Severe thunderstorms will be possible on Independence Day, mainly across parts of the Upper Mississippi Valley, Ozarks, and southern/central Plains. Excessive heat with possible record highs and warm overnight lows will continue to impact much of the West into next week. Dangerous heat is expected across the Southern U.S. and Mid-Atlantic into the weekend. Read More >
Seattle, WA
Center Weather Service Unit
Select forecast office below to display aviation discussion on the right.
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729 FXUS66 KSEW 041027 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 327 AM PDT Thu Jul 4 2024 .SYNOPSIS...Very warm week ahead for Western Washington. Upper level ridge offshore today will slowly drift east over the weekend ending up over Western Washington Sunday and Monday. The center of the ridge will move off to the east Tuesday and Wednesday. High temperatures warming into the weekend peaking Sunday and Monday. Gradual cool down beginning Tuesday with the ridge moving east. && .SHORT TERM /TODAY THROUGH SATURDAY/...Little change in the forecast this morning. Heat advisory will remain in effect for the interior Friday afternoon through Monday evening and Friday afternoon through Sunday evening for the coast. Satellite imagery shows clear skies over most of the area with a small patch of stratus and fog near Grays Harbor. Temperatures at 3 am/10z were in the 50s and lower 60s. Upper level ridge over Western Washington today with the ridge axis offshore near 130W. Light flow in the lower levels turning northerly this afternoon. Stratus and fog near Grays Harbor will dissipate by mid morning. Clear skies over the remainder of the area. Temperatures aloft warming today with 850 mb temperatures rising from plus 10C to 14C to plus 16C to 18C by 00z Friday. Northerly afternoon breeze will cut a couple of degrees off the high temperatures near the water. Highs mid 70s to mid 80s inland and lower to mid 70s coast. Little change in the pattern tonight and Friday with the ridge axis remaining near 130W with northerly flow in the lower levels across the area. Ridge building a little resulting in slightly warmer temperatures aloft Friday afternoon, 850 mb temperatures in the plus 20c to 22C range. Lows tonight in the 50s. Highs Friday warmer with 80s and lower 90s inland and mid 70s to mid 80s coast. Thermally induced surface trough along the Oregon coast Friday will try and move north Friday night into Saturday with the trough ending up over the Western Washington interior Saturday afternoon. Even with the surface thermal trough low level winds above the ground to 850 mb remain northwesterly. Without a good switch to offshore flow highs Saturday similar to Friday, 80s and lower 90s inland and mid 70s to mid 80s coast. Lows Friday night in the mid 50s to lower 60s. .LONG TERM /SUNDAY THROUGH WEDNESDAY/...Extended models in good agreement with the upper level ridge drifting towards the coast Sunday. Ridge axis along the coast Monday moving inland Monday night and east of the Cascades Tuesday and Wednesday. Highs peaking along the coast Sunday, upper 70s to mid 80s, and over the interior Sunday and Monday, mid 80s to upper 90s. Weak onshore flow developing along the coast Monday as the ridge axis moves into the interior with the weak onshore flow spreading to the interior Tuesday as the ridge axis moves east of the Cascades. Even with the ridge axis to the east temperatures aloft will only cool slightly Tuesday and Wednesday. With the onshore flow being rather shallow Tuesday high temperatures will only cool a couple of degrees in the interior, 80s to mid 90s. A little bit stronger onshore flow Wednesday lowering high temperatures a little more, upper 70s to near 90. Highs along the coast Monday and Tuesday in the upper 60s to mid 70s, Wednesday mid 60s to lower 70s. Lows Sunday night for the interior in the upper 50s to mid 60s and mid 50s to lower 60s Monday and Tuesday night. Lows along the coast in the mid to upper 50s. Felton && .AVIATION...Northwesterly flow aloft with a strong upper level ridge offshore and building over the region. Expect VFR conditions under clear skies for most locations through the period. The except will be some local marine stratus near the coast this morning, especially from KHQM and pushing up the valley toward KSHN. Otherwise, diurnally breezy winds expected to pick up, generally from the north. KSEA...VFR conditions under clear skies through the period. Northerly surface winds become breezy around 10-15 kt this afternoon and evening, before easing overnight. Repeat on Friday. 12 && .MARINE...Strong high pressure remains offshore through the week, which will continue to dominate the weather pattern. A building thermal trough will bring breezy northerly winds to the coastal waters and Puget Sound. These will peak each afternoon and evening, and while mostly well below advisory criteria. There`s some potential that winds over the outer coastal waters do occasionally get into the 20-25 kt range, but confidence is low. Meanwhile, the persistent northerly winds will maintain rather steep seas over the coastal waters with seas generally 5 to 7 feet at around 8 or 9 seconds for the remainder of the week. 12 && .SEW WATCHES/WARNINGS/ADVISORIES... WA...Heat Advisory from noon Friday to 10 PM PDT Monday for Admiralty Inlet Area-Bellevue and Vicinity-Bremerton and Vicinity- East Puget Sound Lowlands-Eastern Strait of Juan de Fuca- Everett and Vicinity-Hood Canal Area-Lower Chehalis Valley Area-Olympics-San Juan County-Seattle and Vicinity- Southwest Interior-Tacoma Area-West Slopes North Cascades and Passes-West Slopes North Central Cascades and Passes- West Slopes South Central Cascades and Passes-Western Skagit County-Western Whatcom County. Heat Advisory from noon Friday to 10 PM PDT Sunday for Central Coast-North Coast-Western Strait of Juan De Fuca. PZ...None. && $$ 827 FXUS66 KPQR 041046 CCA AFDPQR Area Forecast Discussion...Corrected National Weather Service Portland OR 330 AM PDT Thu Jul 4 2024 .SYNOPSIS...The hottest weather so far this year will develop by Friday, lingering through the weekend as high pressure strengthens aloft. The heat will be prolonged and dangerous with multiple days expected to reach 100 degrees for most inland valleys. Nights will struggle to cool off, leading to minimal overnight relief, especially in urban areas. This heat wave will continue through at least Sunday, with some potential for it to last several days into next week. No rain is expected through the middle of next week. && .DISCUSSION...Today through next Thursday...Well, it is often said across the Pacific Northwest that the Fourth of July is our unofficial start of peak summer weather, and Mother Nature appears to be right on time this year. A major heat wave will begin to develop today, then continue through the weekend for inland portions of SW Washington and NW Oregon. KEY POINTS: 1. A major heat wave will occur for SW Washington and NW Oregon except for the immediate coast. Temperatures begin to heat up today, with dangerously hot conditions continuing through at least Sunday. 2. The hottest days will likely be Saturday and Sunday. 3. This heat wave will likely be remembered more for its duration than its intensity. Temperatures appear unlikely to reach the extremes encountered during the June 2021 Pac NW heat event. However, three to five consecutive days of 100-107 degree heat with little relief at night is still dangerous, especially to those sensitive to heat struggling to find a place to cool off. 4. The coast will be the place to go to cool off, though the cooling influence of the ocean will only extend a few miles inland. Daytime sea breezes should keep coastal communities mostly in the 70s and 80s for highs. 