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FXUS65 KPIH 142043

Area Forecast Discussion
National Weather Service Pocatello ID
243 PM MDT Mon Oct 14 2019

.SHORT TERM...Today through Thursday. There is a dry, weak wave 
passing to our northeast over Montana and Wyoming currently.
Expect just breezy winds over the area, mainly this afternoon.
Lakes will have choppy waves for those that may still be venturing
out. Tomorrow high pressure ridging builds over our area bringing
continual above normal temperatures and overall clear skies. By 
Wednesday expect a breezy southwest flow ahead of a system moving 
through on Thursday. Temperatures will be around 8 to 12 degrees 
above normal on Wednesday. Relative minimum humidities will be 
low through Wednesday as well, 10 to 20 percent for lower 
elevations and 20 to 30 percent for higher elevations. TW

.LONG TERM...Thursday through next Monday. Thursday models
continue to be in good agreement bringing in a cold front Thursday
night into Friday morning. Expect breezy to moderate winds and 
around 1 to 2 inches of snow for the extreme northwest areas by 
the Sawtooths. Otherwise, expect around 1 inch of snow for our 
northern areas, mainly along the Montana divide above around 7000
feet later Thursday. Snow levels drop Friday morning to around 
4000 to 5000 feet. However, models are having a tough time 
deciding on when the best precipitation chances are. The GFS model
shows zonal flow with light snow over the western Central 
mountains and the Eastern Highlands along the Wyoming border on 
Friday. The ECMWF model shows dry conditions on Friday. However, 
the ECMWF model then shows moderate snow above around 5000 to 5500
feet later Saturday, while the GFS is focusing on the Sunday 
morning with slightly lower snow levels of around 4000 to 4500 
feet. Have gone more in line with ECMWF model for now. Expect 
breezy to moderate winds on Friday, Saturday and Sunday as well. 
Will continue to hone in on the timing and amounts/impact as model
signals become more clear in the next day or two. For Monday both
models show high pressure building in with lingering 
precipitation in breezy northwest flow. TW


.AVIATION...VFR conditions are expected through the forecast period, 
with just a few patches of mid and high cloud cover through 
tomorrow. A passing low pressure trough will promote breezy 
conditions through about sunset (00-01Z) this evening, with W/SW 
winds in the 10-20kt range with occasionally higher gusts at PIH, 
IDA and DIJ. A bit more uncertain at SUN, as the strength of the 
trough is only borderline in terms of its ability to override the 
typical terrain-driven SE winds in the afternoon. Have maintained 
the current forecast which includes a TEMPO group of 28012G20kt from 
22-02Z this evening. Confidence is low on this as winds may maintain 
their typical SE terrain-driven flow until just past sunset when 
flow becomes down-valley. VFR conditions expected through Tuesday 
with mainly light-terrain driven winds at or below 12kt at all TAF 
sites. AD



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