754 FXUS66 KPDT 111501 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 801 AM PDT Mon Sep 11 2023 .UPDATED...Continue to see a transition to a westerly flow as a weak upper level trough gains influence over the Pacific Northwest. This is allowing a little more cloudiness into the region today that will suppress temperatures resulting in cooler temperatures today. Will also see an uptick in winds along portions of the east slopes of the Cascades mainly through the Columbia Gorge and the Kittitas Valley. Minor changes made in the morning forecast to sky conditions, temperatures and winds. .SHORT TERM...Today through Wednesday night...Deterministic models and ensembles remain in excellent agreement on the evolution of the 500 mb pattern over the next few days which gives high confidence in the forecast. A shortwave trough will move across WA today causing a weak marine push and breezy winds this afternoon and evening through the Columbia Gorge and Kittitas Valley. Winds in these locations will be 15 to 25 mph sustained with the ECMWF ensemble showing mean peak gusts around 30 mph this afternoon and evening. High temperatures today will be in the low to mid 80s with 70s in the mountains. On Tuesday another stronger shortwave will begin to move across the area during the evening and clear the region Wednesday morning. This will result in a slightly stronger marine push Tuesday with winds of 18-30 mph and gusts to around 35 mph in the Cascade gaps. The probability of maximum sustained winds of 20 mph or greater Tuesday is 80% at KELN and 73% at KDLS. Where winds will be strongest Tuesday afternoon humidities will be 30-35%. Thus critical fire weather conditions are not expected at this time. On Tuesday night there will be a 20-40% chance of light showers along the Washington Cascade crest...mainly over northwestern Yakima and western Kittitas Counties otherwise it will be dry. Wednesday and Wednesday night a ridge of high pressure will build over the region from off the Pacific bringing continued dry conditions and near normal temperatures. 78 .LONG TERM...Thursday through Monday...Models remain in good agreement with the development of high pressure on Thursday. Dry conditions and warming temperatures will result from this pattern, with the area of high pressure remaining through Sunday/Monday. Temperatures through the period will reach 10 to 15 degrees above normal, with the warmest temperatures expected Saturday and Sunday for much of the area. Sunday will see a swath of moderate confidence (60-70%) in temperatures around 90 degrees across the Columbia Basin, especially across the Tri-Cities and areas north. An approaching system late Sunday and into Monday will push the warm and dry conditions further east, with a slight chance (15-30%) of showers developing across the Oregon and Washington Cascades. Temperatures will see a dip of around 5 degrees from this system on Monday, though still remain around 5 to 10 degrees above normal. Branham/76 && .AVIATION...12z TAFs...VFR conditions continue with dry conditions today. Increased mid-high level clouds favored today, with a line of clouds traveling from west to east through the day. An uptick in wind speed expected for much of the region, with the strongest wind favored near the Oregon/Washington border with a 60-70% chance for winds of at least 25 mph. Branham/76 && .PRELIMINARY POINT TEMPS/POPS... PDT 83 53 79 54 / 0 0 0 0 ALW 85 58 81 56 / 0 0 0 0 PSC 87 60 84 58 / 0 0 0 0 YKM 84 52 82 51 / 0 0 0 0 HRI 87 59 84 57 / 0 0 0 0 ELN 80 54 80 54 / 0 0 0 0 RDM 81 47 78 45 / 0 0 0 0 LGD 84 52 79 50 / 0 0 0 0 GCD 87 50 82 48 / 0 0 0 0 DLS 81 58 81 59 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...78 LONG TERM....76 AVIATION...76