5. Dry northerly winds will accompany the hot temperatures along the Coast Range and Willamette Valley, resulting in rapid drying of fine vegetation. Fire danger will increase rapidly as fuels dry out. Forecast models finally appear fairly locked on to the weather scenario expected to play out over the next few days. We had always known it was going to get hot as a strong upper ridge built over the region - the question was how hot. Fortunately, it appears the most extreme hottest model solutions have fallen off the table with the 00z model/ensemble suite. NBM probabilistic guidance now suggests there is only a 20% chance anywhere in our forecast area will reach 110 deg F with this heat wave - with the best chance being in the Tualatin Valley Sunday afternoon. On the flip side, it is now a near-certainty (80-100% chance) that much of the Willamette Valley will reach 100 degrees by Sunday. This should happen for most of our inland valleys Friday afternoon, with intense heat persisting with our upper level ridge all the way through the weekend. As of the 07z NBM run, here are temperature probabilities for the Willamette Valley on Sunday, where/when the most intense heat is expected: Greater than or equal to 100 degrees: 80-100% Greater than or equal to 105 degrees: 40-70% (highest north) Greater than or equal to 110 degrees: 5-20% (highest north) Greater than or equal to 115 degrees: Less than 5% As recent studies have shown, night time temperatures are often more important during a heat wave, because warm nights can limit the ability to cool off and reset for the next hot day. This compounding effect of multiple hot days with warm nights will exacerbate the the threat of heat-related illness, especially for those who are sensitive to heat and lack the ability to cool off. In that sense, this several day-long stretch of 100-107 degree highs and lows struggling to fall below 70 degrees is potentially more dangerous than just a day or two of intense 110 degree heat followed by a quick cooldown. NBM suggests a 30-40% chance of lows at KPDX failing to reach 70 degrees Saturday night, but the chance is likely much higher than that for much of Portland due to microscale effects like the urban heat island effect which can make temperatures slower to cool off at night. Part of the reason models have backed off from the more extreme hot solutions is the NW flow aloft and associated shortwave energy providing some resistance to the ridge strengthening and bulging northward across the Pac NW. How this NW flow and the northern periphery of the ridge evolve over the weekend will be very important to whether or not this heat wave gets reinforced for a second week. We have seen multiple occasions this year where westerly flow in the NE Pacific "bridges the gap" across the northern periphery of a ridge, causing it to be weaker than it was depicted in early model runs. Either way, all WPC clusters suggest the upper level ridge axis shifts east of the Cascades by Tuesday, which should allow at least some onshore flow by midweek. With 500 mb heights still well above normal, the cooling influence of any offshore flow will be limited east of the coast range due to a shallow marine layer. So... although it should begin to cool down Tuesday night, temperatures will very likely remain above normal inland through most if not all of next week. Weagle .FIRE WEATHER...Increasingly hot weather will combine with dry and gusty afternoon northerly winds this afternoon/evening and again Friday afternoon/evening as thermal low pressure strengthens over SW Oregon. While fuels are not quite ready for our fire weather zones to be Red Flag Warning eligible, these conditions will quickly dry out vegetation over the coming days. Forecast guidance suggests winds will be lighter Saturday, but it will still be very hot, dry, and unstable with thermal low pressure overhead. Those working out on the line today or any day through this weekend should pay special attention to staying hydrated, as the expected conditions can easily cause heat-related illness or worse. Weagle && .AVIATION...Little change in the pattern, with some coastal marine stratus. The only terminal impacted for the rest of the night will be KAST, which will see IFR cigs continuing through much of the night, lifting around 16-18z Thu. VFR conditions are expected afterwards for the rest of the TAF period. Central/southern coastal terminals (KONP) tonight will mostly just remain VFR, though there`s around a 25% chance of intermittent MVFR cigs at times before 16z. Inland terminals will just remain VFR through the night, with NNW winds between 5-8 kts. Daytime hours will just remain VFR for all terminals, and winds will gust right up to 15-20 kt during afternoon and evening hours. PDX AND APPROACHES...VFR conditions throughout the TAF period. Wednesday afternoon brings NW winds up to 10 kt starting at 20z Thu. Winds weaken going into Thu night. /JL && .MARINE...High pressure over the northeast Pacific with a thermally induced low pressure over California/Oregon and the Great Basin. This pattern will persist through the remainder of the week and likely into the start of next week. Small Craft Conditions continue to develop across all the waters each afternoon and evening, with weakening winds in the second half of each night and early mornings going forward. Expect gusts up to 30 kt with similar conditions each afternoon and evening as winds will closely follow a diurnal cycle. Seas will be predominately wind- driven resulting in 5-8 ft at 8-10 seconds throughout the week. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Excessive Heat Warning from noon today to 11 PM PDT Sunday for ORZ104>125. Heat Advisory from noon today to 11 PM PDT Sunday for ORZ126>128. WA...Excessive Heat Warning from noon today to 11 PM PDT Sunday for WAZ202>210. Heat Advisory from noon today to 11 PM PDT Sunday for WAZ211. PZ...Small Craft Advisory until 5 AM PDT Friday for PZZ272-273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland 517 FXUS66 KMFR 040526 AFDMFR Area Forecast Discussion National Weather Service Medford OR 1026 PM PDT Wed Jul 3 2024 .UPDATE...Updated aviation discussion for 06z TAFs. && SYNOPSIS... An extreme heat event will impact the area on Friday and Saturday with high temperatures testing all time highs. Temperatures will cool relatively the start of next week as high pressure moves eastwards. DISCUSSION... Latest satellite imagery shows a wildfire growing within the Marble Mountains southwest of Shelly Lake near the PCT in south west Siskiyou County. Siskiyou County Emergency management is requesting hikers along the PCT to be aware of and avoid this fire. Otherwise, clear skies dominate the rest of the satellite picture as plenty of dry air is spread out over the forecast area. Dry northeast flow along the coast and over southwest Siskiyou County will continue into tonight. Temperatures in Brookings only fell to 75 this morning, so the Chetco effect and downsloping winds should keep things warm there for another 24 hours. The flow pattern will change a bit as high pressure really begins to build in by Friday and Saturday. Some deterministic guidance shows 500 mb geopotential heights approaching 600 dam in Siskiyou County, which is pretty extreme based on Medford Sounding climatology. We`ve only hit 600 dam once at MFR and reaching 598 would