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000
FXUS65 KPIH 160919
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
319 AM MDT Tue Apr 16 2024

.SHORT TERM...Today and Wednesday.
Looking at the current water vapor imagery, our area is in zonal
flow with an upper level low over southwest Canada. Models
continue to show this upper level low and associated cold front
over Canada to drop south today into Wednesday grazing our
northeast area by Island Park. This cold front and breezy zonal
flow will keep winds elevated for the Shoshone, Arco Desert,
Eastern Magic Valley, and the Snake Plain regions. Look for gusts
of 30 to 45 mph for these areas this afternoon. Winds will be
breezy for all areas with gusts of 15 to 25 mph outside of those
mentioned above. Also, look for 3 to 5 inches of snow for the
Island Park area (with 5 to 10 inches for high mountain areas)
tonight into Wednesday. The Upper Snake Plain, Beaverhead
Highlands, and the northern Eastern Highlands will likely see a
trace to 1 inch of snow. Also, patchy fog is possible across the
Upper Snake Plain, Upper Snake Highlands, and Eastern Highlands
this morning. However, breezy winds will keep fog from being
widespread. Temperatures the next couple of days will be on the
cool side for this time of year, 8 to 12 degrees below normal.
Wyatt

.LONG TERM...Thursday through next Tuesday.
As the low pressure system to our north along the US-CA border
rotates eastward, models feature some light, generally high-
elevation precipitation across our northern mountains which
translates to deterministic National Blend PoPs of 25% or less
Thursday afternoon and evening across the central mountains and
Island Park region. Outside of slight chances for light showers
along our borders with WY and MT, mostly dry conditions will persist
through the late week. Heading into the weekend, 500 mb ensemble
clusters feature some minor differences regarding how quickly the
upper low shifts east and a ridge shifts overhead from the west.
About 80% of all members feature predominate ridging over our CWA by
Saturday, with increased uncertainty heading into early next week.
For Sunday, deterministic models show dramatic differences regarding
the next Pacific Northwest low upstream, with about half of the
cluster members reflective of the more southern track of the low as
featured in the ECMWF and Canadian models. Even still, these models
show the closed low passing just to our north and at this time, the
NBM only contains minimal PoPs across SE Idaho through Monday,
increasing to as high as 40% by Tuesday afternoon. Although the
track of this next system will ultimately dictate our temperatures
too, the current forecast features a continuous warming trend
through the duration of the extended period, with the NBM bringing
the Snake Plain and Magic Valley into the upper 60s for daytime
highs by early next week.
Cropp

&&

.AVIATION...
Southwest and west winds will remain a bit breezy early today,
especially at KBYI, where sustained winds remain 15 to 20 kts with
gusts to 30 kts. Winds will increase again later morning and during
the afternoon at KPIH and KIDA as well, with sustained winds
generally ranging 15 to 25 kts. HREF model ensemble mean and
ensemble max wind values indicate gusts reaching 30 to 35 kts at the
three aforementioned terminals. Mid-level and high clouds will
increase again during the afternoon hours, as well. Expect rain and
snow showers to return tonight, with hi-resolution models indicating
up to a 20% chance of precipitation at KPIH by 6z tonight and then a
10% chance at KIDA and KBYI with 30% chance at KDIJ by 10z. Models
show precipitation chances increasing to around 30% at KPIH and KIDA
and 80% at KDIJ around sunrise Wednesday morning.
Cropp

&&

.HYDROLOGY...
Water levels on the Portneuf river continue to run high, just
below moderate flood stage for the Portneuf river in Pocatello.
The river forecast for the Portneuf river in Pocatello shows the
river running very close to these levels through Wednesday and
then start to gradually drop by Thursday but remain in minor
flood stage for the foreseeable future. Cooler temperatures this
week from cloud cover and a weak cold front will slowdown snow
melt which would cause the river to drop slightly.
Wyatt

&&

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

$$