Scattered severe thunderstorms are expected tonight across parts of the Upper Midwest to western Great Lakes. Additional severe storms will also be possible in parts of the northern Plains, central Appalachians, and Mid-Atlantic. Extreme heat is expected to intensify across much of the Southeast and Tennessee Valley, continuing through much of this week. Read More >
Seattle, WA
Center Weather Service Unit
Select forecast office below to display aviation discussion on the right.
|
354 FXUS66 KSEW 290332 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 832 PM PDT Mon Jul 28 2025 .SYNOPSIS...A warming trend is expected through mid week before temperatures cool back to slightly below normal late week. For the lowlands, mostly dry conditions are expected. However, increased cloud coverage is likely for the second half of the week. For the mountains, and particularly the Cascades, afternoon/evening showers or thunderstorms may develop Wednesday and Thursday. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...The forecast remains on track tonight with mostly clear skies and some elevated smoke drifting from primarily the Bear Gulch fire. No updates required this evening and the previous short/long term sections follow. Over the next couple of days, a relatively weak ridge of high pressure will amplify across the west allowing for a slow warming trend for the first half of the week. By Wednesday southerly flow aloft will bring just enough moisture and instability to result in a 10-20% chance of showers/thunderstorms across the Cascades during the afternoon and evening. That said, at this point dynamics are not that impressive and organized convection does not appear likely. Still with relatively weak flow, slow cell motions will need to be watch for any potential hydrologic impacts. && .LONG TERM /THURSDAY THROUGH MONDAY/...Thursday will also see a chance for convection across the Cascades. At this point in time, there appears to be slightly more moisture and dynamic potential thanks to a weak wave moving north through the flow. Still, with marginal instability, storm potential still caps out in the 10-20% range, but chances for decaying convection increases across the Puget Sound region. If nothing else, the added moisture will likely result in increased cloud coverage and slight cooling Thursday across the lowlands. By Friday & Saturday, onshore flow is expected, keeping temperature near or perhaps slightly below seasonable norms. The door will be open late this weekend into early next week for waves to move across the region, potentially resulting in precipitation. However, the chances for precipitation remain low, generally at about 10-20% into early next week. -Wolcott- && .AVIATION...SW flow aloft with strengthening low level onshore flow. VFR/generally clear skies will linger overnight for all but the coast where MVFR ceilings are expected to develop early Tuesday morning. Light low level northerly winds from Snohomish County southward strengthening to 5-10 kt this evening then easing late. KSEA...VFR conditions expected to prevail throughout the TAF period. Westerly winds 5-10 kts will continue to veer to the NW this evening. Winds will ease Tuesday morning, becoming NE 4-5 kt. && .MARINE...Onshore flow will prevail the next few days with strong surface high pressure over the NE Pacific. The strongest winds and seas through the period are associated with westerly winds through the strait with a few gusts up to 20-25 kt this evening and the same for Tuesday evening. The next best chance for more significant winds really looks to be Thursday afternoon/evening and again Friday. For the other waters no significant marine weather impacts are expected with winds and waves remaining short of any thresholds. && .FIRE WEATHER...A warming and drying trend will continue through the middle of the week as southerly flow develops aloft. Fire weather concerns start to increase Tuesday as a trough slowly drifts south from the Gulf of Alaska, allowing for more moist air from the Pacific to move into the region. Instability will begin to increase Tuesday, followed by potential for isolated thunderstorms to develop over the Cascades and Olympics Wednesday and Thursday afternoons. Slow steering flow will cause slow moving storms, capable of producing locally heavy rain which poses a risk for burn scar flash flooding. Despite ample moisture, fuels in the mountains are dry enough that any lightning strikes could prove problematic. At this time, some uncertainty exists over the coverage of thunderstorm activity, especially on Thursday where cloud cover may inhibit the initiation of storms. Conditions will continue to be closely monitored. Thunderstorm potential will shift east of the Cascade Crest on Friday, and increased onshore flow and cooler conditions through the weekend will decrease fire weather concerns across western Washington. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$ 351 FXUS66 KPQR 290450 AFDPQR Area Forecast Discussion National Weather Service Portland OR 950 PM PDT Mon Jul 28 2025 .SYNOPSIS...Hot weather expected through Wednesday in the interior valleys as high pressure builds east of the Cascades. Thunderstorm chances will persist along the Casacdes each day for much of the coming workweek, with highest chance Wednesday and Thursday. && .SHORT TERM...Now through Wednesday Night...Update: Monsoonal moisture moving into the area is producing thunderstorms just to the east of the Cascades. There have been a few thunderstorms popping up within the crest of the Willamette Natl Forest. There continues to be a 15% chance of thunderstorms through the evening. Previous discussion follows. Clear skies and warm temperatures through most of the region today as high pressure continues to build east of the Cascades. The dominant feature impacting the region continues to be an unseasonably deep low centered south of the Gulf of Alaska near 50N. The setup of upper level dynamics is creating southwesterly flow aloft that will turn directly southerly by Tuesday, bringing moist air aloft that will produce showers and thunderstorms in the Lane County Cascades, gradually expanding in coverage through Thursday. As of 2pm Monday, showers and isolated thunderstorms are developing right at the Lane County Cascade crest, though with southwesterly flow, any thunderstorms that develop will rapidly push further east of the Cascades. Chance of thunderstorms taper off going into Monday evening, and similar thunderstorms are expected Tuesday afternoon and evening, with a 10-15% chance of thunderstorms in the Lane County Cascades only. Tuesday looks to be the hottest day this week, with high temperatures seeing a 70-90% chance of exceeding 90 degrees throughout the entire Willamette Valley, with very similar temperatures Wednesday (if not a degree or two cooler). Temperature guidance remains fairly tightly clustered in the low 90s as it has for the for the past several days, lending high confidence to the forecast and likely precluding the need for any heat headlines this week even as HeatRisk creeps up into the Moderate range in a few spots in the Willamette Valley for Tuesday and Wednesday. Although hot weather is expected inland during the first half of the week, the influence of the marine layer will continue to keep coastal communities much more mild in the 60s to perhaps around 70 in some spots through Wednesday. Inland temperatures look to moderate closer to