FXUS66 KPDT 200505 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1005 PM PDT Thu Mar 19 2026 .KEY MESSAGES... - Mountain rain will persist through Friday before transitioning to snow - Above seasonal average temperatures remain through Friday - A system will bring temperatures back to seasonal average Saturday && .DISCUSSION... A stalled 500 to 700 kg/ms magnitude atmospheric river continues with orographic lift creating persistent rain across the Washington Cascade Crest for the next couple of days. High snow levels between 7 and 9k ft AGL will lead to at least another one to two inches of rainfall from Snoqualmie Pass and areas north. With the large western CONUS high pressure, expect one more day of the anomalously warm temperatures. The weather in context tool flags Friday as a potentially record breaking temps at PDT if the temps hits 79F. Likewise overnight lows in the high 40s have potential for record ties or breaking. PSC could tie at 75F and break if the low is 52F. ESAT and shift of tails continues to show extremely high confidence for a rare episode, with both Today and Friday across most for Oregon and into south east Washington. Bend hit 81 degrees yesterday, and the broader area had low to upper 70s depending generally on elevation. The same warm pattern exists with potential for around 80 degrees across the John Day Basin and Central Oregon through Friday. The cold front that has been anticipated for the Friday night time frame looks to become best signaled for fropa as the NAM 1000-500 mb heights fall from around 557dm Friday Evening to 540dm by 12z Saturday. This will also signal the break in the AR moisture stream in WA, favoring showers across the Blues through Saturday. Saturday will be then start of a dry period that will run through about Monday night when mountain showers could return (30-50% chances) across the Washington Cascades. Snow levels averaging around 4-5k ft AGL will translate in the -RA/SN mixed over the Upper Slopes and rain only across the Lower Slopes. These SLs crashing down below 4000 ft by Wednesday, where an all snow precip type would be firmly established across the Cascade Crest in both WA and OR. Russell/71 && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... VFR conditions will prevail across all sites through Friday. Winds generally 10 kts or less overnight, then becoming gusty in the 20 to 25 kt range Friday afternoon. Winds should decrease again Friday evening. && .FIRE WEATHER... Areas of central Oregon into the John Day/Ochoco Highlands are highlighted with an elevated fire weather risk for the balance of This Afternoon, owing to low relative humidity and wind gusts that are expected to continue above 20 mph during the afternoon. The low relative humidity and generally gusty surface winds will still promote rapid fire spread for any dry grasses across the central Oregon and John Day/Ochoco Highlands on Friday afternoon as well. A cold front overnight Friday night into Saturday morning will allow recovery of the low RH values through cooler air getting into the local area. Russell/71 && .HYDROLOGY... The Naches River at Naches, and the reach up and downstream will be prone to exceeding the bank over the weekend. The Naches River at Naches is under a flood warning and has a 99 percent chance of being above minor flood stage at least through Saturday. The Kiona forecast point on the Yakima River has a 24% chance of reaching flood stage based on HEFS (ensembles) by midday Sunday. Russell/71 && .Preliminary Point Temps/PoPs... PDT 48 74 46 58 / 10 10 30 40 ALW 54 74 48 59 / 10 10 40 50 PSC 52 77 49 64 / 20 10 20 20 YKM 49 71 42 58 / 20 30 10 0 HRI 49 76 48 62 / 10 10 20 20 ELN 46 61 39 50 / 40 50 20 10 RDM 44 76 42 57 / 0 0 0 10 LGD 48 77 45 56 / 0 0 30 60 GCD 48 78 46 57 / 0 0 10 50 DLS 50 70 47 59 / 10 20 30 20 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...None. OR...None. && $$ DISCUSSION...71 AVIATION...77 FIRE WEATHER...90 HYDROLOGY...83