871 FXUS66 KSEW 151012 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 312 AM PDT Tue Sep 15 2026 .SYNOPSIS... Upper level trough moving through the area today. Upper level ridge building into British Columbia tonight and Wednesday. Thermally induced surface trough moving up the coastline Wednesday night will shift inland Thursday. Upper level ridge over the area Thursday remaining in place through Sunday with low level onshore flow. Weak system approaching Monday. && .SHORT TERM /TODAY THROUGH THURSDAY/... Satellite imagery shows cloudy skies over the area early this morning. Temperatures at 3 am/10Z were in the upper 40s and 50s. Upper level trough over Southern British Columbia this morning moving through Western Washington later this morning into the early afternoon hours. Skies remaining cloudy/mostly cloudy as the trough moves through with a slight chance of showers. Dry northerly flow aloft behind the trough with skies clearing from the north this afternoon over the northern half of the area. Highs below normal, in the 60s. Upper level ridge building into British Columbia tonight and Wednesday as the upper level trough moves further south. North northeasterly flow aloft will dry out the air mass clearing skies out in the evening. Light flow in the lower levels overnight combined with the recent rains will allow fog to form mostly in the fog prone areas like the Southwest Interior. There will be a little chill in the air Wednesday morning with lows in the mid 40s to lower 50s. Dry northeasterly flow aloft continuing Wednesday with a thermally induced surface trough making its way up the Oregon coast. Low level flow turning offshore. What little fog that does form will dissipate in the morning with the drying air mass in the lower levels. Under sunny skies with a little offshore flow temperatures warming back up to near normal. Highs in the mid 60s to mid 70s. In this scenario it is possible the warmest temperatures will be along the coast. Thermally induced surface trough moving up the coast Wednesday night shifting inland Thursday. The transition to onshore flow along the coast will cool highs back to near 70. Over the interior Thursday will be the warmest day in the forecast period with highs in the 70s. Warmest locations like the Cascade foothills and Southwest Interior could get to 80. Lows Thursday morning in the upper 40s to mid 50s. September is off to a cool start in Western Washington. Seattle average temperature for the first two weeks of the month is 61.8 degrees, 2.7 degrees below normal. This is the coolest start to September in Seattle since 2010 ( 61.0 degrees ). Felton && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Models in good agreement with a flat upper level ridge remaining over Western Washington through the weekend. Low level onshore flow will keep temperatures near normal. Highs in the mid and upper 60s along the coast and upper 60s to mid 70s inland. Lows in the upper 40s to mid 50s. Upper level trough moving out of the Gulf of Alaska first part of next week. Operational models are much slower with this feature versus the NBM which has a system near the coast Monday. For now will leave the low pops in the forecast Monday. Will not be surprised if future runs push this back into Tuesday. There is general agreement that a pattern change is in the offing next week. It is just a matter of when the weekend ridge breaks down. Felton && .AVIATION... Westerly flow aloft will turn northerly tonight as an upper trough drops southward across the Pacific Northwest. VFR ceilings may briefly drop to MVFR across portions of the interior this morning along with a few light rain showers. Ceilings will improve this afternoon with clearing tonight and VFR expected areawide. KSEA...VFR ceilings early this morning are expected to deteriorate to MVFR for a few hours mid to late morning with a few showers in the vicinity. Ceilings will lift and scatter out later this afternoon and evening. Surface winds northerly 4 to 7 knots will rise to 9 to 13 knots late this afternoon. 27 && .MARINE... The flow will turn northerly today then offshore flow at times Wednesday and Thursday as thermally induced low pressure briefly expands northward along the coast. Onshore flow returns Friday and into the weekend as series of systems pass well north of the waters. 27 && .FIRE WEATHER... Minimal fire weather concerns through next week. A weak weather system will move through the area today bringing a chance for light precipitation. Drier and warmer pattern Wednesday into Thursday. Surface winds will briefly transition offshore late Wednesday morning and remain offshore into Thursday morning. This will decrease minimum RH values toward the mid 20s to low 30s, especially in the North Cascades and Southwest Interior. Minimum relative humidity values rebound Friday as onshore flow returns. The onshore flow pattern will continue through the weekend. Felton && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$

020 FXUS66 KPQR 130722 AFDPQR Area Forecast Discussion...UPDATED National Weather Service Portland OR 1220 AM PDT Sat Sep 13 2026 Aviation Discussion Updated... .SYNOPSIS...Expect cooler and unsettled conditions through the weekend as an upper-level low pressure system progresses overhead. Conditions then turn progressively warmer and drier early next week as high pressure builds offshore. Increasing easterly flow by Wednesday and Thursday could bring locally breezy/gusty winds to the Gorge, Cascades and nearby foothills, while also aiding the warmer and drier weather. && .DISCUSSION...Now through Friday...This afternoon an upper- level low pressure system continues to move towards the coastline with rain and showers expected to further develop headed into the evening hours. This precipitation likely persists at times overnight into Sunday morning as the upper low gradually shifts eastward. From this afternoon through Sunday evening most locations from the coast into the Willamette Valley should see around 0.10-0.30 inch of rainfall; measurable amounts but not much more. However, there`s decent confidence noticeably higher amounts fall across the southwest Washington foothills/Cascades into the north Oregon Cascades where closer to 0.50-1.25 inch of rain is anticipated. This is due to a deformation band developing on the northern periphery of the upper-level low helping to consolidate showers leading to locally moderate sustained rainfall. There still remains a slight bit of uncertainty