put us in the top 10 500 mb height recordings. Given how strong this high is and the time of year, we`re getting plenty of heat this weekend. Friday and Saturday are the most concerning as this is when high temperatures will be at their peak during this heat wave. In addition, we`ll be testing the all time high temperature record for Medford of 115 degrees. As of now we`re forecasting a high of 113 on Saturday, which will still easily beat the existing high temperature record of 104 set in 1922. Lows will also be on the warm side, although not exceptionally warm like the 2021 heat wave. Ashland looks like it might not drop below 70, although almost all other valley location should drop below 70. In any case, the NWS HeatRisk algorithm is rightfully predicting extreme risk. This type of heat will be problematic to anyone without access to cooling facilities. For more temperature record information, check out the weather story on our home page. The coast seems like the best place to escape the heat with high temperatures only hitting the upper 80`s. Brookings should improve as well as the northeast flow will weaken and we should get some onshore flow starting around Sunday. The area of high pressure will weaken and track farther east around the start of next week. It will still remain hot, although the NWS HeatRisk drops into the moderate category when considering the region at large. Depending on the model solution one looks at, an upper level wave will approach the California coastline sometime between Tuesday and Thursday. We don`t have thunderstorms in the forecast right now, although the probability of thunder is closer to 10% on Thursday. The air will be awfully dry ahead of this wave, so perhaps that 10 percent is still too optimistic. -Smith AVIATION...04/06Z TAFS...VFR will prevail through the TAF period. Gusty north winds at North Bend will diminish overnight before returning tomorrow afternoon. Gusty breezes at Roseburg will also be present tomorrow. Smoke from the wildfire in western Siskiyou county will settle into the valleys overnight, locally lowering ceilings and visibility. Any smoke tomorrow during the day is expected to be blown generally south. -Miles MARINE...Updated 220 PM Wednesday, July 3, 2024...A strong thermal trough will remain with strong north winds, gales south of Port Orford, and steep to very steep and hazardous seas for all areas through early Thursday. Winds will be strongest and seas will be steepest this afternoon and evening. Conditions gradually improve Thursday morning as the thermal trough pushes inland and expands northward. North to northeast winds will ease some at this time, but seas and winds will remain hazardous to small craft with hazardous warning level seas likely lingering through Thursday night. North winds will continue their downward trend Friday with the strongest winds over the northern outer waters, but they are expected to remain below small craft. Conditions improve further over the weekend with sub-advisory conditions likely for at least the inner waters. Strong high pressure aloft will disrupt the thermal trough pattern, keeping winds in the 10 to 15 knot range. Also the swell is expected to be low with combined seas expected to remain below any advisory levels. -Petrucelli FIRE WEATHER...Updated 200 PM Wednesday, July 3, 2024... ..Near critical fire weather possible today through the next week for much of southern Oregon and northern California... ..RED FLAG WARNING REMAINS IN EFFECT FROM 11 PM THIS EVENING TO 8 AM PDT THURSDAY FOR EAST WIND WITH POOR OVERNIGHT RH RECOVERY FOR FIRE WEATHER ZONES 619 AND 620... Fire weather concerns will remain elevated through the week due to two different patterns. First, a strong thermal trough along the coast will persist through tonight. This will bring moderate to locally poor overnight RH recoveries to upper slopes and ridges again overnight tonight, along with gusty northeast winds of 15-25 mph with gusts to 30 to 35mph. Although the thermal trough will shift northward and winds are expected to relax tomorrow, there will be enough overlap for critical fire weather conditions and a Red Flag Warning remains in effect for 11 PM tonight through 8 AM Thursday for portions of Oregon FWZ 619/620. In the meantime, this pattern will also lead to near critical conditions for portions of the area this afternoon. Minimum humidities of 10-15% are expected in western and central Siskiyou County with north winds of 10 to 15 mph and gusts to 25 mph (strongest in the Shasta Valley near Montague). Similarly, northeast winds also be near critical thresholds in the Illinois Valley at 10- 15 mph with gusts to 20 mph, and with minimum humidities of 10-15%. However, Intel on fuels remains that the live fuels are not quite there while dead fuels are. Therefore, will continue to headline the near-critical conditions this week. As an example of what this means, a wildfire has recently ignited near the Pacific Crest Trail in California Zone 280 where emergency services has issued a fire warning for hikers. This just demonstrates the nature and just how near-critical the conditions are for the next several days. Strong high pressure aloft moves over the region for the latter half of the week and through the weekend. The thermal trough will expand northward, with weaker winds expected along the coast beginning Thursday. Very hot temperatures (100-110 degrees) and very low (low teens/single digit) humidities are expected during this time away from the immediate coast. While afternoon breezes won`t be quite as strong as today, the extreme heat, and long duration of the heat will allow even typically breezy afternoon conditions to result in dangerous weather that is favorable for rapid spread of fire. It is worth noting that we are paying attention to an upper level disturbance forecast to move northward into our area from California. While the atmosphere will be too dry for thunderstorms, this may cause winds to uptick a little bit, especially west of the Cascades. Will continue with the headline for now, but it is worth noting the increase of winds could bring critical conditions to portions of Oregon fire zones 620 and 622 over the weekend. Confidence is low for this scenario, but it is starting to increase. We will continue to collaborate with partnering agencies regarding this situation. -Schaaf/BR-y && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Excessive Heat Warning from 8 AM Thursday to 9 PM PDT Monday for ORZ023>026. Heat Advisory from 8 AM Thursday to 9 PM PDT Monday for ORZ029>031. Red Flag Warning until 8 AM PDT Thursday for ORZ619-620. CA...Excessive Heat Warning from 8 AM Thursday to 9 PM PDT Monday for CAZ080-081. Heat Advisory from 8 AM Thursday to 9 PM PDT Monday for CAZ084- 085. PACIFIC COASTAL WATERS...Gale Warning until 8 AM PDT Thursday for PZZ356-376. Small Craft Advisory from 8 AM to 8 PM PDT Thursday for PZZ350- 356-370. Hazardous Seas Warning from 8 AM to 8 PM PDT Thursday for PZZ356- 370-376. && $$ 122 FXUS66 KEKA 032205 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 305 PM PDT Wed Jul 3 2024 .SYNOPSIS...Extreme, record breaking heat will begin to peak across the southern half of the area today with heat continuing to spread northward at the same time. Heat will bring continued Major Heat Risk alongside enhanced fire weather concerns. && .DISCUSSION...A strong dome of high pressure has properly built over the area over the last 24 hours. Across the southern half of the area, highs in many valleys are already in excess of 100 degrees with even a few locations