seasonal norms in the low 80s from Thursday into the end of the week as the ridge axis shifts farther eastward with time. -JLiu/Muessle .LONG TERM...Thursday through Monday...Wednesday and Thursday show more significant potential for showers and thunderstorms in the Cascades as a cut off low develops in northern California and pushes northward through the area. Wednesday daytime hours see a 15-35% chance of thunderstorms in the Cascades from Lane County to Clackamas County. Thunderstorms slowly expand in coverage northward throughout Wednesday night into Thursday morning, with Thursday daytime hours seeing a 15-35% chance of thunderstorms for the entirety of the Cascades, from Lane County to southern Washington. With southerly flow aloft, a thunderstorm drifting westward into the foothills or even the eastern Willamette Valley is certainly possible, though highest chances will still be in the Cascades. Confidence in thunderstorms outside of the Cascades is still fairly low, and will wait for more CAM guidance in the coming days. That said, confidence is slightly higher regarding thunderstorm potential Wednesday in the Cascades, so have issued a Fire Weather Watch for the southern and central Oregon Cascades zones. Given the combination of hot and dry weather with the increased potential for lightning strikes, there is certainly potential for fire starts with any lightning strikes during this time. Thunder chances will finally begin to wane Friday into the weekend as the upper low finally weakens and flow turns more westerly across the Pacific Northwest. -JLiu/CB && .AVIATION...Continued VFR conditions likely to prevail across inland terminals throughout the period beneath largely clear skies and increasing high cirrus coverage Tuesday afternoon. Along the coast, marine stratus is likely to bring MVFR cigs after 10-12z Tue, with a 40-60% chance of IFR cigs at ONP and around 30% at KAST from 12z Tue to around sunrise. Any low cigs will mix out by 16-18z Tue as conditions return to VFR. Light winds of less than 5 kt tonight across the region will increase out of the north to northwest to 5-10 kt by Tuesday afternoon inland, and 10-15 kt with gusts of 20-25 kt along the coast. PDX AND APPROACHES...VFR conditions beneath largely clear skies continue through the period, with high confidence that marine stratus remains along the immediate coast leaving only a 5% chance of reaching the Portland area. High clouds will increase Tuesday afternoon as convection grows east of the Cascades, but no convective impacts are expected west of the mountains. Northwest winds continue at less than 5 kt through tonight, increasing to around 10 kt Tuesday afternoon. -Picard && .MARINE... Going through the rest of the work week a fairly calm weather pattern likely persists as a ridge of surface high pressure sites across the coastal waters, albeit slowly retrograding westward with time. So, expect generally north to northwest winds through the week into the weekend with gusts of 13-20 kt during the afternoon and evening hours - little change day to day. During this period seas remain in the 2 to 5 ft range with a dominant period of 7 to 10 seconds. -Schuldt && .FIRE WEATHER...Increased instability combined with monsoonal moisture will promote heightened thunderstorm potential. Due to drier lower atmospheric conditions, thunderstorms have the potential to be on the dry side. The combination of higher lightning potential, dry fuels, and drier surface conditions has promoted the issuance of a Fire Weather Watch for the Willamette National Forecast Cascades - especially along the crest. Right now, the probability of thunderstorms ranges from 15-30% with the highest probability occurring on Wednesday. However, Thursday does have similar probabilities for lightning. -Muessle && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Fire Weather Watch from Wednesday morning through Thursday morning for ORZ689-690. WA...None. PZ...None. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland 618 FXUS66 KMFR 282351 AFDMFR Area Forecast Discussion National Weather Service Medford OR 451 PM PDT Mon Jul 28 2025 .UPDATE...Updated the aviation section. && .AVIATION...29/00Z TAFs...Similar to Sunday morning, LIFR low clouds and areas of fog are expected from Brookings southward and North Bend northward (as well as into the Coquille Valley) between around 08Z tonight to 17Z Tuesday. This pattern is expected to repeat on Tuesday night. Inland, VFR levels look to continue through the TAF period. However, isolated to scattered thunderstorms will develop this evening, mainly from the Southern Oregon Cascades eastward and across northern California. There is also a 10-15% chance for thunderstorms into southern Josephine and Jackson counties. These could temporarily lower ceilings and/or visibility, but the main risks with thunderstorms will be gusty outflow wind gusts, cloud to ground lightning and small hail. A similar scenario is expected for Tuesday afternoon/evening with a slight increase in the number of storms expected over much the same area as this evening. -DW && .MARINE...Updated 200 PM PDT Monday, July 28, 2025...Sub-advisory north winds and low seas of 5 ft or less will persist through this evening. Late tonight into early Tuesday morning, stratus and fog will develop and last at least into mid-morning. A relatively weak thermal trough looks to bring gusty northerly winds and steep seas between Port Orford and Pistol River Tuesday morning into the afternoon. The thermal trough will strengthen slightly late in the day on Tuesday with steep seas expected to expand over much of the waters south of Port Orford through Wednesday evening. Conditions briefly improve with low pressure in the area later Wednesday night into Thursday. Slight strengthening of a thermal trough may bring a return of steep seas to the southern waters Thursday afternoon into Saturday evening. -DW && .PREV DISCUSSION... /Issued 331 PM PDT Mon Jul 28 2025/ DISCUSSION...Forecast confidence is high for the period from this evening through Wednesday night. Thunderstorm activity through this evening and Tuesday afternoon/evening will be isolated to scattered, with an amount of storms in the realm of what has occurred during the past couple of days. The main event will be Wednesday afternoon/evening with broader coverage and the potential for stronger storms with downpours, hail, and gusty winds. Throughout the period, the probability will be highest from the Cascades eastward and across northern California. But, besides those areas, a slight chance extends into southern Jackson County today and Tuesday, then a higher probability across southeast Josephine, Jackson, and eastern Douglas counties late in the day on Wednesday. This weather is in response to a train of troughs moving northeast across northern California. There is a chance of thunderstorms later Wednesday night into Thursday morning, focused upon the northern portion of our area, including storms tracking on an easterly flow across Douglas County into Coos County. This region of focused instability, in the vicinity of the trough, may linger over the northern edge of our area on Thursday, but is more likely to shift into northern Oregon. Weaker instability, in the wake of the trough, could produce isolated thunderstorms over south central Oregon and northern California. Model uncertainty increases another notch for Friday and Saturday, but convective activity looks