among high-resolution models as to exactly how far south this area of steadier precipitation could wander. A slight southward nudge would increase rainfall totals across the Portland Metro, particularly Sunday morning. As the upper low moves well east of the Cascades by Sunday afternoon, showers should become more scattered and increasingly focused over higher terrain features. The inland valleys and immediate coast likely trend mostly dry by the mid to late afternoon hours, while the Cascades continue to see lingering showers into the evening. It`s worth quickly highlighting a ~15% chance of thunderstorms was maintained in the forecast for this evening as cold air moving in aloft may provide just enough instability for a stray short-lived T-storm. Cold-core funnel clouds are also possible with the stronger showers through Sunday. These are typically short-lived and largely remain above the ground. Come Monday and Tuesday the low pressure system ejects further eastward with large scale troughing and northwesterly flow holding in place across the Pacific Northwest thanks to a secondary weak shortwave feature sliding down the BC coastline late Monday. Temperatures will warm day to day compared to this weekend, although only a couple degrees each afternoon. Expect highs in the low to mid 70s by Tuesday afternoon - mid 60s along the coast. Then a more noticeable warm-up begins Wednesday into Thursday as a ridge of high pressure which had been forming over the eastern Pacific begins to shift eastward into the region. The bulk of deterministic models and ensemble systems have now converged on this solution. High temperatures to soar well into the 80s across the interior lowlands as a result of this more summer- like pattern. For Thursday afternoon specifically, the latest NBM shows a 15-35% chance for highs to exceed 90s degrees across the central/northern Willamette Valley, 0-10% elsewhere. Easterly flow is also becoming more likely midweek. The strongest winds currently appear on Wednesday into Thursday morning, with gusts of 25-35 mph and isolated gusts near 40 mph possible in more wind-prone areas of the Columbia River Gorge, Cascades and adjacent foothills. The tops of the Coast Range could also become breezy, although confidence here is lower. Currently, there is around a 10-15% chance gusts could exceed 45 mph in the most exposed locations near/within the Columbia River Gorge. The combination of warmer temperatures, lower humidity and increasing east winds Wednesday and Thursday may provide a window of elevated fire-weather concerns. -99/12 && .AVIATION...Through 06z Monday...A low pressure system near the coast will move across the area tonight, pushing east of the Cascades on Sunday. As of 04z Sunday, predominately VFR conditions prevail across the airspace with periods of MVFR this evening at the coast. Scattered rain showers will continue to spread across the area with lowering CIGs likely. Best chance for MVFR conditions will be after 06z on the coast and between 12-20z Sunday for inland terminals. As showers end from west to east after 15-18z Sun, conditions may begin to improve Sunday afternoon. South winds ease overnight, then rise to 5-10 kt out of the southwest by Sunday afternoon. KPDX AND APPROACHES...VFR conditions favored through at least 12z Sunday. Light rain showers possible into Sunday afternoon. Chances for MVFR CIGs increase to around 40% between 14-20z Sunday. South winds around 4-8 kt expected through the period. /DH && .MARINE...A weak surface low centered off the central Oregon coast as of early Saturday afternoon will traverse the waters this afternoon before moving inland over the north Oregon coast by early Sunday morning. Ahead of this system, southerly winds of 8-15 kt will continue, with the strongest winds and gusts to 20 kt limited to areas within 20 NM south of Cape Foulweather. Numerous rain showers are also expected during this time, as well as 15-20% chances of isolated thunderstorms capable of producing gusty and erratic winds and locally heavy downpours through this evening. Onshore flow at 5-10 kt out of the west to southwest continues on Sunday while rain shower coverage decreases through the day. A persistent northwesterly swell at 8-9 seconds will maintain overall seas around 5 ft through the weekend. Surface high pressure rebuilds over the waters through the first half of next week, with northerly flow returning late Monday. Strengthening northerlies through midweek will see 50% or greater chances of winds 20 kt or higher on Wednesday, especially beyond 10 NM south of Cape Falcon. Seas around 5 ft with a dominant northwesterly swell at 8-9 seconds otherwise continue. -36 && .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

932 FXUS66 KMFR 142322 AFDMFR Area Forecast Discussion National Weather Service Medford OR 422 PM PDT Mon Sep 14 2026 .KEY MESSAGES... * Low impact weather expected this week. * Temperatures return to seasonable values today, persisting through the end of the week and possibly trending above normal for the weekend. * Showers/thunderstorms possible Wednesday/Thursday, primarily east of the Coast Range. && .DISCUSSION...After a chilly start to the day for areas east of the Cascades and a cloudy start to the day for areas west of the Cascades, clear skies and seasonable temperatures are underway this afternoon as low pressure from the weekend has moved off to the east. A broad trough aloft lingers over the Pacific Northwest and a thermal trough is in place along the coast at the surface. Not much change in the pattern is expected through Tuesday, and this will maintain breezy north through northeast winds across the region. High temperatures will return to seasonable values today and continue through much of the week...look for highs in the low-mid 80s for the West Side and low-mid 70s for the East Side. Low temperatures will also moderate tonight and through the week, with any chances for frost/freeze being confined to the typically cold areas of northern Klamath/Lake Counties. The pattern changes Wednesday as another upper level low slides down the back side of high pressure over the eastern Pacific. This low pressure isn`t as deep as recent ones, so we won`t experience quite the cooldown we`ve been seeing with these systems. In fact, the orientation of this low will maintain easterly flow over the region Wednesday and Thursday, resulting in a warming effect for areas west of the Cascades due to downsloping off the Cascades. We`ll