636
FXUS65 KPIH 080958
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
358 AM MDT Wed May 8 2024

.SHORT TERM...Today and Thursday.
There is an upper level low over the western Dakotas, which is
continuing to bring moisture mainly across our eastern areas in
northerly flow. To the west, there continues to be strong high
pressure ridging currently over the west coast.

For this morning, expect temperatures in the mid to low thirties
for all lower elevations across the Snake Plain/Arco
Desert/Eastern Magic valley. Thus, have continued the frost
advisory for these areas. Breezy northerly flow is coming down the
Snake Plain and Arco Desert, expect northerly gusts of 25 to 35
mph today. Some gusts will be in the mid 40 mph, especially
coming over the Montana Divide into the Arco desert. There is a
convergence line setting up over the Upper Snake plain and Driggs
area now. Models show this line moving very slowly south this
morning making it to the Lower Snake Plain and Southeast Highlands
by late morning/early evening. Models don`t show northerly winds
taking over the westerly winds in our western areas (Eastern Magic
Valley) by late afternoon/early evening. There is light snow
around 1 inch with up to 2 inches possible in the Upper Snake
plain. Snow levels look to rise and bring rain to the Lower Snake
plain by late this morning. However, if this convergence line
drops down more quickly, some light snow would be possible for the
Lower Snake plain. Most of the snow will be in the Big Hole
mountains and the Southeast Highlands with 2 to 5 inches of
additional snow likely this morning into this afternoon mainly
above 5500 to 6000 feet.

By Thursday, high pressure starts to build into our northern and
western areas. Expect breezy northerly winds to continue mainly
for the Arco Desert and the Snake plain. The Southeast Highlands
will still have lingering light snow and chances of fog in the
morning. Additionally, temperatures in the low to mid thirties
are expected again Thursday morning across our frost/freeze zones.
Another frost advisory will likely be needed for the same areas
Thursday morning as Wednesday morning. In the afternoon Thursday,
scattered showers and isolated thunderstorms, again mainly for
the Southeast Highlands, are likely with heating. Mostly dry
conditions are expected for our entire area by Thursday evening.

Today expect temperatures 10 to 15 degrees below normal and then
moderating some but still 3 to 6 degrees below normal by Thursday.
Wyatt

.LONG TERM...Friday through next Wednesday.
All models are showing high pressure build in across the area and
remain through the period bringing dry and warmer conditions.
Look for temperatures slightly above normal by Friday becoming 8
to 12 degrees above normal for the weekend into early next week.
Temperatures will be the warmest Sunday and Monday, upper 70s
across lower elevations and our southern areas. Both the ECMWF and
GFS model show weaker high pressure by late Tuesday and Wednesday
with a weak system dropping down Montana and Wyoming and grazing
our eastern areas. However, currently both models have slightly
different timing and intensity on this system.
Wyatt

&&

.AVIATION...A low pressure system to our east will continue to
bring rain and snow to our area, mainly our eastern areas today.
Expect breezy northerly winds for KDIJ and KIDA with gusts up to
around 25 kts. Breezy westerly winds are expected for KPIH and
KBYI before turning northerly by the afternoon. Expect snow
showers for KDIJ and KIDA bring MVFR and possibly IFR conditions
(especially KDIJ) this morning. By late morning into the early
afternoon light snow showers are possible for KPIH but will likely
be rain. MVFR conditions are possible for KPIH as well. KBYI has
a chance of MVFR conditions by late afternoon into the early
afternoon but will likely stay VFR all day. KSUN will see some
lower CIGS but will very likely remain VFR all day as well.
Wyatt

&&

.HYDROLOGY...Portneuf and Blackfoot remain the rivers of concern
in East Idaho, though high flows also continue on the Snake River.
Showers continue through today mainly impacting the eastern half
of the forecast area with generally light precipitation. Very cool
temperatures today begin to moderate some by later today, then
begin to warm significantly into the weekend. For now, weekend
high temperatures look to generally be in the 70s at lower
elevations, so expect snowmelt to restart. Forecast flows remain
high for the Portneuf:
Minor Flood for the gage at Pocatello, and fluctuating right at
Minor Flood for the gage at Topaz. Given the fluctuation,
simplified the wording and continued the flood warning until
further notice for that gage. Similar conditions exist for the
Blackfoot, with the river expected to remain at or fluctuating
right around Minor Flood Stage.
DMH

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 9 AM MDT this morning for IDZ051>055.

&&

$$