance of lightning in these areas, and any thunderstorms could produce locally gusty winds and small hail. Precipitation tapers off this evening. Snow levels 6000-7000 ft MSL. Surface winds: light and variable under 10 kt, becoming W-NW 5-15 kt this afternoon. Winds aloft at 10kft MSL: W up to 10 kt. KBOI...VFR. Surface winds: light SE winds this morning, becoming NW 7-12 kt this 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 AVIATION.....JM SHORT TERM...JM LONG TERM....JM

101 FXUS65 KLKN 290911 AFDLKN Area Forecast Discussion National Weather Service Elko NV 211 AM PDT Wed Apr 29 2026 .KEY MESSAGES... * Warming trend thru Sunday * Showers and isolated thunderstorms Wednesday and Thursday afternoons * Strong, gusty south winds in Central Nevada this weekend && .UPDATE... Issued at 156 AM PDT Wed Apr 29 2026 The current forecast remains on track and no significant updates are required. && .DISCUSSION... (This evening through next Monday) WEATHER PATTERN OVERVIEW: High pressure attempts to move into the western U.S. the remainder of this week, prompting a gradual warming trend with afternoon high temperatures reading in the 70s by this weekend. However, a chaotic upper level pattern over greater North America will produce a shortwave that will traverse north to south to the east of the state today and Thursday. This feature will be close enough to create some convective forcing over the eastern third of NV. Better confidence exists in scattered showers both Wednesday and Thursday afternoons as PWAT values in the 0.3-0.4 inch range are sufficient for showers but not so much storm activity. CAPE values (100-200 J/kg) and LI (0 to -2) on Thursday give evidence to said forcing and instability but the lack of moisture over the region at that time leads this forecaster to believe nothing more than showers and some convective build ups are possible. A 15% of isolated convection is probably a bit generous with this current model run. Though will maintain in the forecast isolated thunderstorms over portions of Elko and White Pine Counties Thursday afternoon. Brief ridging will build into the Great Basin Friday and Saturday before a stronger LPC develops and begins to push southward down the West Coast by Saturday afternoon. This will open the region (particularly central and southern NV) up to stronger southwesterly flow as the pressure gradient begins to tighten over the area. While precipitation with this next system looks to be more into Monday and early next week, wind concerns for central NV are certainly in place for the weekend. FORECAST CONFIDENCE & DEVIATIONS: High confidence remains in a warming trend into the weekend. Low confidence exists in thunderstorms this afternoon and Thursday afternoon, mainly due to lack of moisture (see discussion above). Thunder was left in grids as prob (>15%) keeps storms as isolated both afternoons. Better confidence exists in strong gusty winds for central NV this weekend due to incoming weather system. No major changes to grids needed at this time. && .AVIATION...VFR conditions are forecast at all terminals thru Thursday. Afternoon and evening winds will be light at all terminals. Isolated showers and thunderstorms for KEKO and KELY are forecast Thursday afternoon. Temporary restricted flight rules and gusty, erratic winds are possible in and around storms that do move on terminal. && .LKN Watches/Warnings/Advisories... None. && $$ DISCUSSION...92 AVIATION...92