also see increasing chances for showers and thunderstorms Wednesday and Thursday. The highest chances for this is in the usual places...northern California and east of the Cascades...but with east to northeasterly flow in place, showers/thunderstorms will move from east to west, which could bring some activity to portions of Jackson/Josephine Counties as well in the afternoons/evenings. This low pressure shifts eastward on Friday and a brief period of shortwave ridging will follow in it`s place for the weekend. This will bring the return of dry conditions and above normal temperatures (about 5-8 degrees). The flow aloft remains fairly progressive, so the ridge axis moves east of the region late Sunday into Monday. There`s pretty good agreement in at least a broad trough returning to the region, which will bring a cooling trend on Monday into next week. There is disagreement, however, on the extent of that cooling trend. The EC ensemble suite would have a much sharper cool down on Monday compared to the GFS suite. At this time, there aren`t any clear signals for another widespread precipitation event in the next 10 days. The members in the EC suite seem to agree on some precipitation along the coast early-mid next week, but not much for inland areas. The GFS suite on the other hand, is far less optimistic for precipitation, even along the coast. So expect dry conditions to continue for most areas into next week. && .AVIATION (00Z TAFs)... VFR conditions are present areawide into this evening. Then, IFR/LIFR conditions are expected to return overnight along the coast and in coastal valleys north of Cape Blanco, with conditions improving to VFR between 16-18z. Inland, expect mainly VFR. However, local IFR/LIFR may develop in the Umpqua Basin early Tuesday morning (11-18Z). Guidance only supports a 10-15% chance for IFR at Roseburg (RBG) so have kept VFR conditions in the TAF and will continue to monitor. && .MARINE...Updated 100 PM PDT Monday, September 14, 2026...A thermal trough will maintain gusty north winds and steep to very steep seas through Tuesday. Winds peak on Tuesday when a brief period of gale gusts are possible south of Gold Beach. Seas will also be steepest on Tuesday, but conditions will ease somewhat Tuesday night into Wednesday as the thermal trough pattern gets disrupted. An upper level low will settle over the region Wednesday through Thursday. This will maintain gusty, though weaker, north winds, with these north winds becoming more widespread. This could result in advisory level winds and steep seas spreading north of Cape Blanco, but also keep hazardous conditions confined to the outer waters through Wednesday night. Conditions improve Thursday and likely remain below advisory criteria into the weekend. The thermal trough could return over the weekend, however, possibly bringing the return of conditions hazardous to small craft. && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT Tuesday for PZZ356-376. Hazardous Seas Warning from 11 AM to 11 PM PDT Tuesday for PZZ356-376. && $$

187 FXUS66 KEKA 150705 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 1205 AM PDT Tue Sep 15 2026 .KEY MESSAGES... * Slightly warmer temperatures and northerly breezes are expected today. * A weak frontal system arriving Wednesday will likely lead to cooler temperatures and generally unsettled weather with an increased chance for thunderstorm development * Warmer temperatures and dry conditions return end of the week. && .SYNOPSIS...Surface high pressure building offshore will strengthen the onshore pressure gradient against the interior thermal low into early this week. Expect a shallow marine layer pinned along the coast while the interior valleys have dry and seasonably warm conditions. For Wednesday, an evolving upper low will bring cooler temperatures and slight chance for interior thunderstorms. && .DISCUSSION...Warm temperatures remain inland as high pressure and weak upper level ridging remains over the areas today. This will result in strong winds for the coast and valleys inland with gusts up to 20mph possible inland and up to 30mph for the direct coastline. Any coastal cloud coverage in the morning will likely dissipate early as daytime mixing and a deepening marine layer impact the North Coast. Inland valleys could also see morning temps in the low 40s. COme Wednesday afternoon, global models have been steady on an upper level trough ripping down the PacNW coastline before stalling over Del Norte as well as N. Humboldt and N. Trinity counties. This trough will create abnormally cooler temperatures inland and stronger winds for the ridgetops due to the unstable atmosphere. CAPE values and vorticity signals continue with this system even as Hi-Res models start to reach out as far as Wed P.M. which increases the forecast confidence on thunderstorm potential. The Storm Prediction Center has also included the Northern portions of the CWA in a thunderstorm potential. Storms will be limited by forcing and moisture, yet ample life could create a thunderstorm if the ingredients line up well enough. Storm track currently shows storms forming inland before potentially flowing westward towards the coast from the Klamath, Salmon, and Trinity Alp mountains. A small chance of storms is possible Thursday as a weaker impact from this system will still be felt. After this system migrates eastward, ridging returns and will give warmer temperatures for Friday into the weekend. DS && .AVIATION...VFR and northerly winds are expected to continue for coastal terminals. Terminals near Humboldt Bay could see MVFR ceilings develop late tonight with periods of IFR as cloud development has begun in the Eel River Valley. Any ceilings will likely give way to VFR by mid morning as northerly winds return. Inland areas will experience continued afternoon gusts and VFR conditions. && .MARINE...A fairly strong land-sea surface pressure gradient is creating strong breezes with near gale force winds through the overnight hours before building again this afternoon, especially across the area outer waters. Steep waves are to be expected across all of the coastal waters through Wednesday morning with waves of 8 to 10 feet. Winds are still expected to diminish slightly through the afternoon on Wednesday and more significantly Wednesday night as an upper level trough moves down over the area. Some models do show these winds diminishing earlier, but confidence is low on the exact timing. Light southerly winds are expected