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.
&&

$$