891
FXUS65 KPIH 120928
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
328 AM MDT Sun May 12 2024

.SHORT TERM...Today and Monday.
High pressure overhead will keep conditions dry and pleasant for
another day as temperatures continue to warm. Only slight chances
exist for light showers in the Island Park region this afternoon and
evening. Otherwise, much of Southeast Idaho will observe mostly
clear skies throughout the day. Daytime highs will reach into the
mid to upper-70s in our low elevations, 60s in the highlands, and
50s in the mountains. The eastern Magic Valley could even break 80
degrees today as temps climb to around 10 to 12 degrees above
climatological norms. The ridge will begin to break down this
evening with a shortwave working through Idaho on Monday.
Precipitation chances will overspread the region Monday afternoon,
along with chances for isolated to scattered thunderstorms across
the entirety of the CWA. PoPs range 25% to 45% across the majority
of the area with around 50% to 70% chance along the MT Divide and
Island Park area. QPF amounts continue to look modest, with just a
few hundredths forecast across the low elevations, up to one tenth
in the mid-elevations, and 0.15" to 0.20" in the highest terrain of
the eastern mountains. Additionally, the cold front will bring
widespread breezy surface winds during the afternoon, ranging 20
to 30 mph with gusts 30 to 40 mph. We will continue to assess the
potential need for a Lake Wind Advisory for American Falls
Reservoir during this timeframe due to breezy southwesterly winds.
Cropp

.LONG TERM...Tuesday through next Sunday.
Expect another trough to move through northwest flow aloft late
Tuesday grazing mainly our eastern areas along the Wyoming border.
Expect light precipitation chances and breezy to windy conditions on
Tuesday. High pressure builds back in on Wednesday. Expect northerly
flow at least early Wednesday. For now, both the GFS and ECMWF
models are starting to agree on Thursday with the high pressure
ridging weakening some with an approaching wave. Though, high
pressure looks to prevail with dry conditions and just a slight up
tick in winds. On Friday models show a trough passing well east and
north of the area over northern Montana with weak ridging starting
to build in. Saturday weak ridging remains over the area. However,
from here models diverge. The GFS model shows a weak system moving
over northern Idaho. The ECMWF model shows a weak system dropping
down from Oregon into Nevada missing our area on Saturday. For
Monday, the ECMWF model shows an upper level low dropping into our
area. The GFS model has the same upper level low. However, this low
is much slower, coming over our area on Tuesday instead.

Temperatures will be near normal to slightly above normal on Tuesday
and Wednesday before rising to 8 to 12 degrees above normal Thursday
through Saturday. Sunday and Monday are less certain, but, for now,
look to be near normal if not slight below normal. Wyatt


&&

.AVIATION...High pressure will continue to dominate today. Expect
VFR conditions today with just a slight increase in winds along with
few low clouds and a few high clouds this afternoon. A trough will
move through late Monday bringing windy conditions and a slight
chance of precipitation. Wyatt


&&

.HYDROLOGY...A ridge of high pressure will bring drier and warmer
conditions to East Idaho for the weekend. High flows on area
water ways are expected to continue. The Portneuf and Blackfoot
rivers remain the water ways of concern, though there is some hope
that conditions may slowly be improving as water levels are
likely to slowly recede over the week ahead. McKaughan


&&

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

$$