such as Ukiah expected to break 110. Heat will continue to intensify and move north today as gentle offshore flow tonight helps to push heat closer to the coast. Today will most likely be the day of greatest HeatRisk for the southern half of the area with most likely highs of 108 to 116. Areas of extreme risk are expected especially in midslope location which have seen virtually no overnight relief with lows struggling to drop below 80. While most models still show a weak surface low forming off the coast of Central California over the next couple days, few models show it having much impact on the heat. Though it may slighlty weaken heat for the southern half of the area, it will mostly just shift the focus of heat further north into Trinity and Humboldt by Thursday. Regardless, near record breaking heat will continue for the entire interior through the week. Though conditions will be dangerously hot along the Trinity River already today, NBM suggest the peak heat further north around Friday. By this point, NBM shows a 70 to 90% chance of highs above 110 all along the Trinity River Valley. Per usual, Big Bar is expected to be the hottest station with highs around 120. HeatRisk is only slightly diminished in the north thanks to lower nighttime temperatures closer to 60 through the week. Heat will even begin to move towards the coast as the week wears on and onshore flow continues to weaken. High pressure settling through the week will help create an increasingly shallow marine inversion which may, at times, be totally pushed offshore by easterly nighttime winds. While a sea breeze will cool off coastal areas each afternoon, increasingly clear and hot mornings may allow high to approach 80 by late in the week. By Thursday and Friday, NBM shows a 50 to 70% chance of brief highs over 80 as close to shore as Arcata and downtown Crescent City. The vast majority of cluster ensemble members show the ridge persisting and only very slowly beginning to weaken by early next week. Essentially no models show the ridge fully breaking down within the next 10 days. With that in mind, dry and much above average temperatures are here to stay for the foreseeable future. /JHW && .AVIATION...VFR conditions prevail at all terminals with gusty northerly winds >25 knots continuing at CEC. The coastal pressure gradient will begin to slacken and move offshore this evening as the orientation of the high pressure ridge shifts. Winds expected to rapidly diminish and turn offshore overnight, allowing a southerly reversal to round Pt. Arena and develop north of Cape Mendocino just before sunrise. HREF is indicating haze and broken low level ceilings gradually filling in around Humboldt Bay and propagating MVFR ceilings northward. Southerly flow may not be quite strong enough to reach CEC within an already weak marine layer. A more potent stratus deck stemming from the SF Bay area has the potential to fill in along the entire north coast Thursday evening into early Friday morning, substantially enhancing the marine layer and producing widespread IFR ceilings. && .MARINE...Near-shore wave heights are still elevated but slowly diminishing as the coastal pressure gradients slackens and moves offshore. Steep and hazardous seas as well as gales force gusts expected to continue in the northern waters and southern outer waters through tonight, diminishing from south to north. Winds and seas will subside considerably by tomorrow afternoon, rapidly reaching sub-advisory levels across all zones. Hi-res models are anticipating a surge of coastal stratus riding up the coast along a southerly wind reversal late Thursday into Friday, potentially producing widespread marine fog. Northerly winds expected to redevelop late this weekend. && .FIRE WEATHER...The building heatwave will continue to bring enhanced fire danger through the week, but especially through Thursday. As highs climb closer to 110, RH has cratered, with many interior valleys reporting RH values between 5 and 10% this afternoon. Overnight conditions will bring little relief with very poor RH recoveries of 30 to 40%. Even with only gentle terrain winds, such dry conditions will promote critical fire weather conditions each afternoon. There are several areas where enhanced winds will generate more widespread and long lasting critical conditions. As the high cross shore, a building pressure gradient has remained aligned with the Sacramento Valley promoting gusty northeast winds along the Sacramento foothills. These have weakened through this morning, although many sites are still reporting gusts of 12 to 18 mph. With RH values in the single digits, critical fire weather conditions continue in southeast Lake County today. Elsewhere, periods of critical fire weather are expected during the afternoon where terrain winds are enhanced, such as along the Trinity River Valley. Strong thermal belts will help promote critical conditions even at night, especially with moderate, dry northeast winds building each night on high ridges, primarily in the Klamath Mountains. The power of thermal belts have already been observed with some midslope areas not even dropping below 80 this morning. Fire Weather conditions will only slightly begin to ease by this weekend. /JHW && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Heat Advisory from 11 AM Thursday to 8 PM PDT Saturday for CAZ102. Heat Advisory until 8 PM PDT this evening for CAZ104-106- 112. Excessive Heat Warning until 8 PM PDT Saturday for CAZ105- 107-108-110-111-113>115. Red Flag Warning until 8 PM PDT this evening for CAZ264. NORTHWEST CALIFORNIA COASTAL WATERS... Hazardous Seas Warning until 3 AM PDT Thursday for PZZ450. Gale Warning until 2 AM PDT Thursday for PZZ470. Gale Warning until 9 PM PDT this evening for PZZ475. && $$ 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 953 FXUS66 KMTR 040852 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 152 AM PDT Thu Jul 4 2024 ...New SYNOPSIS, SHORT TERM, LONG TERM... .SYNOPSIS... Issued at 1217 AM PDT Thu Jul 4 2024 Day 3 of the heat wave. Extremely hot conditions will continue through the middle of next week for inland areas. Excessive Heat Warnings, Heat Advisories, and Red Flag Warnings are in effect. && .SHORT TERM... (Today and tonight) Issued at 1217 AM PDT Thu Jul 4 2024 Cumulative effects will begin to set in for those without access to suitable cooling. Remember we still have a long way to go with hot weather expected through the middle of next week. In fact this is the longest duration Excessive Heat Warning we have ever issued at the NWS Bay Area Office. The previous record was 162 hours (6.75 days) in September 2022. While it may still change, our warning is currently 204 hours long (8.5 days). A southerly surge is bringing some stratus and fog up the coast in Monterey County and just offshore Santa Cruz, San Mateo, and San Francisco. The Ft. Ord Profiler is showing the marine layer has expanded to 1,000 ft as a very weak upper level disturbance takes a temporary bite out of the ridge, and opposing southerly flow moves up the coast. It`s hard to say how much more territory these low clouds will gain. The HRRR has been over aggressive in these situations before, but shows the return of low clouds this morning along the majority of the coast and even pushing through the Golden Gate. Even if that is too aggressive, the GOES-18 night fog imagery continues to show the clouds gain latitude at this time, so don`t be surprised if there`s some grey clouds along the coast this morning. Whether the marine layer clouds stick around past mid-day