Area Forecast Discussion
Issued by NWS Pocatello, ID

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000
FXUS65 KPIH 220842
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
242 AM MDT Fri Mar 22 2024

.SHORT TERM...Today through Saturday night.
Will have a dry day today as upper ridge moves east over Idaho and
expect warm temperatures again with low elevation highs in the
upper 50s to lower 60s. It is not out of the question for an
isolated shower or thunderstorm very late this afternoon or early
evening but under 20 percent chance. Ridge moves east Saturday and
southwest flow aloft will allow Pacific moisture into Idaho and
rain and snow will spread west to east through the day and
overnight. Snow levels begin in the 6 to 7 thousand foot level
Saturday morning and drop to the 4 to 5 thousand foot level
overnight Saturday night into Sunday morning. Generally light snow
amounts are expected with 1 to 2 inches below 6500 feet with
localized 2 to 5 inch amounts above 7 thousand feet at pass level
through Saturday night. Will see a significant cool down Saturday
with low elevation highs dropping to the lower 50s and mountains
in the 30s and 40s. Lows Saturday night will range from the teens
to 20s mountains to the lower 30s in the Snake River Plain. So the
main impacts will be high elevation snow with most accumulation
above 6500 feet and may have snow covered roads especially at pass
level late Saturday.
GK

.LONG TERM...Sun through Thu night. This period starts with the open-
wave trough directly overhead, making the transition from the warm
sector of this winter storm to the cold sector. Wind aloft will
shift to the northwest with much weaker upper level support so wind
should be lighter. Snow levels will have dropped by the beginning of
this period to the floor of the eastern Magic Valley, with only a
slight rise to around 5000ft Sun afternoon, helping to make any
precipitation a sloppy mix of morning snow followed by rain. Overall
precipitation is lighter, so while there may be snow at lower
elevations, there is less available moisture for anything
significant, especially in the more heavily populated lower
elevations. The afternoon change over to rain below 6500ft continues
through the period.  A second trough late Sun night/Mon morning
continues the development of precipitation. Continued moist
northwest flow aloft favors precipitation on northwest-facing slopes
and the western slopes of the eastern highlands in general, and puts
a precipitation shadow, if anywhere, on the northwest side of the
Snake River plain. On Wed, there is a chance for things to ease up
with the upper level ridge axis moving overhead in some of the
clusters, but there are clusters that favor a return to a warm moist
flow from the southwest or a wet zonal flow, so it may continue wet,
and possibly get wetter, with not a lot of certainty after Tue
night. Messick

&&

.AVIATION...Expect a gradual deterioration in sky condition, with
CIGs developing by early evening in the western airdromes, and late
night hours tonight in the eastern airports. There is a less than 10
percent threat of precipitation for the late night hours tonight at
the end of the current TAFs. Thus there is no operational impacts
during the operational period today and this evening, but CIGs may
have an impact as airports open Sat morning. Wind at some airports
will reach 15KT, but gusts should be limited to 25KT or less. Messick

&&

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

$$


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