Showers and thunderstorms capable of producing widespread heavy rainfall will be possible across much of Puerto Rico today. Heavy rainfall will likely lead to flash, urban and small stream flooding. Some areas may face life-threatening flooding. In the Southeast U.S., strong to marginally severe thunderstorms will be possible this afternoon. Read More >
Seattle, WA
Center Weather Service Unit
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000 FXUS66 KSEW 191056 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 356 AM PDT Fri Apr 19 2024 .SYNOPSIS...Upper level ridge offshore today moving east through Western Washington late tonight and Saturday morning. Next front arriving Saturday evening. Upper level trough behind the front late Saturday night into Sunday morning moving into Eastern Washington Sunday afternoon. Upper level ridge building offshore Sunday night moving through Western Washington Monday. Weak upper level trough over the area later Tuesday and Wednesday with another front possible for Thursday. && .SHORT TERM /TODAY THROUGH SUNDAY/...Satellite imagery shows clear skies over Western Washington early this morning. Cross cascade gradient has turned negative with easterly winds picking up in the Cascade foothills and along the coast. Wide variety of temperatures at 3 am/10z. Locations not exposed to the east winds in the mid to upper 30s while locations with some easterlies in the upper 40s. Upper level ridge offshore moving into Western Washington today. This combined with the increasing offshore flow will give the area a warm day. High temperatures around 10 degrees above normal, in the 60s to mid 70s. Expect the coast and Cascade foothills to be the warmest locations. Upper level ridge axis over Western Washington tonight with a low level offshore flow continuing into Saturday morning. Like this morning, locations exposed to the east winds will only drop into the 40s while more sheltered locations like Olympia get as cold as the mid 30s. Ridge axis moving east of the area by late Saturday morning. Front offshore approaching but with the jet digging into the southern portion of the front the front will become negatively tilted slowing down its eastward progress. Rain west of the Puget Sound by afternoon with a chance of rain over most of the interior. The Northwest Interior still looks dry through the afternoon hours. High temperatures are going to be a tough call. Low level offshore flow continuing but the increasing middle level clouds will reduce the amount of daytime heating over the interior. Significantly cooler along the coast with highs near 60. Slightly cooler over the interior with highs in the 60s. A few places in the Cascade foothills could still get to 70 degrees. Rain changing to showers after midnight Saturday night as the front moves through Western Washington. Unlike last night where the models were showing a cold pool of air behind the front along the coast, the models this morning have this cold pool well to the north near Haida Gwaii. Will not have any post frontal thunderstorms mentioned for the coast this morning. Snow levels near 5000 feet ahead of the front with a few inches of snow in the higher elevations especially in the North Cascades. Snow levels dropping to 3000-3500 feet behind the front early Sunday morning but the main batch of precipitation is with and ahead of the front leaving only a couple of inches of snow for the passes. Lows Saturday night in the upper 30s to mid 40s. Upper level trough behind the front over Western Washington Sunday morning moving into Eastern Washington Sunday afternoon. Shower activity over the lowlands decreasing in the afternoon. Cool air aloft plus low level onshore flow making for a brisk day with highs only in the lower to mid 50s. .LONG TERM /MONDAY THROUGH THURSDAY/...Extended models in good agreement with an upper level ridge building offshore Sunday night moving into Western Washington Monday. Under sunny skies highs warming into the upper 50s to mid 60s. Ridge shifts east Monday night with an upper level trough approaching Western Washington Tuesday. With the trough staying offshore we should squeeze out one more dry day with highs again in the upper 50s to mid 60s. Model consistency falls apart Tuesday night through Thursday. There is general agreement that an upper level trough will be over Western Washington Tuesday night into Wednesday night with the ECMWF weaker with this feature versus the GFS. ECMWF has an organized front moving into the area Thursday while the GFS has this system moving inland south of the area. Ensembles don`t show any clear trend so given the uncertainty will have chance pops in the forecast Tuesday night through Thursday. Highs Wednesday cooling into the mid 50s to lower 60s. Thursday even cooler with mid to upper 50s. Felton && .AVIATION...Flow aloft will remain out of the northwest through the TAF period as an upper level ridge continues to build offshore. A thermal trough also remains positioned off the coast for offshore flow continuing. Weather remains dry as well with VFR conditions/clear skies expected. Gusty north winds up to 20 kt remain possible through this afternoon - which will decrease to under 5 kt and become northeasterly - picking up again in the afternoon to 20 kt. A frontal system will arrive later on Saturday for breezy winds and the next chance for precipitation. KSEA...VFR/clear skies through the TAF period. Gusty winds out of the north beginning after 17Z at 20 kt will diminish overnight to around 5 to 8 kt northeasterlies, and pick up out of the north again overnight into Saturday. Kristell .MARINE...An upper level ridge will begin to move inland today. A thermal trough remains positioned off the coast of Washington for continued offshore flow. Northerly winds (with easterlies in the Strait of Juan de Fuca) will continue through today. The next approaching system for this weekend will increase gradients in the central Strait of Juan de Fuca (with stronger easterly winds to 25 kt). Additional gusty winds are possible Saturday and Sunday with the next system, including potential westerly gales in the Strait. Seas remain around 3 to 6 ft through Saturday, before rising to 10 to 12 feet on Sunday. Seas may be steep over the weekend with coincident periods. Kristell && .HYDROLOGY...No river flooding expected in the next 7 days. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory from 8 AM this morning to 8 PM PDT this evening for Central U.S. Waters Strait Of Juan De Fuca. && $$ 000 FXUS66 KPQR 191004 AFDPQR Area Forecast Discussion National Weather Service Portland OR 303 AM PDT Fri Apr 19 2024 .SYNOPSIS... High pressure holding steady over the region through tonight, with another mild day on tap, along with breezy east to northeast winds on the west slopes of the Cascades and to some degree, the Coast Range. Cooler for Saturday, as a front moves across the region. May see spotty light rain as well on Sat into Sat night. Dry and mild again to start next week, but cooler showery weather returns by Wed. && .SHORT TERM...(TODAY THROUGH SUNDAY)...Quite a difference this am as compared to 24 hours ago. This due to the offshore flow over the region. Where winds have stayed up, temperatures are still in the upper 40s to mid 50s, such as Portland/Vancouver metro with temperatures still in 50 to 55 as of 2 am. Not a lot of wind, but enough considering most of this warm is due to the downslope of the air mass down the west slopes of the Cascades. Where winds have gone calm, temperatures are in the upper 30s to lower 40s. Similar conditions along the coast, where light east wind is keeping it mild, with much cooler conditions in the windless valleys. Overall, not much change today as compared to Thursday. Most areas will again rise into the 60s, with lower to middle 70s for many areas. Have boosted todays highs over what NBM (National Blend of Models guidance) has, as NBM is often behind the 8-ball with such offshore patterns. Gradients will pick up again, mostly in response to daytime heating on the west side. Generally, east to northeast winds gusting 15-30 mph in the usual spots (those exposed to east winds) such as along the coast into the Coast Range. Bit stronger with gusts up to 40 mph in the Cascades foothills and perhaps parts of the east Portland/Vancouver metro into the western Columbia Gorge for the afternoon/evening. Winds more north to northeast as move south of Portland towards Salem and Eugene and not as strong with gusts maxing at near 15 mph. Still expecting a mild wind-reversal along the coast in the afternoon, with east to northeast winds becoming southerly to south of Florence in the afternoon, and as far north as Newport by sunset as the thermal trough shifts inland to sit over the Coast Range. This will allow for cooler ocean air to spread back across the coastal zones at that time. But, offshore flow persists on to the north overnight, such as at Astoria. Likely be one of those afternoons where Newport cools to 59 with light south wind, whileAstoria is around 70 with an east wind in the late afternoon. Changes gradually arrive tonight into Sat, as a front well offshore approaches. Will see offshore flow gradually weaken tonight. Mid and high clouds increasing later tonight into Sat. Models have been slowing the front, and like that trend. Few sprinkles along the coast Sat am, but think main rain arrives along the coast towards noon, with spotty rain or showers spreading further inland in the afternoon. With the bulk the lift with the front staying farther north over Washington, rainfall amounts will vary across the region, with 0.10 to 0.25 inch along the coast/coastal mountains, and 0.02 to 0.10 for the inland areas. With the onshore flow and clouds, will be cooler on Sat, with the 50s along the coast, and upper 50s to lower 60s inland. High pressure offshore will being building inland on Sunday. This will end the shower potential, with morning clouds giving way to mix of sunshine and clouds. Overall, fairly pleasant day, with temperatures near that expected for mid-April. /Rockey .LONG TERM...(MONDAY THROUGH THURSDAY)....Ensemble guidance points towards another transitory ridge shifting across the region Monday into Tuesday, with dry and mild weather. Will trend temperatures back to the 60s along the coast, and 70s for interior lowlands. But, models area back to bringing another upper trough to the region by mid-week. As such, would see a bit cooler temperatures again, along with increasing potential of showers. /Rockey && .AVIATION...VFR but breezy as offshore flow strengthens through this morning. Easterly/northeasterly winds continue today with east winds will strengthen after 15Z Fri as KTTD-KDLS pressure gradients tighten slightly. The strongest winds will be through the Columbia River Gorge and into the Portland Metro Area, where east winds could gust up to 25-30 kt through 00-02Z Sat. Winds ease this evening as the offshore pressure gradient eases. PDX AND APPROACHES...VFR expected through the TAF period. East winds strengthening after 15-17z Fri to around 18-22 kt with gusts up to 25-30 kt through 00-02z Sat. East winds begin to weaken in the evening to near 10 kt. /mh/Alviz && .MARINE...East to northeast winds today as high pressure resides east of the Cascades and a thermal trough over western WA/OR. This pattern breaks down tonight as a Pacific front approaches. Southerly winds increase through the day Saturday as the front moves through the waters, with Small Craft winds and choppy seas likely into Sunday. Seas building to 8 to 12 ft Saturday with the front, then settle to around 8 ft Sunday. /mh && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...None. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland 000 FXUS66 KMFR 190938 AFDMFR Area Forecast Discussion National Weather Service Medford OR 238 AM PDT Fri Apr 19 2024 .DISCUSSION...High pressure will maintain very nice early spring weather across most of SW Oregon and Northern California today. Some high clouds will drift by at times, but overall, expect mainly sunny skies with a mild afternoon. High temperatures will be largely in the 70s in the valleys west of the Cascades and into the 60s over the East Side. The air mass is quite dry, so humidity this afternoon will drop into the teens and 20s in many areas -- keep the lip balm and skin moisturizer handy. This will also likely prevent any potential pop-up sprinkles/showers from reaching the ground over SE sections of the CWA (though there is a about a 5-10% chance) due to some weak instability over there. Better chance for this is over the Sierra/NW Nevada. Dry weather is expected tonight into Saturday as a weak short wave upper ridge swings through. However, a cold front will approach the coast on Saturday. Some rain showers are likely to move into the coastal waters during the morning, and then eventually move onshore Saturday afternoon. Given the preceding dry air mass, it will be difficult for these showers to get very far inland Saturday afternoon/evening. This is evident in the PoP forecast with PoPs