Area Forecast Discussion
Issued by NWS Spokane, WA
Issued by NWS Spokane, WA
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852 FXUS66 KOTX 231227 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 527 AM PDT Thu May 23 2024 .SYNOPSIS... Today will feature scattered afternoon showers and thunderstorms mainly across north Idaho as well as north central and northeast Washington. Friday, Saturday and Sunday will cool with highs in the 60s and low 70s with chances for afternoon and evening showers and thunderstorms. Memorial Day will be the warmest and driest day of the holiday weekend with afternoon temperatures well into the 70s. A return of cool, wet weather expected midweek. && .DISCUSSION... Today and Tonight: For most of the region, a brief break between systems is expected. The Wednesday Low will continue to move South and East, while another Low begins to develop over Gulf of Alaska. It will lead to a dry, cool day for the Cascades and areas South of Hwy 2 and I-90. A Low over Central Washington will push a shortwave trough over North Washington and North Idaho. It will bring precip chances to these areas. Models are indicating Cape values of up to 200 J/Kg through the afternoon and bringing a chance of thunderstorms in these areas. Most areas are expected to receive a couple of hundredths to a tenth of an inch. Portions of Northeast Washington and North Idaho could receive near 0.25". Shower activity will taper off overnight as a brief weak ridge builds over the region. Highs for the day will be will in the 60s to low 70s. Overnight lows will be in the 40s. Friday: The ridge will start to weaken early in the morning as the next Low begins to push into the Pacific Northwest coast. Precip chances will gradually increase through the day. It will mainly bring afternoon showers over the mountain portions of the Inland Northwest, while the Basin will remain relatively dry. Highs will continue to be in the 60s and low 70s. Overnight lows will be in the 40s. /JDC Saturday through Wednesday: The weekend will start off with a robust shortwave moving through bringing breezy winds, intermittent showers across the region, and thunderstorms in the northern mountains. Areas that will see the most rainfall with this wave include the northern mountains, Cascade Crest, eastern third of WA, Blue Mountains, and ID Panhandle. Probabilities for greater than 0.1 inches of rain range from 40 to 70 percent in those areas. Wind gusts of 20 to 30 mph are expected for most locations across the region. By Sunday the shortwave will have moved to our east, placing us in zonal westerly flow. Sunday is looking mainly dry with the exception of a few afternoon showers possible for orographically favored areas - i.e., the Cascade Crest and ID Panhandle mountains. High temperatures Saturday and Sunday will be typical for this time of year in the 60s and 70s, and lows will be in the 40s - also right around what is seasonally normal. With the new week will come a new pattern in the form of a ridge of high pressure. An upper-level ridge will move in on Monday, squashing any remaining shower chances and sending temperatures well into the 70s and even low 80s for some spots. How long the ridge will stick around is uncertain though, with some models suggesting it will move out by Tuesday and others keeping it over us until Wednesday. If the ridge remains over us through the day on Tuesday, temperatures on Tuesday will be even warmer than those on Monday, and highs in the 90s won`t be out of the question for the deep Columbia Basin southeast of Moses Lake. Current ensembles are giving this area a 10 to 20 percent chance of hitting the 90s on Tuesday. After the ridge moves out, another shortwave trough will be quick to take its place, which means cooler temperatures and more showers and thunderstorms are likely in store for us over the latter half of next week. More details on that as it gets closer. /Fewkes && .AVIATION... 12Z TAFS: Low level upslope flow into the Palouse and Idaho Panhandle will be favorable setup for increasing areas of MVFR stratus overnight with localized IFR conditions as well. The atmosphere will destabilize Thursday afternoon with a 20-30% chance of thunderstorms mainly over the northern mountains, but there is at least a 10% chance of storm as far south as the Spokane/Coeur d`Alene areas between 22z-02z. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Moderate to high confidece on timing of KCOE ceiling becoming VFR. Low to moderate confidence on the afternoon thunderstorms. The storms are expected to not impact TAD sites. /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 63 44 69 47 63 42 / 10 20 20 20 30 10 Coeur d`Alene 59 44 67 46 60 44 / 20 30 20 30 40 10 Pullman 59 39 66 44 58 40 / 0 10 20 40 30 10 Lewiston 66 45 73 51 66 47 / 0 10 20 40 30 10 Colville 64 38 68 41 63 36 / 70 60 50 40 60 20 Sandpoint 58 44 64 44 60 42 / 60 50 40 40 60 20 Kellogg 57 45 64 47 56 44 / 20 20 40 40 60 20 Moses Lake 73 43 73 47 70 42 / 10 10 10 10 10 0 Wenatchee 71 46 70 49 66 46 / 0 0 10 10 10 0 Omak 72 44 72 47 67 44 / 30 10 20 20 20 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$