to trend to lesser probability and coverage of storms with more of a westerly flow aloft that would favor a focus on the east side. Early next week, models are tending to come back into phase with the broad upper trough that has been sitting over the Gulf of Alaska finally pushing into the Pacific Northwest, with believe it or not, a stable, slightly cooler pattern. FIRE WEATHER...Updated 200 PM PDT Monday, July 28, 2025...The attention remains on thunderstorm activity expected this week. Temperatures, humidities, and breezy afternoon winds will all remain near seasonable levels this week, so the main fire weather concern will be daily thunderstorm chances. We`ll be in a relative lull in terms of thunderstorm coverage today. Mainly isolated coverage is expected along and east of the Cascades/northern California with some pockets of scattered across western Siskiyou, northern Klamath and eastern Lake Counties. From Tuesday onward, we expect a heightened level of thunderstorm activity through at least Thursday, with the greatest coverage expected to be Wednesday and storms continuing overnight for some areas into Thursday morning. Another trough (negatively-tilted) swings into central California, turning the flow southerly as it tracks northward through Oregon. This pattern will maintain daily thunderstorm chances through at least Thursday, if not into Friday. Confidence is highest for areas along and east of the Cascades and across northern California to see at least scattered (if not widespread) coverage during this pattern, but the more challenging aspect is how far west will storms make it, and will there be any overnight (nocturnal) thunderstorm potential this week. For now, the forecast supports increased thunderstorm activity for East Side/norCal beginning on Tuesday. We`ve upgraded the Fire Weather Watch for Tuesday to a Warning for FWZs 285/623(eastern)/624/625. For FWZ 284, and other zones across northern California, coverage looks to be mostly isolated, though another pocket of scattered is possible across western Siskiyou (FWZ 280). Areal coverage of storms looks greatest on Wednesday with this day seeing the best potential for storms west of the Cascades. This is when the negatively tilted trough nears the forecast area and guidance shows a shortwave at the base of this trough moving up into Modoc county from the Sierras early Wednesday morning. This would likely result in some shower activity across the Modoc, but there isn`t a good signal for lightning with these showers at this time. Couldn`t rule out some strikes, however, with about a 10% chance of lightning. This shortwave strengthens during the day Wednesday while moving northwestward through the region, resulting in a rather significant trigger for thunderstorm initiation. Scattered to widespread thunderstorms are likely on Wednesday and we`ve gone ahead with a Fire Weather Watch for much of the area (excluding 615/618/619/282). The majority of activity is expected during the afternoon and evening, but as this shortwave swings northward in the evening and overnight Wednesday, thunderstorm activity could continue across northern portions of the forecast area. We`ve started the watch for FWZ616 for Wednesday evening, and carried it through Thursday morning. Additionally, we`ve held onto the watch for 617/623/624/625 through Thursday morning as well. As we move into the overnight hours, the focus for concern shifts to the northern portions of 623/624/625, roughly north of a line from Crater Lake to Summer Lake. At this time, the nocturnal threat looks limited to the northern areas, but subtle changes in the location of this shortwave could change that, so stay tuned for updates. The current forecast maintains similar conditions on Thursday, but there is some uncertainty on how much thunderstorm coverage will materialize due to any lingering cloud cover from overnight activity. Additionally, we`ll be in a less favorable dynamic region as the trough will have shifted north of the area. The greatest coverage is more likely to be where there isn`t cloud cover in the morning, which at this time looks to be east of the Cascades and across northern California. We`ll try to hone in on these details over the coming shifts. By Friday, activity should trend less, however, guidance shows additional shortwaves moving through in a westerly flow pattern. This would result in decreasing chances of storms west of the Cascades while maintaining thunderstorm chances east of the Cascades and across northern California. On the other hand, temperatures will remain near seasonal norms, if not a few degrees below over the upcoming weekend. /BR-y && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Fire Weather Watch from Wednesday afternoon through Wednesday evening for ORZ620>622. Red Flag Warning from 2 PM to 11 PM PDT Tuesday for ORZ623>625. Fire Weather Watch from Wednesday evening through Thursday morning for ORZ616. Fire Weather Watch from Wednesday afternoon through Thursday morning for ORZ623>625. Fire Weather Watch from Wednesday afternoon through Thursday morning for ORZ617. CA...Fire Weather Watch from Wednesday afternoon through Wednesday evening for CAZ280-281-284-285. Red Flag Warning from 2 PM to 11 PM PDT Tuesday for CAZ285. PACIFIC COASTAL WATERS...Small Craft Advisory from 3 AM Tuesday to 8 PM PDT Wednesday for PZZ356-376. && $$ 599 FXUS66 KEKA 290752 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 1252 AM PDT Tue Jul 29 2025 .SYNOPSIS...Slight thunderstorm chances continue each afternoon for interior areas around the Klamath Mountains. Near normal to slightly below normal temperatures expected into early this week. Another upper low could bring increased chances for thunderstorms by mid week. && .DISCUSSION...Some mid-level moisture remains in the area making isolated thunderstorms possible Tuesday afternoon in mostly the Trinity Horn region. Chances of thunderstorms are less than 15% on Tuesday. High pressure is expected to generally remain east of the area. This will keep temperatures near seasonal normals with highs in the upper 80s to low 90s in interior areas. Coastal stratus is expected to form each night during this time with the potential for some clearing into the afternoons with highs in the low to mid 60s along the coast. Models indicate that an upper level low in the Gulf of Alaska will exert influence over Northwest California by Wednesday, increasing chances for isolated to scattered dry thunderstorms for Trinity, NE Humboldt, and interior Del Norte counties. Chances for dry thunderstorms are most likely on Wednesday, but could also occur Thursday and Friday. && .AVIATION...6Z TAFs...Broad troughing with embedded shortwave disturbances are maintaining a deep marine layer. This will continue to greatly reduce the chances for lower ceilings and fog (visibility of 1/2 SM or less). MVFR to IFR ceilings are forecast under this setup. The stratus is once again slow to recover from the full clearing on Monday, but progress will continue. After being fully disrupted over the past 24 hours, the low level inversion is showing some signs of restrengthening. Southerly wind reversal eddies will develop Tuesday and will further add to more diurnally persistent stratus. Soundings show further deepening likely under this continued pattern and this will keep the stratus more persistent. Some isolated thunderstorms may form in Trinity County Tuesday afternoon. Higher thunderstorm coverage is likely Wednesday. JJW && .MARINE...The northerly winds will continue slowly increasing through the waters. This is mostly seen now in the southern zones where 20-25 kt winds are forecast. Some highly localized gale strength gusts will develop around Cape Mendocino over the afternoons and evenings. Northerlies up to 20 kts will spread into the north outer zone 470 Tuesday night through Wednesday. Short period seas are forecast to reach 5-7 feet Wednesday through Thursday. A Small Craft Advisory is now included in this zone. The northerlies will remain stronger in the southern waters over the extended forecast through this week. && .FIRE WEATHER...Isolated to scattered dry thunderstorms are possible from the middle to end of this week for mostly northern Trinity County. Around the Trinity Horn, chances for thunderstorms are 20 to 30% with areas of extreme NE Humboldt, interior Del Norte, and northern Trinity County having a 10 to 20% chance. Lightning strikes could have the potential for fire starts. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Fire Weather Watch from Wednesday morning through Wednesday evening for CAZ204-283. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 3 AM to 3 PM PDT Wednesday for PZZ470. Small Craft Advisory until 3 PM PDT Wednesday 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 165 FXUS66 KMTR 290453 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 953 PM PDT Mon Jul 28 2025 ...New AVIATION... .KEY MESSAGES... Updated at 228 PM PDT Mon Jul 28 2025 - Slightly warmer temperatures continue through this weekend but generally remain below seasonal averages. - Breezy afternoon/evening winds continue through this weekend with gusts between 20 to 25 mph. && .UPDATE... Issued at 915 PM PDT Mon Jul 28 2025 Stratus hasn`t really made a return yet this evening. Slivers of stratus have started to from along the Monterey Peninsula and around Half Moon Bay. The marine layer may only get to 1000ft, maybe 1500ft, which means the stratus will not be as expansive tonight. Coastal sites have the best chance of stratus tonight, with perhaps interior North Bay locations seeing patchy stratus early Tuesday morning. && .SHORT TERM... Issued at 228 PM PDT Mon Jul 28 2025 (This evening through Tuesday) Slightly warmer temperatures, but remaining below seasonal normals, continue through the rest of the week. In the larger synoptic scale, upper level troughing continues over the Western United States while an upper level ridge continues to build over the Central United States. This ridge serves as a blocking high that is preventing troughing over the West Coast from progressing eastward. With troughing continuing, the marine layer will maintain a depth of around 1500-2000 ft through much of this week with No Sky July continuing. At the same time, the arrival of a drier and warmer air mass will help to keep our temperatures warmer and potentially mix out stratus coverage faster Tuesday morning. There is some potential for drizzle Tuesday morning, but it is expected to be patchy in nature given the much drier air mass in place. We can expect our weather to remain relatively stagnant for much of this week given the blocking high preventing the trough from from moving to the east. High temperatures on Tuesday will be in the upper 80s to low 90s across the interior, in the 70s to low 80s along the Bay Shoreline, and in the upper 50s to 60s along the coastline. Diurnally breezy onshore winds gusting to 20 to 25 mph continue along the coastline, ridgetops, and gaps/passes during the afternoon and evening. Wind gusts will be closer to 30 to 35 mph in areas where terrain promotes wind funneling (Altamont Pass region). && .LONG TERM... Issued at 228 PM PDT Mon Jul 28 2025 (Tuesday night through next Sunday) Not much variation between the Short Term and Long Term forecasts through at least this weekend and likely into early next week. Upper level troughing persists over the West Coast with upper level ridging over the Central United States. This will keep temperatures fairly consistent all week with interior highs in the 80s to low 90s, 70s to 80s along the Bay Shoreline, and upper 50s to 60s along the coastline. The marine layer is expected to remain fairly consistent around 1500-2000 ft with stratus returning overnight and patchy drizzle along the coastline. Diurnally breezy winds continue in the afternoon/evening with gusts between 20 to 25 mph with locally higher gusts possible across mountain gaps/passes (e.g. Altamont Pass region). Friday into the weekend we start to see some indications that the upper level pattern is shifting. The prevailing upper level pattern over the West Coast will still be troughing next weekend, but, high pressure over the Four Corners region will start to expand eastward into southern California. This won`t result in any significant changes to our temperature forecast for this upcoming weekend, as a passing shortwave trough will help negate building high pressure, but it may signal a change is on the horizon. Longer term guidance continues to indicate troughing will persist through early next week before ridging shifts westward and builds over the West Coast. Both the European and GFS models are getting more onboard with this scenario and showing ridging showing up by early August. Guidance from the CPC shows that we are leaning above normal on the 8-14 day outlook (August 5th - August 11th) which is in agreement with the model trends we have been seeing. Looking at it statistically, the CPC breaks it down that there is a 46% chance of above normal temperatures, a 21% chance of below normal temperatures, and a 33% chance of near normal temperatures during that time period. This is still a ways off but it is a good sign that models have been relatively consistent over the last few days. && .AVIATION... (06Z TAFS) Issued at 952 PM PDT Mon Jul 28 2025 Dry air is filtering into the area, limiting low clouds for all but HAF and MRY, which has MVFR CIGs. Winds look to reduce across the district into the early night, becoming light to moderate through the night and much of Tuesday morning. CIGS look to form in the bays and the North Bay interior overnight, and into the morning, but could be inconsistent for SFO, STS, and APC. Sites begin to clear in the late morning with most TAF sites going VFR in the afternoon. The exception will be HAF, which will go from IFR to MVFR CIGs, but will not clear through the TAF period. Expect modest wind increases into Friday with most areas peaking around 15 kt winds with some gusts specifically in the SF Bay reaching above 20 kts. Winds reduce again that evening with CIGs quickly returning into the bays and becoming widespread again late that night. Vicinity of SFO...VFR lasts early Tuesday. Winds reduce into the night, becoming moderate as cloud cover begins to filter into the SF Bay. Moments of IFR CIGs look to affect SFO in the early to mid morning, but look to erode by the late morning. Breezy west winds return into Tuesday afternoon but reduce in the late evening as IFR CIGs return. