Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
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687 FXUS66 KPDT 232313 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 413 PM PDT Sun Jun 23 2024 .Updated for Aviation... .AVIATION... 00Z TAFS...VFR conditions are expected for the next several days. Gusty winds 35 to 40 kts at DLS and 25 to 30 kts elsewhere will continue through this evening before decreasing to 10 kts or less everywhere. DLS will gust 20 to 25 kts again Monday afternoon. && .PREV DISCUSSION... /issued 234 PM PDT Sun Jun 23 2024/ SHORT TERM...This afternoon through Tuesday night...Dry air aloft will continue to mix to the surface this afternoon resulting in widespread relative humidity in the upper single digits to mid- twenties across the lower elevations of our forecast area. In conjunction with breezy to locally windy southwesterly to northwesterly winds, this is producing elevated fire weather conditions. Red Flag Warnings remain in effect for fire weather zones OR640, OR641, and WA691 through 8PM this evening. Winds through the Kittitas Valley will remain supportive of low- end advisory criteria through this evening -- sustained winds of 20-30 mph with gusts of 35-45 mph are forecast. Tonight, winds will slacken. Monday, quieter weather returns to the region with a dry zonal flow aloft. Tuesday, an offshore closed low will approach the PacNW. Meanwhile, an upper-level ridge will amplify over the northern Rockies. The result will be a shift to southwesterly flow aloft. Temperatures will also warm on Tuesday -- the probability of reaching or exceeding 90 degrees for our population centers is high (70-90%). Tuesday night, a shortwave will eject northeastward around the base of the closed low and usher in some low-end precipitation chances (5-14%). There is a signal for some weak elevated instability in numerical guidance, but confidence is currently low (<40%) in anything more than isolated showers. Moreover, confidence is very low (<10% chance) in lightning. Plunkett/86 Long Term...Wednesday through Sunday...A trough will move over to the PacNW starting Wednesday through Thursday, bringing increased winds and cooler temperatures across the region. Confidence remains low (<30%) for mountain showers at the crest of the WA/OR Cascades due to limited moisture associated with trough and cold front. Cooler temperatures will arrive late Wednesday through Thursday with the arrival of the trough. However, temperatures will then be above normal again with an arrival of the ridge Friday through Saturday across the forecast area. Sunday temperatures decrease by few degrees as a shortwave trough passes, but will remain within a few degrees of normal. Wind gusts will occur late Wednesday afternoon at 25-35 mph through early night around the Columbia Basin, Columbia River Gorge, Kittitas and Yakima valleys. Probability is moderate for wind gusts exceeding to 40 mph (60%). High confidence for increased wind gusts in these areas Thursday as well with the trough passing. Friday through Saturday, winds will settle down with the upper ridge building over the forecast area. Starting late Sunday, locally windy conditions will return across the forecast area with wind gusts at 25-35 mph before decreasing overnight (50% probability). Feaster/97 AVIATION...18Z TAFS...VFR prevailing for this period. KDLS/KPDT/KYKM/KALW/KPSC currently have some clouds, but clear skies for KRDM/KBDN. As the system passes, increasing winds will be a concern for all sites sustaining at 12-20kts with wind gusts around 20-30kts. Wind conditions should improve later this evening. Feaster/97 && .PRELIMINARY POINT TEMPS/POPS... PDT 48 81 50 91 / 0 0 0 0 ALW 52 84 54 94 / 0 0 0 0 PSC 52 86 56 95 / 0 0 0 0 YKM 46 83 56 91 / 0 0 0 0 HRI 52 86 55 95 / 0 0 0 0 ELN 47 81 53 90 / 0 0 0 0 RDM 43 84 48 91 / 0 0 0 0 LGD 47 81 49 90 / 0 0 0 0 GCD 47 87 52 94 / 0 0 0 0 DLS 52 84 55 94 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Red Flag Warning until 8 PM PDT this evening for ORZ640-641. WA...Red Flag Warning until 8 PM PDT this evening for WAZ691. Wind Advisory until midnight PDT tonight for WAZ026. && $$ SHORT TERM...86 LONG TERM....97 AVIATION...77