001 FXUS66 KPDT 131617 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 816 AM PST Wed Feb 13 2019 .SHORT TERM...Today and tonight...A cold front currently stretches from southeast Washington back to western Oregon. The front has been producing rain and snow with a few pockets of freezing rain. The main concern going forward will be snow accumulations along the Blue mountain Foothills today and over the mountains of eastern Oregon today and overnight. Some winter weather advisories are in effect for this and others may be needed as the day goes on. The front will continue to slowly sag southward today and by midnight mainly be over southern Oregon. However, it will begin to lift back northward late tonight and early Thursday as a warm front. Colder air over Washington will begin to move southward today due to a light northerly wind. This will bring cooler temperatures today and overnight back to northern Oregon. && .PREV DISCUSSION... /issued 346 AM PST Wed Feb 13 2019/ SHORT TERM...Today through Friday...Very active next couple of days with mixed precipitation causing significant travel concerns. A cold front will sag southward across Oregon today and stall south of the forecast area this evening. Precipitation will end northwest to southeast through the day. Some mixed snow and freezing rain will be possible across extreme southern Washington and northern Oregon this morning. Moderate snows are expected in the Oregon mountains where advisories are in effect. The cold front will lift northward as a warm front late tonight and Thursday as a low pressure system moves northeast from southwest Oregon to northeast Washington. This will set the stage for snow over the northwestern half of the forecast area and rain in the southeast with high snow levels. In the transition zone along the Blue Mountain foothills...Lower Columbia Basin...into portions of north central and central Oregon there will be a good potential for some freezing rain. Ice accumulations will likely exceed .10 inches in some areas and could approach .25 inches in isolated cold pockets. Winter Highlights may be needed later today for the freezing rain. Farther nw snowfall amounts appear to be sufficient to issue Winter Storm Watches with this forecast package for North Central Oregon...Simcoe Highlands...and the Yakima and Kittitas Valleys. By late Thursday evening the warm layer aloft will likely be eroded and precip type should change over to all snow...but by that time amounts should be tapering off somewhat. A few mainly mountain snow showers may continue into Friday. 78 LONG TERM...Friday night through Tuesday...An upper level blocking ridge initially near 150W will migrate slowly east during the long term period. Multiple systems will dive down the backside of the ridge into the eastern Pacific Ocean and the Pacific Nortwest during the long term period. Friday night and Saturday an upper level low near 50N 130W will dive south near the coast, then move southeast into SW OR and northern CA Saturday night and Sunday. This will keep a trough over WA and OR through the weekend. The trough will keep showers lingering over the Cascades and central OR to the northern Blue Mountains. Monday the blocking high will build into WA and OR with dry northerly flow bringing colder air into the area. Upslope may trigger a few showers in the mountains. Tuesday another system will move from the Gulf of Alaska into southern Canada and the Pacific Northwest for another round of snow. Northerly flow will keep us quite cool Friday through Tuesday with highs and lows 5-10 degrees below normals for this time of year. Coonfield AVIATION...12Z...MVFR or IFR conditions will develop at all TAF locations this morning as a front pushes slowly south today with a mixture of wintry precipitation changing to snow. Winds will be mostly from the southwest to west which will gradually turn to the northwest generally less than 12kt. 76 && .PRELIMINARY POINT TEMPS/POPS... PDT 33 26 32 25 / 100 10 80 70 ALW 31 27 35 29 / 100 10 70 70 PSC 30 24 32 27 / 90 10 90 70 YKM 31 20 30 22 / 10 10 90 70 HRI 34 27 31 25 / 90 10 90 70 ELN 30 16 29 19 / 10 0 70 70 RDM 42 29 40 24 / 70 40 70 40 LGD 38 28 41 30 / 100 20 60 60 GCD 42 33 46 29 / 100 50 80 70 DLS 35 30 33 30 / 30 30 90 60 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Winter Weather Advisory until 3 PM PST this afternoon for ORZ502- 503-506-509. Winter Storm Watch from late tonight through Thursday evening for ORZ510. Winter Storm Watch from late tonight through Thursday evening for ORZ041. WA...Winter Weather Advisory until 3 PM PST this afternoon for WAZ030. Winter Storm Watch from late tonight through Thursday evening for WAZ520. Winter Weather Advisory until 10 AM PST this morning for WAZ028- 029. Winter Storm Watch from late tonight through Thursday evening for WAZ024-026-027-521. && $$ 91/84/84