or not, the general theme of much cooler temperatures along the coast will continue. There is also some good news beyond the coast as high temperatures this afternoon will be 5-10 degrees cooler than yesterday. That`s not enough to end the heat wave, however. We will still see temps in the upper 90s and low 100s for inland areas today. If you want to beat the heat this holiday, the immediate Bay Shore will be in the 70s and 80s, with the Pacific Beaches in the 60s and 70s. With light winds, it will be a nice day at the beach. In fact, it may even be a bit chilly at some beaches if the clouds stick around. If you can`t make it to cooler weather, be sure to take precautions to avoid heat illness. Stay in the AC or shade, hydrate, take it easy, and check on your neighbors. It is imperative to take measures to protect yourself, loved ones, and animals during this extreme heat. Given that today is Independence Day, a holiday in which many activities take place outdoors (parades, picnics, BBQs, community gatherings, fireworks displays), extra caution is urged. For areas of Extreme Heat Risk, consider suspending outdoor events or modifying them to take place early in the day or indoors in an air conditioned environment. Aside from these measures, there are many other things you can do to protect yourself, including staying hydrated by drinking hydrating beverages such as water or sports drinks with electrolytes, and avoiding dehydrating beverages such as alcohol and caffeine-laden drinks. && .LONG TERM... (Friday through Wednesday) Issued at 1217 AM PDT Thu Jul 4 2024 Unfortunately the temperatures will rebound, and Fri-Sat look nearly as hot as Tue-Wed. During this time, the high pressure ridge responsible for this heat wave will be centered directly over the Bay Area. This will bring the potential for 850 temps to reach 30C over the weekend. This threshold has only been hit 6 times out of roughly 56,000 weather balloon observations dating back to 1948. There does appear to be a modest cool down to start next week and HeatRisk starts to slide back into the moderate category. Most inland areas will still be in the 90s, but there wont be nearly as many thermometers reading triple digits. The ridge will gradually flatten and slide east through next week, with more relief expected later in the week. Heat is the number 1 weather related killer in the United States. Unfortunately lives will be lost during this heat wave. Follow these tips to protect yourself, your loved ones, and your animals. -Stay inside in an air conditioned environment between 10am and 7pm. -Suspend unnecessary outdoor activities during the extreme heat, but if you must be outdoors, take frequent breaks in the shade or AC and drink cool water. -Know the signs and symptoms of Heat Exhaustion vs. Heat Stroke! Heat Stroke can be deadly if not treated immediately by a medical professional. Call 911 if you suspect someone is suffering from Heat Stroke. -Wear a lifejacket, swim near a lifeguard, and check conditions before entering the water if going to a river or ocean to cool off. Rivers and the ocean are extremely cold, and Cold Water Shock can turn into paralysis and drowning if you are not careful. -Use a cool and damp towel on your body if you do not have AC and are feeling hot. Or, take a cool shower or bath. -Do not leave kids or pets in a parked car. -Ensure pets and livestock have access to shade and water. && .AVIATION... (06Z TAFS) Issued at 1030 PM PDT Wed Jul 3 2024 Stratus has developed on the Big Sur coast and into parts of Monterey Bay, with moderate confidence of LIFR stratus over the Monterey Bay region, dissipating sometime Thursday morning. The rest of the region remains generally VFR through the TAF period with light winds overnight with breezy onshore winds setting up Thursday afternoon. Vicinity of SFO...High confidence of VFR through the TAF period. Light winds overnight, building to a breezy west-northwest flow Thursday afternoon with wind speeds at 10-15 knots. Low confidence in model output that shows some chance of stratus through the Golden Gate Thursday night into Friday morning. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Stratus is already building into the region with moderate confidence that it extends into MRY and SNS. Expect the stratus to clear out sometime on Thursday morning although timing remains a bit uncertain. Breezy onshore flow sets up Thursday afternoon followed by a chance for stratus to return to MRY in the evening, although confidence is low. && .MARINE... (Tonight through next Tuesday) Issued at 907 PM PDT Wed Jul 3 2024 Light moderate winds continue into the weekend with possible gusty and strong winds in the northern outer waters that will pose hazardous to small crafts into tonight before easing. Waves start to diminish Thursday morning, bringing relatively calm conditions over the waters into Friday. && .FIRE WEATHER... Issued at 257 PM PDT Wed Jul 3 2024 Red Flag Warnings are in effect for the North Bay Interior Mountains, East Bay Hills, and Santa Cruz Mountains until 9 PM Saturday. Red Flag Warnings are in effect for the Marin and Sonoma Coastal Range until 5 AM Friday. Red Flag Warnings are in effect for the Santa Lucia Mountains, San Benito County, and the Southern Salinas Valley from 9 AM Friday through 9 PM Saturday. This heat wave will bring very low RH and the long duration will cure and dry the fuels. ERC values are exceeding or approaching the max moving average for a number of regions. Thankfully the winds won`t be very strong, but with such high temps, low RH and critically dry fuels, it only takes 6-11 mph winds to trigger RFW criteria. Conditions are dangerous, and we urge extreme caution. Please rethink the use of any fireworks this year, including the safe and sane, or even those seemingly-innocuous sparklers and pop-its. Perhaps consider not lighting them off at all this year, and instead enjoy a professional display in your community, or even on TV. Its not worth the risk. Don`t Be the Spark! && .BEACHES... Issued at 1224 AM PDT Wed Jul 3 2024 Beaches will be a popular destination over the Holiday and as one of the few places to escape the oppressive inland temperatures. Fortunately the waves are relatively low energy, but that doesn`t alleviate all beach safety concerns. Ocean temperatures are in the mid-50s. This cold water may catch some off-guard. Cold water shock can set in very quickly. Wear a life jacket, dress appropriately, limit time in the water, swim near a lifeguard and follow their instructions. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Coastal Flood Advisory until 5 AM PDT Friday for CAZ006-506-508. Heat Advisory until 7 PM PDT this evening for CAZ006. Excessive Heat Warning until 11 PM PDT Wednesday for CAZ502>504- 506-510-512>518. Red Flag Warning until 5 AM PDT Friday for CAZ502-503. Red Flag Warning until 9 PM PDT Saturday for CAZ504-512-515. Heat Advisory until 11 PM PDT Wednesday for CAZ508-528-529. Red Flag Warning from 9 AM Friday to 9 PM PDT Saturday for CAZ516>518. PZ...Small Craft Advisory until 3 AM PDT early this morning for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Flynn LONG TERM....Flynn AVIATION...DialH MARINE...Behringer Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea 740 FXUS66 KOTX 041013 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 313 AM PDT Thu Jul 4 2024 .SYNOPSIS... Weather conditions are expected to be dry and generally fair the next seven days. There will be a long duration heatwave starting after July 4th. It is expected to last through midweek. && .DISCUSSION... Today through Thursday: Independence day will feature above temperatures 4 to 7 degrees above normal (low 80s to low 90s) high with very sunny skies. The offshore ridge will continue to deepen today bringing even warmer temperatures to us by the weekend. Temperatures by Friday will be 8-13 degrees above normal (mid 80s to near 100 degrees). Sunday through Wednesday temperatures are forecast to be 13 to 17 degrees above normal (mid 90s to upper 100s). There is an elevated fire threat Friday afternoon in the evening as a dry shortwave increases the Seattle-Wenatchee pressure gradient to 5-8 mb in the aftenoon and evening hours. Winds will gust up to 25 mph near Wenatchee as RHs are rising into the upper teens to low 20s in the late afternoon to evening hours. HeatRisk increases to "major" by Sunday for all major population centers in central and Eastern Washington. For Monday through Thursday, all major population centers are forecasted to be in the "major" HeatRisk as temperatures will be in the mid 90s to upper 100s with low temperatures in the 60s and low 70s. There is increasing confidence for "Extreme" HeatRisk for the L-C valley and the lower river valleys of central Washington. There is a 55% chance for Lewiston and Clarkston to hit 110 degrees or greater Tuesday! Cluster guidance indicates a slow "cooldown" into the mid 90s by next Friday as the ridge axis is still centered over Montana. The duration of this heatwave is impressive. The current record for consecutive 95+ degrees at Spokane International AP is 10 days in August of 1967. This is hard to beat To be in the top 10 for consecutive 95+ degrees, Spokane International only needs to be 95+ degrees for 5 days which is what our forecast is calling for. /Butler && .AVIATION... 06Z TAFS: VFR conditions are expected for the TAF sites for the period. Expect passing high clouds and a few afternoon fair weather cumulus. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in VFR conditions. ----------------------- Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance For additional probabilistic information for NWS Spokane airports, please refer to the Aviation Dashboard on our webpage: https:/www.weather.gov/otx/avndashboard && .PRELIMINARY POINT TEMPS/POPS... Spokane 87 57 93 61 92 61 / 0 0 0 0 0 0 Coeur d`Alene 83 55 88 60 88 59 / 0 0 0 0 0 0 Pullman 83 54 89 57 90 56 / 0 0 0 0 0 0 Lewiston 92 62 98 66 99 64 / 0 0 0 0 0 0 Colville 84 50 90 53 90 53 / 0 0 0 0 0 0 Sandpoint 81 51 88 53 86 55 / 0 0 0 0 0 0 Kellogg 79 59 86 62 84 61 / 0 0 0 0 0 0 Moses Lake 92 58 99 63 98 64 / 0 0 0 0 0 0 Wenatchee 91 65 99 68 98 69 / 0 0 0 0 0 0 Omak 92 60 98 63 97 62 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Heat Advisory from noon Sunday to 10 PM PDT Thursday for Central Panhandle Mountains-Northern Panhandle. Excessive Heat Warning from noon Saturday to 10 PM PDT Thursday for Coeur d`Alene Area-Idaho Palouse-Lewis and Southern Nez Perce Counties-Lewiston Area. WA...Heat Advisory from noon Sunday to 10 PM PDT Thursday for Northeast Mountains-Okanogan Highlands. Excessive Heat Warning from noon Saturday to 10 PM PDT Thursday for Central Chelan County-Lower Garfield and Asotin Counties-Moses Lake Area-Northeast Blue Mountains-Okanogan Valley-Spokane Area-Upper Columbia Basin-Washington Palouse- Waterville Plateau-Wenatchee Area-Western Okanogan County. Heat Advisory from noon Saturday to 10 PM PDT Thursday for Western Chelan County. && $$ 778 FXUS66 KPDT 041051 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 351 AM PDT Thu Jul 4 2024 .UPDATED AVIATION DISCUSSION .AVIATION...12Z TAFS...VFR conditions will remain through this TAF period with clear skies. Winds will be generally light. Feaster/97 && .PREV DISCUSSION... /issued 259 AM PDT Thu Jul 4 2024/ SHORT TERM...Today through Friday...A ridge of high pressure continues building offshore of the region shown from the water vapor imagery. This supports a warming trend of high temps in the 90s to lower 100s across the forecast area with temps 5-20 degrees above normal into next week. Observed from the NBM, probability of exceeding 100 degrees for Friday is broadly 20- 50% around the Columbia Basin and the eastern Columbia River Gorge, but locally 60-80% for central OR. Given the incoming heat wave and low relative humidity, this will facilitate Moderate to Major HeatRisk across the lower elevations and elevated concerns for fire weather potential due to critically dry environment. And due to these conditions, heat advisories and warnings have been issued starting Friday into next week. Winds will be light across the forecast area with occasional wind gusts between 15-25mph around Kittitas valley (80-100% confidence). Feaster/97 LONG TERM...Saturday through Thursday...Sensible weather concerns through the extended forecast will revolve around a prolonged heatwave that will bring Moderate to Major HeatRisk across many lower elevation and mountain valley locations. An upper level ridge of high pressure will be the main synoptic feature impacting the region through the latter half of next week. The ridge axis will start offshore western CONUS on Saturday, then gradually push east over the region where it will be centered along the 114W Meridian by Thursday. With the ridge overhead, very dry conditions will develop area-wide, while very hot temperatures develop and linger through Thursday. Winds will also generally be light with locally breezy conditions developing in the afternoons through late next week. High temperatures across most lower elevations will generally be between 100 to 105 degrees (confidence 90-100%), while temperatures between 105 to 110 will develop across the Columbia Basin (confidence 75-90%). Ensembles also indicate that temperatures between 95 to 100 degrees will develop in some mountain valley locations across the Cascade east slopes, Blues, and Wallowas by early next week(confidence 75-85%). Lawhorn/82 && .PRELIMINARY POINT TEMPS/POPS... PDT 90 58 95 61 / 0 0 0 0 ALW 93 60 98 63 / 0 0 0 0 PSC 94 62 100 64 / 0 0 0 0 YKM 93 59 100 62 / 0 0 0 0 HRI 95 60 101 62 / 0 0 0 0 ELN 92 59 98 63 / 0 0 0 0 RDM 93 53 98 57 / 0 0 0 0 LGD 87 55 92 57 / 0 0 0 0 GCD 91 55 96 57 / 0 0 0 0 DLS 97 65 104 67 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Excessive Heat Warning from noon Friday to 10 PM PDT Thursday for ORZ041-044-507-508-510. Heat Advisory from noon Friday to 10 PM PDT Thursday for ORZ505- 511. WA...Excessive Heat Warning from noon Friday to 10 PM PDT Thursday for WAZ024-026>029-521. Heat Advisory from noon Friday to 10 PM PDT Thursday for WAZ523. Fire Weather Watch from Friday afternoon through Friday evening for WAZ690. && $$ SHORT TERM...97 LONG TERM....82 AVIATION...97 322 FXUS65 KREV 040929 AFDREV Area Forecast Discussion National Weather Service Reno NV 229 AM PDT Thu Jul 4 2024 .SYNOPSIS... * A long duration heatwave will result in a moderate to major HeatRisk through at least the middle of next week. * Dry conditions are expected into next week with chances of showers and storms remaining below 10% through the weekend. * Breezy afternoon winds may produce elevated to locally critical fire weather conditions on Sunday. && .DISCUSSION... This Independence Day will be a hot and dry one as temperatures soar into the upper 80s to low 90s for Sierra communities and flirt with 100F across lower western Nevada valleys. While it will cool off after sunset, it will still be quite warm in the immediate hours after the sun goes down when most firework shows are ongoing, especially across western Nevada. If your Independence Day plans take