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Winds look to reduce into the mid evening becoming light for the night. An eddy in the Monterey Bay will complicate the arrival of CIGs into the night, IFR CIGs expected to before the late night, but the eddy could delay consistent filling until later into the night. Additionally, the oscillation looks to add extra moisture to MRY, calling for moments of LIFR CIGs and pockets of mist for the early to mid morning. The terminals clear in the early afternoon on Tuesday as winds increase, but winds cut off that evening and IFR CIGs quickly return. && .MARINE... (Tonight through next Sunday) Issued at 525 PM PDT Mon Jul 28 2025 Moderate to breezy winds gradually increase into the night across the waters leading to widespread hazardous conditions for small craft. Moderate to fresh winds will prevail with locally stronger coastal jets. Moderate to rough seas will prevail through Friday. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 9 AM PDT Tuesday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory until 3 AM PDT Tuesday for Pt Pinos to Pt Piedras Blancas 0-10 nm. && $$ SHORT TERM...Kennedy LONG TERM....Kennedy 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 235 FXUS66 KOTX 290731 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 1231 AM PDT Tue Jul 29 2025 .KEY MESSAGES... - Temperatures warming into the 90s to 100s next week with widespread Moderate and localized Major HeatRisk Tuesday and Wednesday. - 10-20 percent chance of thunderstorms Wednesday over the mountains then widespread 15-30 percent chance Thursday. 10-30 percent chance lingers over the northern mountains and ID Panhandle Friday. && .SYNOPSIS... Temperatures will trend warmer today and tomorrow with highs in 90s and low 100s. Isolated dry thunderstorms on Wednesday over the mountains will bring a risk for new fire starts. There are increasing chances for wet thunderstorms Thursday and Friday. && .DISCUSSION... Tuesday through Wednesday: Early thunderstorms are again anticipated this morning as a few minor disturbances continue making their way across Oregon. Areas of potential thunderstorms will be similar to yesterday: Garfield, Asotin, Nez Perce, and Lewis counties could see cells moving northeast. Meanwhile, a ridge strengthening over western Canada will promote a warming trend through Thursday. Temperatures will be at their hottest on today and tomorrow, with high 90s to low 100s anticipated throughout much of the area. Low temperatures these nights will be in the mid 60s, which could create some problems for people prone to heat-related illnesses without adequate cooling. Widespread moderate to local major HeatRisk is anticipated both days. The strengthening ridge will provide a transition from southwesterly flow to southerly flow, and lift coming from lowering heights in California will make its way through the area, increasing thunderstorm potential. This afternoon, NBM shows a 5-10 percent chance of thunder with surface based CAPE values around 100-200 J/kg. On Wednesday, a shortwave will move through the area and provide further lift. CAPE values increase to 500-800 J/kg. However, due to the dry air mass in place, these thunderstorms moving through the area will be mostly dry, with lightning and outflow winds being the main concerns. As such, a Fire Weather Watch has been issued for the East Washington Central Cascades Wednesday afternoon. Thursday through Friday: Lower heights and moisture forming over California will result in a more robust surge of warmth and moisture Wednesday through Friday. Additionally, on Thursday, as heights down in the southwest lower further, a shortwave will move through the area, providing a boost in lift as well. As of right now, NBM thunder probabilities increase from 5-10 percent on Tuesday to 10 to 15 on Wednesday, and further to 15 to 30 percent on Thursday and Friday afternoon. Thunderstorm coverage also increases, with much of the forecast area showing chances for thunder. Surface-based CAPE also jumps from 200-500 J/kg on Wednesday to 500-1000 J/kg on Thursday and Friday, with localized areas of 1000-2000 J/kg in northeastern Washington and in the northern Idaho Panhandle. Long and medium range models are now showing PWATs 150-200 percent of normal, indicating a good surge of moisture. This moisture will create wetter thunderstorms, bringing higher chances of heavy rainfall rates within cores in addition to lightning and strong outflow winds. This could result in potential flood issues, particularly within burn scars. Thunderstorms on Friday will be mostly confined to the northern mountains and northern Idaho Panhandle. Medium range models are beginning to pick up on the convection as well, and are in agreement with the longer range models that the environment Thursday and Friday will be favorable for thunderstorms. /AS && .AVIATION... 00Z TAFS: VFR conditions will continue with some high clouds moving across the region. Small chances for morning thunderstorms to skirt areas Lewiston and southward, but not enough confidence to put in TAFs. Winds will be mostly light. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in VFR conditions through the TAF period. Low confidence in afternoon thunderstorms impacting LWS after 06z. && .Preliminary Point Temps/PoPs... Spokane 95 63 97 67 96 62 / 0 0 0 10 20 40 Coeur d`Alene 94 64 97 67 95 62 / 0 0 0 20 20 40 Pullman 93 59 95 62 91 58 / 10 0 0 20 20 50 Lewiston 101 69 103 71 99 68 / 20 0 0 20 20 40 Colville 94 54 96 56 95 54 / 0 0 0 10 20 40 Sandpoint 91 59 92 61 92 58 / 0 0 0 20 20 50 Kellogg 92 66 93 69 91 63 / 0 10 0 20 20 50 Moses Lake 99 62 101 69 98 64 / 0 0 0 10 20 30 Wenatchee 98 72 100 74 96 70 / 0 0 0 20 30 40 Omak 98 66 100 68 99 66 / 0 0 0 10 30 40 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...Fire Weather Watch from Wednesday afternoon through Wednesday evening for East Washington Central Cascades (Zone 696). ID...None. && $$ 796 FXUS66 KPDT 290541 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1041 PM PDT Mon Jul 28 2025 Updated Aviation Discussion .AVIATION...06Z TAFs...Mostly VFR conditions to prevail through the period. Another round of thunderstorms are expected to develop to the south of sites RDM/BDN tomorrow after 21Z, with chances nearing 30% at site BDN for thunderstorm impacts. Site RDM chances are less than 20%, so have opted not to include mention in the TAF. Winds will be light, 12kts or less, through the period at all sites...except for sites near thunderstorms where erratic gusty outflow winds may develop. Site BDN observation station is currently not reporting observations, therefore amendments for changing conditions will not be issued. Lawhorn/82 && .PREV DISCUSSION... /issued 418 PM PDT Mon Jul 28 2025/ UPDATED AVIATION. AVIATION...00Z TAFs...VFR conditions prevail for all airport sites. Thunderstorms are moving into the region and have a couple of cells close to RDM/BDN. Went ahead and put in a PROB30 group for RDM/BDN. Wasn`t too confident to issue a line for the storms since they don`t appear to be widespread in that part of the region. Most of the thunderstorm activity is situated in Eastern Oregon from the John Day Valley eastwards. Some of the heavier storms that pass through a site could temporarily put MVFR conditions on that site, but nothing prolonged is expected. No precip issues expected for other sites, but will keep monitoring if the forecast changes. PREV DISCUSSION... /issued 200 PM PDT Mon Jul 28 2025/ DISCUSSION...Satellite and radar imagery shows mostly clear skies across the region with convection activity developing over the eastern mountains. With the S/SW flow aloft continuing along the ridge, isolated to scattered thunderstorms will remain being our popular threat through tomorrow during afternoon and evening hours over central OR to the