Area Forecast Discussion
Issued by NWS Spokane, WA
Issued by NWS Spokane, WA
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892 FXUS66 KOTX 122256 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 356 PM PDT Sun May 12 2024 .SYNOPSIS... An approaching system will deliver breezy conditions into Monday, especially closer to the Cascades and western Columbia Basin. A chance for showers will come to the Cascade crest, northeast Washington and the northern Idaho Monday, lingering over Idaho Tuesday. Temperatures will cool for Monday and Tuesday, rebound around midweek, then decrease again later in the week as the next shower and breezy winds chances come in. && .DISCUSSION... Sunday: Today is shaping up to be a dry day in Eastern Washington and North Idaho. Some cumulus build ups have been observed over higher terrain. Expecting some passing mid and high level clouds with a dry frontal passage tonight after dark. Winds will become breezy as the pressure gradient tightens near the Cascades into the Waterville Plateau early this evening, with speeds near 15-25 mph, with gusts near 30-40 mph. Areas just downwind of the Blue Mountains will see some winds near 15 mph and gusts of 20-30 mph. Speeds abate a little overnight into early Monday. Monday: A second wave comes through tomorrow afternoon increasing low bringing increased cloud cover tomorrow and additional breezy winds. There is a 15% chance of showers near the Cascade crest tomorrow through much of the day with increased moisture thanks to onshore flow. High resolution models also indicate a 15% chance of thunderstorms in Northeastern Washington and the northern Panhandle with this wave passage tomorrow. Wind gusts tomorrow will be of a similar magnitude to this evening. Tuesday: Mostly dry with some sporadic shower activity over northern Idaho. Tuesday morning will be a bit breezy with north winds down the Okanogan Valley. There is a 40% chance of gusts greater than 25 mph before the upvalley winds decrease wind speeds in the afternoon. Wednesday through Sunday: The weather pattern in the extended features an upper ridge off the coast with troughs dropping down into the region from the northwest. Roughly 70% of the 100 member grand ensemble from the GFS, ECMWF, and Canadian models favor this setup, with the bulk of the moisture from these troughs passing north of the Canadian border and breezy winds being the main impacts. The other 30% show more of a zonal flow over the region with dry and quiet weather. Going with the majority, the forecast favors a cooling trend from above normal temperatures in the mid 70s to mid 80s Wednesday and Thursday, down towards normal values in the mid 60s to mid 70s by next weekend. Typical spring time breezes are also forecast, except Thursday where there is a 60-80% chance of gusts of reaching 30-40 MPH or higher in parts of Central Washington include the Wenatchee area and Waterville Plateau as a dry cold front passes through. JW && .AVIATION... 00Z TAFS: VFR conditions expected at TAF sites. Winds will remain breezy through the night with gusts near 30kts possible especially in the Cascade gaps. There will be risk for LLWS as a low level jet strengthens in advance of the shortwave, with the potential near PUW, MWH and, if the mixing decouples, near EAT. North Idaho has a 15% chance of thunder after 18z Mon. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: There is high confidence in VFR conditions. Low confidence in showers and precise timing of winds near the Cascades and EAT, as well as low to moderate confidence in LLWS overnight/early Monday near PUW, MWH and EAT. ----------------------- 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 51 75 47 75 48 80 / 0 0 0 0 0 0 Coeur d`Alene 50 72 47 72 47 76 / 0 10 10 0 0 0 Pullman 50 69 47 69 48 75 / 0 0 0 0 0 0 Lewiston 55 78 52 77 52 83 / 0 10 0 0 0 0 Colville 47 75 44 77 45 81 / 10 20 10 0 0 0 Sandpoint 49 70 48 69 46 75 / 0 30 30 20 0 0 Kellogg 53 68 49 67 50 73 / 0 20 10 10 0 0 Moses Lake 53 79 48 80 51 86 / 0 0 0 0 0 0 Wenatchee 56 74 50 79 54 84 / 0 0 0 0 0 0 Omak 52 78 48 80 51 85 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$