Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
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092 FXUS66 KPDT 102315 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 420 PM PDT Fri May 10 2024 Updated Aviation Discussion .SHORT TERM...Today through Sunday...Clear skies prevail over the region as an upper-level ridge remains centered just off the coast of Oregon. This ridge will allow temps to climb well above average - as much as 20 degrees in some areas - with highs potentially eclipsing the 90s over the weekend across the lower Basin and Gorge. This ridge will flatten out by Sunday as a shortwave arrives and brings gusty winds to the forecast area. This system has little in the way of moisture, so outside of a weak orographic shower over the Cascade crests, expecting a dry forecast for the period. Gap flows are where we expect the strongest winds Sunday afternoon, namely the Gorge, Oregon Basin, Kittitas Valley, and Simcoe Highlands. NBM probabilistic guidance has a low chance (30-40%) of winds reaching advisory criteria, so expecting more of a typical springtime breezy day rather than anything truly significant. Rivers and streams will continue to see rises as mountain snowmelt accelerates under anomalously warm temps. Naches still looks to be the only river that will reach bankfull, however should high pressure build back in next week, more prolonged river rises could occur. The long term period is very much in the air, however, so enjoy the pleasant weather while it lasts! Evans/74 .LONG TERM...Monday through Friday...Models in good agreement through Tuesday, but begin to diverge significantly on their evolution of an upper level ridge over the eastern Pacific Ocean. EOFs show a variance of 53+% from Wednesday onward with the WPC clusters shifting between a dominant ridge and a weak trough or zonal flow. The ensembles show a similar pattern where GFS wants to develop an upper level ridge over the eastern Pacific Ocean and moving it inland but weakening it by Friday while the ECMWF retrogrades the upper ridge allowing for a more troughy pattern over the Pacific Northwest. The deterministic models paint a similar picture with the GFS showing a strong ridge developing over the eastern Pacific Ocean and moving inland over the weekend while the ECMWF mimics its ensemble solution. These differences from Wednesday onward will have significant impacts on temperatures and precipitation chances. If the GFS solution panes out, it will be hot and dry with daytime highs approaching 15-20 degrees above normal by the weekend. If the ECMWF has the correct solution, it will be near to below normal with periods of rain. As a result, there is very low confidence (80-90%) in which solution will pain out so the best solution is to keep close to NBM which is trending warmer, but not as warm as the GFS. NBM is drier too which presently is the way to go until models start settling in on a solution. With a couple of shortwave troughs moving through the area Monday into Monday night, we can expected breezy to windy conditions over the Columbia Basin, especially through the Gorge and the Kittitas Valley. There may be some afternoon/evening showers over the mountains too, especially Northeast Oregon. Earle/81 && .AVIATION...00Z TAFs...Clear skies and light terrain driven winds for the next 24 hours. Wister/85 && .PRELIMINARY POINT TEMPS/POPS... PDT 51 83 54 83 / 0 0 0 0 ALW 55 86 60 85 / 0 0 0 0 PSC 55 90 58 90 / 0 0 0 0 YKM 52 89 52 88 / 0 0 0 0 HRI 53 89 58 87 / 0 0 0 0 ELN 53 86 54 84 / 0 0 0 0 RDM 46 83 47 80 / 0 0 0 0 LGD 49 80 50 81 / 0 0 0 0 GCD 48 80 49 81 / 0 0 0 0 DLS 57 89 57 84 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...74 LONG TERM....81 AVIATION...85