106 FXUS66 KPDT 170926 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 230 AM PDT Tue Sep 17 2019 .SHORT TERM...Today through Thursday...Fall has arrived early, as yesterday's cold front brought temperatures in the 50s to mid 60s (65-70 in the Lower Columbia Basin) and numerous showers. Rainfall amounts generally ranged from a few hundredths across south central WA and north central OR to 0.1-0.25 inch for areas east-southeast of the Blue Mountains and 0.25-0.6 inch along the Blue Mountains down to central OR. The parent upper low is over central ID with wrap around precipitation continuing in far eastern Wallowa County. The rest of the area will have a brief break in precipitation before the next system arrives today. A warm front will spread precipitation to the WA and northern OR Cascades by sunrise this morning, then over the remainder of the OR Cascades and as far east as Prosser- Arlington-Condon-Prineville by noon. By 5 PM, the warm front will bring widespread rain (snow levels 7000-9000 feet) to all areas. Temperatures this afternoon will only rise into the mid-50s to mid- 60s. These are temperatures that are seasonal average for mid October--not mid September. Winds aloft are increasing and there will be breezy winds in some areas with high gusts along exposed ridges. The closed low associated with today's warm front will weaken into an open trough as it travels across WA/OR Wednesday. Numerous showers will develop during the day, and just about anywhere in the forecast area may observe a few lightning strikes and small hail due to the cold air advection aloft and steep lapse rates. Rainfall amounts over the next 36 hours will range from 0.2-0.6 inch with higher amounts along the Cascades. Some of the higher peaks of the Cascades, Strawberry Mountains, and the Wallowas above 7000 feet will have at least several inches of snow. By 12Z Thursday, the trough will be over the eastern third of WA/OR and will continue to bring scattered showers Wednesday night over central and northeast OR. A drier northerly flow aloft will follow, and precipitation will end over south central WA and north central OR. The trough will show little movement on Thursday, therefore showers are likely and possibly a few thunderstorms will develop from the Blue Mountains eastward while the western half of the forecast area will have partly to mostly cloudy skies and a few mountain showers. Temperatures will be about the same or a little warmer on Thursday. Wister .LONG TERM...Thursday night through Tuesday...An upper trough will exit the region Thursday night and be replaced by a northerly flow on Friday and Friday night ahead of an upper ridge building in from the west to arrive on Saturday. There will still be some lingering showers over the mountains in an upslope northerly flow behind the trough on Friday, but then it will be dry in all areas on Saturday and a few degrees warmer with temperatures rebounding back into the lower to mid 70s in the lower elevations on Saturday. The upper ridge will persist Saturday night, but then a cold front and another upper trough will drop down from the northwest on Sunday bringing another chance for rain, especially in northern areas. After that the long range model diverge from each other significantly for Monday and Tuesday. The Canadian has a broad upper ridge over the region while the ECMWF and GFS both have a deep upper trough exiting the area with a northerly flow aloft over the forecast area. Due to the uncertainty and inconsistency in the models, have opted to not make too many changes and go with the National Blend of the Models (NBM) almost entirely. This has a few showers over the forecast area on Monday, with mostly dry conditions on Tuesday. Temperatures are to be near normal by Tuesday. It will be breezy at times, especially on the ridge tops while weather systems move through the area, but otherwise winds will not be too strong, and generally 5 to 15 mph. 88 && .AVIATION...12Z TAFs...A wet weather system will move into the region and bring lowering CIGs and visibilities with increasing rain from the west. This may cause periods of MVFR conditions by this afternoon and tonight. The lower elevation TAF sites will be mostly VFR. It will also become locally breezy to windy this afternoon and evening as this weather system moves into the region with wind speeds of 15 to 25 kts at flight levels between 5K-15K feet MSL, and 5 to 15 kts at the surface. 88 && .PRELIMINARY POINT TEMPS/POPS... PDT 63 51 64 50 / 70 80 50 40 ALW 66 54 67 50 / 50 70 50 40 PSC 67 54 69 51 / 60 50 30 40 YKM 59 46 65 47 / 80 50 50 30 HRI 66 53 69 52 / 70 60 40 40 ELN 60 46 64 45 / 80 60 60 30 RDM 58 43 59 42 / 80 90 80 50 LGD 62 47 59 45 / 60 90 80 60 GCD 58 47 58 45 / 80 100 80 60 DLS 63 52 65 52 / 90 70 70 30 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ 85/88/88