Bancroft, Idaho Weather Forecast Discussion

920
FXUS65 KPIH 200341
AFDPIH
Area Forecast Discussion
National Weather Service Pocatello ID
941 PM MDT Fri Sep 19 2025
.KEY MESSAGES...
- Average to Above Average Temperatures Continue Through the
  Weekend
- Virga Possible Today, Although A Few Sprinkles Possible
- Showers and Storms Over the Weekend, Especially Sunday
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 105 PM MDT Fri Sep 19 2025
Monsoon moisture is still increasing and will continue to do so
through the weekend. The potential for any type of shower or
thunderstorm develop is fairly slim through tonight. Any real
threat will be across the South Hills and Albion Mountains.
Elsewhere any chance is 10% at best, and most likely wouldn`t be
much more than sprinkles. The threat of gusty thunderstorm
winds, or any increase in wind is really low. The chance
increases tomorrow, especially south of a Driggs to Hollister
line. Most showers and storms will produce light rain, but where
stronger storms develop or we get multiple storms over the same
location...moderate rainfall accumulation is possible. There is
a 10-20% chance of more than 0.25" across the South Hills,
Albion Mountains, and southeast highlands. There is a 5-10%
chance of seeing more than 0.50 in the same areas.
&&
.LONG TERM /SATURDAY THROUGH FRIDAY/...
Issued at 105 PM MDT Fri Sep 19 2025
The best chance of showers and storms areawide will be Sunday,
and eastern areas on Monday. There is better agreement today on
what happens with the closed low early next week, which is to
close it off east of the Divide. We will see a decent amount of
moisture with the storm as it develops. Most of the
precipitation falls in higher elevations with this storm. There
is 15-35% chance of more than 0.25" in the central mountains and
up to 50-60% in the eastern and southeast highlands. The
potential for over 0.50" peaks between 20-50% along and east of
I-15 through Monday morning. Those chances are in a given 12
hour period anywhere from 6am Sunday - 6am Monday. Showers and
storms will linger east of I-15 Monday, but Tuesday and
Wednesday looks dry as high pressure rebuilds for a short time
over our area. The end of next week COULD be showery again. The
Blend of Models follows the trend of the GFS and ECMWF, which
brings a closed low far enough north to increase clouds and kick
off some showers and storms. Temperatures are trending much
cooler for Monday. Valley highs are now only expected to be in
the mid to upper 60s, which is 5-10 degrees BELOW AVERAGE. We
should rebound quickly next week and push back above average for
the end of September.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 927 PM MDT Fri Sep 19 2025
Low approaching from the south will bring on and off cirriform
CIGs tonight, then in the morning a low to mid- level cloud deck
should start moving in, first seen at KBYI and KPIH, then by
mid-day at KIDA, KDIJ, and KSUN. TSRA and SHRA will develop
during the afternoon or early evening, beginning at KBYI and
KPIH. These are the only airdromes that appear to be threatened
with thunder. KSUN and KDIJ have a threat of showers, with KSUN
in the evening (due to the low) and KDIJ in the afternoon (due
to afternoon heating). Only KIDA appears to avoid precipitation,
at least in the afternoon and evening. No impact to VSBY is
expected, and the risk of TSRA just barely rises to the PROB30
level.
Wind will not be as light, driven by slope-valley or just
variable in direction. Only KSUN appears to have the slope-
valley wind, and then just for the morning and early afternoon. A
southerly component should kick in during the day on Sat for the
other airports. Outside of TSRA, wind should not exceed 12KT.
For thunderstorm outflow, there is not upper level support for
any moderate to strong outflow, so have put in a minimum of
15G30KT.
&&
.FIRE WEATHER...
Issued at 105 PM MDT Fri Sep 19 2025
Despite the cloud cover across the region, little to no
precipitation is expected today, even across the south where the
"chances" are best. Maybe a sprinkle this afternoon and evening.
Chances increase for Saturday, and again on Sunday as a surge of
moisture moves in and a Pacific shortwave shifts inland. Sunday
would be the better chances of measurable precipitation, with higher
elevation regions seeing a 25-35% chance of a wetting rain. Those
chances rise to 35-45% east of I-15 for Sunday evening and overnight
as the frontal system associated with the low shifts through the
region. Following the frontal system, temperatures will be below
normal for Monday, with most lower elevation highs in the mid 60s-
low 70s. A ridge of high pressure building into the region Monday
through at least Wednesday should keep the region dry. There is
quite a bit of uncertainty after midweek with respect to breaking
down the ridge and allowing another system into the state, but for
now any precipitation chances look isolated at best to round out the
week.
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Keyes
LONG TERM...Keyes
AVIATION...Messick
FIRE WEATHER...DMH

NWS PIH Office Area Forecast Discussion