139
FXUS65 KPIH 131925
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
125 PM MDT Mon May 13 2024

.SHORT TERM...Tonight and Tuesday
An upper level trough moving through eastern Oregon and western
Idaho this afternoon has brought an end to our mostly clear skies
and dry weather. Afternoon satellite imagery continues to show
continued development of the CU field across the region with
already a handful of thunderstorms having developed. Hi-res CAMs
continue to point towards areas along the Nevada/Utah borders and
into the eastern Highlands as the primary area for precipitation
today, but valley locations will get in on the action as well. Not
expecting any widespread severe thunderstorm activity today but
some storms will certainly be capable of gusty winds to 40-45 mph
and maybe some small hail. In addition to the storms, winds have
picked up across a good chunk of the region as well and this will
continue through the daylight hours. Precipitation should begin to
diminish after sunset with precip free conditions expected
overnight.

A secondary shortwave will dip down across the region overnight and
into the early morning on Tuesday. This secondary shortwave will
spark additional shower and storm development on Tuesday. Tomorrow`s
activity will likely favor the eastern half of the region.  Similar
to today, not expecting anything severe but a stronger storm or two
will be possible. Temperatures tomorrow will run about 5 degrees
cooler than today`s highs as slightly cooler air moves in behind
today`s trough but still should run on the warmer side of average.
McKaughan

.LONG TERM...Wed through next Mon night
The upper level trough is still passing to the east Wed/Wed
night. This means the northwest flow will keep precipitation going
along the entire eastern highlands from MT to UT. The upper level
ridging behind the trough lasts 24 hours for a dry period. On
Fri, the upper level flow becomes flat. Most of the solution
clusters indicate dry flow, but 25 to 30 percent show some
possible troughing. This compares to the deterministic GFS showing
a strong trough punching up the winds very strongly with some
light precipitation. So I would put that Fri and thus beyond are
low confidence right now. And the clusters mostly agree with 45 to
55 percent indicating a wet pattern, and the rest (depending on
the day) indicating dry pattern. On Mon, there is little
consensus, with most indicating at least a chance for a wet
pattern. There is an upper level trough somewhere in the Pacific
Northwest are along the coast, possibly as far north as the BC
coast. Consensus temperatures are still at or above normal with
Thu a day when temperatures in eastern Idaho may easily reach 80
degrees. This may push river stages higher if there is snow
available in the river`s basin. Winds have good upper level
support to be elevated during this time if surface wind aligns for
westerly or northwesterly wind. Messick


&&

.AVIATION...
VFR conditions expected to prevail outside of any showers and
thunderstorms. Expecting precipiation to move across the region this
afternoon and evening as an upper level trough swings through the
area. Still not much in the way of confidence as to if/when any
impacts will be seen at terminals so will maintain VCTS wording for
now and add TEMPOs if confidence increases. Gusty SW/W winds also
being observed at KPIH, KBYI and KIDA and this will continue through
sunset. Precip and winds should diminish around 02-04Z with quiet
conditions expected for the overnight period. Additional
shower/storm development is possible once again Tuesday but will
likely be focused more across the eastern part of the region which
should keep KSUN and KBYI void of any precipitation concerns.
McKaughan

&&

.HYDROLOGY...
The Portneuf and Blackfoot rivers remain the water ways
of concern, though forecasts continue to trend down with water
levels throughout the upcoming week despite a very slight uptick
of water levels on the Portneuf River over the last 24 hours.
McKaughan

&&

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

$$