037
FXUS65 KPIH 052025
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
225 PM MDT Wed Jun 5 2024

.SHORT TERM...Today through Thursday Night.
Early afternoon satellite imagery shows a H5 ridge of high
pressure over the WRN CONUS which will continue to lead to a
warming trend through the weekend across SE Idaho as conditions
remain mostly dry. Courtesy of 25-40 kt 700 mb winds aloft, winds
remain elevated regionwide with observed gusts around 25-45 mph of
which are currently strongest across the Shoshone/Arco/Mud Lake
Desert. A LAKE WIND ADVISORY will remain in effect through this
evening for American Falls Reservoir as a result. Winds will begin
to subside overnight tonight with lighter winds in the forecast
for Thursday as a H5 ridge axis shifts overhead, keeping wind
gusts at or below 25 mph associated with lighter 700 mb winds.
High temperatures today will be in the 70s/80s in the valleys
and will warm by another 6-10 degrees for Thursday, bringing
highs up into the 80s/90s which is about 15 degrees above normal
for early June.

While this H5 ridge feature will remain the dominant feature
overhead through Thursday night, a H5 shortwave trough lifting NE
out of Nevada will help to introduce isolated showers and
thunderstorms starting Thursday afternoon which will continue
through the overnight hours. The convective environment Thursday
will support 300-600 J/kg of SBCAPE, 25-35 kt of 0-6 km shear,
and 7-9 degree/km 700-500 mb lapse rates, supporting the primary
threat tomorrow with stronger storms centered around dry
microbursts and gusty outflow winds with gusts in excess of 40-50
mph. The emphasis on these storms will be across the Magic Valley
and Snake River Plain south to the Utah border where the HREF
probability of sustained winds greater than 34 mph shows a 30-70%
chance, indicative of wind gust potential greater than 40-50 mph.
Convective initiation will begin around 2-6 PM across SW/CNTRL
Idaho before storms lift NE across the Snake River Plain through
the evening hours. Isolated showers will then be possible
overnight south/east of the Snake River Plain as unsettled weather
continues into the weekend. MacKay

.LONG TERM...Friday through next Wednesday.
The heat is on for Friday and through the weekend with highs
still expected to be in the mid 80s to mid 90s through the Snake
Plain and Magic Valley with Saturday being the hottest day of the
three. Granted, the Friday and Sunday are only "cooler" by a
couple of degrees each afternoon. In addition to the heat, we will
see thunderstorm potential each afternoon, too. Both the ECMWF
and GFS show a weak shortwave passing through the area on Friday,
which will be the driving force for about a 10 to 20 percent
thunderstorm chance in the Southern Hills, Snake Plain, and
Eastern Highlands. As a transient ridge moves through on Saturday,
that will hamper our storm chances a bit, but afternoon heating
will provide a small bit of instability so most will stay dry, but
an isolated storm or two can`t be ruled out. A cold front passing
through on Sunday will provide a 20 to 30 percent chance of
storms across all of eastern Idaho. This will cool our
temperatures just a bit for Monday, knocking highs down by about 5
degrees. Don`t worry, the upper 80s to low 90s look to be back by
Wednesday! AMM

&&

.AVIATION...For the 18Z TAFS through 18Z Friday.
The rest of today will be nearly a repeat of yesterday with
mostly sunny sky conditions through the rest of the day and breezy
winds. Gusts through the evening at BYI, PIH, and IDA will range
from 25 to 30 kts with gusts closer to 20 kts at SUN and DIJ.
Gusts will back off overnight and be lighter overall on Thursday,
near 15 kts at all sites. It will be dry through the first half of
Thursday with a 10 to 20 percent chance of showers and storms in
the evening. AMM

&&

.FIRE WEATHER...
Seasonably warm and mostly dry weather will continue into early
next week courtesy of a high pressure ridge overhead as a series
of shortwave troughs pass through the region starting tomorrow
through early next week. This will help reintroduce isolated
showers and thunderstorm chances starting Thursday with an
emphasis on gusty outflow winds with stronger storms. High
temperatures each day through midweek next week will be in the
70s/80s/90s in the valleys and 50s/60s/70s in the mountains.
Elevated winds today with gusts around 25-45 mph will subside
starting tomorrow with an emphasis on convective stronger gusts as
synoptic wind gusts stay at or below 30 mph each day. MacKay

&&

.HYDROLOGY...
The flood warning continues for portions of Teton county as small
streams/creeks continue to run high. While levels have dropped
just slightly from yesterday, the increased flooding risk still
exists as snowmelt from the Tetons will feed into these creeks and
streams as temperatures continue to warm over the next several
days. The Teton River is also running at an elevated level and is
currently forecast to hit action level overnight while nearly
reaching minor flood level by Friday afternoon. AMM

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 8 PM MDT Wednesday for IDZ054.

Flood Warning until 4 PM MDT Friday for IDZ065.

&&

$$