Thursday as the low moves through and then out of the area. Northerly winds are expected to increase on Friday and more so over the weekend. MKK && .FIRE WEATHER...High pressure building off the coast will continue the warming and drying trend across Northwest California today. Wednesday afternoon or overnight an upper low entering over Del Norte, Humboldt, and N. Trinity counties has the potential to cause a few thunderstorms. There is still a lot of uncertainty on the details of these storms, yet the most likely scenario seems to be storm forming over the Salmon, Klamath, and Trinity Alps before flowing towards the coast. Storm chances remain low overall, yet the potential area for these storms has increased due to the models remaining fairly steady with this systems storm track. There will likely be rain with each of these storms, yet some lightning that strokes away from the core of the storm could start a fire. It is possible that the there could be a few storms on Thursday, but these are expected to be limited to northern Trinity county and Siskiyou county. Warmer and drier weather along is expected to return Friday and Saturday. MKK/DS && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 AM PDT Wednesday for PZZ450. Small Craft Advisory until 8 PM PDT Wednesday for PZZ455- 470. Small Craft Advisory until 3 AM PDT Thursday for PZZ475. && $$ NOTE: The full forecast discussion is now regularly issued between 10 am/pm and 1 pm/am. Additional updates will be issued as needed. Visit us at https://www.weather.gov/eureka Follow us on Facebook and Twitter at: https://www.facebook.com/NWSEureka https://www.twitter.com/NWSEureka For forecast zone information see the forecast zone map online: https://www.weather.gov/images/eka/zonemap.png

056 FXUS66 KMTR 151045 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 345 AM PDT Tue Sep 15 2026 ...New MARINE, FIRE WEATHER... .KEY MESSAGES... Updated at 1206 PM PDT Mon Sep 14 2026 - Cooling trend and below normal temperatures through mid-week; return to seasonal temperatures late week into weekend && .SHORT TERM... Issued at 1204 AM PDT Tue Sep 15 2026 (Today and tonight) Interesting to see some high clouds continue to stream over the heart of the Bay Area early this morning. In fact, the stream of clouds have been like a conveyor belt of upper level moisture over the last 36-48 hrs. Why the conveyor belt like feed? While the longwave pattern shows broad troughing over the West (including CA) it also shows a weak upper level disturbance parked well NE of the Hawaiian Island. The sub-tropical jet is the connection between that weak disturbance and CA. Impactful? No. Interesting to see a feed for a longer period of time? Yes. Now onto the forecast. Marine layer struggled to fully form last night due to dry air and offshore flow. Tonight we`re dropping the offshore flow, but dry air remains. As of midnight stratus still remains patchy, but as the night moves on there is higher conf that stratus will become more widespread over the coastal waters and move locally inland. The limiting factor will be the lingering dry air. Monday was a warm up day, but Tuesday will be a transition day in the other direction. Broad upper trough will get a boast from a highly amplified jet nosing into AK and the downstream trough deepening. Onshore flow will kick a little more today as well. Winds will be strongest along the coast, inland valleys, and inland gaps/passes (Altamont). Onshore flow and dropping 500mb heights will bring a general cooling of 3 to 5 degrees nudging much of the region to below normal for this time of year. Moistening in the low level and falling 500mb heights will once again promote better stratus development Tuesday night into Wednesday with the depth increasing of 1000-1500 ft for the marine layer. && .LONG TERM... Issued at 1204 AM PDT Tue Sep 15 2026 (Wednesday through Monday) How a about a little taste of late fall to begin the Long Term. The aforementioned amplified jet will to drive another upper low down the PacNW coast and into NorCal/OR. Latest guidance actually cuts off the low from the main flow pattern. Not only are we getting another upper low, but this one will be chilly for this time of year with 850mb temps dropping close to 10C, which is an anomaly of 5 to 7. So what does this mean for overall sensible weather? The cooldown in temperatures will continue with highs dropping another 3 to 8 degrees. Highs will be mainly 60s coast and upper 60s to mid 80s interior. Onshore flow will bring gusty conditions again. The marine layer will be a tricky one. Generally speaking one would expect a deeper marine layer and that`s what the forecast has Wednesday into Thursday. However, one always has to watch stratus development as the airmass aloft begins to approach the current SST. If they`re too close, stratus production generally declines. Confidence is too low at this point to remove stratus, but will monitor nonetheless. Given that the stratus mid- week is tricky and not classic, impacts from extreme nocturnal drying events are less likely. The upper level low departs eastward late Thursday into Friday with shortwave ridging to follow. Subtle warming trend develops for next weekend with interior locations solidly returning to the 80s and far interior mid 90s. && .AVIATION... (06Z TAFS) Issued at 1007 PM PDT Mon Sep 14 2026 Gentle to moderate onshore breezes continue this evening, becoming light overnight. Above the surface, a weak offshore flow continues to keep stratus out of most terminals this TAF period but will gradually diminish by Tuesday morning. Wednesday night looks more promising for widespread stratus due to the absence of an offshore flow and the passage of an upper-level trough, which will allow the marine layer to deepen. That being said, VFR prevails this evening except at HAF where MVFR ceilings have already formed. Medium confidence for APC to develop borderline MVFR-IFR ceilings early Tuesday morning and scatter out by mid Tuesday morning. Diurnal onshore breezes increase Tuesday afternoon into the evening. Vicinity of SFO...VFR with gentle onshore breezes through the night. Low confidence on the development of MVFR ceilings tonight, therefore the TAF advertises SCT decks. If ceilings become robust overnight, they will likely be short-lived and scatter out by late Tuesday morning. Wednesday has a higher chance of developing MVFR ceilings, likely after the current TAF cycle. Diurnal onshore breezes prevail through the TAF period. