272 FXUS66 KPDT 162339 AAA AFDPDT Area Forecast Discussion...UPDATED AVIATION. National Weather Service Pendleton OR 439 PM PDT Wed Apr 16 2025 .SHORT TERM...Today through Friday night... Key Messages: 1. Breezy winds this afternoon and again on Thursday. 2. Dry conditions persist through the week. 3. Cooling temperatures Thursday before warming Friday. Current radar and visible satellite imagery shows very light returns along the northern Blue Mountains under mostly clear skies. This is a result of a weak upper level shortwave that is dropping through eastern Washington and Oregon from the north this evening ahead of another shortwave following in its wake on Thursday. Isobars will tighten with each passing system to provide widespread breezy winds this evening into the overnight period, with sustained north-northeast winds of 15-20 mph and gusts of 30-35 mph peaking after 5 PM. Winds are expected to slowly dissipate around midnight before increasing again late Thursday morning through Central Oregon, John Day Basin, and the Blue Mountains and foothills. Winds will begin to subside after 8 PM Thursday as an upper level ridge moves in from the west-southwest into Friday. A dry and cool airmass is associated with these synoptic features, allowing for high temperatures Thursday to drop 8-12 degrees from today and peak in the low to mid-60s across the Lower Columbia Basin, Blue Mountain foothills, Gorge, and Central Oregon. Limited cloud cover associated with this dry system will bring down overnight temperatures into the low to mid-30s, with freezing temperatures expected in Deschutes County. Moderate overnight humidity recoveries will arrive tonight and linger overnight Thursday associated with the two passing systems, with afternoon humidities dropping into the upper-teens to mid 20s from low to high elevations. North flow aloft on Thursday will slowly turn to more out of the west into Friday to bump high temperatures back into the upper 60s to low 70s as a quick ridge slides in the area. 75 .LONG TERM...Saturday through Wednesday...Models are in good agreement in having a series of weak shortwaves move through the area during the long term period, but the overall weather looks benign. The systems are very weak and models indicate almost no precipitation except along the Washington Cascade crest and even there the amounts are fairly light. The main impact will be tighter pressure gradients leading to breezy winds most afternoon, though nothing that would approach wind advisory levels. Temperatures in general should be a couple of degrees above normal for mid April. The Extreme Forecast Index highlights marginally noteworthy winds in the Eastern Columbia Gorge and western Blue Mountain Foothills and Oregon Columbia Basin Saturday and Sunday with values around 0.75. Overall forecast confidence is good then drops off somewhat on Tuesday and Wednesday as the usual model differences arise. Saturday will have a weak shortwave cross the area with just a few hundredths of an inch of QPF along the Washington Cascade crest in the morning and little anywhere else through the day. Snow levels are at 4500 feet, so rain is expected at pass level. A slightly stronger wave arrives Sunday with a chance of rain showers along both the Washington and Oregon Cascade crest and the eastern mountains. QPF amounts are barely measurable except along the Washington Cascade crest again which looks to get less than a tenth of an inch rain with snow levels around 4000 feet. Each afternoon, northwest winds of 15 to 25 mph are expected. Models show additional shortwaves arriving Monday and Tuesday afternoon, though with little if any precipitation. Winds will be lighter as well and mainly northwesterly at 10 to 20 mph. Wednesday shows a transitory ridge over the area ahead of a fairly strong closed low in the Gulf of Alaska. Temperatures will be in the upper 50s and 60s Saturday through Tuesday then warm a few degrees to the mid 60s to lower 70s Wednesday. The mountains will mainly be in the mid 40s to mid 50s through the period. Perry/83 && .AVIATION...00Z TAFs...VFR conditions area-wide with satellite showing increasing mid clouds across south central WA and the lower basin. Northerly flow regime in place after a passing cold front earlier today and reinforcing northerly flow tonight-tomorrow. Initial mid clouds we are seeing, bases 9-10 kft, will lessen and clear out mainly after 06Z. Otherwise, current breezy winds that are in place will lessen similarly around that timeframe. Winds will pick up 18Z tomorrow onward though not as gusty at KPSC, KALW, KPDT, and KDLS terminals. However, gusts more likely than not at central OR terminals up to 20 kts in the afternoon. && .PRELIMINARY POINT TEMPS/POPS... PDT 33 60 34 67 / 10 0 0 0 ALW 35 60 38 66 / 0 0 0 0 PSC 37 65 37 72 / 0 0 0 0 YKM 37 65 38 70 / 10 0 0 0 HRI 36 65 37 71 / 0 0 0 0 ELN 33 62 35 69 / 10 0 0 0 RDM 31 60 31 68 / 0 0 0 0 LGD 33 55 32 61 / 10 10 0 0 GCD 31 56 31 62 / 10 0 0 0 DLS 40 68 41 73 / 20 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...75 LONG TERM....83 AVIATION...80