547
FXUS65 KPIH 130753
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
153 AM MDT Mon May 13 2024

.SHORT TERM...Today through Tuesday.

A pair of shortwave troughs will work through this afternoon and
Tuesday afternoon. This will help fire off scattered thunderstorms.
The first shortwave is a bit deeper and the consensus of high res
models shows two main west-east areas for storms developing this
afternoon. The first area is from Custer County east across the
lower and upper snake Plain into the upper Snake highlands. The
second area is roughly across the southern and southeastern
highlands. So the Magic Valley up into Blaine County looks like an
isolated threat this afternoon. Storms are not expected to be
severe, although there looks like there could be enough instability
that a few wind gusts over 40 mph could be possible along with some
small hail. In addition to storms, we are expecting breezy
conditions today. Winds look marginal for a lake wind advisory with
about a 40 percent chance of reaching 20 mph sustained for 2 or more
hours on American Falls Reservoir. So will probably hold off on a
lake wind advisory at this time. Temps look mild once again with
most highs in the Snake Plain and Magic Valley in the mid 70s with
60s common in the valley locations of the mountains and highlands.

On Tuesday, the second shortwave trough arrives. This one is a
little more shallow with better chances across the upper Snake Plain
and Upper Snake highlands. Coverage looks more isolated elsewhere.
Once again, not expecting severe weather but some gusts over 40 mph
and small hail are possible with the stronger storms. Winds on
Tuesday look a little lighter and the probability of reaching lake
wind thresholds falls to 20 to 30 percent. Temps on Tuesday with
cooler air filtering in behind the first shortwave are about 5
degrees cooler with highs around 70 in the Snake Plain and Magic
Valley and generally lower to mid 60s for most of the valleys in the
mountains and highlands. Although there are some indications that
the highs around Challis could overachieve somewhat.

13

.LONG TERM...Wednesday through next Monday. We should be mostly dry
for the middle and end part of the week. A few showers or storms are
certainly possible along the Divide and Wyoming border. Temperatures
will be right back to near 80 across portions of the Snake Plain,
Magic Valley and southern valleys. Just as quick, we switch back
into another deepening area of low pressure across the West. While
there are differences in where this low sets up, the general idea is
supported by around 75% of the cluster forecasts.  The weekend looks
5-15 degrees cooler, breezy, with showers and thunderstorms around.
Keyes

&&

.AVIATION...Main problem today is thunderstorm coverage this
afternoon. Looks like best chances for storms is around IDA and DIJ,
but storms may be around at the other sites as well. BYI looks less
likely to see storms although they may see convective outflows from
storms trekking through the south hills. Erratic wind gusts to 40
kts are possible near storms. Outside of storms, expect breezy
conditions with sustained winds of 15 kts and gusts to 25 kts likely
at many locations. Most likely looking at a crosswind developing at
KSUN this afternoon with gust potential to 20 kts although
confidence in the gusts is less and not sure if will include in 12z
tafs or not.

13

&&

.HYDROLOGY...The Portneuf and Blackfoot rivers remain the water ways
of concern, though forecasts continue to trend down with water
levels throughout the upcoming week. McKaughan/13

&&

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

$$