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Gentle onshore winds continue through the night and increase by Tuesday morning. High confidence for IFR ceilings to develop around midnight, filling in over MRY first followed by SNS. Stratus is expected to scatter out by late Tuesday morning resulting in a short period of VFR conditions. An earlier onset of MVFR stratus is expected tomorrow evening around sunset. && .MARINE... (Today through Sunday) Issued at 248 AM PDT Tue Sep 15 2026 Northwesterly breezes will diminish across the inner coastal waters and the southern coastal waters today. Hazardous conditions for small craft will linger across the northern outer waters through Wednesday morning. Moderate to rough seas will prevail through today before subsiding to become slight to moderate Wednesday through Friday. && .FIRE WEATHER... Issued at 345 AM PDT Tue Sep 15 2026 The transport of cooler air on northwest winds relative to sea surface temperatures in the upper 50s to lower 60s continues to help produce coastal stratus early this morning. The marine layer depth varies from 1500 to 2000 feet. Above the marine layer temperature inversion, humidities are currently in the mid 20% to 30% range. The depth of cool air transport will increase which will gradually increase humidities at higher elevations during mid to late week. Before humidities reach a maximum, there may be temporary, small areas of nocturnal drying at highest elevations, coverage though should be minimal. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 9 AM PDT this morning for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory until 3 AM PDT early this morning for Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 9 AM PDT Wednesday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...MM LONG TERM....MM AVIATION...Navarrete MARINE...Canepa 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

329 FXUS66 KOTX 150924 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 224 AM PDT Tue Sep 15 2026 .KEY MESSAGES... - Scattered showers along the northern Washington mountains, and North Idaho Panhandle Tuesday. - 20 to 40 percent chance of showers and thunderstorms Thursday night into Friday over Southeast Washington and the Central Panhandle mountains. - Warmer temperatures Wednesday through Sunday with afternoon highs in the mid 70s to low 80s. && .SYNOPSIS... Cool temperatures will continue Tuesday with scattered showers over areas of higher terrain. Temperatures rebound into the 70s and 80s Wednesday through Sunday with mainly dry conditions. Southeast Washington and the Central Panhandle mountains will be the exceptions with a 20 to 40 percent chance of showers and thunderstorms Thursday night into Friday. && .DISCUSSION... Today through Wednesday: An upper level trough developing over British Columbia will swing south through the area later this (Tuesday) morning through the afternoon. It will bring light rain showers to the Cascades, northern mountains, and northern Idaho Panhandle. Places such as Omak, Colville, Chelan, and Bonners Ferry have a 20 percent chance and above at seeing 0.10 inches of rainfall from Tuesday through Wednesday morning. Forcing associated with the incoming low combined with modest instability (a couple hundred J/kg of CAPE) will support a 10 to 15 percent chance of thunderstorms across areas receiving rain. Soundings show saturated mid and low levels (RH values greater than 80 percent), and PWATs near 0.7 inches. This indicates that main threats with any thunderstorms will be isolated heavy downpours. Elsewhere, expect dry conditions. By Wednesday, the low will shift southward and retrograde slightly eastward. Rising heights downstream of a ridge off the Canadian coast will promote a warming and drying trend over the Inland Northwest. Temperatures on Wednesday will be in the mid 70s, which is right around normal for this time of year. No precipitation is expected. Thursday through Monday: The aforementioned low will then begin weakening and moving northeastward. While much of the forecast area will continue seeing a drying trend, the low will brush far southeast Washington and the central Idaho mountains Thursday night into early Friday morning. Main areas impacted will be the Lewiston and Camas Prairie areas. A 10 to 20 percent chance of thunderstorms will accompany these light rain showers. While PWATs will still be high, mid and low level moisture will be lower than on Tuesday, and DCAPE values will be near 1000 J/kg. This suggests that the main threat with these thunderstorms will be gusty outflow winds. After this low weakens and moves completely out of the forecast area, high heights will dominate the weather pattern, bringing a warming and drying trend through the weekend starting on Thursday. Temperatures will progressively rise through the weekend, with mid range guidance showing high temperatures reaching the 80s by Sunday. After the brief showers Thursday into Friday, the forecast area sees near zero chances of precipitation through the weekend. Cluster analysis unanimously supports this warming and drying trend through Sunday. Beyond Sunday, however, cluster analysis lowers slightly, though 75 percent of clusters broadly show a low pressure system approaching the coast. There is little agreement on track, strength, and placement, but this does hint at a potential return to unsettled weather next week. /AS && .AVIATION... 06Z TAFS: All terminals have improved to VFR and are expected to stay that way through the forecast period. A low dropping into the area tomorrow brings a small chance of rain (HREF shows around 10 to 20 percent) at GEG, SFF, and COE around 20Z. MWH and EAT see chances of rain earlier - around 16Z. EAT has the highest chances of seeing some rain showers, and these are included in the TAF. There is a small chance of patchy fog and lowered ceilings Tuesday morning. While HREF/RRFS probabilities don`t support it, some BUFKIT soundings show a saturated enough surface to support fog. There is not enough confidence to include fog at specific terminals. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Moderate to high confidence in widespread VFR conditions returning through the forecast period. Low confidence in patchy fog and lowered ceilings, which is the highest impact alternate scenario and would require amendments. /AS ----------------------- 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 64 44 72 46 77 48 / 0 10 0 0 0 0 Coeur d`Alene 64 45 72 46 76 48 / 0 10 0 0 0 0 Pullman 65 42 73 44 72 45 / 0 10 0 0 0 10 Lewiston 71 50 77 52 77 53 / 0 0 0 0 10 20 Colville 63 37 75 39 80 42 / 40 10 0 0 0 0 Sandpoint 63 42 71 43 76 45 / 10 10 0 0 0 0 Kellogg 63 45 71 47 76 49 / 0 10 0 0 0 10 Moses Lake 66 45 75 47 79 48 / 10 10 0 0 0 0 Wenatchee 64 51 74 54 80 57 / 20 10 0 0 0 0 Omak 64 45 76 48 80 51 / 60 10 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...None. ID...None. && $$

