511 FXUS66 KSEW 181609 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 909 AM PDT Mon May 18 2026 .SYNOPSIS... High pressure will remain situated offshore through much of next week, maintaining near-normal temperatures across western Washington with cloudy mornings and sunshine in the afternoons. A few weak systems will move over the top of the ridge towards the middle of next week, bringing little more than a few periods of sprinkles. && .SHORT TERM /TODAY THROUGH WEDNESDAY/... Upper-troughing currently over the Great Basin while an upper- level ridge is just offshore the PNW. High clouds are currently streaming in under northwest flow aloft. Stratus has been confined to west central Washington between the Kitsap Peninsula and into the South Sound with the edges beginning to erode away. This will give way to mainly just high clouds and some fair weather cumulus across the area this afternoon. High temperatures are forecast in the 60s across the interior with 50s along the coast. Increasing onshore flow will lead to breezy winds through the Strait of Juan de Fuca this evening with gusts up to 30 mph on Whidbey Island before gradually decreasing later tonight. HREF suggests a 35% chance of gusts exceeding 35 mph. Overnight lows will fall into the 40s. Upper-ridging is likely to maintain through midweek as conditions remain rather benign. Weak disturbances will attempt to traverse along the periphery of the ridge - maintaining slight (15% or less) PoPs but mostly for the mountains. Temperatures are to remain near-seasonal throughout this period with highs in the 60s to near lower 70s and lows in the 40s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... The upper level ridge offshore will begin to flatten on Thursday as a low pressure system slowly strengthens and lowers from the Gulf of Alaska. Conditions are favored to remain dry into the first half of the weekend as zonal flow sets up aloft, with continued mild temperatures. Ensembles are honing in on a potential pattern change by the end of next weekend, with increasing chances for widespread rainfall arriving Sunday evening. However, the details remain uncertain at this time. 41 && .AVIATION... North/northwesterly winds will persist aloft as an upper level ridge remains nudged over the region. Onshore flow will continue in the low levels, which allowed for some localized stratus to push inland this morning, mainly for areas along the coast, the Southwest Interior, and the south Sound where these terminals are seeing MVFR/IFR conditions likely through 18z (most likely for KHQM, KPWT, and KOLM). Expect cigs at the remainder of the terminals to remain VFR through the day. Winds remain light southerly at 6 kt or less across the majority of the interior terminals this morning, outside of KPAE, where winds continue out of the north. Winds along the coast are light northwesterly and KCLM remains westerly between 8-12 kt under increased onshore flow. Winds will increase to 7-10 kt this afternoon and look to switch to the north across the interior between 00-03Z tonight. A weak, splitting frontal system will move into the area tonight into Tuesday, with the main impact being more widespread stratus by Tuesday morning. KSEA...MVFR ceilings this morning with broken clouds at the terminal around 1500 to 2000 ft. Ceilings will rebound to VFR likely after 17z and will remain VFR throughout the day. A much greater probability (40-45 percent) exists of ceilings dropping to MVFR by Tuesday morning. Winds are southerly and will increase to 7-10 kt this afternoon, before switching to the north between 00-03Z. 14/Mazurkiewicz && .MARINE... High pressure will remain situated over the northeastern Pacific through much week, bringing a prolonged period of north/northwesterly winds to the coastal waters. A weak, splitting frontal system will move into the waters tonight into Tuesday and will bring an increase of onshore flow along the central and eastern Strait of Juan de Fuca, with another round of small craft westerlies expected this afternoon and evening. High pressure will build back into the coastal waters in the wake of the front. Onshore flow will persist throughout much of the week and will result in daily pushes of westerly winds along the Strait. The next weak frontal system looks to move into the area waters Thursday into Friday, followed by another late next weekend. Seas will generally hover between 6-8 ft through the first half of the week, before increasing towards 8-10 ft mid to late week. The latest GEFS probabilistic guidance is highlighting roughly a 20-40 percent chance of seas exceeding 9 ft by next weekend. 14 && .HYDROLOGY... The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated during this time as needed. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory from 2 PM this afternoon to 5 AM PDT Tuesday for Central U.S. Waters Strait Of Juan De Fuca- East Entrance U.S. Waters Strait Of Juan De Fuca. && $$

