682
FXUS65 KPIH 060903
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
303 AM MDT Mon May 6 2024

.SHORT TERM...Today and Tuesday
Our next round of precipitation is pushing through the region
already this morning. With it, rain and snow is expected with snow
likely the most dominant precip type once again despite the fact
that it is May. An upper low basically over the region will keep
temperatures well below normal once again today with highs in the
40s and 50s regionwide. Early this morning however, most spots are
in the 30s and with the freezing level just above the surface,
expecting snow for the first part of the day. Not expecting much
if any accumulations in the Snake Plain or Magic Valley with
marginal surface temps although some light accumulations on
elevated and grassy surfaces is certainly possible. We will see
accumulations however above 5500 feet or so in the eastern
highlands and Winter Weather Advisories remain in place into the
first part of the day Tuesday. 3 to 6 inches of snow is expected
in these areas with much higher amounts expected above pass
levels. A Winter Storm Warning continues in the Bear River Range
where 1 to 2 feet could fall in the next 36 hours or so.

In addition to the cold and snow, winds will also be an issue today
(and tomorrow) and a Wind Advisory continues for the Magic Valley,
South Hills and into the Arco Desert and lower Snake River Plain.
Winds in the 25-35 mph range are expected with gusts in the 40-50
mph range likely. Tuesday looks very similar as far as winds and
temps are concerned. Precip however will be more showery in nature
as things begin to dry out slowly as we transition back into a more
seasonal, warmer, drier pattern by mid/late week. McKaughan

.LONG TERM...Wed through Sun
Precipiation still on track to end Wed night, with high pressure
dominating the upper levels over the northern Rockies and northern
Great Basin from Thu morning to the almost the end of this
period. For Wed/Wed night, none of the precipitation from the
departing low will amount to 0.10 in any 24 hour period. The only
possibility would be enough warming and some unstable air that
afternoon/evening thunderstorms would be an issue. Thu and Sun
appear to be the current best likelihood days, and it is all
focused on the eastern highlands, from MT border to the UT border.
Just in time for Mother`s Day, a very weak shortwave breaks down
the upper level ridge over the Panhandle and the very northern end
of the forecast area. This may trigger some afternoon showers and
thunderstorms.

Another forecast challenge will be how the temperatures react to
sunny days, clear nights, and the occasional thunderstorm. Wed
continues very cool with a very cold start to the day and only
eking out the warmest elevations to the lower 50s. Overnight lows
will challenge the freezing point again for Wed night, then the
clear skies of Thu allow afternoon temperatures to soar 10 to 15
deg F above the previous day, though still below climatic normals.
Thu night and Fri are still the days we reach or surpass climate
normals, and the warming levels off to a gradual 1 deg F per day.
This is likely to do with the upper level pattern of easterly to
northerly airflow; thus the extended MOS guidance is trending
warmer than the NBM and other consensus guidance. Have gone the
the more gradual warming trend.

Breezy winds continue for portions of the forecast area Wed, then
some gusty northerly wind for Thu and Fri, and thus the slower rise
in temperatures. The southerly wind returns on Sat. Beyond Thu, the
winds really weaken and are not seen as an issue at all. Messick


&&

.AVIATION...
MVFR conditions likely to prevail for most of the first half of the
day as rain/snow push back into the region. In addition to the
precip, winds will be quite windy at KBYI, KPIH, KIDA and to a
lesser extent KSUN and KDIJ. Nevertheless, it should be an impact
day at all terminals across eastern Idaho. Precip early will likely
be in the form of snow with precip a transition to a mix or all snow
in the valley terminals by early afternoon. Could see some
thunderstorms as well later although chances are probably on the
lower end, kept in VCTS for now. Should see a bit of a break on the
precip by later in the evening but winds will remain elevated
through the period and into Tuesday.

&&

.HYDROLOGY...
Flooding has dropped to minor flood stage at the Portneuf River
at Pocatello potentially rising back into moderate flood stage in
a few days after all the precipitation falls over the next few
days. Either way, minor flooding is expected to continue here and
at Topaz. Flood warnings also remain in effect for the Blackfoot
River near Shelley at Wolverine Canyon with the river remaining at
flood stage and also near Blackfoot where the river remains in
flood stage. With more precipitation the next few days, rivers
will be to be monitored closely. McKaughan

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 6 AM this morning to 8 PM MDT this evening
for IDZ051-052-054>057.

Winter Weather Advisory until 6 AM MDT early this morning for
IDZ056-057.

Winter Storm Warning until 6 AM MDT Tuesday for IDZ060.

Winter Weather Advisory until 6 AM MDT Tuesday for IDZ062>066.

&&

$$