not even reaching 15% here in Medford. PoPs will be highest along the coast 18z Sat-00z Sun (50-70%), then lower to 20-40% Saturday evening. Farthest east precip chances (20-40%) reach the Cascades north of Highway 140. It should be noted that it will get breezy Saturday afternoon/evening in many areas from the WSW, shifting to NW as the front moves through (peak gusts 25-35 mph). The front shifts east of the area Saturday night with high pressure building in on Sunday/Monday. Frost/freezing conditions are possible during this period of dry weather during the late nights/early mornings in the valleys west of the Cascades. It will only be nominally cooler on Sunday, with high temperatures closer to normal across NW sections, but remaining at least a few degrees above normal elsewhere. Monday will warm up substantially (up 5-10 F over Sunday). Another thermal trough will strengthen in NorCal resulting in another round of N-NE winds late Sunday through Monday. This should even bring the milder weather to portions of the SW coast (Brookings). The next chance at precip won`t come until Tuesday of next week. Some guidance is showing the upper trough offshore staying well to our north and west with a bit of a moisture surge from the south. This could cause some showers (thunder?) in parts of NorCal and maybe from the Cascades eastward Tuesday afternoon/evening. Models aren`t too bullish on this just yet with NBM PoPs only peaking up around 20%. The upper trough should send a cold front onshore at midweek with a bit of a cool down and a chance of showers. -Spilde && .AVIATION...Other than some high clouds at times and a slight uptick in diurnal breezes this afternoon, VFR will prevail area wide through the next 24 hours. Coastal areas won`t be nearly as gusty as yesterday. -Spilde && .MARINE...Updated 200 AM Friday, April 19, 2024...A weakening thermal trough will maintain steep, hazardous seas through early this morning. Steep seas will shift to beyond 10 NM from shore and south of Cape Blanco by late morning, then subside below small craft advisory levels this afternoon. Conditions improve tonight with relatively light winds and low seas into Saturday, though a weak cold front will move through on Saturday with some rain. Gusty north winds and steep seas are expected to return later in the weekend with possible gales and very steep, hazardous seas south of Cape Blanco late Sunday into Monday. -Spilde && .MFR WATCHES/WARNINGS/ADVISORIES... OR...None. CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT early this morning for PZZ350-356. Small Craft Advisory until 11 AM PDT this morning for PZZ370. Small Craft Advisory until 2 PM PDT this afternoon for PZZ376. && $$ MAS/MAS/MAS 000 FXUS66 KEKA 191132 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 432 AM PDT Fri Apr 19 2024 .SYNOPSIS...Above normal afternoon temperatures will continue across the interior valleys into early next week. A weak cold front will bring a slight chance of light rain and drizzle to the North Coast on Saturday followed by breezy northerly winds on Sunday. && .DISCUSSION...Pics from sky depicts high clouds continues streaming across Northern California this morning, while southerly wind reversal aided coastal stratus moving northward reaching the southwestern portion of Mendocino Coast. Overnight temperatures have been running 3 to 8 degrees warmer compared to last night. Upper level ridge weaken slightly and is expected to shift eastward today through Saturday. Expect another pleasant day with above normal temperatures to continue across the interior valleys today. Interior temperatures are forecast to be few degrees warmer compared with yesterday`s reading, with highs in the upper 70s to mid 80s. Coastal areas are expected to be near normal temperatures, with highs forecast in the 50s. HREF guidance indicated low stratus clouds charging up along and lapping the Mendocino Coast throughout the day, and forming offshore over the waters and spread onto the North Coast tonight in advance of a weak front. A weak front associated with a transient shortwave trough will bring a push low level moisture and perhaps some light rain and drizzle to Del Norte and northern Humboldt counties, primarily during the afternoon on Saturday. Otherwise, dry weather and some cooling of interior high temps are expected in response to breezy west-northwest winds and greater cloud cover across the interior. Surface high pressure will build in quickly over the Pacific Northwest Saturday night and Sunday in the wake of the front. Breezy northerly winds are forecast to redeveloped over mostly coastal areas as surface pressure gradients tighten on Sunday. NBM probabilities indicates a 60-80% chance for wind gusts from 30-40 MPH along the exposed ridges and coastal headlands of Del Norte/Humboldt Counties on Sunday. Also, gusty west-northwest winds will most likely develop through channeled terrain in the interior behind the front Saturday evening. After a brief period of interior warming and upper ridging, interior temperatures are forecast to trend down mid to late next week and more seasonable values as another upper-trough-complex impacts the west coast. The magnitude and rate of cooling remains highly uncertain at this point with 25-75th spreads on the order 10F for high temps and 5F for low temps. Current forecast is for near normal temperatures; highs in the 60s and lows mostly in the 40s. There are subtle indications for convection across mainly Trinity County on Tuesday as an upper trough with limited moisture generates instability. Potential for precip (showers) will also increase mid to late next week, though amounts will most likely wont be very much with RAW ensemble probabilities of 20% to 30% for > 1 inch of rain in 24-hours for the western slopes of Del Norte and northern Humboldt. Stay tuned. ZVS/DB && .AVIATION...VFR conditions and light offshore winds again this morning beneath a ridge of high pressure and scattered cirrus. A marine stratus shield observed on satellite south of Point Arena is expected to migrate north this afternoon, but should remain south of Cape Mendocino. Diurnally driven winds will produce westerly winds along the coast and northerly upslope flow at UKI this afternoon before returning to light offshore flow. Coastal southerly flow reversal will become more substantial tonight into Saturday morning, enhanced further by an approaching frontal boundary. HREF indicates a strong marine stratus signature rounding the Cape during this period, highlighting the potential for