889
FXUS65 KPIH 091500
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
900 AM MDT Thu May 9 2024

.UPDATE...
Allowed the FROST ADVISORY to expire on-time at 9 AM as
temperatures across the advisory zones have generally risen above
40 degF. No changes to the WIND ADVISORY. We will be evaluating
whether or not another FROST ADVISORY will be needed for a zone or
two tonight over the next several hours, although an overall
warming trend has begun in our wx pattern. - KSmith

&&

.PREV DISCUSSION... /issued 351 AM Thu May 9 2024/

SHORT TERM...TODAY THROUGH FRIDAY NIGHT...
There is broad troughing from the Dakotas to Utah with a low
centered over the western Dakotas and one centered over southeast
Utah. There continues to be strong high pressure ridging off the
Pacific coast with a ridge of high pressure folded over the Canada
and United Sates border. There is currently high pressure and dry
air over our northern areas and weak instability and moisture
over our southeast areas.

Expect cool temperatures in northerly flow today. A frost advisory
remains in effect for the Shoshone, Eastern Magic valley, and
Upper Snake Plain for this morning with temperatures in the low
30s to mid to upper 30s. There continues to be breezy northerly
winds dropping down the Snake Plain, especially the Arco desert
where a wind advisory remains in effect for gusts near 40 to 45
mph. Look for isolated to scattered showers and isolated
thunderstorms for our Southeast Highlands this afternoon as the
area heats up. There is a 20 to 40 percent chance of thunderstorms
mainly across the Utah border. However, little if any accumulated
rain and high mountain snow is expected for today. Temperatures
will rise to near normal today.

By Friday, expect mostly clear skies, dry conditions, and even
warmer temperatures, 4 to 8 degrees above normal. A frost advisory
may be needed again Friday morning but mainly for the Arco desert
and the Snake Plain. The low pressure in Utah might bring enough
moisture and instability to our extreme southeast areas by Bear
Lake, but it is not that likely. - Wyatt

LONG TERM...SATURDAY THROUGH NEXT THURSDAY...
Look for very nice conditions, mostly clear skies, and warmer
temperatures through the weekend into Monday with high pressure
ridging folding southward over into the area and building in.
Temperatures will be in the 70s across the area for daytime highs
Saturday through Monday. A few areas by Shoshone may even hit 80
degrees. This is about 10 to 15 degrees above normal. By late
Monday into Tuesday, both the GFS and ECMWF models show a system
clipping our eastern areas dropping south out of Montana into
Wyoming. Expect breezy winds and clouds with a chance of overall
light precipitation mainly along the Wyoming border. Temperatures
look to be around 3 to 6 degrees above normal still. From here,
models completely diverge, the ECMWF model brings back high
pressure Wednesday into Thursday with dry and warmer conditions.
In contrast, the GFS model brings another system over our northern
areas late Wednesday into Thursday bringing breezy winds and a
chance of precipitation as well as cooler temperatures. - Wyatt

AVIATION...
High pressure will keep KSUN and our northwest areas dry today.
Instability and moisture from a low just our south over Utah will
bring the chance of afternoon showers for all other sites. There
is a chance of isolated thunderstorms mainly south of KBYI and
KPIH. However, there is still a 10 to 20 percent chance of
thunderstorms on station for KBYI and KPIH this afternoon. Have
just put in vicinity showers for all TAFS but KSUN. Have left out
vicinity thunderstorms for KBYI and KPIH for now. Otherwise,
expect breezy northerly gusts of 20 to 25 kts by mid to late
morning extending into the afternoon for all TAF sites except
KSUN. There is a chance of wind shear early to mid morning today
mainly for KPIH. - Wyatt

HYDROLOGY...
Recent precipitation and warming temperatures are expected to
influence East Idaho waterways in the coming days. Whatever
snowfall was realized recently at mid-slope is likely to melt off,
and temperature profiles support some snow melt at higher
elevations. Flood Warnings remain in place for the Blackfoot and
Portneuf rivers. High, fast, and cold flows are expected to
continue and/or increase on other waterways. As the conditions
turn warmer and drier, people recreating on/near East Idaho
rivers and streams are urged to remain cautious, and keep children
and pets away from the water. - DMH

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 PM MDT this evening for IDZ052.

&&

$$