102 FXUS66 KPQR 180941 AFDPQR Area Forecast Discussion National Weather Service Portland OR 240 AM PDT Mon May 18 2026 .SYNOPSIS...Dry and benign weather is expected across the region through much of the next week as high pressure builds over the Northeast Pacific, bringing a warming trend. Weak systems aloft may bring enhanced cloud cover on some days, but rain chances are minimal. && .DISCUSSION...Now through Sunday...A weak upper level disturbance passing over the region this morning will maintain high level clouds through late morning, before skies become mostly sunny this afternoon. Concerns for hazardous weather remain minimal through the next week. There is high confidence that upper-level ridging and surface high pressure will build over the Northeast Pacific, with increasing uncertainty in the amplitude and position of the upper ridge later in the forecast. Early in the period, while the ridge is centered well offshore, upper shortwaves within northwesterly flow aloft may produce increased cloud cover, but chances for rainfall remain 5% or less through the middle of the week. On clearer nights, areas of fog are most likely to develop within sheltered valleys. As the ridge axis shifts east, temperatures will trend upward through at least Thursday, reaching the 60s along the coast and upper 70s to around 80 degrees along the I-5 corridor. Later in the forecast period, uncertainty in the evolution and possible break-down of upper-level ridging introduces a similar uncertainty in forecast temperatures. Highs are most likely to continue in the 60s to mid 70s, but the spread of possible outcomes becomes wider: chances of reaching 80 degrees along the I-5 corridor are generally 15-45% Friday and Saturday, but there are also 10-25% chances of remaining below 70 degrees. The next opportunity for widespread rain holds off until late next weekend when there is greater consensus that the ridge breaks down. 36/DH && .AVIATION...A weak upper level disturbance is pushing high clouds across the area this morning within the northwest flow aloft. Marine stratus with MVFR CIGs near KAST is expected to persist through 18z this morning. Elsewhere, predominately VFR conditions are expected through at least 03-06z Tuesday. Though, there remains low chances (10-20%) for MVFR stratus to back build off the Cascades toward inland terminals, except 20-30% at KTTD, between 12-18z this morning. Chances for MVFR stratus increase again near KAST after 03z Tue, and at northern inland terminals after 06z. Light north to northwesterly winds again expected to become breezy this afternoon. KPDX AND APPROACHES...VFR conditions expected through at least 06z Tuesday, though there remains a 10-20% chance for MVFR stratus between 12-18z this morning. High clouds expected to clear out this afternoon. Light northwest winds expected to increase to 8-10 kt by 22z this afternoon. /DH && .MARINE...Northerlies are expected to persist through much of the week as the summer-like pattern settles in. Strongest winds are expected during the afternoon and evening periods as a surface thermal trough strengthens over the southern Oregon coast. A Small Craft Advisory has been issued for the inner coastal waters south of Cape Foulweather later this afternoon into this evening for gusts up to 25 kt. Similar conditions are expected on Tuesday. Seas around 6 to 8 feet are expected through the week as well. Small Craft Advisories are in place for the Columbia River Bar early this morning, and again early Tuesday morning, for strong ebb currents which will produce hazardous conditions to small craft. Strong ebb currents are possible during the morning hours each day this week. /DH && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory until 8 AM PDT this morning for PZZ210. Small Craft Advisory from 5 AM to 9 AM PDT Tuesday for PZZ210. Small Craft Advisory from 2 PM this afternoon to 11 PM PDT this evening for PZZ253. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

157 FXUS66 KMFR 180712 AFDMFR Area Forecast Discussion National Weather Service Medford OR 1212 AM PDT Mon May 18 2026 .DISCUSSION...The weather will be quiet with little impact as dry and stable conditions persist this week. With near unanimous agreement across the model suites, forecast confidence is high through Friday with upper level ridging gradually building into our area from the west. High pressure will remain anchored offshore through Wednesday, then build slightly eastward for additional warming on Thursday and Friday, when daytime highs expected to be around 10 or 15 degrees above normal for mid to late May. Slight cooling is possible next weekend or early next week, with a trough expected to move into western Canada. The majority of ensemble members keep the moisture associated with a couple of cold fronts well north of our area, but the second front around Memorial Day could be strong enough and near enough for a marine push and chance of showers for Coos and Douglas counties northward. && .AVIATION...18/12Z TAFs...Some marine stratus is forming near Cape Blanco this evening and the models have some of that spreading into Roseburg overnight. The boundary layer in some of the models do hint at stratus forming in the Umpqua Basin overnight with IFR ceilings developing for a few hours. Otherwise, those should clear out as we mix out into the day. VFR will prevail in all other areas for the next 24 hours. && .MARINE...Updated 1200 AM PDT Monday, May 18, 2026...A thermal trough will bring a typical pattern of gusty north winds and steep to very steep seas over the coastal waters much of this week. Winds will be strongest and seas will be highest during the afternoons/evenings. Through this stretch, very steep seas of 10- 12 ft are most likely south of Cape Blanco with steep seas (6-9 ft) north of Cape Blanco. Ensembles indicate winds will strengthen Wednesday into Thursday with a potential (50-70% chance) for gales across portions of the southern waters (especially from around Gold Beach south). && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Hazardous Seas Warning until 11 PM PDT Tuesday for PZZ356-376. Small Craft Advisory until 11 PM PDT Tuesday for PZZ350-370. && $$