097 FXUS66 KPDT 151012 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 312 AM PDT Tue Sep 15 2026 .KEY MESSAGES... - Temperatures will slowly warm to above normal by the end of the week. - Slight chance to chance (10-30%) of thunderstorms over the Blue Mountains region Thursday and Friday. && .DISCUSSION... Water vapor imagery shows a shortwave trough moving southeast along the BC coast. This system will facilitate our next chances of rain, with a slight chance (15-25%) of showers arriving to the Washington Cascades later this morning. The shortwave will then develop into a closed low over the Pacific Northwest later this afternoon through tonight and provide modest chances (15-40%) of precipitation across central Oregon and the surrounding mountains. Ensemble NWP guidance is in reasonably good agreement regarding the track of the low, but some uncertainty exists in its location for Wednesday through Friday. In general, ensemble mean 500-hPa heights and vorticity show the low retrograding slightly on Wednesday, tracking from southwest Oregon to northwest California, or just offshore. The forecast area will remain mostly dry on Wednesday, increasingly so the farther southwest the low tracks. The low is then expected to eject northeast across the Pacific Northwest Thursday through Friday, though clusters of ensemble solutions continue to show some differences in timing and magnitude of the low during this period. Over half of members advertise a solution that is conducive to convection Thursday (Blue Mountains region and portions of central Oregon) and Friday (northeast Blue Mountains). Chances of thunderstorms are highest on Thursday (15-30%), especially for the northeast Blue Mountains. Chances drop to 10-15% for Friday, highest over Wallowa County. All ensemble members indicate the low will exit to the east by Saturday, with transient upper-level ridging replacing it over the Pacific Northwest. This would facilitate above-normal temperatures and dry conditions areawide. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... VFR conditions are expected through the TAF period. CIGS will lower during the day as low pressure moves toward the region by the end of the period. There is a very low (<20 percent) chance of SHRA by the end of the period as well, mainly at YKM, DLS, BDN and RDM. However, since the chances are so low, have not included in any of the individual terminals at this time. Winds will mainly be 10 kts or less, though there is a chance 30-40 percent) of winds gusting to around 15 kts in the afternoon at BDN and RDM for a couple of hours. && .Preliminary Point Temps/PoPs... PDT 68 44 72 47 / 0 10 0 0 ALW 70 48 75 52 / 0 10 0 0 PSC 71 46 78 48 / 10 10 0 0 YKM 66 47 74 48 / 10 10 0 0 HRI 71 46 76 47 / 0 10 0 0 ELN 60 42 70 45 / 20 10 0 0 RDM 69 39 68 37 / 0 40 10 0 LGD 71 45 74 45 / 0 10 0 0 GCD 74 45 74 45 / 0 20 10 10 DLS 73 54 80 55 / 0 10 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...None. OR...None. && $$ DISCUSSION...86 AVIATION...77

357 FXUS65 KREV 150740 AFDREV Area Forecast Discussion National Weather Service Reno NV 1240 AM PDT Tue Sep 15 2026 .KEY MESSAGES... * Typical afternoon breezes today will increase on Wednesday, producing minor fire, recreation, and travel impacts. * Low pressure brings a low chance of rain and thunderstorms to areas near the Oregon border Wednesday and Thursday. * Warm and dry weather is favored Friday through the weekend. Chances of rain and breezy winds may return early next week. && .DISCUSSION... A dry and mild weather pattern remains in place today with daytime highs in the 70s and 80s, which is about on par for mid-September. Typical west breezes return this afternoon with gusts reaching 25-30 mph. Dry and breezy conditions may support brief elevated fire concerns along the Sierra Front in the afternoon. A compact upper low will dig into northern California on Wednesday before lifting northeast to the northern Rockies on Thursday. In response, winds will increase from the Tahoe-Reno area south to Mono and Mineral Counties Wednesday afternoon, yielding S-SW gusts around 30-35 mph. A few windier spots (i.e., US-395 between Mammoth and Mono Lake) may see gusts of 40-45 mph. Meanwhile, Sierra ridges will be gusting to 50 mph at times Wednesday night into Thursday morning. These winds will overlap RH reductions to 7-15%, which should support a few hours of elevated to locally critical fire weather conditions across far W Nevada into Mono County. Other potential wind impacts include choppy lakes, gusty crosswinds along US-395/I-580 between Reno and Mammoth, and bumpier flights in/over the Sierra. Also, lingering gusty winds will contribute to a chilly, brisk morning for higher Sierra elevations on Thursday. Farther north, chances of rain showers increase to 10-20% Wednesday afternoon across portions of Lassen County into the Surprise Valley and far N Washoe County. Weak instability and moisture will also support a 10-15% chance of thunderstorms in the afternoon. A few showers may develop farther south closer to I-80 on Wednesday, but will be dependent on the eventual track of the low pressure. Low (10-20%) shower and thunderstorm chances linger through Thursday, but will be confined to areas near the Oregon border. A dry frontal passage is expected Friday as the low pressure departs the region. East to northeast breezes will develop in its wake, becoming gusty at times along and west of the Sierra crest. Weak high pressure moves over the region late this week, allowing warm and dry weather to prevail Friday through the weekend. Another low pressure passage increases the potential for breezy winds and showers to return early next week, but confidence remains low. -Salas && .AVIATION... Widespread VFR conditions prevail today, with light morning winds becoming SW-W gusts at 20-25 kt after 19Z. Winds are expected to increase on Wednesday, lending to LLWS concerns and mountain wave turbulence along the eastern Sierra. -Salas && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$

