633
FXUS65 KPIH 211001
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
401 AM MDT Fri Jun 21 2024

.SHORT TERM...Friday and Saturday
Relatively quiet, but hot, weather looks to continue across the
region today and into Saturday. Early morning satellite shows some
high clouds streaking over the region which will likely continue for
the first part of the day. As we get into the afternoon and evening,
a weak shortwave will swing through the area and could spark a few
isolated showers and thunderstorms across the far eastern portions
of the area. Hi-res CAMs do have some support for this but it looks
like activity will be very isolated and predominantly east of the I-
15 corridor. Temperatures will be warm, with valley highs in the
80s, maybe a few spots reach 90, with 70s in the mountains.

As the shortwave moves east into Saturday, weak ridging begins to
amplify over the area and this will turn up the heat even more for
the weekend. Current forecast has lower to mid 90s across the Snake
Plain and Magic Valley with 80s across the mountain zones. As we`d
expect with such warm temps, not expecting much in the way of cloud
cover. Temps look to stay warm through a good chunk of next week.
More on that below. McKaughan

.LONG TERM...Sunday through next Friday.
Under a well-defined H5 ridge of high pressure for Sunday, the
warmest temperatures so far this year are expected with highs
ranging from the mid 80s to upper 90s. These high temperatures are
about 10-20 degrees above normal for late June but with overnight
lows in the 40s/50s/60s, sufficient overnight recovery will help
to reduce HeatRisk concerns. As a result, there is the potential
for a low-end HEAT ADVISORY but have held off on any issuance at
this time. Near record to record warmth will be possible across
the Snake River Plain and ERN Magic Valley as well on Sunday. In
addition to the seasonably warm weather, winds will be on the rise
starting Sunday as a H5 trough moves onshore to WRN Canada. This
system will bring a dry cold front across SRN Idaho Sunday night
into Monday with gusty winds both days supporting gusts around
30-50 mph, peaking diurnally each afternoon. Behind that exiting
cold front, temperatures will cool by around 4-6 degrees for
Monday before climbing back up another 4-6 degrees on Tuesday
where highs will remain consistent through Wednesday/Thursday.

Dry, SW flow will continue to support very dry and seasonably warm
weather through much of next week with breezy winds each afternoon
as ensemble solutions point to the potential suppression of this
ridge feature late next week. The GEFS/EPS ensembles remain in
agreement around this time period, showing a H5 low in the NE
Pacific moving onshore to the PacNW and NRN Rockies around that
Thursday/Friday timeframe. As a result, the NBM temperatures begin
a cooling trend starting Thursday where they cool by around 4-8
degrees before dropping another 6-10 degrees on Friday. This would
leave highs on Friday in the 70s to low 80s which is right around
normal for this time of year. Little to no precipitation is
expected at this time with this system but a combination of
monsoon moisture building out of the SW CONUS and the trough
passage late next week will help to reintroduce isolated showers
and thunderstorms, mostly in the mountains. Warmer, SW flow looks
to fill in behind this exiting trough at this time for next
weekend with high temperature seeing a warming trend into the
start of July. MacKay


&&

.AVIATION...
For the 12Z TAFS through 12Z Saturday.
Predominant VFR and dry conditions will continue into early
Saturday y as a Pacific trough passes over the NRN Rockies. This
system will work to introduce a slight chance of showers and
thunderstorms this afternoon and evening with the HREF model
showing a 10-20% chance of thunder at KDIJ and a 10-20% chance
just east of KIDA and KPIH in the mountains. As a result, best
chances of convection will remain confined along southeast of the
Snake River Plain with less than a 10% chance of activity
elsewhere. Dry conditions will return regionwide for the weekend
as a ridge of high pressure shifts overhead. Winds through the TAF
period will range from light and variable to 6-12 kts with gusts
to around 15-20 kts. MacKay

&&

.FIRE WEATHER...
Main impacts will be some isolated thunderstorms this afternoon
mainly in zones 411, and 413. Coverage looks to be very isolated
however so most locations will remain dry. These dry conditions
will linger through Wednesday with very hot conditions as high
temperatures will run 10 to 15 degrees above normal. Minimum
humidity will be 10 to 20 percent through Wednesday as well. Next
chance for convection will be next Thursday mainly again in the
extreme east. Wind will increase substantially Sunday and will
have some breezy to windy conditions Sunday through next Thursday.
Wind speeds will be 15 to 30 mph most likely through that period
in the afternoons. McKaughan

&&

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

$$