Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 070935

Area Forecast Discussion
National Weather Service Pocatello ID
235 AM MST Sun Mar 7 2021

.SHORT TERM...Tonight through Tuesday.

Dry weather is expected today as we await a larger
storm system for the week. Temperatures should be above normal once
again but with much less wind. A cold front will march through
central and east Idaho Monday afternoon into Monday evening. Most of
the precipitation will occur in the mountains and highlands.
However, this system is a little more moist so we expect to see more
precipitation in the eastern highlands than we saw with Saturday`s
system. Expect all snow in the central mountains with a rain/snow
mix in the Snake Plain and eastern highlands changing over to all
snow as the snow levels fall from 6000 feet to valley floors.
However, snow amounts look generally light with up to 2 inches
possible for the mountains and highlands. Maybe a dusting across the
Snake Plain during the overnight hours going into Tuesday morning.
Expect breezy conditions once again Monday. Expect unsettled and
cooler conditions for Tuesday as a broader low pressure system moves
onshore. Precipitation chances are better across the mountains and
highlands. But snow amounts continue to look light with additional
amounts on Tuesday and Tuesday night of an inch or so possible.


.LONG TERM...Wednesday through next Sunday night. Overall trends in
the long term portion of the forecast continue to point to less
active conditions. A broad area of low pressure is expected to be
positioned off of the central California coast by midweek. Model
consensus now tracks this low well to our south, as it is shown
lumbering eastward across the southern Great Basin into early next
weekend. The best chance for shower activity will be on Wednesday,
as a weak area of low pressure will drift southeast across Montana.
Snow shower activity will be mainly focused across higher terrain
areas, although a rogue shower could sneak into the Snake Plain.
Model consensus is reasonably well-clustered in their depiction of
the development of a high pressure ridge building across the region
Friday and Saturday, with a configuration resembling a Rex block.
There is some disagreement with how long this pattern remains in
place. Canadian and ECMWF camps opt to keep the ridge in place while
the GFS brings a "kicker" low pressure trough into the region by
Sunday. WPC cluster analysis reveals 59% of ensembles favor keeping
the ridge in place through day 7 -- and this makes sense as Rex
blocks tend to have some staying power. Nonetheless, the GFS
scenario can`t be totally discounted quite yet. All things
considered, the extended looks fairly quiet with seasonable



.AVIATION...Boundary layer saturation and stratus development was a
bit more robust than anticipated, as an area of stratus has been
observed expanding in coverage across the Arco Desert. The extreme
eastern edge  of the stratus shield resides near KIDA, where the
ASOS is currently reporting SCT008. Given that the edge of the
stratus is very near the terminal, expect fluctuations in cloud
coverage until the stratus mixes out by mid-morning. There is an
outside chance of stratus at KDIJ as well through mid-morning.
Otherwise, VFR conditions are expected. Upvalley SW to W winds in
the 5-10kt range will flip 180 degrees and become downvalley (NE-E)
by 15-18Z. Winds will become mainly variable at KDIJ by this time,
with typical mountain-valley circulation winds at KSUN.




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