813 FXUS66 KSTO 141815 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1115 AM PDT Mon Sep 14 2026 For additional details on weather and expected impacts over the next 7 days, please visit weather.gov/sto/briefing. .KEY MESSAGES... - Critical fire weather conditions through this afternoon due to gusty winds and low daytime humidity - Red Flag Warning in place for portions of the Sacramento Valley and adjacent foothills until 5 PM PDT Today - Precipitation Chances (10-25%) Wed-Thu for Shasta County, Coast Range, and Southern Cascades with nonzero thunderstorm chances (5-15%) && .DISCUSSION... Today-Tuesday: The main weather highlight this morning is ongoing gusty north winds along the Interstate corridor around 15-30 MPH. These winds have generally peaked this morning and will gradually weaken through the afternoon and evening. Dry conditions are expected to continue this afternoon with Valley afternoon humidities in the teens. Given the combination of winds and low relative humidity, our Red Flag Warning remains in effect for portions of the northern & central Sacramento Valley and adjacent foothills until 5 PM this evening. Please be sure to continue fire safety practices and outdoor burning is not recommended. After today, an approaching upper level low from the Pacific NW will bring a pattern change of cooler temperatures, increased moisture, and precipitation chances midweek. Valley highs on Tuesday will be in the upper 80s to low 90s and localized areas of RH in the northern Sac. Valley and eastern Central Valley foothills. Wednesday-Saturday: First day of cooler weather with highs in the low to mid 80s in the Valley and upticks in humidity for several days. With this our aforementioned low may bring chances for isolated thunderstorms around the mountains of Shasta County and Southern Cascades, however current guidance keeps any activity further north and west. There is still some model uncertainty regarding exact location and intensity but pattern recognition points to most likely outcome of the bulk of shower/thunderstorms, if occurring, closer to the CA coast and further north than our forecast area. That being said, we will monitor to monitor and reevaluate any thunderstorm/lightning fire weather threats as we get closer! Currently, we have a 5-15% chance of thunder near the Coast Range with an 10-25% chance of wetting rains across the Shasta County and Southern Cascades mountains. Precipitable water forecast show limited support for any widespread thunderstorm development at the moment with dry forecast soundings across various sites as well, keeping fire weather concerns as minor impacts at this time. Beyond Thursday, high pressure begins to develop again and will see temperatures rebound to near seasonable and dry conditions, particularly over the northern SAc. Valley, and breezy afternoon winds. As always, be sure to follow the forecast at weather.gov/sacramento for any updates! && .AVIATION... VFR conditions prevail across TAF sites and interior NorCal over the next 24 hours. North winds in the Central Valley gradually decrease this afternoon and become less than 12 kts after 00Z Tuesday. Period of breezy downslope winds in the mountains and foothills with gusts 15-20 kts from 03Z to 16Z Tuesday. Winds turn southerly after 18Z Tuesday with gusts 15-25 kts at times. && .STO WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 5 PM PDT this afternoon for Butte County Below 1000 ft-Central Colusa County Incl. I-5-Central Glenn Co & Interstate 5-Eastern Colusa County-Eastern Glenn County- Glenn/Colusa Coast Range Above 3000 ft-N. Sac Valley in Tehama County-Shasta Metro-Sierra (Tehama-Plumas) 1000-3000 ft- Sutter/Yuba counties below 1000 ft-W. Glenn/Colusa Foothills 1000-3000 ft. && $$

817 FXUS65 KMSO 150841 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 241 AM MDT Tue Sep 15 2026 .DISCUSSION... KEY MESSAGES: - Chilly start this morning across southwest Montana and north central Idaho with patchy valley fog. - Warming and drying through mid week, then wetter Thursday into Friday. Clear skies south of Highway 200 in western Montana and north-central Idaho allowed temperatures to drop near or below freezing early this morning, leading to patchy frost and valley fog that may expand through daybreak. North of Highway 200, cloud cover remains thicker, keeping temperatures slightly milder. Expect passing mid- to high-level clouds across the region today, with a few light, scattered showers remaining confined near the Canadian border. Sunny skies and warmer temperatures arrive Wednesday as high pressure briefly builds over western Montana and central Idaho. Rain chances return Thursday into Friday as a slow-moving weather system pulls abundant monsoonal moisture into the Northern Rockies. While widespread severe weather is not expected, afternoon heating will trigger scattered thunderstorms. Because these storms will likely move slowly, the primary hazard will be intense downpours. High pressure builds into the Northern Rockies as the low departs Saturday afternoon, bringing warm and dry conditions through at least early next week. Confidence remains high for dry weather through Monday, though approximately 30% of ensemble members show a cooler, wetter pattern returning by mid-week. && .AVIATION...Patchy valley fog will continue to expand through daybreak across southwest Montana and north central Idaho (potentially including terminals like KMSO and KHRF), bringing localized IFR visibilities and ceilings before burning off around mid-morning. Farther north toward KGPI, thicker cloud cover will limit fog development, though VFR mid-to-high level ceilings and isolated light showers near the Canadian border will persist through the afternoon. A northerly wind gradient may help to enhance the early evening north winds at KMSO, and KGPI may experience more variable wind rather than the typical southerly lake breeze. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$