mist/fog and thick low level stratus at the coastal terminals. Stratus may produce MVFR/IFR ceilings reduced visibilities before the front crosses the coast Saturday afternoon. && .MARINE...Seas continue to diminish admist light northerly winds as the last of the small crafts expire in the northern outer waters. Light winds and a small long period swell ensure calm seas through Saturday, with wave heights falling to 2-4 feet. Winds will briefly turn southerly ahead of a weak frontal passage Saturday afternoon before a swift resurgence of northerly winds behind the boundary overnight into Sunday. NBM is still indicating 80-90% probabilities of >34 kt gusts developing downwind of Cape Mendocino before expanding to the northern and southern waters by Sunday afternoon. Responsive wind waves alongside a long period NW swell will produce steep and hazardous seas exceeding 10 feet by late Sunday. The tightening pressure gradient developing ahead of another offshore ridge will enable gale winds to continue in the outer waters through Monday morning, further enhancing the sea state to wave heights 12 to 14 feet. Uncertainty remains as to how quickly the axis of elevated winds will retreat offshore before another trough complex approaches the PNW on Tuesday. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... None. && $$ 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 000 FXUS66 KMTR 191134 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 434 AM PDT Fri Apr 19 2024 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 215 AM PDT Fri Apr 19 2024 Cooler conditions are expected today and tomorrow with light drizzle possible each morning. Temperatures rebound late weekend and early next week. A return to unsettled conditions arrives Tuesday and persist throughout late next week. && .SHORT TERM... (Today and tonight) Issued at 215 AM PDT Fri Apr 19 2024 A well defined marine layer is in place this morning (around 1800- 2000 ft per Fort Ord Profiler) and will support patchy drizzle in the upslope regions this morning. Otherwise, this afternoon sunny conditions will return to inland areas with temperatures expected to warm into the low to mid 70s. Meanwhile, the coast remains in the upper 50s to mid 60s under mostly cloudy conditions. Tonight, expecting clouds to make a return back inland and become more widespread with low temperatures in the upper 40s to lower 50s. Again, patchy drizzle will once again be possible. Saturday will feature slightly warmer temperatures inland, but only by a few degrees. Wind will also be on the increase with breezy northwest winds near the coast, in the coastal hills, and into the region`s valleys. Looking for gusts of 25-35 mph in these areas by Saturday afternoon. && .LONG TERM... (Saturday through Thursday) Issued at 215 AM PDT Fri Apr 19 2024 By Sunday and Monday, ridging dominates the pattern once again with interior areas warming to near 80 degrees with 60s and 70s as one gets closer to the coast. By Tuesday, a change to more unsettled conditions return as an upper level low approaches the region. This pattern will persist throughout late week and points to possible wet weather during the latter half of the week. However, there is no major concerns for flooding and may end up being widespread light drizzle if not light rain. Temperatures also turn cooler with highs in the upper 50s at the coast and mid-to-upper 60s inland from Tuesday throughout late week. Stay tuned! && .AVIATION... (12Z TAFS) Issued at 434 AM PDT Fri Apr 19 2024 Conditions across the region at this time range from VFR-IFR. Satellite imagery shows coastal stratus continuing to develop inland. Light onshore flow will continue to help move stratus inland, bringing low CIGs for most terminals this morning. Towards the late morning to early afternoon today, stratus should begin to mix out and recede, ushering in widespread VFR conditions. Winds onshore and breezy this afternoon, then easing to become light into the nighttime hours. Stratus is expected to make a return in the late night of Friday to early morning of Saturday, bringing MVFR conditions to near-shore terminals. Vicinity of SFO...Low clouds continue to aggressively push closer to the KSFO terminal this morning. Model agreement in the earlier TAF issuance period did not indicate any significant stratus push into the terminal, however, current satellite imagery suggests KSFO will very likely develop MVFR CIGs shortly. Models continue to indicate conditions remaining VFR at KSFO, but given current imagery, models appear to be missing the mark entirely. As a result, extra attention is likely needed for the TAF this morning as conditions change. Have updated the KSFO TAF to reflect MVFR conditions as a result of stratus CIGs through at least sunrise this morning. Otherwise, starting in the late morning, KSFO should achieve VFR conditions. VFR then lasts through the remainder of the TAF period. SFO Bridge Approach...Low clouds will impact the approach, bringing MVFR/IFR CIGs. Monterey Bay Terminals...IFR conditions persist through the morning. Low clouds will be slow to recede and mix out. As a result, VFR not expected to return until the late morning to early afternoon today. Winds onshore and breezy in the afternoon, then easing to become light towards sunset with stratus and MVFR CIGs making a return around the same time. && .MARINE... (Today through Wednesday) Issued at 434 AM PDT Fri Apr 19 2024 Moderate breezes out of the northwest and fair weather prevail over much of the waters through at least Saturday afternoon. Come the evening of Saturday, northwesterly winds increase to become strong and gusty. Swell builds into Sunday out of the northwest as gusty conditions continue but look to diminish towards the middle part of the next week. Light southerly swell continues to move through the waters this weekend and through the next work week. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ SHORT TERM...RGass LONG TERM....RGass AVIATION...AC MARINE...AC 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 000 FXUS66 KOTX 191106 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 406 AM PDT Fri Apr 19 2024 .SYNOPSIS... Dry weather conditions will be in place through Saturday. Winds will be breezy from the northeast. A strong cold front arrives early Sunday morning ushering gusty westerly winds and chance for showers. Mild and dry weather returns for the start of work week. && .DISCUSSION... Today through Saturday: The remnants of an expansive low pressure system that stretches from Ontario to the Pacific NW will begin to moderate today as high pressure inches closer to the WA Coast. 