903 FXUS66 KEKA 180741 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 1241 AM PDT Mon May 18 2026 .SYNOPSIS...Gusty north winds continue to ease today. Clear and dry conditions will remain through the week with a warming trend through Thursday. && .KEY MESSAGES... -Strong north winds will weaken today and through the week with only moderate north winds close to shore. -Generally clear skies and dry conditions, even along shore, through the week. -Conditions will warm through Thursday with highs in the interior peaking near 90. .DISCUSSION...Strong north winds continue to subside for Northwest California, especially near shore when compared to yesterday, but will persist through early today around the rim of the Sacramento Valley, especially Lake County. Strong mixing will continue to keep skies clear as temperatures begin to warm, especially across the interior. Wind overnight will continue to preclude any frost formation. High pressure will already begin to weaken but move more onshore today and through the week. This will lead to much weaker north winds with some moderate gusts to 20 mph still pushing in right along shore in the afternoon. Interior winds will transition to a more terrain controlled regime. Conditions will remain very dry with warming temperatures through the week. Highs will most likely top out around 90 for the interior on Thursday. This will constitute only a minor HeatRisk for this time of year. Hotter temperatures will help reform a marine inversion. Any stratus and fog; however, will most likely be very shallow and mix out quickly during the day. Compared to previous runs, most ensemble members continue to show a weak trough in the far extended forecast, but have it delayed until after next week. Rather most models show high pressure slowly weakening, allow temperature to drop, through next weekend. A trough early next week could bring some light showers or thunderstorms, but the vast majority of models currently remain dry. /JHW && .AVIATION...VFR conditions are expected for terminals in Northwest California as gusty north winds remain elevated, but quickly diminish early this morning. Winds will remain elevated for higher elevation areas of the Yolla Bollys and Lake County. Winds have diminished for more protected areas; however, winds remain elevated aloft, bringing LLWS concerns mostly for Mendocino County. && .MARINE...The pressure gradient relaxes slightly and the strongest winds move farther off the coast as the high pressure builds in. However, a large area of gale force gusts around 34-45 kts expected across all zones, with the strongest winds downwind of Cape Mendocino. Steep to very steep, hazardous seas will continue with the elevated winds. Conditions will remain hazardous across the waters for much of the workweek with strong to gale force gusts north winds and steep to very steep seas. Gale force winds and very steep seas are forecast to persists across the outer waters through Friday. /ZVS && .FIRE WEATHER...Strong north winds will continue, but diminish into the early morning. Winds will especially remain elevated around the rim of the Sacramento Valley and in Lake County today. Winds will weaken by this evening and transition to more gentle terrain wind through the week. Conditions will remain very dry with high temperatures increasing to near 90 for the interior by Thursday. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Gale Warning until 3 AM PDT early this morning for PZZ450- 455. Gale Warning until 3 AM PDT Wednesday for PZZ470-475. && $$ 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

069 FXUS66 KMTR 181550 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 850 AM PDT Mon May 18 2026 ...New UPDATE... .KEY MESSAGES... Updated at 1147 PM PDT Sun May 17 2026 - Breezy to windy conditions, especially across the North, East, and South Bay Mountains and the Santa Cruz Mountains through today - Hazardous beach conditions through this morning - Hazardous marine conditions expected through today - Elevated fire weather concerns continue through today across the interior with low humidities and strong gusts && .UPDATE... Issued at 842 AM PDT Mon May 18 2026 Gusty offshore winds continue through this morning with winds gradually easing this afternoon/evening. The Wind Advisory remains on track to expire at 11AM PDT across the higher elevations. Notably, the current hourly temperatures are running 6-7 degrees above what the current forecast has. This is likely due to the stronger offshore (NE) winds bringing in warmer and drier air, with some additional warming from downsloping occurring at the base of the mountains. Bumped temperatures up using the NBM90th percentile to better account for the already warmer temperatures observed this morning. This puts the interior into the 80s to low 90s today with the coast staying in the 70s. Winds don`t look to switch onshore again until after peak heating (3/4PM) so would not expect much marine influence on today`s high temperatures outside of the direct coastline. && .SHORT TERM... Issued at 1147 PM PDT Sun May 17 2026 (Tonight through Monday) An upper level low pressure system digs into the tri-state area of CO, UT, and WY by late Monday morning. We remain under the influence of the broader trough associated with it, leading to breezy offshore flow. North to northeast winds pick up tonight across the Santa Cruz Mountains, the interior North Bay Mountains, and the Eastern Santa Clara and East Bay Hills. Sustained wind speeds of 15 to 30 mph along with gusts up to 50 mph, though localized gusts up to 60 mph are expected for favored ridges, gaps, and passes. These winds will usher in drier air to the region as well, keeping the fire weather threat elevated for interior Bay Area and Central Coast locations. In terms of more every day hazards from the winds, impacts include, but are not limited to difficult driving, especially for high profile vehicles, downed tree limbs, the potential for power outages, and the possibility of loose or unsecured items being blown around. Winds begin to ease late Monday morning