eastern mountains. This has led us to issuing a Red Flag Warning for Tuesday from 1 PM to 11 PM for OR ORZ697-698-700-705 and a Fire Weather Watch for ORZ696-699. Low to moderate instability persists with MUCAPE values of 500-1000 J/Kg, effective shear at 20-30kts and anomalously high PWATs (>0.70 inches). These parameters show that these storms` severity may become slight to enhanced. For Wednesday, the SPC Outlook shows general risk for thunderstorms across majority of our region. Slight chance (<30%) of these storms may develop over Deschutes County through Grant County before showers linger late Wednesday evening into overnight. Thunderstorms may become mainly dry with chances of wetting rain (CWR) less than 0.10 inches, thanks to the upper ridge and thermal trough. This will increase potential for abundant lightning to impact any new or ongoing fires. Strong winds may also develop, given the wind parameters show inverted-V sounding profiles, DCAPE above 900, and steep lapse rates for dry microburst. These storms will then gradually move across the eastern mountains and portions of the Foothills of the Blues-OR by Friday night. We should have a break over the weekend into Monday across most locations, though the Wallowas may have a slight chance (<20%) of thunderstorms around Monday afternoon. Convection activity should weaken during overnight hours, leaving behind light showers. Fire weather concerns will remain elevated for abundant lightning/severe winds that could impact any fires in these aforementioned locations. Tomorrow and Wednesday will be our hottest days of this week with high temperatures reaching from the high 90s to the triple digits. Thursday onwards, temps will cool by a few degrees once a weak system arrives. Winds will be breezy (15-25 mph) through Wednesday before increasing to locally windy conditions around the Gorge and Kittitas Valley Thursday afternoon into the weekend. Feaster/97 && .PRELIMINARY POINT TEMPS/POPS... PDT 62 99 65 99 / 10 0 10 0 ALW 67 100 70 100 / 10 0 0 0 PSC 60 101 62 102 / 0 0 0 0 YKM 62 99 67 101 / 0 10 0 10 HRI 62 102 65 102 / 0 0 0 0 ELN 61 98 66 99 / 0 0 0 10 RDM 52 94 56 93 / 20 10 20 20 LGD 61 94 62 95 / 20 10 10 10 GCD 59 94 60 94 / 30 20 30 20 DLS 65 101 69 101 / 0 0 0 10 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Red Flag Warning from 2 PM to 11 PM PDT Tuesday for ORZ697>700- 705. Fire Weather Watch from Wednesday afternoon through Thursday morning for ORZ700-704-705. WA...Fire Weather Watch from Wednesday afternoon through Wednesday evening for WAZ695. && $$ SHORT TERM...97 LONG TERM....97 AVIATION...82 082 FXUS65 KREV 282138 AFDREV Area Forecast Discussion National Weather Service Reno NV 238 PM PDT Mon Jul 28 2025 .KEY MESSAGES... * Areas of showers and isolated thunderstorms expected through the afternoon and ending in the evening. * Thunderstorm activity increases Tuesday and Wednesday, posing a risk of heavy rain and flooding, gusty outflow winds, small hail, and frequent lightning. * A drying trend will limit thunderstorms after Wednesday with increasing breezes possible over the weekend. && .DISCUSSION... Weak low pressure is lifting through northern California per 19Z moisture-channel imagery and will assist in shower and thunderstorm development this afternoon. Coverage will be limited today -- even more so than yesterday -- with greatest likelihood favoring Lassen County, the Surprise valley into far N Washoe County, and from the Quad Counties to the US-95 corridor. Showers and storms may develop along the Sierra north of Tahoe, but odds of this occurring are lower. Otherwise, it`ll take well-placed outflows to initiate storms away from these areas. Thunderstorms will be capable brief heavy downpours, gusty outflow winds and blowing dust near desert sinks and playas, small hail, and lightning. Thunderstorm activity trends upward Tuesday and Wednesday as a better defined low pressure area pivots through the region. Greater instability coupled with rich moisture aloft will increase chances of storms to 20-40% and 30-60% Tuesday and Wednesday afternoons, respectively. NE California and NW Nevada will continue to be the most favorable areas, including Tahoe communities and the Greater Reno-Carson-Minden area. Guidance remains keen on the prospect of nocturnal showers and storms from the Tahoe Basin northward Tuesday night into Wednesday morning, which corresponds to when the low pressure moves overhead. Potential impacts are the usual suspects -- strong outflows, small hail, lightning and new fire starts, blowing dust -- but heavy rain and flash flooding is possible given abnormal moisture aloft. Needless to say, expect more stormy weather through midweek. Moisture scours out in the wake of the low passage, reducing thunderstorm chances and coverage after Wednesday. There is still the potential for increased afternoon breezes and elevated fire concerns this weekend into early next week, but confidence remains low on timing/magnitude. -Salas && .AVIATION... * VFR conditions will give way to MVFR for some terminals. Clouds will continue to develop as storms arrive once again for this afternoon. Chances are greatest for KCXP and KMEV (20-25% chance), while KTRK, KRNO and KTVL have lower chances (10-15%). KSVE may see showers initiate nearby then move northward into the afternoon and evening. Gusty outflow winds, small hail, heavy rains and frequent lightning are possible as well as terrain obscuration in the vicinity of ongoing storms. * Showers and storms return each day this week for much of the region, with the later week storms firing near the Oregon border. HRICH && .FIRE WEATHER... Thunderstorm coverage and lightning density increases Tuesday and Wednesday, elevating the potential for new ignitions regionally. However, there are competing factors that limits confidence in the overall lightning threat for midweek. Abundant lightning is becoming more probable each afternoon, particularly in northeast California and near the Oregon border where thunderstorm coverage is favored to be greatest. Storm motions will also be moderate, reducing the residence time of rain cores over any lightning start. To make matters more complicated, there is the possibility of nocturnal lightning Tuesday night into Wednesday morning from the Tahoe Basin northward as the low passes overhead. With all that being said, thunderstorms will trend on the wetter side owing to rich moisture aloft. Furthermore, the areas near the Oregon border have received considerable rainfall over the last several days, keeping fuels saturated. The main takeaway is that increasing lightning production from wetter thunderstorms is expected Tuesday and Wednesday, and may result in new ignitions away from rain cores. -Salas && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ 942 FXUS66 KSTO 282022 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 122 PM PDT Mon Jul 28 2025 .DISCUSSION... .SYNOPSIS... Chances for afternoon and evening mountain thunderstorms this week, with the highest chances today along the Coastal Range and Wednesday along the Sierra/southern Cascades. Otherwise, near normal temperatures expected this week as periodically breezy onshore winds persist. && .KEY MESSAGES... * Today: - Slight chances (10-20%) for isolated mountain showers and thunderstorms this afternoon and evening. Highest potential over the Coastal Range and Shasta County mountains. - Main storm hazards include lightning, brief heavy