087
FXUS65 KPIH 272025
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
225 PM MDT Mon May 27 2024

.SHORT TERM...Tonight through Tuesday Night.
Early afternoon satellite imagery shows a H5 ridge axis of high
pressure directly over the Gem State which will continue to shift
east into Tuesday as temperatures see a warming trend and
conditions remain dry with plenty of sunshine. Highs in the
60s/70s on Memorial Day will increase by around 6-8 degrees on
Tuesday with the warmest day so far this year expected as highs
climb into the 70s/80s. High confidence (80-90%+) supports 5/6 of
our climate sites (all except Stanley) hitting that 80 degree
mark for the first time this year on Tuesday. When looking at
climatology, Tuesday May 28th will be in the top 10 latest first
80 degree dates for Pocatello, Burley, and Rexburg which goes to
highlight the overall, cooler than normal spring so far.

Changes begin tomorrow as a H5 low in the NE Pacific moves
onshore to WRN Canada and in the process, helps to reintroduce a
mix of isolated to scattered showers and thunderstorms starting
Tuesday afternoon and continuing into early Wednesday. The main
forcing mechanism for convection tomorrow will be a H5 shortwave
trough lifting NE out of Nevada and Utah as a reinforcing cold
front begins to build in overnight Tuesday helping to keep
precipitation chances going. While the convective environment for
Tuesday will only support around 300-600 J/kg of SBCAPE, elevated
0-6 km shear around 25-40 kts and steep 700-500 mb lapse rates
will support the potential for severe thunderstorms across the
Magic Valley northeast into CNTRL Mountains and Snake River Plain.
The primary hazards with stronger storms will center around wind
gusts in excess of 40-50 mph with the HREF model highlighting this
aforementioned corridor with a 70-90% chance of sustained winds >
30 kts and even a 10% hatch area around the Magic Valley for
sustained winds > 50 kts. As a result, look for downsbursts and
gusty outflow boundaries potential with stronger storms Tuesday
afternoon and evening.

Isolated showers and thunderstorms will continue overnight as a
cold front begins to move through Idaho out of the PacNW with the
main impact from that front being strong winds building in behind
it for Wednesday. Precipitation amounts through 6 AM Wednesday
will remain on the lighter side, generally in that T-0.10" range
with higher totals across NRN Custer County in that 0.10-0.30"+
range with locally higher totals dependent on convection. MacKay

.LONG TERM...Wednesday through next Monday.
Main impact Wednesday will be windy conditions mainly in the
Snake River Plain with widespread 20 to 30 mph sustained winds and
gusts over 40 mph. Will have lingering showers and thunderstorms
mainly in the eastern highlands where will be likely with isolated
further west through the Snake River Plain into the central
mountains. It will be much cooler with highs in 50s mountains and
60s valleys. Dry conditions will overspread southeast Idaho
Thursday through Sunday. Winds will die down Thursday but it will
be the coolest day of the long term with highs in the 50s mountain
to lower to mid 60s valleys. Will begin to warm with highs in the
60s to 70s Friday, then 70s and 80s by Sunday. Will be
occasionally breezy with strong zonal flow aloft. GK

&&

.AVIATION...For the 18Z TAFS through 18Z Tuesday.
Will be VFR with clear skies this evening and light winds. May
see convection and some thunderstorms near SUN by Tuesday
afternoon. After 18Z at the other sites expect convective activity
as well. Winds generally remaining light Tuesday with a
substantial increase Wednesday. GK

&&

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

&&

$$