into the afternoon and will continue to decrease into the evening and overnight hours. Offshore winds should bring some warmer temperatures to the region, the 90s for the interior Bay Area valleys, the 60s to low 70s along the coast, and the mid 70s to low 80s for the Central Coast Valleys. && .LONG TERM... Issued at 1147 PM PDT Sun May 17 2026 (Tuesday through next Sunday) Upper level troughing looks to hold just west of the Desert Southwest and into southern CA Tuesday into Wednesday, leaving us with teetering between quasi-zonal and barely trough-y. Weak offshore lingers at least over the interior mountain ranges through Tuesday into Wednesday, with onshore flow trying to make a diurnally driven push each afternoon/evening. During this time high pressure just to the west of us (over the eastern Pacific) builds, pushing towards the coast mid week. The upper level trough begins to meander south to southwest of southern California late week. This should bring a return of onshore flow to the region and perhaps the marine layer. Current guidance suggests we could see a 500ft marine layer return by Wednesday, with a 1000-1200ft marine layer by Thursday and Friday. Will need to keep an eye on this as it will affect how temperatures pan out. && .AVIATION... (12Z TAFS) Issued at 449 AM PDT Mon May 18 2026 Strong winds aloft continue to move through the region causing widespread LLWS (both in speed and directions)into the mid to late morning. Gusty winds will be possible across most sites north of the Monterey Bay through the morning. Winds aloft decrease into the mid to late morning and begin to match up with moderate to breezy surface winds. The general wind pattern switches from northerly to westerly into the night, with winds becoming light into the late night. Haze from sea spray will continue to affect the coast. Vicinity of SFO...VFR through the TAF period. Gusty northerly winds continue to affect the terminal with even stronger winds aloft, leading to LLWS. Winds aloft reduce slightly and align better with gusty surface winds in the mid morning. Gusts reduce into the mid afternoon and winds turn more northwest before winds turn light into the night. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR through the TAF period. Surfaces wind stay light through the morning with stronger winds aloft continuing to offer LLWS. Expect surface winds to increase and turn northwest into the late morning, while winds aloft reduce. Moderate northwest winds will ease and become light into the night, with MRY going southerly. && .MARINE... (Today through Saturday) Issued at 449 AM PDT Mon May 18 2026 Winds are reducing across the marine environment, but widespread gale- force gusts are no longer expected. Seas and winds will still offer hazardous conditions for small craft into the mid weak before easing for most zones. Winds will remain hazardous for small craft into the late week for the northern outer zone. && .FIRE WEATHER... Issued at 449 AM PDT Mon May 18 2026 Strong and gusty north to northeast winds continue to affect the region. Expect peak gusts greater than 30 mph for most areas, with around 45 to 55 mph along through gaps and passes, and across higher terrain. These winds will begin to reduce in the late morning but remain breezy until the late night. Daytime humidity retentions loos to stay around 10- 25% across the interior regions and higher peaks, with limited overnight humidity recoveries. Humidities will be slow to recover into the work week as a light offshore flow will continue to affect the district. && .BEACHES... Issued at 449 AM PDT Mon May 18 2026 A Beach Hazards Statement remains in effect for west facing beaches along the Pacific Coast through 9 AM due to strong winds over the marine environment leading to hazardously strong wind waves and overall rough seas. Dangerous swimming, boating, and surfing conditions can be expected. Large breaking waves can overpower swimmers resulting in significant physical injury and increase the risk of drowning. Gusts will stay strong along the immediate coast, causing blowing and drifting sand and increased sea spray. Water rescue attempts may be hampered by reduced visibilities from the sea spray. Remember, NEVER turn your back on the ocean. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement until 9 AM PDT this morning for CAZ006- 505-509-530. Wind Advisory until 11 AM PDT this morning for CAZ504-512-514- 515. Coastal Flood Advisory until 3 AM PDT Tuesday for CAZ506. PZ...Gale Warning until 9 AM PDT this morning for SF Bay N of Bay Bridge. Small Craft Advisory until 9 PM PDT this evening for Mry Bay- Pigeon Pt to Pt Pinos 0-10 nm. Small Craft Advisory until 3 AM PDT Tuesday for Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 9 AM PDT this morning for Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 3 AM PDT Wednesday for Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory until 9 AM PDT Tuesday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...KR LONG TERM....KR AVIATION...Murdock MARINE...Murdock 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