500mb temperatures warm nearly 10C today basically eliminating any threat for afternoon showers. The main weather impact for the next 24 hours will be breezy northeasterly winds. Offshore pressure gradients between Kalispell, MT and Portland, OR are already near 11 mb and expected to range between 11-15 mb through tonight. This is in response to cooler Canadian air sliding down the Continental Divide creating surface high pressure and warmer air nosing along the CA/OR coastline creating thermally induced lower pressure. Strongest winds will be found through the Purcell Trench and across the Columbia Basin with speeds up to 20 mph and gusts to 35 mph. Exposed ridgetops of Northeastern WA and North Idaho can expect similar speeds. Winds will weaken going into Saturday with a slow shift back to the southeast and then south as the next cold front approaches. Saturday will deliver another day of dry conditions with plenty of sunshine as the ridge axis passes through the Inland Northwest promoting stable weather conditions. Temperatures today (FRI) will be several degrees warmer, especially for NE WA and N ID which experienced quite a bit of shower activity on Thursday. Afternoon highs will be in the upper 50s to mid 60s. On Saturday, widespread 60s return with areas along the Snake River Valley creeping into the lower 70s. Saturday night - Sunday: A robust shortwave and associated cold front will swing through the region ushering windy conditions and chance for showers. This is well agreed upon amongst the forecast models with subtle differences with the speed/timing of the front. General timing brings the cold front toward the Cascades around midnight and to the ID/WA border around 3AM. This is likely to bring a sharp increase in winds overnight with sustained speeds of 20-30 mph and gusts 30-40 mph. I am more confident with the sustained winds given the strength of the front and strong cold air advection. Would not rule out gusts 40-50 mph for some wind prone areas and exposed benches and ridgetops but right now, a bulk of the winds aloft are closer to 30-35kts which good news and a limiting factor for gusts over 40 mph. In the past, these type of fronts can be impactful due to the sharp increase in winds. Typically, the strongest speeds only last 1-2 hours with these nocturnal events but this is not to say it will not remain windy through the day Sunday as wind speeds persist in the 15-25 mph range with gusts around 30 mph. Added patchy blowing dust to the Western Basin for early Sunday morning yet this comes with low confidence. Would not rule out minor tree damage (small branches) and a few power outages. Potentially the biggest impact will be light weight objects blowing around like garbage cans, lawn furniture, and trampolines. Be sure to secure those patio umbrellas before heading to bed on Saturday! The front will not bring much in the way of precipitation with amounts ranging between a trace and tenth from the lee of the Cascades to the Palouse and Camas Prairie. The Bitteroots and Selkirks carry a greater chance for a tenth or more with probabilities around 40% for at least 0.10". Numerous showers will also be intercepted along the immediate Cascade Crest where amounts could vary from 0.25-0.60". Snow levels will come crashing down as well falling to 3000 feet before sunrise Sunday morning with slushy accumulations possible over Stevens Pass. The best chance for precipitation over the Basin-Palouse will come with the frontal passage early Sunday morning. Showers will continue for the Cascades Crest, Northeastern WA, and North Idaho into Sunday afternoon. Monday through Thursday: High pressure returns to the region early in the work-week bringing another period of warming and drying. Temperatures for Monday morning will likely start off cool with temperatures in the lower 30s and potential for freezing temperatures. Temperatures rebound into the 60s by the afternoon and continue to warm into Tuesday with many more locations across the lower Columbia Basin showing increasing odds for 70s. Winds will be lighter. The next Pacific trough arrives middle to late week with yet another change in the weather pattern toward cooler and unsettled. There are considerable differences with the evolution of the next trough. Leaning toward an arrival closer to Thursday-Friday but this will fine tuned over the coming days. As we transition air masses, winds are likely to become breezy conditions and precipitation chances will return. /sb && .AVIATION... 12z TAFS: A tight northeast pressure gradient will result in gusty northeast winds down the Purcell Trench and over the Columbia Basin. Expect gusts of 20-30 kts for KSZT-KDEW-KCOE-KGEG- KMWH on Friday. Shortwave ridging into region for Friday will result in less cloud cover and VFR conditions. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: There is high confidence in VFR conditions through the TAF period. ----------------------- 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 56 34 64 39 57 33 / 0 0 0 30 10 0 Coeur d`Alene 54 33 63 38 54 32 / 0 0 0 50 20 0 Pullman 56 33 64 37 52 33 / 0 0 0 30 10 0 Lewiston 64 36 71 43 60 38 / 0 0 0 20 0 0 Colville 56 26 63 35 57 30 / 0 0 0 50 20 0 Sandpoint 51 34 59 38 52 32 / 0 0 0 70 40 10 Kellogg 51 32 62 39 50 34 / 0 0 0 60 30 10 Moses Lake 63 37 69 40 62 34 / 0 0 0 20 0 0 Wenatchee 60 37 63 41 59 37 / 0 0 0 20 0 0 Omak 61 34 65 40 62 35 / 0 0 0 30 10 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$ 000 FXUS66 KPDT 191157 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 457 AM PDT Fri Apr 19 2024 Updated Aviation Discussion .AVIATION...12Z TAFS...VFR prevails during this period with mostly current clear skies for most sites and some clouds at KRDM/KBDN (FEW to BKN, 200-250 kft). KPDT/KRDM/KBDN/KYKM/KPSC may have clouds coming by later tonight (50% confidence). Winds remain light through the day while shifting mostly north and east. Though, KYKM might experience some breezy winds in the late morning. Feaster/97 && .SHORT TERM...Today through Sunday night...Nighttime microphysics RGB imagery reveals mostly clear skies across the entire forecast area this morning. On the synoptic scale, the forecast area is between an offshore upper-level ridge and a trough downstream over the Northern Plains. This is translating to a dry northwesterly flow aloft with a well-defined West Coast thermal trough (WCTT) along the OR coast resulting in low-level east-northeasterly