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000
FXUS65 KPIH 180722
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
122 AM MDT Thu Apr 18 2024

.SHORT TERM...Today and Friday. We will one or two more rounds of
showers, as very weak "waves" drop southeast along the Divide. A
few pockets of flurries may still be around at sunrise, as the
convergence band has been stubborn to dissipate. As we get into
this afternoon and evening, isolated showers are expected across
the central mountains and along the Montana border toward Monida
and Island Park. Don`t be surprised even with warmer
temperatures, we see some rain mixed with snow and/or graupel. We
could see a few showers elsewhere over higher terrain, but the
chance is well under 10%. We MAY see a repeat for Friday, although
that potential looks less certain. We did maintain a 10-ish
percent chance in the same areas. Temperatures today remain on the
cool side, with 40s and 50s in the valleys. Friday looks warmer,
on the order of 5 degrees across the board. Overnight will remain
on the cold side, which will help slow down any ongoing
snowmelt/runoff issues.  Keyes

.LONG TERM...Saturday through next Thursday.
High pressure will build in from the West on Saturday, allowing for
a continuation of dry conditions area-wide. On Sunday, deterministic
models show the next closed low passing to our north across Canada
with the associated trough across the ID panhandle and zonal flow
over southern Idaho, making for a breezy to windy day across all of
SE Idaho. At this time, the NBM only introduces PoPs across the high
terrain on Sunday. Different from previous runs, the GFS is slower
to shift the upper low eastward and is now more in line with the
ECMWF timing. The impacts of this looks to be minimal PoPs in the
Tetons/Island Park region on Monday as the system continues shifting
eastward and both models now show the ridge axis shifting overhead a
day later, meaning mostly dry conditions persisting through Tuesday
now. Temperatures will follow a continuous warming trend during this
timeframe. The NBM features daytime highs right around
climatological norms late this week but then warming to well above
normal by early to middle of next week, with forecast highs in the
low 70s across the Snake Plain and Magic Valley, 40s in the
mountains, and 50s in mountain valleys. As the next closed low
approaches the Pacific Northwest coast, models feature a shortwave
moving onshore and impacting SE Idaho late Tuesday into Wednesday,
marking the beginning of an active pattern with widespread
precipitation chances by Thursday of next week. This aligns well
with the Climate Prediction Center`s outlooks for closer to normal
temperatures and above normal precipitation. Cropp

&&

.AVIATION...Winds will be much lighter today, generally 8 kts or less. While the
high terrain could see some very isolated showers, any precipitation
is expected to remain north of all terminals today. Considering the
saturated lower levels of the atmosphere, the National Blend model
does include around a 10-20% probability of IFR or LIFR CIGs at KDIJ
and as high as a 15% chance at KIDA throughout the morning. Any
remaining mid-level and high clouds will continue to scatter today,
leaving FEW to SKC by late tonight/early Friday. Cropp

&&

.HYDROLOGY...Water levels on the Portneuf river continue to run high, just
above moderate flood stage for the Portneuf river in Pocatello.
The river forecast for the Portneuf river in Pocatello shows the
river running above flood stage for the foreseeable future. At
Topaz, levels remain and are forecast to remain very near minor
flood stage for the rest of the week. McKaughan

&&

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

$$