225 FXUS65 KPIH 201932 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 132 PM MDT Wed Oct 20 2021 .SHORT TERM...Tonight through Fri night. Some weak showers occurred this morning over some of the western zones, but they faded quickly in their easterly progression, with nothing left for the eastern 2/3 of the forecast area. So the next two days are quiet as a brief and low amplitude (thus weak) upper level ridge transits the area. In spite of the few clouds and the trough, temperatures will continue to warm. By Fri, afternoon highs in the Snake River plain will approach 70 def F, with low 60s even in the Stanley area. This is aided by the shift from westerly to southwesterly flow, which occurs right ahead of a major winter storm that begins its arrival Fri night in the western zones, so over mainly the central Idaho mountains and south central highlands. Expect increasing wind, which at the surface has already shifted to a southerly component, and by Fri night should be southwest to west. Messick .LONG TERM...Saturday through next Wednesday. The trend is still toward very wet and cooler conditions heading through the weekend and early next week. Concerns are showing up now as we might see this low split as it moves through the western U.S., which would definitely impact rain and snow amounts here in central and eastern Idaho. The GFS, ECMWF and cluster forecasts are showing some form of this happening. Snow levels remain pretty high until the biggest push comes through on Monday. Tuesday morning's forecast has them down to the valley floors in the central mountains, and between 5500- 7000ft (highest east of I-15) elsewhere. With the flow coming from the west and southwest, it appears favored areas will be portions of the Sawtooths, Boulder and Pioneer Mountains, the Montana Divide/Yellowstone-Teton border region and the Bear River Range. These areas could easily see 1-2" of rain/melted snow, which would equate to well over 1 foot of snow. Please note that these amounts are over 2-3 days total and will likely fluctuate quite a bit until we get closer to those days in question. The idea here though is that we will see a significant pattern change coming and many areas could see much needed precipitation. Winds will be breezy early next week, especially on Monday. With the potential split with the low, it appears for now the highest winds may be to our south. Keyes && .AVIATION...Quite a bit mid level cloudiness in the next 24 hours. The question will be if any showers impact TAF sites. For now, we are carrying VCSH at SUN only as the current forecasts indicate they may actually see precipitation in the area. That said, later amendments and TAFs may need to change to VCSH or -SHRA if we see indications of precipitation actually hitting the ground. Locally gusty south winds are possible at PIH and BYI, and potentially DIJ. Keyes && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$