418 
FXUS65 KPIH 120939
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
239 AM MST Sat Dec 12 2020

.SHORT TERM...Today through Monday night. Upper low is currently 
positioned over the ID/MT border and should continue moving 
southeast. Light snow is seen on radar in northern Utah, and some 
lingering showers are continuing over the Upper Snake Plain north of 
HWY 20. Models suggest this activity will taper off this morning 
leaving us with some gradually clearing conditions throughout the 
day and tonight. By mid-day tomorrow, the next weather system will 
be knocking on our western border and expanding into the rest of 
southeast Idaho by Sunday evening. Most of the region will see some 
snowfall through Monday afternoon. The greatest accumulations look 
to be south and east of the interstates--about 3 to 6 inches in the 
Southeastern Highlands. Only about 1 to 3 inches in the Sawtooth 
Range. Hinsberger

.LONG TERM...Tuesday through Saturday. Unsettled pattern continues 
through the week. Operational GFS has transitioned back to prior 
solutions with train of shallow progressive shortwaves, similar to 
ECMWF solution. Tuesday should be best chance at a break in the 
pattern with upper ridge over the region. Ridge continues into 
Wednesday but models favor weak shortwave topping the ridge axis, 
still providing light snows to mainly higher elevations. Thursday 
should be arrival of deeper shortwave, but there are slight 
differences in timing between GFS and ECMWF with ensembles appearing 
to favor a blend between the two. Models then favor development of 
next ridge on Friday as upper trough digs into the central rockies. 
Finally, Saturday showing good agreement with next snow maker. 
Probabilistic snow favors the Thursday system as the best chances 
for more significant impacts, but even then, there is still higher 
confidence in minimal to moderate impacts at worst, likely due to 
the progressive nature of the system. Overall forecast favors some 
chances of precipitation nearly every day for most areas, but 
snowfall amounts look low enough to be minimal worry for travel 
impacts at this time. DMH

&&

.AVIATION...Wrap around band of snowfall continues to impact the 
upper portions of the Snake Plain and portions of the Eastern 
Highlands this morning, with greatest aviation impact at KIDA/KRXE 
and KDIJ with MVFR and occasional IFR ceilings/vsby. Further south, 
a few isolated pockets of very light SHSN have developed but so far 
ceilings and vis remain MVFR/VFR. A few pockets of lingering 
stratus may continue after sunrise, but otherwise expect conditions 
to improve through the day today as upper low shifts out of the 
region. With high pressure settling in overnight, there may be some 
concern for stratus/fog especially over areas with fresh snow cover. 
Approaching higher cloud cover ahead of next system may mitigate 
this, however. DMH


&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$