757 FXUS66 KOTX 181200 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 500 AM PDT Mon May 18 2026 .KEY MESSAGES... - Pop up showers and isolated thunderstorms primarily over the higher terrain will return Monday afternoon. - Cold overnight temperatures will bring a threat of morning frost Monday. This could impact sensitive plants or crops. - Conditions trend drier and warmer through the workweek regionwide, with periodic breezy winds for the Cascades and central WA. && .SYNOPSIS... Diurnally forced showers with isolated afternoon thunderstorms will continue today Monday. Precipitation chances decrease and afternoon highs trend warmer through the workweek, climbing back into the 70s and 80s by Thursday and continuing through next weekend. Breezy winds are expected at times through the Cascade gaps and across the western Columbia Basin. && .DISCUSSION... Today through Friday night: A deep longwave trough of lower pressure will remain over the CONUS for this weekend through the workweek. The axis of this longwave trough will slowly migrate over the Rockies by through Wednesday and then over the Plains by Thursday into Friday. The Inland Northwest will remain under the backside of this trough today with a conditionally unstable air mass. Lingering showers over extreme eastern Washington into the Idaho Panhandle early this morning will wane with decreasing instability at mid levels. However, diurnal heating will destabilize the lower levels of the atmosphere for the afternoon. There will be a lack of instability over the Columbia Basin today, which should result in much of the showers and thunderstorm activity confined to mainly the higher terrain today. Instability parameters will be much less compared to Sunday with upper levels trending warmer. Much less likely to see as much small hail like we`ve seen with this storms, but some is expected with slightly stronger thunderstorms over the mountains. Convection will also be capable of wind gusts up to around 20-25 mph and infrequent cloud to ground lightning strikes. Best potential for thunderstorms today will be over northeast Washington into the Northern Panhandle with 20-25% chance of occurring. Convection is expected to wane more quickly into the evening hours compared to Sunday. We then see a drying trend into mid week as a ridge of higher pressure in the eastern Pacific nudes east into the Northwest. There is a shortwave disturbance that pushes across BC on Tuesday and does bring a 20-30 percent chance for showers across the far northern mountains closer to the Canadian border, and this potential could linger into Wednesday for North Idaho as the shortwave pushes across fairly slowly. There is a 15% chance that places like Lauier, Northport, Metalline Falls, Porthill, and Eastport may also see a passing thunderstorm. Temperatures warm up above normal by Wednesday with our highs back into the 70s. The risk for morning frost will decrease as well as temperatures see a slow warm into the weekend. Saturday through Sunday: Model ensembles remain in pretty good agreement with a shortwave trough of lower pressure to flatten the ridge. There is uncertainty with how deep this shortwave will be. About 80 percent of the ensemble members show this disturbance to be fairly weak with minimal cooling of just a few degrees Saturday into Sunday. Westerly winds will see an increase. Stronger wind gusts of up to around 30 mph will be across the Cascades and into the western basin and up to around 20-25 mph potentially into places like Spokane and the Palouse. Winds would pick up Saturday afternoon, but could also remain fairly breezy into Sunday as well. Models continue to diverge as we head into the beginning of next week. Outliers such as the 00Z operational ECMWF and Canadian indicate a deep trough to dig in into BC and potentially as far south as the Pacific Northwest. This scenario would represent more cooling and a better potential for showers than what is in the forecast. The NBM suggests a more zonal flow pattern with the potential for progressive weaker waves that could bring light shower activity but nothing looking all that substantial. After our warm up late in the week, temperatures look to cool near normal for Sunday into the beginning of next week. /SVH && .AVIATION... 12Z TAFs: A moist boundary layer is in place early this morning across far eastern Washington and north Idaho. Nighttime microphysics satellite imagery reveals a stratus deck between 4.5k-7kft from Sandpoint to Pullman and patchy shallow fog from Deer Park to the Spokane metro area. Given the stratus deck across north Idaho, confidence is lower for fog development at KCOE. Fog at KGEG/KSFF may bring IFR/MVFR conditions through 16-17Z. Convective showers with isolated thunderstorms are expected 18Z-04Z primarily over the mountains of northeast Washington into the Idaho Panhandle. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Confidence is low for visibility restrictions and IFR conditions with radiational fog at KGEG/KSFF this morning. Low confidence for stratus to bring MVFR conditions to KCOE and KPUW. ----------------------- 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 41 69 44 72 45 / 10 10 0 0 0 0 Coeur d`Alene 64 41 67 44 70 45 / 20 20 10 0 0 0 Pullman 62 39 65 42 68 43 / 10 0 0 0 0 0 Lewiston 67 43 71 46 73 48 / 10 0 0 0 0 0 Colville 69 36 71 40 75 41 / 20 30 10 10 0 0 Sandpoint 62 40 66 43 68 43 / 30 30 10 10 0 0 Kellogg 61 39 66 43 68 43 / 20 20 10 0 10 10 Moses Lake 73 42 75 46 78 49 / 0 0 0 0 0 0 Wenatchee 72 48 74 51 77 54 / 10 0 0 0 0 0 Omak 73 43 75 48 78 51 / 10 10 10 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...Frost Advisory until 7 AM PDT this morning for Northeast Mountains-Okanogan Highlands-Spokane Area-Washington Palouse. ID...Frost Advisory until 7 AM PDT this morning for Central Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse- Northern Panhandle. && $$