winds. These winds are keeping breezy conditions along ridges and preventing a widespread freeze for the lower elevations. That said, have opted to issue Freeze Warnings for the foothills of the northern Blue Mountains of OR/WA due to near- to sub-freezing temperatures that have developed in areas that have decoupled. Sub-freezing temperatures for these zones are not expected to be ubiquitous (elevated ridges that do not decouple will stay warmer), but enough of our population centers are being impacted to warrant the highlights. Elsewhere, have also opted to issue a Freeze Warning for the lower Columbia Basin of OR where temperatures are hovering near freezing. The Yakima Valley is observing a wide range of temperatures - lower 30s to lower 40s depending on the influence of the previously mentioned northeast winds. Have opted to not issue a Freeze Warning here as coverage of sub-freezing temperatures this morning is expected to remain patchy. Offshore winds will persist through the day as very little changes on the synoptic scale. Expect locally breezy east-northeast winds, especially for ridges and elevated plateaus with low afternoon RH. Tonight into Saturday morning, the offshore upper-level ridge is expected to push onshore, followed by a trough passage Saturday afternoon and evening. This will lead to a reversal in wind direction. Ensemble guidance is still exhibiting some uncertainty with regard to the exact track of the trough, and sustained winds and gusts associated with it. Confidence is low-medium (20-50% chance) in reaching Wind Advisory criteria Saturday afternoon and evening across the Columbia Plateau region. Otherwise, some light precipitation is forecast for the mountains, primarily the Cascades, with mostly dry conditions for the lower elevations. Sunday, precipitation chances taper off as the trough exits to the east and an upper-level ridge moves along the coastline. Breezy west winds are forecast through Sunday, but are not expected to reach advisory levels (<20% chance). Plunkett/86 && .LONG TERM...Monday through Friday...Starting Monday morning to Tuesday night, an upper-level ridge moves over the PacNW as the previous trough passes through North Rockies. Late Tuesday night, another trough will occur onshore that will dominate over PacNW as it deepens throughout Thursday. Dry conditions for Monday and Tuesday will stick around due to the ridge building over the region. Rain showers are expected in the low elevations Wednesday into Thursday night with low possible chance (<30%) of snow within the mountain areas. Snow levels will be around 2000-4000ft Monday but increases up to 4000-6000ft Tuesday into Thursday night. As the deepening trough continues over PacNW, chances of precipitation increases while snow levels remain high (>70% confidence). Breezy conditions will occur with wind gusts up to about 20-30 kts across the Simcoe Highlands and Kittitas Valley Wednesday but might come and go until the end of these next few days (50-70% confidence). Temperatures will moderate between the upper 60s to low 70s through this period (50-70% confidence). Feaster/97 && .PRELIMINARY POINT TEMPS/POPS... PDT 63 34 66 38 / 0 0 0 20 ALW 67 37 69 42 / 0 0 0 40 PSC 68 40 71 44 / 0 0 0 10 YKM 65 35 67 36 / 0 0 0 10 HRI 67 37 70 42 / 0 0 0 20 ELN 61 33 64 37 / 0 0 0 20 RDM 62 33 70 30 / 0 0 0 0 LGD 60 33 69 36 / 0 0 0 20 GCD 64 36 73 35 / 0 0 0 10 DLS 67 42 68 43 / 0 0 0 10 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Freeze Warning until 9 AM PDT this morning for ORZ044-507. WA...Freeze Warning until 9 AM PDT this morning for WAZ026-029. && $$ SHORT TERM...86 LONG TERM....97 AVIATION...97 000 FXUS65 KREV 190902 AFDREV Area Forecast Discussion National Weather Service Reno NV 202 AM PDT Fri Apr 19 2024 .SYNOPSIS... Above average highs in the 60s for Sierra communities and 70s for lower valleys today. A few valleys may see highs surpass 80 degrees this weekend into Monday. Isolated shower chances near the Sierra this afternoon, otherwise dry weather remains through the weekend. Increased shower chances return next week. && .DISCUSSION... Above average temperatures will be with us through early next week, increasing snowmelt on slopes and stream flows on area rivers and streams. See the Hydrology section below for more details on the warm weather affecting area waterways. Just how warm will we be? We expect the Reno International Airport to see their first shot at temperatures above 80 degrees this weekend. Western Nevada valleys will see high 70s to low 80s this weekend, while Sierra valleys will see upper 60s to low 70s for daytime high temperatures. These warmer days may have you seeking outdoor recreation, however there is a chance (15-20%) to see an isolated thundershower for Alpine and Mono counties this afternoon. Also a slight chance (5-10%) of terrain driven showers near the Tahoe Basin today as well, so keep your eyes to the skies if you are outside. Morning clouds on Saturday will clear out and leave us with clearing skies through the day, a great day to get outside and enjoy. Be sure to wear sunscreen this weekend, as abundant sunshine will be with us. Sunday we will see some clouds to the north, but another stellar sunny day to enjoy is setting up. This good weather train will keep rolling into early week before we look ahead to more unsettled weather for midweek. A series of troughs will approach the West Coast, reintroducing showers to our forecast. Ensembles have yet to agree on the track and timing of these low pressure circulations, which will determine where the precipitation will land and how our temperatures will be impacted. For now, we have 20-30% chances for showers across the Sierra and western Nevada. Looking beyond, our extended outlooks are signaling a wetter pattern returning. Less clear will be how our temperatures shake out for the end of April and beginning of May. HRICH && .AVIATION... * VFR conditions will prevail this weekend, although KTRK could see some patchy FZFG Saturday and Sunday mornings. Winds will be light with the exception of Saturday afternoon. Gusts of 20-25 kts will reach western Nevada valley terminals, while Sierra valley terminals may see gusts 15-20 kts. * Showers and storms are anticipated along the Sierra from the Tahoe Basin to the south into Mono County. Chances for showers are 20-25% with the greatest threat for KMMH. Showers have a 10-15% chance of containing lightning.HRICH && .HYDROLOGY... Above normal temperatures combined with mostly sunny skies will increase snowmelt leading