you outdoors, plan for a hot and sunny day by wearing light clothing, applying sunscreen, and drinking plenty of water before and while in the heat! Our heatwave will stick around for several days as amplified high pressure aloft slowly traverses from the eastern Pacific to the Four Corners area. In response, temperatures will gain around 2-3 degrees per day through Saturday and Sunday, which remain favored as the hottest days of the next seven. In fact, the weekend heat is likely to be record-breaking for many locales, including Reno where Reno-Tahoe Int`l Airport has over a 90% chance of breaking the record daily high temperature for both July 6th (forecast: 106F; record: 101F) and July 7th (forecast: 106F; record: 102F). The rest of this week and weekend will likely be dry as chances of showers and storms remain below 10%, although intense differential heating may prove sufficient for isolated afternoon showers Sunday into next week. The aforementioned upper ridge will gradually shift eastward early next week, which will allow for a degree or two of cooling each day through the end of the week. Even still, temperatures will remain well above average for much of next week as the heat refuses to relinquish its impact on the region. Winds will also become a bit more breezy each afternoon beginning Sunday with gusts up to 20-25 mph. -Salas && .AVIATION... The primary weather concern will be density altitude issues amid a long duration heatwave that lasts into next week. Otherwise, widespread VFR conditions and typical afternoon breezes will prevail. -Salas && .FIRE WEATHER... Well above normal temperatures, very low daytime humidities with poor overnight recoveries, and deep afternoon mixing heights will continue through at least the middle of next week. Winds will remain light outside of typical afternoon breezes through Saturday, but will increase Sunday afternoon as gusts approach 25-30 mph for the Sierra and Sierra Front. This may yield a multi-hour period of elevated to locally critical fire weather conditions Sunday afternoon. Winds will ease slightly after Sunday but will remain breezy in the afternoon each day with gusts reaching up to 20 mph. -Salas && .REV Watches/Warnings/Advisories... NV...Heat Advisory from 10 AM Saturday to 10 AM PDT Wednesday NVZ002. Excessive Heat Warning from 10 AM Saturday to 10 AM PDT Wednesday NVZ001-003>005. CA...Heat Advisory from 10 AM Saturday to 10 AM PDT Wednesday CAZ070>073. && $$ 279 FXUS66 KSTO 040939 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 239 AM PDT Thu Jul 4 2024 .SYNOPSIS... Widespread Major to Extreme HeatRisk into the middle of next week. Elevated fire weather concerns in the Valley and adjacent foothills due to very hot and dry conditions. && Key Points - Long-duration, dangerous heat event into mid next week, impacting holiday outdoor events. - Excessive Heat Warning remains in effect for the Valley, Delta and foothills through 11 PM Tuesday. - Heat Advisory remains in effect for the Sierra, southern Cascades, and Burney Basin from 11 AM today until 11 PM Tuesday. .Discussion... Anomalously strong high pressure will dominate the pattern through the forecast period, bringing an extended period of dangerous heat. The EFI also highlights the extreme nature of this heat event. NBM probabilities indicate a 75-100% chance of high temperatures of 110 deg F or higher through the northern and central Sacramento Valley, and a 30 to 75% chance in the southern Sacramento and northern San Joaquin Valleys Friday-Saturday. Daytime highs will range from 105-118 degrees across the Valley, Delta, and foothills, with 80s to around 110 in the mountains. The hottest temperatures are still expected on Friday-Saturday. Overnight temperatures will provide little to no relief from the heat with lows ranging from the upper 60s to mid 80s; warmest in the thermal belt regions of the foothills. Widespread Major to Extreme HeatRisk is expected across the Valley and foothills, with Major HeatRisk over the mountains. This level of rare, long-duration extreme heat with little to no overnight relief affects anyone without effective cooling and/or adequate hydration. An Excessive Heat Warning remains in effect for the Valley, Delta, and foothills until 11 PM Tuesday. Additionally, a Heat Advisory remains in effect for the Sierra, southern Cascades, and Burney Basin until 11 PM Tuesday. Check on sensitive groups, stay hydrated, strongly consider canceling outdoor activities, and stay in a cool place, including overnight. DO NOT leave children or pets in unattended vehicles. The extended period of very hot and dry conditions will bring elevated fire weather concerns to the Valley and foothills. Know your wildfire risk and have an emergency plan in advance. && .EXTENDED DISCUSSION (Monday THROUGH Thursday)... Ensembles and clusters show a gradual eastward progression of the upper high late weekend into next week, resulting in a minor downward trend in high temperatures through midweek. High temperatures in the 105-113 F range are still anticipated through early next week in the Valley and foothills, with a slight cool down closer to highs in the 100-110F range into mid next week. Some overnight relief from the heat will be possible early next week near the Delta Breeze influenced areas. Low temperatures into the low to mid 60s will be possible in these areas through mid next week, with upper 60s to mid 70s still likely through the remaining Valley and adjacent foothills locations. In terms of HeatRisk, widespread Major to Extreme HeatRisk is expected through early next week, with Moderate HeatRisk near Delta influenced areas. By mid-week, widespread Moderate HeatRisk is expected across the region, with some areas of Major/Extreme HeatRisk (mainly in the foothills). && .AVIATION... VFR conditions expected across interior NorCal next 24 hours. Increasing south to west gusts to 20 kts in Delta and immediate vicinity through approximately 00z Friday. && .STO WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 11 PM PDT Tuesday for Carquinez Strait and Delta-Central Sacramento Valley-Motherlode-Mountains Southwestern Shasta County to Western Colusa County-Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-Northern San Joaquin Valley-Shasta Lake Area / Northern Shasta County- Southern Sacramento Valley. Heat Advisory until 11 PM PDT Tuesday for Burney Basin / Eastern Shasta County-West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park. && $$ 942 FXUS65 KMSO 040844 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 244 AM MDT Thu Jul 4 2024 .UPDATE...No major changes expected in the messaging of our upcoming heatwave in the Northern Rockies. && .PREV DISCUSSION... /ISSUED 132 PM MDT Wed Jul 3 2024/ ..A Northern Rockies Heatwave Likely July 5-12... DISCUSSION... Confidence remains high that an extended period of heat will start this weekend and continue well into next week. The middle of next week looks to be the hottest period, with valleys in central Idaho hitting the 100-115 degree range and western Montana valleys reaching 90-105 degrees by next Wednesday (July 10th). Nighttime temperatures are expected to cool only into the 50s to 60s, which will make it difficult for those without air conditioning or other means of cooling down to find respite from the heat. Please check on the elderly, those susceptible to heat,and protect all animals and livestock during this stretch of hot temperatures. An aspect that is less certain during this period of hot temperatures is the thunderstorm forecast. The latest model guidance trends