694 FXUS66 KPDT 181035 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 335 AM PDT Mon May 18 2026 .KEY MESSAGES... - Breezy Gap winds Today and Tuesday - Pleasant weather for most of the week with a warming trend - Mountain showers in the Wallowas This afternoon && .DISCUSSION... GOES satellite showed cirrus overspreading east of the Cascades but mainly clear conditions across the much of eastern Oregon with the caveat of lingering mid level clouds from earlier rain showers over the Wallowas and northern Blue Mountains of Washington. Roughly 20 to 50 % chances remain for shower across the Wallowas This afternoon, where snow could mix in but is unlikely to accumulate even above 6500 ft AGL. Models going forward show a gradually building ridge across the PAC NW as 500 mb heights rise from about 564dm to 570 by Tuesday. This sunny high pressure setup will bring some modification to surface temperatures especially in the second half of the week where highs in the 80s should be returnable by Thursday and Friday. Westerly gap and valley winds will also be a diurnally driven sensible weather beginning with the Kittitas valley and the Eastern Columbia Gorge, and adjacent Blue Mountain foothills. Here, areas around Ellensburg has about 75% chances for wind gusts above 30 mph but little if any appreciable chances for gusts above 40 mph. Strongest winds in the region look to be along ridge tops. As the transition form the cooler airmass to the a warmer on on Wednesdays with the upper ridge becoming more centered across Washington and Oregon, the winds will become lighter over a broader area. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Light and variable winds this morning will take time to develop more of a westerly trend, but by early afternoon, westerly gust to 20 and 30 mph can be common in DLS and YKM as gap winds develop across passes and valleys. Cirrus will be the primary clouds and VFR flight category is anticipated for all terminals. && .Preliminary Point Temps/PoPs... PDT 69 42 73 46 / 0 0 0 0 ALW 69 46 72 50 / 0 0 0 0 PSC 75 45 78 49 / 0 0 0 0 YKM 74 44 77 48 / 0 0 0 0 HRI 73 44 76 48 / 0 0 0 0 ELN 68 41 70 44 / 0 10 0 0 RDM 68 31 73 37 / 0 0 0 0 LGD 64 36 70 40 / 0 0 0 0 GCD 65 34 71 39 / 0 0 0 0 DLS 73 45 75 50 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...None. OR...None. && $$ DISCUSSION...71 AVIATION...71

305 FXUS65 KREV 180705 AFDREV Area Forecast Discussion National Weather Service Reno NV 1205 AM PDT Mon May 18 2026 .KEY MESSAGES... * Expect widespread freezing to near freezing temperatures this morning and again Tuesday. * A ridge builds back into the region by mid-week, allowing for warmer and drier conditions into the weekend. && .DISCUSSION... We tied a snowfall record at the Reno Int`l Airport today with officially a trace of snow, thanks to the cold frontal passage today. Expect a very cold morning today with lows near to below freezing for much of the area. Overnight lows rebound a bit Tuesday morning, but will remain on the chilly side. As for today, expect breezy afternoon winds with highs back to the mid 60s (valleys) and upper 50s (Sierra). We remain in a troughing upper-level pattern, with a low sitting off the coast of Baja California and high pressure building off the coast of the PacNW. This will allow for weak pressure gradients aloft, letting us slowly warm up through the week (as the ridge progresses eastward) with light and typical diurnal winds. Dry conditions will also accompany the warming trend. Looking towards the holiday weekend, there`s a ~40% chance to see highs above 90 degrees in Reno and ~40% chance to see over 80 degrees in Tahoe. Shower chances look slim to none for the weekend as well. -Giralte && .AVIATION... VFR conditions expected for all terminals today with breezy east/northeasterly afternoon winds (gusts up to 20 kts), albeit not nearly as strong as the winds yesterday. -Giralte && .REV Watches/Warnings/Advisories... NV...Lake Wind Advisory until 5 AM PDT early this morning NVZ002. CA...Lake Wind Advisory until 5 AM PDT early this morning CAZ072. && $$

284 FXUS66 KSTO 171909 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1209 PM PDT Sun May 17 2026 For additional details on weather and expected impacts over the next 7 days, please visit weather.gov/sto/briefing. .KEY MESSAGES... - A Red Flag Warning is currently in effect for the Valley and Delta below 1000 feet, and continues until 8 PM Monday. - Critical fire weather concerns for the Valley & Delta, with gusty north winds and low humidity. Strongest winds through tonight along and west of the I-5 corridor. - Above-normal temperatures continue through the forecast period with Minor to Moderate HeatRisk. && .DISCUSSION... ...Today & Monday... Highs are expected to be in the high 70s to low 80s across the Valley, and in the 60s to mid 70s in the foothills. Gusty north to east winds peak today in the Valley, with gusts up to 40 to 50 mph through the evening. Valley winds will gradually decrease overnight before picking up slightly again on Monday; however, wind speeds on Monday will generally be lower than today, up to 35 mph in the Valley through Monday evening. Delta wind speeds will continue to gust up to 50 mph through Monday evening. A Wind Advisory for portions of the Valley and Delta remains in place until 8pm tonight. Additionally, with daytime humidities falling into the single digits and teens throughout the Valley, and poor overnight recoveries, a Red Flag Warning remains in place for elevations below 1000 ft through 8pm Monday. ...Tuesday to Saturday... A warming trend continues on Tuesday and through the late week, with increasing areal coverage of Moderate HeatRisk in the Valley and foothills. Thursday also sees 70 to 90% chance of triple digit temperatures, primarily in the central and southern Sacramento Valley east of I-5. Daytime relative humidities will also remain in the single digit to teen range through at least the end of the week. This means that even with light winds in the forecast for the remainder of the week, some elevated fire weather risk will remain. It therefore remains important to practice fire safety this week! There is some indication that ridging will flatten out and