rain, gusty winds, small hail, and possible fire starts. - Elevated fire weather conditions are expected in the mountains into the due to the lightning threat and any strikes outside the main precipitation core will pose the threat for fire starts. - Afternoon highs in the 80s and 90s throughout the Valley as high temperatures return to near normal. * Tuesday-Thursday: - Mountain thunderstorm chances decrease to less than 10% on Tuesday, with chances then increasing to 15-30% overnight Tuesday through Wednesday evening. Highest chances expected along the Sierra/southern Cascades, with a potential lull in activity mid to late Wednesday morning. - Lingering mountain thunderstorm chances (10-20%) expected on Thursday during the afternoon and evening hours, with a trend toward a drier pattern late week into the weekend. - Elevated fire weather conditions are expected in the mountains due to the lightning threat and any strikes outside the main precipitation core will pose the threat for fire starts. - Slight warming trend through early this week, but highs will remain near to slightly below normal. Expect Valley highs in the 90s Monday and Tuesday. - Periodically breezy onshore flow expected during the afternoons and evenings. * Friday-Next Weekend: - Isolated mountain thunderstorm chances less than 10% at this time. - Periodically breezy onshore flow persists, with a slight uptick in wind speed possible by Sunday. Probability of wind gusts > 30 mph on Sunday: 15-30% - Near to slightly below normal temperatures expected to continue. .Changes from previous forecast... - Increasing chances (15-30%) for isolated to scattered mountain thunderstorms overnight Tuesday into Wednesday morning and again Wednesday afternoon/evening. && .AVIATION... Generally VFR conditions expected to prevail next 24 hours across interior NorCal. MVFR/IFR possible in isolated mountain thunderstorms through 03z Tuesday, primarily north of Interstate 80. Otherwise, breezy onshore surface winds up to 12 kts expected through Valley and Delta, with lighter terrain driven winds at higher elevations. Gusts 20-25 kts in Delta and vicinity through 06z Tuesday, decreasing overnight. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$ 416 FXUS65 KMSO 290755 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 155 AM MDT Tue Jul 29 2025 .DISCUSSION... KEY MESSAGES: - The KMSO Radar (Missoula, MT local weather radar) will remain offline due to scheduled maintenance through the first week of August. - Showers and thunderstorms expected each day through the weekend. - Flash Flood Watch for Tuesday afternoon/evening for slow moving storms producing moderate to heavy rainfall across Lemhi county into west central Montana The Northern Rockies will be under weak southwesterly flow through the work week. This flow pattern will be conducive for afternoon and evening showers and thunderstorms. A few weak disturbances moving through the flow could kick off storms during the overnight hours into the morning. The upper level winds will be relatively light today and Wednesday causing slow moving storms. Any storms producing moderate to heavy rain fall these afternoons could causing localized flooding especially over burn scars or flood prone areas. The concern is great enough that a flash flood watch has been issued for Lemhi county and portions of west central Montana for this afternoon through the evening. A more organized disturbance will push through the Northern Rockies Thursday into Friday. This feature will increase the coverage of shower activity across the region. Then a weak trough is expected to push into the region by the weekend causing cooler temperatures along with more widespread precipitation. While the models have differing solutions on how Thursday of this week through next Thursday will happen, they have one thing in common. For western MT and north-central ID above normal precipitation and below normal temperatures, at times 10+ degrees below normal. Lemhi County ID may be closer to normal precipitation with below normal temperatures. && .AVIATION...Disorganized convection will affect the Northern Rockies yet again today. With increasing atmospheric moisture the threat of strong outflow wind gusts is slowly fading, while threats of moderate to heavy showers increase. By 29/2100z, showers and thunderstorms will be in the vicinity of KSMN and KBTM and after 30/0000z at KHRF. Activity at other terminals is low probability but cannot be ruled out. Any shower will be capable of briefly (30-45 minutes) degrading visibility to 4SM. Vicinity to showers will also have the possibility of outflow gusts up to 30 Kts, 40 to 50% probability. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Flood Watch from this afternoon through this evening for Bitterroot/Sapphire Mountains...Butte/Blackfoot Region... Flathead/Mission Valleys...Lower Clark Fork Region... Missoula/Bitterroot Valleys...Potomac/Seeley Lake Region... West Glacier Region. ID...Flood Watch from this afternoon through this evening for Eastern Lemhi County...Western Lemhi County. && $$ 987 FXUS65 KBOI 290231 AFDBOI Area Forecast Discussion National Weather Service Boise ID 831 PM MDT Mon Jul 28 2025 .DISCUSSION...Showers and thunderstorms have continued into the evening as expected, with several storms becoming strong with radar indications of hail near 1" in diameter. Wind gusts up to 48 mph have been observed so far. Latest mesomodel guidance suggests that storms will continue until around midnight. The Red Flag Warning will be allowed to remain in place until its 04Z expiration time. No changes are planned to the forecast. && .AVIATION...Generally VFR. Scattered showers/thunderstorms, mainly over east Oregon, producing local LIFR/IFR in heavy rain and hail cores. Storm outflow wind gusts to 30-45 kt. Mtns obscured in storms. Decreasing activity after 29/06Z, then redeveloping in E Oregon and portions of SW Idaho Tue afternoon. High density altitude Tue. Surface winds outside of storms: NW-N 5-15 kt. Winds aloft at 10kft MSL: variable 5-10 kt. KBOI...VFR. Threat of outflow winds from distant storms tonight, creating erratic gusts to around 30 kt. A 15% chance of a showers reaching terminal before 29/06Z. Then, virga/sprinkles Tue morning. Surface winds outside of storms: generally W-N 5-15 kt. && .PREV DISCUSSION... SHORT TERM...Tonight through Wednesday night...Afternoon and evening thunderstorms will mostly diminish around sunset similar to recent days. An upper disturbance over northern CA this afternoon will be slow to lift through our area and could keep thunderstorm activity going overnight in SE Oregon and in SW Idaho along the ID/OR border. Have a slight chance (15%) to cover this potential. Expect any nighttime shower/storm activity would bring more lightning than rain or outflow winds. Southwest flow will continue to inject moisture and periodic upper waves into region through Wednesday. The focus of development will remain over SE Oregon and the w-central Idaho mtns as has been the last few days while more organized/stronger storm development will be across SE Oregon and along the ID/OR border, especially in conjunction with passing upper lows. There will be no significant changes to the air mass so wind gusts of 30-50 mph will capture most outflow potential with locally severe gusts possible from strong cells or organized lines that form. Storms will be capable of putting down heavy rain with localized quarter to half