Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
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403 FXUS66 KPDT 090954 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 254 AM PDT Thu May 9 2024 .SHORT TERM...Today through Saturday...Benign weather will accompany the upper level ridge overhead accompanied but a noticeable uptick in temperatures. Temperatures will peak on Saturday as the upper level ridge continues to amplify. As stated above, an upper level ridge has made its way towards the forecast area and models show it tilted towards the east with the leading edge directed from southwest to northeast. An upper level low that has formed over the Four Corners will assist in a synoptic set up that will aid in the strengthening of the upper level ridge. This set up will bring northeasterly winds across the region through today as the upper level ridge continues to strengthen and move fully over the area. Dry conditions will persist with the EFI signaling an increase above the climatological normal across the Cascades today. Raw ensembles show well over 80% probabilities that the Columbia Basin, Gorge and foothills of the Blues will see temperatures above 80 degrees today, mid elevations will see low to mid 70s and the higher elevations will see the low to mid 60s. Friday through Saturday the models remain in firm agreement with the amplification of the upper level high pressure persisting over the region. Dry conditions will continue to dominate with the EFI signaling the eastern portion of the Cascades will begin seeing temperatures above climatological normal. Raw ensembles show that 70- 80% of the Columbia Basin, Gorge and the foothills of the Blues will see temperatures above 80 degrees, the mid elevations will see the upper 70s to low 80s and the higher terrains in the low to mid 70s. Saturday raw ensembles show yet another increase in temperatures with 70-90% of the ensembles showing the Basin, Gorge and foothills of the Blues seeing temperatures above 85 with a few isolated locations in the Basin seeing low 90s. The mid elevations will see low to mid 80s and the higher elevations will see upper 60s. With the rise in temperatures, guidance has begun to pick up on a slight heat risk for Saturday through portions of the Columbia Basin. If you are outside on Saturday enjoying the warmth, please be mindful and wear sunscreen, drink plenty of fluids and remember that the rivers will be fast flowing and still dangerous cold. Bennese/90 .LONG TERM...Sunday through Thursday...Ensemble models are showing good agreement with the weakening and flattening of the western USA ridge Sunday and Monday by a shortwave trough passage. After that the ECMWF ensemble maintains a more flat ridge pattern with the storm track north of the region on subsequent shortwave impulses. Meanwhile, the GFS ensemble allows these subsequent shortwaves to push the storm track further south and more likely to directly impact the forecast area. Current deterministic models are even further apart with ECMWF re-building the ridge over the Pacific Northwest Midweek while the GFS has a closed low moving through western Canada and clipping the Pacific Northwest. Overall the WPC cluster analysis shows higher support of the ECMWF ensemble solution through the extended forecast period. So Sunday will see the onset of the weak trough passage. This will provide some weak cold air advection to increase westerly winds in the afternoon and lower high temperatures slightly from Saturday peak highs. Continued breezy cold air advection into Monday with the trough passage occurring will see high temperatures drop further into the 70s to low 80s while mountains see 60s. Overall this will be a dry trough passage other than a few possible showers along the central and northern Washington Cascade crest. Going with the ECMWF ensemble solution will continue to see a flat ridge across the Pacific Northwest Tuesday through Thursday maintaining a slightly above normal temperature pattern with breezy conditions. Any precipitation is likely to be confined to a few showers along the Cascade crest. && .AVIATION...06Z TAFs...(Previous Discussion)...VFR conditions to prevail through the period. Few-sct decks AOA 20kft will impact sites throughout the period. Winds will be light less than 12kts through the period, with wind direction diurnally driven. Lawhorn/82 && .PRELIMINARY POINT TEMPS/POPS... PDT 73 46 79 51 / 0 0 0 0 ALW 77 50 82 54 / 0 0 0 0 PSC 81 52 86 55 / 0 0 0 0 YKM 80 48 86 52 / 0 0 0 0 HRI 79 49 85 52 / 0 0 0 0 ELN 79 50 83 52 / 0 0 0 0 RDM 71 40 78 46 / 0 0 0 0 LGD 70 44 76 48 / 0 0 0 0 GCD 71 42 78 47 / 0 0 0 0 DLS 80 54 86 57 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...91 LONG TERM....90 AVIATION...82