therefore that temperatures will cool slightly over the weekend, but there is still some uncertainty in the forecast. Make sure to stay up to date at weather.gov/sacramento. && .AVIATION... VFR conditions are expected over the next 24 hours. Northerly winds 20-30 kts with gusts 30-40 kts for the Valley and Delta through tonight. Then, northerly wind gusts up to 15-30 kts in the Valley and Delta until 00z Tuesday. Northeast to east winds 20-35 kts with gusts up to 35-50 kts over the Sierra through tonight, then gusts up to 20-35 kts through mid-day Monday. && .STO WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 8 PM PDT Monday for Butte County Below 1000 ft-C. San Joaquin County including Stockton-C. Solano County including Fairfield-C. Stanislaus County including Modesto-C. Yolo/NE Solano including Woodland-Central Colusa County Incl. I-5-Central Glenn Co & Interstate 5-Eastern Colusa County-Eastern Glenn County-N. Sac Valley in Tehama County-NE San Joaquin Valley Below 1000 ft-SW Solano County including Vallejo-Sac Metro/W. El Dorado/Amador County-Sacramento County Delta-San Joaquin County Delta-Shasta Metro-Sutter/Yuba counties below 1000 ft-Tracy Triangle Below 1000 ft-W. Stanislaus County Above 1000 ft & I-5-W. Yolo County including Capay/I-505. Wind Advisory until 8 PM PDT this evening for Butte County Below 1000 ft-C. Solano County including Fairfield-C. Yolo/NE Solano including Woodland-Central Colusa County Incl. I-5-Central Glenn Co & Interstate 5-Eastern Colusa County-Eastern Glenn County-N. Sac Valley in Tehama County-SW Solano County including Vallejo- Sacramento County Delta-San Joaquin County Delta-Shasta Metro- Sutter/Yuba counties below 1000 ft-W. Yolo County including Capay/I-505. && $$

145 FXUS65 KMSO 181359 CCA AFDMSO Area Forecast Discussion National Weather Service Missoula MT 142 AM MDT Mon May 18 2026 .DISCUSSION... KEY MESSAGES: - Frost/freeze concerns remains Tuesday morning. - Northwest flow becomes established for the rest of the week with unsettled but mild conditions. Clear skies are allowing temperatures to drop overnight. Expect widespread temperatures in the 20s and low 30s this morning and while there will be moderation Tuesday, expect another cold start. For the kids, a jacket in the morning will be carried home during the afternoon. Vulnerable vegetation will need to be taken care of over the next two mornings. Afternoon heating today and potentially again tomorrow will allow for isolated showers, production of graupel, and potentially a lightning strike or two. We will remain in northwest flow with a high pressure ridge just off the west coast. In the simplest terms, this week will see a warming trend and by Friday temperatures will be a few degrees above normal. A few disturbances will slide south along the eastern part of ridge producing periods of showers. Currently, the models are not overly excited, however, Wednesday evening into Thursday could be a period of more organized shower activity, especially along the continental Divide. && .AVIATION...Cold mornings may allow for fog in the vicinity of terminals, especially KBTM and KGPI. Otherwise, the atmosphere will remain unstable but dry, showers may develop in the vicinity of KGPI between 18/2100 and 19/0000z. Thunderstorms are very low probability, 20% or less, however a lightning strike is possible in the Flathead Valley and surrounding mountains. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Frost Advisory until 8 AM MDT this morning for Kootenai/Cabinet Region...Lower Clark Fork Region. Frost Advisory until 9 AM MDT this morning for Flathead/Mission Valleys...Missoula/Bitterroot Valleys. ID...None. && $$

684 FXUS65 KBOI 181149 AFDBOI Area Forecast Discussion National Weather Service Boise ID 549 AM MDT Mon May 18 2026 .UPDATE...Updated aviation discussion. && .KEY MESSAGES... - Mountain showers on Monday, otherwise dry, breezy and slightly warmer. - Dry with temperatures warming back above normal starting on Wednesday. && .SHORT TERM /Through Wednesday Night/... Issued 257 AM MDT MON MAY 18 2026 The tight surface pressure gradient behind an eastward exiting low pressure system will continue to generate breezy northwest winds today across much of the area. Wind gusts between 25 and 35 mph can be expected this afternoon, though they will not be quite as strong as what was observed on Sunday. While a stable air mass dominates the lower elevations, lingering afternoon instability will support a slight chance of light showers over the mountains today, with minimal accumulation expected. Northwest flow aloft will carry into Tuesday as high pressure builds over the Pacific. A more stable and dry air mass will keep conditions clear across the region, allowing temperatures to warm back to near normal values for this time of year. By Wednesday, an embedded shortwave trough will move through the intermountain west, tracking across our area into Wednesday night. This system will bring an increase in cloud cover along with light, isolated showers primarily focused across the West Central Mountains of Idaho. The arrival of this shortwave and its associated cloud cover will also work to slow down the overall warming trend as we transition into the long term period. && .LONG TERM /Thursday through Monday/... Issued 257 AM MDT MON MAY 18 2026 A trough over Montana will dig into southern Idaho on Thursday, bringing cooler temperatures and a slight chance of high terrain showers (10-20% chance). This trough will quickly move east on Friday, bringing a return to dry northwest flow through Saturday with temperatures 5-10 degrees above normal. A weak shortwave passage will bring another low chance of showers over high terrain late Saturday into Sunday, but forecast confidence