395
FXUS65 KPIH 302024
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
224 PM MDT Thu May 30 2024

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT...
Weak troughing today...the wrn fringes of yesterday`s departing
storm system...will transition to weak ridging Fri. All of this
spells quiet wx with dry, mostly sunny/clear conditions and winds
trending lighter each day (still a bit breezy today) as well as a
warming trend as today`s 60s turn into tomorrow`s upper 60s to low
70s. Main impacts-based focus of the short-term forecast was looking
at low temps Fri AM, and it does indeed appear one more FROST
ADVISORY is needed up most of the Shoshone to Snake Plain corridor
(although excluding the Ern Magic Valley zone this time). Exact low
temps will be very borderline for frost formation...generally 32 to
36 degrees, so frost coverage may be quite patchy and will tend to
favor outlying areas west of our I-15 population centers where temps
will be coldest. However, did not feel comfortable holding without
the advisory and banking on all locales staying above freezing, not
to mention a few areas got 1-2 degrees colder than forecast last
night. The good news? This MIGHT be the last FROST ADVISORY we need
this spring! 01

.LONG TERM...SATURDAY THROUGH NEXT THURSDAY...
Overall pattern remains shallow and progressive through the early
part of next week, with good ensemble cluster agreement on both
depth and timing of upper flow. Weak shortwave drives through late
Saturday/Saturday night for potential showers through Sunday,
mainly across the north. Precipitation amounts remain low.
Breezy/windy conditions expected Sunday as well, along with
temperatures dropping to near normal levels after a very warm
Saturday. Stronger low shifts into the region Sunday night into
Monday, with much better chances of precipitation. NBM means
exceed 0.25" for a significant portion of the Central Mountains
through Monday night, with 90th percentile (1 in 10 chance of
exceedance) around an inch. Current deterministic values put total
precipitation for this event in the 0.25-0.75" range for a good
portion of the Sawtooth Rec Area/Frank Church regions, along with
a sliver of the Yellowstone region north and east of Island Park.
Although this is Day 5 of the extended, the clusters and ensembles
appear to be in good agreement with a persistent trend, though it
is worth noting that the 10th percentile (9 in 10 chance of
exceedance) keeps most areas dry. WPC has already preliminarily
brushed the central mountains in a marginal risk for excessive
rainfall for Monday, so this would be the highest confidence
period for the best chance at rainfall. Following this system, the
trend for Tuesday and beyond is for dry and turning warmer again,
as an amplified ridge slowly builds into the intermountain west.
Could lower elevations reach 90 for the first time this season?
The 6-10 and 8-14 day outlooks keep highlighting much above normal
temperatures, and the NBM spreads continue to point to at least
upper 80s. Stay tuned. DMH

&&

.AVIATION...
Breezy conditions continue for the Snake Plain terminals KBYI/KPIH/KIDA
today with sustained winds 15-20kts and gusts around 25kts. Winds
diminish overnight and remain around/below 10kts into Friday.
Expect generally clear skies with a few afternoon build ups, with
VFR CIGS. DMH

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 3 AM to 8 AM MDT Friday for IDZ051>054.

&&

$$