Area Forecast Discussion
Issued by NWS Spokane, WA
Issued by NWS Spokane, WA
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991 FXUS66 KOTX 302302 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 402 PM PDT Thu May 30 2024 .SYNOPSIS... Overnight temperatures near to and below freezing is expected again Friday morning. Drier weather Friday will occur with light showers mainly over the mountains for Saturday. A dynamic storm system will push across the region late Sunday into Monday bringing widespread rain followed by gusty winds and the potential for afternoon thunderstorms on Monday. Next week will see a warming and drying trend and confidence is increasing for temperatures warming into the 80s and 90s. && .DISCUSSION... Tonight: Another cold night is expected across the region. Ensemble guidance has trended upward a degree or two. With poor verification the last couple days, the forecast was lowered a couple of degrees below guidance. The current highlights are fine and no adjustment was made. One concerning areas is the Camas Prairie area. Probability of freezing temps is still only around 20% in the area. Some cold pockets that drop into the upper 20s. Overall the lows for the night will be in the upper 20s and 30s. Friday through Sunday: A ridge pattern will move over the region and last through most of Sunday. There will be weak wave of moisture on Saturday will bring light showers to the higher terrain with little to no accumulation expected. A lesser chance of a stray shower chance over the Basin is possible. The wave will bring breezy winds to the Cascades Gaps and western portion of the Basin. Speeds will generally be sustained in the teens and gusts up to 30 MPH. By Sunday, the ridge breaks down as a Low begins to press into the Pacific Northwest. Highs will be in the upper 60s and 70s. Lows will be in the upper 30s and 40s. /JDC ...Beneficial rains for the Inland Northwest Monday... Sunday night through Thursday: A large tap of Pacific moisture moving along the base of a strong low pressure system will move into the region beginning late Sunday and continue through Monday. 180-200% of normal precipitable water values will be widepsread across the region. Precipitation chances will begin to increase late Sunday afternoon and evening and continue through Monday. Widespread rains are expected. We are still several days out, but precipitation amounts are looking to be a tenth to a quarter of an inch in the valleys and lower elevations of central WA; 0.40 to around an inch for the valleys of eastern WA and north ID; and over an inch along the crest of the Cascades, and the mountains of extreme northeast WA and the ID Panhandle. These rains will be beneficial to the region, creating rises on local creeks, streams, rivers and lakes. Some ponding of water is possible for areas that do not have proper drainage. The time period to watch out for will be Monday morning when precipitation amounts will be heavier over a shorter period of time. Cannot rule out localized rock or mud slides for the ID Panhandle, but at this time, the probability looks low. Monday windy conditions are expected in the afternoon and evening hours. NBM is a bit slow to catch on to what MOS guidance is showing. Have trended forecast towards the 90th percentile of the NBM which has sustained winds of 20 to 30 mph and gusts 30 to 45 mph across much of central WA and onto the Palouse and Spokane area. The more protected valleys of northeastern WA and north ID will not see winds as strong as this. With the good dynamics of this front moving through, if we can get just a little bit of partial clearing, there will be afternoon and evening thunderstorms. Currently, it does not appear the trough is taking on a strong negative tilt, so our forecast of 20-30% chance of thunder is good for now. Showers remain in the forecast for Tuesday as the ridge begins to build to our south. Temperatures will remain on the cool side with highs in the 60s to around 70 through Tuesday. Wednesday onward a ridge will build somewhere over the western US. There are some discrepancies of where the ridge sets up, which will directly impact how hot we will get. For now, plan on warming conditions. By Thursday temperatures will be 7 to 10 degrees above average, which is 80s. Friday through the weekend we could see temperatures warm further, with 90s for parts of central WA and the LC Valley. Those who are not acclimated to these hot temperatures for early June could experience heat exhaustion if outside during the hottest times of the day. Those choosing to go to bodies of water should be aware that the waters are still cold and swift and could create hypothermia and difficulty swimming. /Nisbet && .AVIATION... 00Z TAFS: VFR conditions expected for TAF sites over the next 24 hours. Isolated to scattered showers are occurring with cumulus clouds over Northeast Washington and North Idaho Panhandle, especially near the Sandpoint and Bonners Ferry and possibly Colville and Chewelah airports. Few to scattered fair weather cumulus is expected across KGEG- KSFF-KCOE corridor and on the Palouse (KPUW) and Lewiston- Clarkston Valley (KLWS). Expect VFR conditions and westerly winds of 8-12 kts this afternoon. Winds will calm overnight. Drier air will bring less clouds and warmer temperatures for Friday. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Confidence is high for VFR conditions for TAF sites. Low confidence in thunderstorm developing over Northeast Washington and North Idaho Panhandle fro the afternoon. /JDC ----------------------- 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 37 70 47 73 49 70 / 0 0 0 0 0 10 Coeur d`Alene 36 68 46 71 48 67 / 0 0 0 0 10 10 Pullman 36 67 47 69 48 68 / 0 0 0 0 0 10 Lewiston 43 76 51 79 55 75 / 0 0 0 0 0 10 Colville 32 71 42 70 42 69 / 0 0 0 20 20 20 Sandpoint 37 67 45 68 47 67 / 10 0 0 10 20 20 Kellogg 38 65 47 69 52 67 / 0 0 0 0 10 10 Moses Lake 37 76 50 79 48 72 / 0 0 0 0 0 10 Wenatchee 43 75 57 74 52 70 / 0 0 0 0 0 20 Omak 39 76 51 76 47 71 / 0 0 0 10 0 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Frost Advisory until 8 AM PDT Friday for Central Panhandle Mountains-Idaho Palouse-Northern Panhandle. WA...Frost Advisory until 8 AM PDT Friday for Spokane Area-Upper Columbia Basin-Washington Palouse-Western Okanogan County. Freeze Warning until 8 AM PDT Friday for Northeast Mountains- Okanogan Highlands. && $$