to minor to moderate rises in rivers and creeks draining largely snow covered watersheds. While no flooding is expected in the area, many waterways will be running cold and fast, with gradually increasing flows into early next week. The West Fork of the Carson near Woodfords is expected to rise above the action stage each night through Tuesday, but remain below flood stage. Rivers and streams draining mostly snow covered terrain below about 7500 feet are likely to see their seasonal peaks by early next week. Basins with significant higher elevation terrain will retain plenty of snow for higher flows with subsequent warmups.The Lower Humboldt is expected to have very high flows for many weeks with minor flooding likely in May or June, or even into early July. Exercise caution around rivers and streams, remember mountain rivers and streams often reach their highest levels from snowmelt at night. -TB && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ 000 FXUS66 KSTO 190930 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 230 AM PDT Fri Apr 19 2024 .Synopsis... Warm and dry weather continues into early next week. Locally breezy at times. && .Discussion... A batch of high clouds is moving across NorCal early this morning as the upper ridge has weakened slightly by a passing short-wave trough. Offshore surface pressure gradient has weakened and transitioned to weak onshore and profiler data indicate the marine layer has returned to the coast with a depth of 1.5-2k ft. This may bring some minor cooling to the Delta and south valley today, but otherwise little change from Thursday is expected. Shower chances are expected to remain further south in the Sierra closer to the vort center currently approaching the coast near Vandenberg. Ridge rebounds over the weekend and into early next week with highs expected to be well above-average (10-15 degrees), especially Sunday and Monday when warmest temperatures will be in the mid to upper 80s through the Central Valley with an outside chance for the first 90 degree readings of the season. && .EXTENDED DISCUSSION (Tuesday THROUGH Friday)... Dry weather expected Tuesday under weak upper level ridging, then short wave trough progged to deepen over the CWA Wednesday into Friday. This will result in a threat of precip mainly over the northern and eastern foothills and mountains and Northern Sac Valley. Storm total QPF looks to be light with minimal impacts to mountain travel. Above normal high temperatures forecast Tuesday, then near to slightly below normal through the remainder of the week. && .AVIATION... VFR conditions over interior NorCal next 24 hrs. Sfc wind mainly below 12 kts except vcnty of Delta SWly sustained wind up to 20 kts. && .STO WATCHES/WARNINGS/ADVISORIES...None. && $$ 000 FXUS65 KMSO 190846 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 246 AM MDT Fri Apr 19 2024 .DISCUSSION...I trough extending westward from the Great Lakes region still has us under a cooler air mass today. However, high surface pressure east of the Continental Divide is setting up easterly flow, which flows down off the Continental Divide, into western Montana and Idaho today. Also, while the upper level trough remains over our region, it is filling in today as we transition to a ridge of high pressure for Saturday. That means we can look forward to a cooler than average day today with a chilly east wind, but, there will be fewer if any snow showers today. Temperatures bump up quickly under mostly sunny skies for Saturday as an upper level ridge takes over, but just for a day. By Sunday another cold front is coming. This next one won`t be as cold as the last one though, so we`re expecting showers Sunday and early next week to mainly be rain in the valleys with mountain snow. All the long term models and ensembles point to the active, but not really intense Spring weather pattern to continue for the next couple of weeks. && .AVIATION...Rising heights today along with some light easterly downslope flow from the Continental Divide will keep showers at a minimum today. VFR conditions expected through Saturday as a ridge builds in. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$ 000 FXUS65 KBOI 190920 AFDBOI Area Forecast Discussion National Weather Service Boise ID 320 AM MDT Fri Apr 19 2024 .SHORT TERM...Today through Sunday night...Warming through Saturday as a Pacific upper ridge comes inland and over our CWA. Mostly clear today and tonight then increasing high clouds Saturday. Low temperatures tonight 33 to 39 degrees in the southern Idaho agricultural valleys. Pacific cold front will bring a 20-40 percent chance of rain showers to northern-most zones Saturday night and clouds to remaining zones. Sunday will be clearing, windy, and cooler as an upper trough passes north of our CWA. Clear and colder Sunday night with decreasing west winds. Lows in the 20s and 30s, with southern Idaho ag valleys between 32 and 38 degrees. Sunny, breezy, and cool Monday, then clear and not as cold Monday night. .LONG TERM...Monday through Friday...An upper level trough will move by to our north on Monday as an upper level ridge moves into the Pacific Northwest. This will keep temperatures near normal with dry conditions. The ridge will move overhead on Tuesday with temperatures warming around 10 degrees from Monday. The pattern will become more active Wednesday through Friday as an upper level trough approaches our area, although models differ in timing and strength. Ensembles favor keeping our area in the warm sector on Wednesday, with temperatures trending cooler Thursday and Friday as the trough moves inland. Precipitation chances will increase Wednesday through Friday to 20-50%, with the highest chances in the mountains. Even with the cooler air associated with the trough, snow levels are expected to remain above 5500-6000 ft MSL. Breezy conditions will also accompany the trough towards the end of the week. && .AVIATION...VFR. Increasing high clouds this afternoon with mid-level cumulus developing over the higher terrain. Surface winds: variable less than 10 kt, becoming E-SE 5-15 kt after 19/15Z. Winds aloft at 10kft MSL: SW-NW 5-15 kt. KBOI...VFR, mostly clear skies. Winds SE 5-10 kt, becoming variable less than 10 kt around 21Z this afternoon. Weekend Outlook...VFR and high clouds Saturday. Clouds lowering but conditions mainly remaining VFR Saturday evening into Sunday, with isolated MVFR showers and mountain obscuration in Baker County and West Central ID. Decreasing clouds Sunday evening. Snow levels generally 5500-7500 ft MSL during showers. Surface winds: SW-SE 5-15 kt Saturday, and W-NW 10-25 kt Sunday. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise SHORT TERM...LC LONG TERM....ST AVIATION.....ST 000 FXUS65 KLKN 191003 AFDLKN Area Forecast Discussion National Weather Service Elko NV 303 AM PDT Fri Apr 19 2024 .SYNOPSIS...Period of generally fair and warm weather continues thru the weekend and into early next week. Weather becomes more active mid week with gusty winds and opportunity for wetting rain. && .SHORT TERM...Tonight through Saturday night Generally zonal flow over the forecast area today and Saturday along with warming temperatures. 10% probability for high elevation rain and snow showers in and near NE. Nye and White Pine Counties this afternoon in association with a weak shortwave embedded in the flow. A stray shower or two may move over the valleys with virga and breezy downdrafts noted, but no accumulating rainfall is expected for the valleys with hardly a wetting rain/snow possible for the high terrain. Generally light westerly winds across the area will be in place. PWATs progged in the 0.35” to 0.45” range combine with daytime heating Saturday afternoon to produce cumulus buildups and maybe a light shower or two to the high elevations. However, precipitation probabilities remain below 10%. Virga and breezy downdrafts are again the favored mode for Saturday afternoon if any cells grow strong enough given the marginal PWATs and lack of any notable environmental instability or dynamic lifting mechanism. Breezier west/southwest winds are expected across NW Nevada Saturday afternoon with gusts around 20 to 25 mph. Lighter winds observed farther east and south. Daytime high temperatures today will be in the 60s with overnight lows in the low 30s to low 40s. Daytime high temperatures on Saturday will be in the mid 60s to mid 70s with overnight lows in the mid 30s to mid 40s. && .LONG TERM...Sunday through Friday Sunday the deformation zone over central Nevada will fully wash out by Sunday evening as supportive upper level features move farther east. Monday into Tuesday morning, models have come in to much better agreement with the upper pattern, with the GFS and ECMWF now showing a progressive split flow pattern setup with quick moving northern, and southern stream upper level shortwave ridges transiting Nevada, with the northern ridge leading the southern by about ½ a day in time. However as the ridges move east of NV they look to amplify in response to an upstream trough digging south out of the gulf of Alaska and a much weaker southern stream counterpart. These next systems will begin influence Nevada, with the northern trough approaching the Pacific NW coast, and the southern system approaching central CA, Tuesday morning. Models still a bit unsure given the split flow pattern on how manage the interaction of the northern and southern stream systems, for now have keep the forecast basically as is for Tuesday afternoon through Friday. Precipitation chances will jump up Tuesday evening through Wednesday, as the first shortwave passes through, and will be followed by a stronger shortwave Thursday evening. This first system at this time doesn’t look to well organized, but models show a 20% of isolated rain showers Tuesday evening, increasing to 40% by Wednesday morning. After a brief lull Wednesday afternoon through Thursday morning the stronger of the pair of systems will move into NV Thursday and Friday with each bringing a 40% to 60% of scattered showers and thunderstorms with some snow above 8000 ft. Amounts with the first system look to be on the very light side with up to 0.05” for the valleys and passes, and up to 0.10” for the mountains. Forecast snow levels look to be very high with this first system, above 9000 ft, so the precipitation will fall mainly as a light rain. As for the second system, confidence is two low at this time to offer exact amounts as the main impacts will occur just outside of the forecast window. Temperatures and Winds: Spring like temperatures will continue for the Silver State through Wednesday of next week as daytime highs range in upper 60s to low 80s. Highs cool for Thursday and Friday with the upper system overhead, back into the upper 50s to upper 60s. Overnight lows will follow a similar trend with lows hovering in the upper 30s to upper 40s through Wednesday. Lows cool a bit also with the active pattern with lows in the upper 20 to upper 30s for Thursday and Friday. Winds will be generally out of the W to NW at speeds of 10 to 20 MPH with gusts up to 30 MPH through the weekend. Winds shift to more of a W to SW direction Tuesday through Friday as a upper trough approaches NV, but will remain at similar speeds of 10 to 20 MPH with gusts up to 30 MPH possible. && .AVIATION...VFR conditions expected for all terminals over the next 24 hour period. Winds will be light Friday with typical diurnal flows at less than 10 knots. A few high level clouds will be across the area Friday morning. Cumulus and a few showers with little to no precipitation or virga are expected across White Pine county including at KELY during the day on Friday. This could bring brief, gusty winds to KELY between 20Z and 01Z. However, chance for thunder remains below 10% so VCTS is not expected at KELY. && .HYDROLOGY...Many streams, creeks, and rivers across northern and central Nevada continue to observe elevated flows. Mostly dry conditions are expected thru the weekend and into early next week, however temperatures will also trend warmer which will help to accelerate the melting of mid and high elevation snowpack. The Bruneau River is currently in action stage, but may rise to minor flood stage in the coming days. The Humboldt River at Battle Mountain is currently in action stage and expected to slowly recede over the coming days. The Owyhee River near Wildhorse is currently in action stage and expected to gradually rise in the coming days, forecast to reach minor flood stage in the Tuesday timeframe. The Owyhee River near Mountain City is expected to remain in minor flood stage over the next several days. Wildhorse Dam is currently in action stage and is expected to gradually rise, but remain below minor flood stage over the coming days. The Humboldt River at Comus is expected to reach action stage late tonight or Saturday morning. Additional rises are forecast with the river reaching near flood stage Monday night. && .LKN Watches/Warnings/Advisories... None. && $$ 92/98/93 |
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