857
FXUS65 KPIH 312016
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
216 PM MDT Fri May 31 2024

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT...
Weak ridging over the region today, tonight, and Sat AM will
continue to support dry conditions, mostly sunny/clear skies, fairly
modest winds, and high temps in the mid-60s to low 70s. Low temps
Sat AM should average 3-5 degrees warmer than what we saw this
morning, thus frost is not expected to be an issue (and hopefully
won`t be an issue again this spring). By Sat afternoon, a weak
shortwave trough crossing the Rockies will support increased clouds
and perhaps a few showers/t-storms, especially in our mntn areas.
The NBM continues to advertise a dry-leaning forecast for most,
while several of the HREF CAMs lean into much more shower/storm
potential, especially across the Central Mntns to the MT divide and
also across the srn highlands. Shower potential may expand
into/increase over the Snake Plain and ern highlands overnight into
Sun AM. None of this looks particularly heavy or long-lasting...in
fact most areas should be dry for most of the period...but we did
massage PoPs slightly higher to nudge toward the HREF concept.
Meanwhile, even with some additional clouds and a shower or two,
high temps Sat afternoon will generally gain another 6-10 degrees as
our warming trend continues, topping out in the 70s to near 80 for
most population centers. 01

.LONG TERM...SUNDAY THROUGH NEXT FRIDAY...
Very little has changed with the extended period from previous
runs, with continued good agreement via ensemble clusters.
Remnants of Saturday system continue weak chances for showers
mainly eastern highlands during the day Sunday, along with a
slight dip in temperatures and return to windy conditions. Monday
still appears to be the impactful day early in the period as
stronger shortwave trough shifts across Idaho with precipitation
onset late Sunday night. Almost all of East Idaho has at least a
35% probability of a wetting 0.10" rainfall, except right along
the Utah border and in the normally shadowed Arco Desert. Moving
the 24-hr accumulation up to 0.25" still results in at least 25%
probabilities most areas. The central mountains, particularly
across the Sawtooth and Frank Church areas are still showing >50%
probability of exceeding 0.50" of rainfall, which drops off
rapidly moving east, except around 35% chances in the Big Holes,
Tetons, and higher elevation areas surrounding Island Park. WPC is
maintaining the Marginal risk of Excessive Rainfall Monday for
the regions north of Sun Valley including Stanley and Challis.
There is still roughly a 15-30% chance of thunderstorms as well,
and thus those precipitation amounts could fluctuate with
localized convection. Snake Plain still looks windy Monday as
well, with NBM showing >30 mph across a large swath of the Upper
Snake Plain. Precipitation does continue into Monday night, and
lingers mainly across the Wyoming border Tuesday. Though, as ridge
begins to build on Tuesday, temperatures should start creeping
back up. Amplified ridge builds through the rest of the week,
though there are some cluster differences in where the ridge axis
sets up and how amplified it gets. Current NBM deterministic runs
put 80s back in lower elevations by Thursday, with more than a few
locations hitting 90 by Friday. NBM probabilistic values put a
>50% chance to hit at least 90 both days mainly west of American
Falls into the Eastern Magic Valley. DMH

&&

.AVIATION...
A ridge of high pressure today will keep winds light and mostly
clear VFR skies in place through tonight. DMH

&&

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

&&

$$