toward thunderstorm chances on Saturday in western Montana, especially along the Divide. && .AVIATION...Lingering showers continue along the crest of the Continental Divide early this morning and will continue to move east and dissipate with time. High pressure will strengthen from the west and gradually shift over the Northern Rockies in the next 24-48 hours, bringing a prolonged period of heat to the region. && .MSO WATCHES/WARNINGS/ADVISORIES... MT... Excessive Heat Watch from Tuesday afternoon through Wednesday evening for Kootenai/Cabinet Region...Lower Clark Fork Region. ID...Excessive Heat Watch from Monday afternoon through Wednesday evening for Northern Clearwater Mountains...Southern Clearwater Mountains. Excessive Heat Watch from Sunday afternoon through Wednesday evening for Lower Hells Canyon/Salmon River Region... Orofino/Grangeville Region. && $$ 000 FXUS65 KBOI 040920 AFDBOI Area Forecast Discussion National Weather Service Boise ID 320 AM MDT Thu Jul 4 2024 .SHORT TERM...Today through Saturday night...Dry northwest flow aloft will persist through the short term as a strong upper level ridge remains anchored to the West Coast and upper level troughing continues over the Northern Plains. The upper level ridge will very gradually build inland into the weekend, bringing several degrees of warming each day. Highs today will be near normal under sunny skies. By Saturday, lower elevations will see highs in the mid 90s to around 100 degrees, warmest in southeast Oregon and far southwest Idaho which will be closest to the ridge axis. The heat will continue to build during the long term period. Winds today will be lighter than yesterday but still locally breezy with gusts 15-25 mph southeast of Boise. Winds will increase Friday and Saturday as systems pass well to our north with afternoon gusts 20-35 mph, strongest in the Magic Valley. This will combine with very dry conditions to create elevated fire weather concerns. .LONG TERM...Sunday through Thursday...Models remain consistent with the strength and eastward progression of a large intense high pressure ridge that will deliver dry conditions and a prolonged heat wave across the region. The hottest temperatures coincide with the ridge axis, which targets Oregon early next week then shifts into Idaho by Monday or Tuesday. High temperatures trend slightly hotter each day, peaking on Wednesday and Thursday. Record or near record temperatures are likely at many locations. The models are indicating some limited moisture moving up from the the south as the ridge axis shifts to the east by Wednesday, but not enough to mention any showers or thunderstorms at this time. && .AVIATION...VFR under clear skies. Surface winds: variable less than 10 kt becoming mainly NW 6-12 kt with gusts to 20 kt after 18Z. Winds aloft at 10kft MSL: NW 10-20 kt. KBOI...VFR under clear skies. Variable or southeast winds to 6 kt becoming NW 5-15 kt after 18Z. Weekend Outlook...VFR under mostly clear skies. High density altitude due to hot temperatures. Variable winds less than 10 kt during the late evenings through mornings, and generally NW 5-15 kt with gusts of 15-25 kt during the afternoons and early evenings. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Excessive Heat Watch from Saturday afternoon through Wednesday afternoon IDZ012-029. Excessive Heat Watch from Monday afternoon through Wednesday afternoon IDZ014>016-030-033. OR...Excessive Heat Watch from Saturday afternoon through Wednesday afternoon ORZ061>064. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise SHORT TERM...ST LONG TERM....BW AVIATION.....BW 193 FXUS65 KLKN 040943 AFDLKN Area Forecast Discussion National Weather Service Elko NV 243 AM PDT Thu Jul 4 2024 .SYNOPSIS...Building high pressure over the Great Basin produces a stretch of dry weather and a prolonged warming trend. Heat impacts are almost certain as valley temperatures breach 100F for many locales over the weekend. && .SHORT TERM...Today through Friday Night Region of strong high pressure resides along the California coast this morning with northwesterly flow situated over the forecast area. High pressure lazily meanders east into the western U.S. thru Friday with heights gradually increasing over Nevada. Main sensible weather effects will be dry conditions under mostly sunny and clear skies along with the typical afternoon breezes also present with gust 20 to 30 mph throughout the region. Elevated fire weather condtions will be in place and the proper precautions should be exercised during any Independence Day celebrations. Temperatures will be warm with daytime highs residing in the mid 80s to mid 90s today and overnight lows in the upper 40s to upper 50s. Friday will see daytime highs in the upper 80s to upper 90s and overnight lows again in the upper 40s to upper 50s. && .LONG TERM...Saturday through Thursday High pressure and the associated upper level ridge over the west coast of the CONUS will be firmly in place by the start of the forecast period Saturday. The hot, dry air mass will be the status quo through the weekend into the beginning of the work week as temperatures climb across the region prompting Excessive Heat Watch in western and southwestern portions of the CWA Saturday morning through Wednesday morning next week. The heat also has the potential to break triple digit records in some locations across northern Nevada Monday and Tuesday. High temperatures will gradually rise across the region through the weekend from upper 90s into the low to mid 100s especially in western and southern counties of the CWA . Ensemble model probabilities are confident in better than an 80% chance of 95F or better for much of the Silver State Sunday through Tuesday. Overnight lows will provide some relief but gradually warm into the 60s (and low 70s for lower elevations and valleys) through the weekend. Major to extreme HeatRisk values especially in the western and southwestern counties of the CWA are expected through Wednesday even as the ridge begins to push eastward by Monday evening. Model consensus holds the axis of the ridge over the area by Wednesday morning promoting dry southwest flow. This will do little to abate the hot temperatures in the region by the end of forecast period as triple digit high temperatures in some locations will continue through Thursday. && .AVIATION...VFR conditions are expected through Thursday. Light drainage winds this morning will transition to the northwest around 10 knots across central and northern Nevada under clear skies. A strengthening high pressure area will bring increasing temperatures to many areas leading to increasing density altitude particularly over the weekend into early next week. && .FIRE WEATHER...Dry weather and a warming temperature trend present thru the weekend and into next week as high pressure builds over the Great Basin. Elevated fire weather conditions will also be present with minimum afternoon RH values residing less than 15% into next week, especially paired with afternoon breezes with a 30-40% probability for wind gusts 25 to 30 mph each afternoon and evening. Winds look to be strongest over this weekend, especially Sunday afternoon, with a 60-70% probability for wind gusts 25 to 30 mph. && .LKN Watches/Warnings/Advisories... Excessive Heat Watch from Saturday morning through Wednesday morning Humboldt County...Northeastern Nye County...Northern Lander County and Northern Eureka County...Northwestern Nye County...Southern Lander County and Southern Eureka County. && $$ 92/99/93/92 |
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