956 FXUS66 KOTX 081211 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 511 AM PDT Sun Apr 8 2018 .SYNOPSIS... Today will be windy across central and eastern Washington. Sustained west winds around 25 mph with gusts up to 40 mph will be possible across the Palouse and Columbia Basin. High pressure will produce mild and dry weather on Monday, but rainy and breezy conditions will return Tuesday. More rain and mountain snow is expected Wednesday through Friday. && .DISCUSSION... Today and Tonight: Low pressure circulating just west of Vancouver Island will eject across WA as an open wave today. Enough westerly flow across the Cascades will result in a rain shadow in the lee of the mountain range. Places like Wenatchee, Omak and Moses Lake are expected to remain dry after a wet day yesterday. The same cannot be said for the eastern half of the forecast area. Although we are no longer tapping into the Atmospheric River, the atmosphere is plenty moist enough for precip to be rung out ahead of the upper level low pressure system. Modest amount of westerly flow will focus higher precip amounts across the Central Panhandle Mountains due to orographics. This precip is expected to back fill into the Palouse for a wet day in the Pullman/Moscow areas and up Highway 195 and 95 to Spokane and Coeur d'Alene respectively. More rain at low to mid elevations will result in additional water across an already saturated watershed of the Coeur d'Alene, St. Joe and Palouse River basins. Expect some more rises today on area rivers and streams, however, these rises will be modest since rain rates will be relatively light compared to yesterday morning. The other good news from a hydrology point of view is that snow levels will be a little bit lower with snow expected above 4,000 feet. So not much if any high elevation snowmelt will contribute to additional runoff. Lookout Pass and Stevens Pass will be snow covered this morning until road temperatures are able to warm up enough for snow to melt in the late morning. The southern portion of the upper basin into the Palouse will be windy today. No changes were made to the wind forecast. Winds are expected to be sustained between 20-30 mph, but the rain should dampen the gust potential as mixing potential should be fairly poor across this area today. Monday and Monday night: Monday will be a dry day in between weather systems and temperatures warmer to near normal. It will be a good day to try and get some work down outside before precip returns at times through the rest of the week. /SVH Tuesday and Wednesday: A pair of frontal systems are forecast to arrive Tue and Wed. Tuesday's front will feature mild temperatures, high snow levels, and relatively light precipitation amounts during the afternoon and evening as the surface low along the front shears into southern BC. The track of the low to our north coupled with modest mid-level flow should minimize rain amounts in the lee of the Cascades. At this time, it looks like Wenatchee, Moses Lake, Grand Coulee, and Ritzville will receive a few hundredths at best. Amounts across the Panhandle and northeast Washington should be limited to a quarter inch or less Tue afternoon through Tue night. Wednesday's frontal system should be wetter with a deeper moisture plume and stronger jet digging into northern California and southern Oregon. The heaviest rainfall will occur over nrn California, but frontal forcing and deformation Wed night into Thu morning should produce a swath of moderate precipitation across the Idaho Panhandle. The evening runs of the GFS and ECMWF suggest up to a half inch of precipitation across SE Washington into the Panhandle. With snow levels potentially as low as 3000-4000 feet we may see more late season snow for the mountains of Shoshone, Bonner, and Boundary counties. Thursday and Friday: A powerful storm system will emerge east of the Rockies on Thursday and eastern/central Montana will feel the brunt of this storm with wind driven snow. Our region will experience more breezy weather and an abundance of rain and mountain snow showers. On Friday the cold upper trough will likely pull eastward leading to decreasing showers. The GFS, ECWMF, and Canadian models suggest a bit of a ridge on Friday, but it will be a "dirty ridge" with Pacific moisture spreading into BC and northwest Washington. It looks like chilly temps and lots of clouds. Next Weekend: Our unsettled and wet weather pattern doesn't appear to relent next weekend. If the medium range models verify, we might eek out some dry weather on Saturday before more precip Sat night into Sunday. /GKoch && .AVIATION... 12Z TAFS: An upper level trough of lower pressure will swing across the region this afternoon. Widespread showers are expected ahead of this feature impacting the KGEG, KSFF, KCOE, KPUW and KLWS TAF sites. These sites will also see MVFR cigs through the morning and into the early afternoon. Westerly flow across the Cascade Mtns will result in enough downsloping off the higher terrain to keep KEAT and KMWH dry and VFR through Sunday night. Stronger winds aloft in the westerly flow will mix down by mid morning with gusts between 25-35 kts expected across the basin and into the Spokane Area and Palouse by the early afternoon. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 51 37 55 39 58 36 / 90 30 0 0 50 10 Coeur d'Alene 47 38 53 37 56 36 / 100 60 10 0 60 20 Pullman 46 37 56 42 58 37 / 100 40 0 0 50 20 Lewiston 53 40 62 44 64 42 / 20 20 0 0 40 20 Colville 54 35 56 36 57 35 / 60 10 10 0 40 20 Sandpoint 46 36 49 34 52 36 / 90 30 20 0 70 40 Kellogg 43 35 49 34 54 34 / 100 80 20 0 70 30 Moses Lake 61 37 62 43 62 38 / 30 0 0 0 30 10 Wenatchee 56 40 61 44 60 38 / 20 0 0 0 50 10 Omak 59 38 61 43 60 37 / 30 10 0 0 50 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$