inch amounts possible. Northerly storm motion of 15 to 20 mph would limit any flood concerns to burn scars. Temperatures are near normal through the period which puts lower elevations in the mid 90s through Wednesday. LONG TERM...Thursday through Monday...The upper-level ridge over the Southern Great Plains and the upper-level low pressure system in the Gulf of Alaska will continue to be the driving forces behind the southwest flow aloft. Embedded shortwave trough features will move through the area, continuing to bring monsoonal moisture and aid in destabilization for afternoon and evening thunderstorms. The chance of showers and thunderstorms across most of the area Thu/Fri/Sat afternoons range from 15-40% for showers and similar for thunderstorms; the highest probabilities are found in eastern Oregon and across the higher terrain of southwest Idaho. PWATs will remain (and rise a bit) to near the 75th percentile of climatology for this time of year (near .75" averaged spatially, locally higher/lower). CAPE values of near 500 J/kg through Saturday are common among models, although some show the potential for values to exceed 1000 J/kg. As has been the case in recent days, storms that develop will likely fire along higher terrain before moving N-NE. Hazards at play with storms that develop include: gusty outflows, heavy rain, lightning, and even hail. This pattern may finally break Saturday into Sunday. The GFS, ECMWF, and Canadian have the upper-level ridge wane in strength, which will cause more of a W-SW flow aloft. With this, a strong shortwave trough looks to come through the region sometime Sunday into Monday. With it, a cold front will provide some relief from the heat early next week. The intensity of this front is anyones guess at this point, which is currently leading to a wider range of precipitation chances in both spatial and temporal coverage. As we get closer to this event, models will begin to agree, which will likely lead to higher chances around a particular solution. As this feature moves through, the area will switch over to NW flow aloft, cutting off the stream of Pacific moisture that has been subjecting the area. Temperatures will be near normal Thursday, before dropping to a few degrees below normal Friday through Monday. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...Red Flag Warning until 10 PM MDT /9 PM PDT/ this evening ORZ670-672>675. Fire Weather Watch from Tuesday afternoon through Tuesday evening ORZ670-672. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise DISCUSSION...SP AVIATION.....SH SHORT TERM...DG LONG TERM....CH 701 FXUS65 KLKN 281019 AFDLKN Area Forecast Discussion National Weather Service Elko NV 319 AM PDT Mon Jul 28 2025 .KEY MESSAGES... Updated at 146 AM PDT Mon Jul 28 2025 * Southerly afternoon breezes continue across central Nevada with gusts 20 to 30 mph thru next week * Isolated, mostly dry, thunderstorms in and near Humboldt and northwest Elko Counties thru the first half of the week * Thunderstorm activity shifts east the latter half of the week, focused in and near Elko County with mostly dry storms && .DISCUSSION... (Today through next Monday) WEATHER PATTERN OVERVIEW: Synoptic pattern remains relatively unchanged thru the week as a robust upper cut off low resides over the Gulf of Alaska with an upper trof along the west coast. Southwesterly flow will continue over the Great Basin thru the week. Southerly afternoon breezes remain present across central Nevada with gusts 20 to 30 mph, and the higher end of the range will be situated across White Pine County. Winds more modest across northern Nevada. Though an upper perturbation embedded within the mean southwesterly flow looks to move thru the region from the Pacific in the Wednesday time frame. This is anticipated to produce stronger south- southwesterly surface winds within the forecast area Wednesday and Thursday, with the strongest gusts again situated across White Pine County. Though advisory criteria winds are not expected. Isolated dry thunderstorms are expected this afternoon in and near Humboldt County with the latest progs indicating a slight reduction in atmospheric moisture content this afternoon. Occasional lightning strikes and gusty and erratic outflow winds with gusts 45 mph or more will be the main concerns. Isolated dry thunderstorms look to continue each afternoon into mid week, primarily within Humboldt County and northwest Elko County as areal extent again expands as atmospheric moisture content is indicate to modestly increase again. Thunderstorm activity indicated to shift east the latter half of the week, focused in and near Elko County, though low confidence is still expressed in the exact areal coverage of storms until the prognostics come into better agreement. Temperatures will reside a few degrees warmer today, warming to around average, and remaining so thru the week. FORECAST CONFIDENCE & DEVIATIONS: High confidence in the short term forecast though exact coverage of thunderstorms slightly uncertain. As noted, increasing uncertainty with regard to areal coverage of dry thunderstorms as the week progresses. && .AVIATION... VFR conditions expected at all terminals over the next 24 hour period. Thunderstorms will develop in and near Humboldt County this afternoon. VCTS will not be in the TAFS for KBAM or KWMC, however there is still a 10% chance for thunderstorms at KWMC and KBAM. Southwesterly winds at the northern terminals are expected to be light below 10 kts, however downdrafts from any storms that move in vicinity of KWMC and KBAM may increase winds. KENV and KEKO are expected to be dry with light winds. For central Nevada terminals KTPH and KELY, clearer skies but increase in southerly winds at 10-12 kts with gusts up to 20-22 kts. && .FIRE WEATHER... Elevated fire weather conditions continue to persist across central Nevada this afternoon due to southerly wind gusts between 20 and 30 mph along with minimum afternoon relative humidity residing in the single digits. Overall synoptic pattern remains relatively unchanged thru next week, and southerly afternoon breezes can be expected across central Nevada thru the week. The higher end gusts will be located within zone 425, especially Wednesday and Thursday as an upper perturbation moves thru the Great Basin. Across northern Nevada, winds will be more modest, though main concern will be for continued afternoon isolated and mostly dry thunderstorms. Storms this afternoon will be focused in and near zone 437. Latest progs indicating a slight reduction in atmospheric moisture content this afternoon with isolated dry storms present. Isolated thunderstorms are forecast with mostly dry storm modes thru at least Wednesday, with areal extent again expanding as atmospheric moisture content is indicate to modestly increase again. Storms will primarily be located within zones 437, and the northern halves of 424, 438, and 469. Thunderstorm activity indicated to shift east the latter half of the week, focused in and near Elko County, though low confidence is still expressed in the exact areal coverage of storms until the prognostics come into better agreement. Warmer temperatures expected today and thru the week. && .LKN Watches/Warnings/Advisories... None. && $$ DISCUSSION...92 AVIATION...97 FIRE WEATHER...92 |
US Dept of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
Seattle, WA
3101 Auburn Way South
Auburn, WA 98092
Comments? Questions? Please Contact Us.