726 FXUS65 KBOI 150918 AFDBOI Area Forecast Discussion National Weather Service Boise ID 318 AM MDT Tue Sep 15 2026 .KEY MESSAGES... - Slight warming and drying trend Tuesday and Wednesday, with light winds. - Cold temperatures tonight will bring patchy fog and frost to the mountain valleys. - A low pressure system will bring light precipitation and isolated afternoon thunderstorms across the area Thursday and Friday. && .SHORT TERM /Through Thursday Night/... Overnight lows in high terrain will approach freezing, bringing patchy valley fog and frost this morning. Southwest flow aloft will keep daytime temperatures warm and conditions mostly dry today and tomorrow. Winds will generally be light and terrain driven, with mostly sunny skies. On Wednesday, a low pressure system over western Oregon will deepen and move slightly further east compared to previous model runs. This will bring a 40-60% chance of precipitation over the region on Thursday, with a slight chance of afternoon thunderstorms over northern zones. Two day rainfall accumulations will total between 0.05-0.15 inches, with higher elevations in the West Central Mountains approaching 0.50-0.75 inches of rain. Warm daytime temperatures will keep snow levels above 9,000-10,000 feet MSL through the short and long term period. Southerly winds will be elevated over south central Idaho as the low moves into the region on Thursday, with gusts up to 35 mph. && .LONG TERM /Friday through Tuesday/... Precipitation chances look to decrease across the region on Friday, but mountains in central Idaho and northeast Oregon look to keep at least a 30-40% chance of showers and a 10-15% chance of thunderstorms through Friday night. Southerly flow aloft will keep temperatures near normal through Friday, ahead of cooler temperatures on Saturday with the low center moving over the region. The low pressure system will then exit to the east on Saturday, with showers and cooler temperatures lingering over the central Idaho mountains. High pressure will build in over the region on Sunday, with temperatures trending slightly above normal (3-5 degrees) on Monday. A cold front associated with a broad upper level trough then looks to move in sometime on Tuesday, bringing slightly cooler temperatures and a slight chance of mountain rain showers. && .AVIATION /06Z Tuesday through Wednesday/... Issued 1208 AM MDT TUE SEP 15 2026 Generally VFR. Areas of fog/low stratus possible overnight in mtn valleys. Increasing high clouds this afternoon, mainly north and west of KTWF/KJER. Surface winds: variable under 10 kt overnight becoming E-SE 5-10 kt after Tues/17Z. Winds aloft at 10kft MSL: W-SW 10-20 kt. KBOI...VFR. Increasing high clouds Tue/PM. Surface winds: SE 4-10 kt early Tue/AM. Becoming variable, leaning NW, under 10 kt Tue/PM. && .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...SA LONG TERM....SA AVIATION.....NF

691 FXUS65 KLKN 150934 AFDLKN Area Forecast Discussion National Weather Service Elko NV 234 AM PDT Tue Sep 15 2026 .KEY MESSAGES... * Elevated fire weather conditions in Central Nevada Tuesday thru Thursday * Low chance for showers along the Oregon and Idaho borders, and the eastern half of White Pine County Wednesday and Thursday && .DISCUSSION... (Today through next Tuesday) WEATHER PATTERN OVERVIEW: Upper level trof continues to deepen as it moves south thru British Columbia. Latest numerical model solutions depict a cut off low forming over Oregon tonight, with the low residing over NorCal thru Thursday before ejecting east. This will produce elevated winds, especially across central Nevada and White Pine County, each afternoon thru Thursday. South- southwesterly gusts will be 25 to 35 MPH, reaching around 45 MPH across the high terrain. Patchy blowing dust can be expected. Significant precipitation will not be present, though locations along the Idaho and Oregon borders may experience a brief light rain shower or two under the influence of the upper low, especially the northwest quadrant of Humboldt County. Concurrently, significant moisture across Utah, thanks to a northerly push of subtropical moisture from the desert southwest, will spill into portions of Nevada and provide a low chance for a brief shower or dry thunderstorm across the eastern half of White Pine County, primarily over the Snake Range. Temperatures across northern Nevada cool several degrees Thursday as the low and associated cooler air mass influence the region. Temperatures gradually warm thru the weekend with a return to daytime highs in the upper 70s to mid 80s across the valleys by Sunday. Weather looks to be dry though a low chance (10%) for rain showers across central Nevada will be present early next week as a weak Pacific low pressure system moves into Central California from the west. FORECAST CONFIDENCE & DEVIATIONS: There is high confidence in breezy to strong south-southwesterly winds each afternoon thru Thursday as an upper level trof passes thru the western U.S. Moderate confidence in a 10% to 15% chance for isolated showers Wednesday thru Thursday for far northern Nevada, as well as eastern White Pine County where a dry thunderstorm or two may also be present. Low confidence in a 10% chance for light rain across central Nevada early next week. && .AVIATION...VFR conditions will be present at all terminals thru Tuesday night. Afternoon breezes will be present across central Nevada terminals including KTPH and KELY with south- southwesterly gusts 25KT to 30KT. Patchy blowing dust may cause brief reductions in VIS, primarily at KTPH and KELY, though confidence is not high enough to include BLDU in the TAF. && .FIRE WEATHER...Elevated fire weather conditions will be present across central Nevada thru Thursday due to breezy south-southwest winds each afternoon. Gusts between 25 and 35 MPH are expected, reaching as high as 45 MPH across the high terrain. The strongest winds will be within zone 425. However, the limiting factors for critical fire weather conditions will be fuels, and min RH values near or above 15% across zone 425. Min RH looks to reside around 10% to 15% along with fuels remaining cured for zones 426, and 427, though winds will be slightly more modest and critical fire weather conditions look borderline at this time. Breezes will also be present across northern Nevada though gusts will generally be around 20 MPH. An upper level low and associated cold front will provide a low chance (10% to 15%) for light rain showers along the Idaho and Oregon borders thru Thursday. Wetting rains are not expected under any such activity. There is also a low chance (10%) for light showers and a dry thunderstorm or two within the eastern half of zone 425 and primarily the Snake Range each afternoon thru Thursday. That said, the vast majority of thunderstorm activity will remain to the east within Utah where atmospheric moisture profiles and instability are much more conducive for the development of thunderstorms. && .LKN Watches/Warnings/Advisories... None. && $$ DISCUSSION...92 AVIATION...92 FIRE WEATHER...92