Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
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451 FXUS66 KPDT 150001 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 501 PM PDT Tue May 14 2024 Updated Aviation Discussion .AVIATION...00Z TAFs...VFR conditions expected over the next 24 hours. Winds breezy at RDM/BDN this evening but should lessen by tonight. YKM will see stronger gusts start up later this evening and should lessen again by tomorrow morning. Finally DLS may see some breezes this evening into the night, but stronger gusts not expected until later tomorrow morning. Skies either clear or some high clouds possible, but CIGs will not be impactful. Goatley/87 && .PREV DISCUSSION... /issued 223 PM PDT Tue May 14 2024/ SHORT TERM...Tonight through Thursday Night... Key Points for the next few days: 1) Continued breezy to windy conditions for the Kittitas Valley becoming widespread across the area Thursday afternoon. 2) Water levels remain high along the Naches River. Weather through the next couple of days will be quiet with few concerns as a ridge centered offshore remains in control of our weather. Expecting mostly clear skies with no chance of precipitation through Wednesday night with temperatures warming 4 to 5 degrees from today with highs in the upper 70s to mid 80s. NBM temperatures probabilities show very little spread between the 10th and 90th profiles, so confidence is high. Winds will be the main forecasting challenge as while pressure gradients have mostly relaxed, they remain strong over the Washington Cascades and expect the Kittitas Valley to see 20 to 30 mph northwest winds late this afternoon and again tomorrow. Winds will be lighter elsewhere. By Thursday afternoon, a trough will be sliding south through British Columbia and flattening the ridge in to a zonal westerly flow. The trough will bring a chance of light rain showers to the Washington Cascade crest Thursday afternoon and night with just minor amounts of precipitation expected. The rest of the area will be dry though there will be increased clouds. The trough will tighten pressure gradients and much of the area will have west to northwest winds of 15 to 30 mph, Thursday afternoon and night though it does not appear that any Wind Advisories will be needed. Water levels on the Naches River continue to be high with the Naches River at Cliffdell just an inch or so below action stage. It is expected to rise very slowly to above action stage by tomorrow afternoon. It is then forecast to stay just slightly above action stage through Sunday morning before dropping down below action stage. The Naches River at Naches continues to be about six inches below action stage but is expected to remain steady and not reach action stage in the next week. Probabilistic forecasts give the Naches at Cliffdell a greater than 95 percent chance of reaching action stage while the Naches River at Naches has only a 6 percent chance of reaching action stage, though my suspicion is that it should be higher than that. In any event, the water levels on the Naches River should not cause any significant impacts. Perry/83 LONG TERM...Friday through Monday...Models continue to struggle on the strength and impact on our area of a broad upper level trough over western Canada. EOFs depict the greatest variance in the strength of a shortwave ridge Friday, but then it becomes how deeply the aforementioned trough digs southward through the rest of the period. WPC cluster analysis shows a general upper level trough over the area with the deepest trough bouncing between cluster members which may just be a timing issue as disturbances rotate around main low over the Northwest Territories and Nunavut of Canada. Ensemble members show a general trough over the area deepening through the period with the GFS ensemble a little more broad and weaker by Friday. The deterministic models are quite different in their solutions. ECMWF generally depicts weaker shortwaves moving through the general northwest flow while the GFS is deeper. As a result, the GFS is a little more optimistic with precipitation chances over the mountains. At this time, the best chance of receiving 0.1 inch is Monday with the mountains showing a moderate (45-60%) chance while the basin, foothills and Central Oregon show a low chance (15-25%). Overall, the weather will remain generally unsettled with precipitation amounts remaining on the light side. There`s a moderate-high chance (65-85%) we`ll see some breezy conditions through the Columbia River Gorge, Kittitas Valley, and portions of the Lower Columbia Basin Friday. Daytime highs will be near to slightly below normal through the period. Earle/81 && .PRELIMINARY POINT TEMPS/POPS... PDT 48 79 52 81 / 0 0 0 0 ALW 53 81 56 83 / 0 0 0 0 PSC 54 86 57 88 / 0 0 0 0 YKM 49 85 51 82 / 0 0 0 0 HRI 51 85 56 85 / 0 0 0 0 ELN 51 79 52 74 / 0 0 0 0 RDM 43 80 46 81 / 0 0 0 0 LGD 45 76 49 79 / 0 0 0 0 GCD 44 78 48 80 / 0 0 0 0 DLS 53 84 56 78 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...83 LONG TERM....81 AVIATION...87