Area Forecast Discussion
Issued by NWS Spokane, WA
Issued by NWS Spokane, WA
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587 FXUS66 KOTX 282140 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 240 PM PDT Tue May 28 2024 .SYNOPSIS... A return of showers and thunderstorms today with a cold front passage. A few storms could be strong with gusty outflow winds in southeastern Washington and the Idaho Panhandle. Frosty conditions is expected Wednesday night into Thursday morning. Cool and showery conditions will continue through the end of the week with drier and temperatures warming back up to near normal for the start of the weekend. && .DISCUSSION... Today and tomorrow: Cloud cover and showers over Eastern Washington this morning lasted much longer than anticipated. Low level lapse rates are slowly improving this afternoon and showers are becoming more vigorous in the Spokane area. The severe threat is very low (less than 5% chance) for Spokane/Cda/Northern Mountains thanks to the cloud cover. Far southeastern Washington and the Camas Prairie have much steeper low level lapse rates thanks to less cloud cover and more surface heating. Convective inhibition has started to decrease in southeastern Washington and the southern Panhandle over the last couple hours and cumulus towers have been growing in northeastern Oregon. The best cape/shear parameter space remains largely untapped and the cams are still hinting at storms clipping the L-C valley, Camas Prairie, and rural Shoshone County. The main timing remains now through 10 pm for stronger cells. Storms are capable of large hail (around an inch or so), damaging wind, and frequent lightning. Wednesday looks showery and breezy, particularly through the Cascade gaps and Columbia Basin. Temperatures tomorrow look around 10 degrees cooler with highs in the upper 50s and 60s. /Butler Thursday and Friday: The trough continues to push east into the northern high plains. A transient ridge will move into the Inland Northwest providing a dry forecast and warming temperatures. Skies will be mostly clear Thursday with clouds increasing Friday afternoon ahead of the next weather feature. There will be some breezy Cascade gap winds late Thursday afternoon and evening with gusts to 25 mph. Saturday through Monday: Clouds will continue to increase Saturday with partly cloudy to mostly cloudy skies through the weekend as weak troughing moves into the region. There is a 20-30% chance of showers across the mountains of northern WA and the ID Panhandle and a 15% chance of thunderstorms along the Canadian border. The area for showers expands late Sunday afternoon and evening for the entire region as a very large low pressure system in the Gulf of Alaska begins to move south. There is a 40% of showers Monday and that continues into Tuesday for the mountains. It looks like a ridge will begin to build Wednesday onward with the potential for the hottest temperatures so far this year beginning next Friday the 7th and continuing through the weekend. /Nisbet && .AVIATION... 18Z TAFS: A cold front moving into the region will bring isolated to scattered showers/thunderstorms and gusty winds. Convection today will have relatively high cloud bases at 8 kft agl and higher. Best chances for thunderstorms will be near KPUW and KLWS this afternoon after 20Z with stronger convection expected to develop to the southeast of these terminals. The rest of the region east of a line of KMWH to KOMK will primarily see high based convective showers that will have a less than 20% of developing into a thunderstorm. A westerly pressure gradient will tighten this afternoon with winds gusting as high as 30 kts through the Cascades and across the exposed areas of the basin, including all TAF sites. Expect convection to be pushing out of the area to the east between 06-08Z this evening. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Confidence is low that thunderstorms will impact airport terminals today. Best chances of 20-30% will be in the afternoon after 21Z for KGEG-KSFF-KCOE-KPUW-KLWS. There is less than a 5% chance that thunderstorms will impact the KEAT and KMWH terminals today. /SVH ----------------------- 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 43 62 38 65 41 70 / 20 20 10 0 0 0 Coeur d`Alene 43 59 37 61 40 69 / 30 40 20 0 0 0 Pullman 42 57 37 61 40 67 / 50 20 20 0 0 0 Lewiston 50 66 44 69 46 77 / 60 10 10 0 0 0 Colville 37 59 31 65 35 71 / 40 70 10 0 0 0 Sandpoint 43 57 36 61 39 67 / 50 70 40 10 0 0 Kellogg 45 55 38 59 42 66 / 70 50 50 0 0 0 Moses Lake 42 67 38 72 41 75 / 10 10 0 0 0 0 Wenatchee 44 64 43 69 45 74 / 10 10 0 0 0 0 Omak 40 66 37 69 40 75 / 20 20 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$