482 FXUS66 KPDT 121730 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1030 AM PDT Fri Apr 12 2019 Updated aviation discussion .SHORT TERM...Today and tonight...A moist northwest flow continues today with the main moisture plume now oriented northwest to southeast across eastern Washington and into northeast Oregon. Most of the precipitation is now confined to these areas as upslope showers continue to feed into the northern Blue Mountains. Some snow is still expected through the day with snow levels rising up to around 5000 feet in the afternoon. Expect current winter storm warnings and advisory to be allowed to expire at 11 AM as the trend will be for showers to decrease this afternoon. The upper level ridge of high pressure off the coast will begin to shift inland today and will eventually bring the precipitation to an end by this evening. && .HYDROLOGY...Rain amounts of 0.50 to close to an inch have occurred along and over the Blue Mountains over the past 12 hours. This has kept the streams and river high with some increase in flows overnight. As shower activity slowly shifts east today, should start to see flow decrease, but will be quite slow with some flooding along them expected through tonight. Will continue current areal warnings over the next 24 hours. River flood warnings will continue to Umatilla at Gibbon, Walla Walla at Touchet and John Day at Service Creek. 93 .AVIATION...18Z TAFs...Scattered upslope showers will continue near ALW/PDT into this afternoon with ceilings around 050-070 AGL while the remaining terminals stay dry and partly cloudy. Skies will continue clearing overnight but then increasing high clouds return early Saturday. Winds remain generally less than 10KTs, except 10- 15KTs at DLS today. && .PREV DISCUSSION... /issued 251 AM PDT Fri Apr 12 2019/ SHORT TERM...Today through Sunday night. Strong northwest flow aloft remains over the region this morning. Skies are mostly cloudy. Radar continues to show precipitation over northeastern Oregon and southeastern Washington with good upslope flow into the Blues. Expecting a tenth to a quarter inch additional rain here. Snow level about 4-5k with several more inches snow accumulation this morning. Elsewhere amounts will be much less. Offshore upper ridge building into the region later today. Clouds and precipitation will be decreasing. Fair weather tonight with the ridge overhead. An upper level trough will then push a cold front through the forecast area Saturday. This will bring additional rain with some higher elevation snow. Breezy westerly winds late in the day after frontal passage. Another brief break Sunday with a drier westerly flow aloft. Partly to mostly cloudy skies. The next system then moves into the Pacific northwest Sunday night and Monday with rain and higher elevation snow again. 94 LONG TERM...Monday through Friday...Precipitation will continue Monday into Tuesday as moist westerly, then southwesterly flow ahead of an upper level low coming ashore near the mouth of the Columbia River streams through the region. QPF amounts will be on the lighter side, .2 to .4 inches in the mountains falling largely as snow (snow levels 3000-4000 ft) with less than a tenth of an inch for the lower elevations falling as rain. Majority of model/ensemble solutions shift the ridge in the Pacific onshore by late Wednesday and keep it over the Inland Northwest through the remainder of the forecast which should result in warming and drying conditions with highs in the lower elevations reaching the upper 60s to lower 70s by Friday. While the drier conditions will be good news for those living near streams, creeks and rivers, high temperatures in the northern Blues will be in the mid 50s to lower 60s continuing a rapid melt-off where there is still a substantial amount of snow water equivalent waiting to come down above 4500 feet. Peck && .PRELIMINARY POINT TEMPS/POPS... PDT 57 38 56 38 / 40 10 60 60 ALW 59 40 57 41 / 50 10 70 70 PSC 65 41 59 41 / 30 0 50 20 YKM 63 37 58 36 / 10 0 50 10 HRI 63 40 59 40 / 30 0 50 30 ELN 58 36 53 35 / 10 0 50 10 RDM 56 30 56 34 / 10 0 30 30 LGD 51 33 54 36 / 60 20 50 90 GCD 50 33 55 36 / 40 10 30 70 DLS 63 40 57 40 / 10 0 60 40 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Winter Storm Warning until 11 AM PDT this morning for ORZ502- 503. Winter Weather Advisory until 11 AM PDT this morning for ORZ050. WA...Winter Storm Warning until 11 AM PDT this morning for WAZ030. && $$ 91/93/93