Blackfoot, Idaho 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

286
FXUS65 KPIH 292016
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
216 PM MDT Thu May 29 2025

.KEY MESSAGES...

- Isolated thunderstorms and scattered showers expected this
  afternoon and tonight in the upper Snake River highlands.

- Warming trend will lead to near-record high temperatures on
  Saturday.

- A low entering the intermountain west on Sunday night will
  bring strong cooling and precipitation.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 140 PM MDT Thu May 29 2025

This period will turn very dry and hot for this time of year
after this evening. Right now, convection is starting to pop
up in the upper Snake River highlands and especially just north
of the ID-MT border. Cells are tracking southeastward and so
expect cells to move into the forecast area, tracking as far
south as the Big Hole mountains. There should be a strong slow
down around 1800 MDT, with convection shutting off after
midnight. Not expecting any issues with convection or
precipitation again until Sun afternoon. Incoming low pressure
still could be a closed low with moderate amounts of
precipitation and convection, or an open wave bringing moderate
to strong wind and lighter amounts of precipitation with
convection. But not a great chance of experiencing precipitation
on Sun afternoon, with slight chances everywhere except in the
Bear Lake basin.

Temperatures will be the highlight of this period. Guidance is
still forecast record-tying afternoon highs on Sat for Pocatello
airport. North wind in the upper Snake River plain may linger
long enough to prevent records in Rexburg and Idaho Falls, but
it will be close. With a nearly cloudless sky, expect large
temperature swings from morning low to afternoon high. Border
line Heat Advisory criteria were being met in Challis-Ellis, and
Malta-Almo areas, but very limited in extent. Temperatures cool
down on Sun thanks to increasing cloud cover from the incoming
low.

Under the high pressure, wind will be light, then on Sun it
should get at least breezy for the Snake River plain and eastern
Magic Valley.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Issued at 140 PM MDT Thu May 29 2025

Today`s theme for the long term forecast is: QPF whiplash.
Yesterday, the long term forecast looked cool and wet. While there
is still decent confidence in cooler (than Saturday) temperatures,
total moisture heading our way has significantly decreased. This is
main due to a change in models showing what is currently Tropical
Storm Alvin in the Eastern Pacific moving more eastward than
northeastward like they showed yesterday. The low they also showed
dropping south out of British Columbia is now more of a deep trough
instead of a closed low traveling almost directly over Eastern
Idaho. This has taken our forecast QPF totals of a widespread
quarter to half inch for valleys down to only a tenth of an inch and
our 1 to 1.25 inches in the mountains down to only a quarter to a
half inch. This is a significant drop, but we will really have to
watch and see how TS Alvin evolves and the direction it takes along
with the trough dropping out of Canada early next week and how
strong it will be. There is still agreement on a cool down with
highs falling into the low and mid 70s on Monday, mid to upper 60s
on Tuesday, and back into the low 70s by Wednesday. This isn`t quite
as dramatic of a drop as what had been in the forecast (due to the
same changes mentioned above with respect to QPF), and models still
have quite the range in temperatures for Monday through Wednesday,
so we will continue to play the "wait and see" game for now. The
second half of the week looks warmer and drier at this point.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1130 AM MDT Thu May 29 2025

VFR conditions are expected to persist at all sites throughout this
afternoon and evening. Winds will pick up slightly at BYI this
afternoon with gusts up to 20kts at times.  Once again, the best
chance for an afternoon storm will exist at DIJ with the 24-hr HREF
prob thunder showing about a 60 to 70 percent chance. However,
chances are increase a bit at PIH and IDA to around 30 to 50
percent, so have included a PROB30 at those 3 sites from 22Z this
afternoon to 03Z this evening. If a storm passes over a site, look
for gusts around 40 to 50 mph. Expect nearly a repeat on Friday,
though it should be a drier day with fewer thunderstorms.

&&

.FIRE WEATHER...
Issued at 245 AM MDT Thu May 29 2025

Above normal temperatures and mostly dry conditions will
continue through the start of the weekend, with isolated showers
and thunderstorms possible this afternoon ahead of dry
conditions back regionwide for Friday and Saturday. Highs
through the weekend will be about 10-20 degrees above normal for
this time of year in the 70s/80s/90s. Temperatures will peak on
Saturday, with record warmth expected. Aside from some isolated
showers and storms today, hot and dry conditions will be the
overall trend with humidities each day across lower elevations
dropping to the teens/20s, possible even into the single digits
on Saturday. Our next system remains on track to move in late
Sunday into Monday with colder temperatures, scattered showers
and thunderstorms, and mountain snow showers above around 8000
feet through Tuesday and Wednesday. By Tuesday, highs will have
dropped from near record to record levels on Saturday to the
40s/50s/60s. Precipitation totals will come into focus over the
coming days as model guidance continues to struggle on exactly
how this ridge of high pressure ultimately breaks down and what
ends up replacing it but confidence remains high on cooler
temperatures.

&&

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

&&

$$

SHORT TERM...Messick
LONG TERM...AMM
AVIATION...AMM
FIRE WEATHER...MacKay