is very low. By Sunday, a ridge of high pressure will build into the region, bringing warm and dry conditions ahead of a strong upper level low diving down off the British Columbia coast. Models diverge substantially on the path of this upper level low early next week, with some members (ECMWF) bringing this low directly over the region by Monday evening. Current forecast does not favor this outcome, with a strong bias towards the warm and dry scenario on Monday. && .AVIATION /12Z Monday through Tuesday/... Issued 539 AM MDT MON MAY 18 2026 Generally VFR. Patchy fog/stratus in sheltered mtn valleys through morning. Scattered showers redevelop Monday PM across E Oregon and mtns of SW Idaho. Brief MVFR/IFR and obscuration in mtn precip. Monday snow levels: 5500-6500 ft MSL. Surface winds: W-N 10-20 kt with areas of gusts to 20-25 kt. Winds aloft at 10kft MSL: N-NE 20- 35 kt. KBOI...VFR. Foothill showers return Monday PM. Surface winds: NW 10-18 kt with gusts around 25 kt, decreasing to SW-NW 4-8 kt after Tues/03Z. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Freeze Warning until 8 AM MDT this morning for IDZ016. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise AVIATION.....SA SHORT TERM...JDS LONG TERM....SA

593 FXUS65 KLKN 180822 AFDLKN Area Forecast Discussion National Weather Service Elko NV 122 AM PDT Mon May 18 2026 .KEY MESSAGES... * Temperatures will be cold with below normal readings at all locations today * Overnight lows are expected to drop to below freezing this morning * A slow warmup will start today and persist through the rest of the week && .UPDATE... Issued at 112 AM PDT Mon May 18 2026 Added patchy freezing fog to the valleys in northern Nevada due to the precipitation received over the area yesterday. Skies are expected to scatter out later this morning. The freezing fog is expected to burn off quickly due to the early sunrise. No other changes have been made. && .DISCUSSION... (This evening through next Saturday) WEATHER PATTERN OVERVIEW: Strong late season upper trough currently pushing into northern Nevada has over-performed so far with respect to prior forecasts across Humboldt and Elko counties as snowfall with the front has kept temperatures cooler than expected and with precipitation amounts higher than forecast. Elko so far had seen about 0.21 of water which fell as 1.6 inches of snow so far this morning. Winnemucca has seen 0.17 of water including 0.2 of snow so far. Models suggest that this performance should continue as the front moves into central Nevada this afternoon and evening. Still think the snow rain transition will be at 4500 feet, but could drop to valley floors if clouds can keep the sun at bay. Winds are still expected to be the main story with this system though as model trends outside of the NBM support current wind headlines across northern and central Nevada. The NBM is the low outlier with respect to winds so went ahead and upped the winds to better capture current trends with this system. This afternoon the precipitation will become more isolated to scattered, and become more convective in nature as the upper low moves overhead bringing stronger dynamical lift. So it would not be a surprise to see a few rumbles of thunder this afternoon especially across central NV as better instability develops. Overall amounts look to be better with up to an additional 0.10 of water for the valleys and 1 to 3 of snow for the mountains of northern NV. Amounts for central NV have risen too, with precipitation approaching Eureka and snow starting in Ely. Current trends favor 0.05 to 0.5 of water for the valleys, and up to 2 to 7 for the mountains, with the higher amounts favoring eastern White Pine County. Upper trough look to make its exit across Utah and into CO Monday afternoon. Temperatures this afternoon and Monday will be cool, with highs in the 30s and 40s today, recovering into the 40s and 50s Monday afternoon. After Monday weak WNW flow will develop across NV along with weak and subtle ridging aloft. This will be in place through next weekend allowing for quiet conditions to return, along with a warming trend that will see temperatures warm back into the upper 70 to low 80s by next Sunday. Overnight lows will bottom out Monday morning in the upper teens to upper 20s, however as the warming trend gets under way lows to will warm back above freezing, reaching the upper 30s to upper 40s by Sunday night. Winds after Monday will shift back to the west to northwest, with speeds of 10 MPH to 20 MPH with gust up to 30 MPH in the afternoons. FORECAST CONFIDENCE & DEVIATIONS: Departure: Went ahead and had to bump up the winds/wind gusts for the High Wind Warning and wind advisory areas across Humboldt, N Elko, S Lander, S Eureka, N Nye, and White Pine Counties as the NBM winds were not representative of current trends. There is high confidence for strong northerly winds Sunday through Monday morning as upper trough digs through eastern Nevada. There is high confidence for scattered to numerous light rain and snow showers for Elko and White Pine counties as upper trough pushes strong cold front through the region through Monday morning. There is high confidence for isolated to scattered light valley rain and mountain snow showers for western NV through Monday morning. There is high confidence for a return to quiet weather conditions through the following weekend as WNW flow aloft with subtle ridging allows temperatures to warm back into the upper 60s to low 80s by next Sunday. && .AVIATION... Patchy FZFG is possible this morning across the northern valley locations with VCFG near KEKO. Winds will be breezy in the afternoon NW10-20G30KT. && .LKN Watches/Warnings/Advisories... None. && $$ DISCUSSION...86/98 AVIATION...98