Special Weather Statement, NWS Pocatello, ID

Area Forecast Discussion
National Weather Service Pocatello ID
318 AM MDT Mon Aug 2 2021

.SHORT TERM...Today through Wednesday.
Little change in forecast today as high moisture content remains
over Idaho and expect another round of afternoon showers and
thunderstorms with localized very heavy rain expected. An embedded
upper level system in the flow is expected to concentrate the
heaviest rain today in the eastern mountains but anyone could see
a thunderstorm with heavy rain through the day. Flash Flood
watches remain in effect through 9 pm tonight for all mountain
areas with significant terrain enhanced effects possible. Expect
high temperatures will below normal today with clouds and rain
again limiting their rise. Expect significant drying Tuesday into
Wednesday with showers limited to the far eastern highlands
Tuesday and only isolated central mountain coverage Wednesday.
With the drying, high temperatures will be back to near normal
range by Wednesday with low elevations reaching 90 degrees or
higher in many areas.
GK

.LONG TERM...Thursday through Monday.
A more significant Pacific trof and associated cold front will
spread more widespread showers and thunderstorms into southeast
Idaho Thursday into Friday. Expect breezy conditions both days as
the front works east. Also expect a big cool down on Friday with
below normal highs returning with highs in the 70s and 80s. Expect
mainly dry conditions Saturday through Monday with cooler
conditions expected to continue with a weak upper level trof over
the region. Could see continued breezy conditions through the
extended with decent westerly flow continuing.
GK

&&

.AVIATION...One more day of deep moisture expected for East Idaho
today.  Pattern has generally been thunderstorm development during
the afternoon and evening hours, with showers outside of those
times. We are starting to see the beginning of a drier flow push
into the western portions of the forecast area this afternoon, so as
we move into the later portions of the day, the threat for TS/SH at
KBYI/KSUN begins to weaken. That drier air works across all of East
Idaho overnight, so though a few thunderstorms may still be possible
headed into Tuesday especially for KPIH/KIDA/KDIJ, the heavy rain
threat is drastically diminished. DMH

&&

.FIRE WEATHER...Heavy rain threat continues for one more day before
drier air begins to push monsoonal flow off to the east. Showers and
thunderstorms remain forecast for today, then only across eastern
portions of the East Idaho fire district for Tuesday. With high
pressure in place for Tuesday, expect a rebound in temperatures and
humidities back toward seasonable levels. A system pushes into the
PacNW states Wednesday, and there is a threat for isolated showers
and thunderstorms mainly across the central mountains. That spreads
across the rest of East Idaho for Thursday. Any of this activity
should be a mix of wet and dry, but certainly less productive as far
as rainfall is concerned than we have seen the past several days.
The next system drives across the region for the weekend, with a
few thunderstorms across the Salmon-Challis and Targhee NFs, but
gusty winds could be a concern. DMH

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through this evening for IDZ056>064-069-
071>074.

Flash Flood Watch from noon MDT today through this evening for
IDZ065>068-070.

&&

Special Weather Statement
National Weather Service Pocatello ID
1146 AM MDT Mon Aug 2 2021

IDZ060-061-021845-
Bear Lake Valley ID-Bear River Range ID-
1146 AM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL BEAR LAKE COUNTY
UNTIL 1245 PM MDT...

At 1145 AM MDT, Doppler radar was tracking a strong thunderstorm near
Bear Lake Idaho Portion, moving east slowly.

Gusty and erratic winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Bear Lake Idaho Portion, Saint Charles and Fish Haven.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

If on or near Bear Lake, move to safe shelter now! Do not be caught
on or near the water. Gusty winds and choppy waves are likely.

&&

LAT...LON 4212 11149 4212 11124 4200 11124 4200 11150
TIME...MOT...LOC 1745Z 283DEG 7KT 4202 11142

TAX

Special Weather Statement
National Weather Service Pocatello ID
1235 PM MDT Mon Aug 2 2021

IDZ062-021915-
Blackfoot Mountains ID-
1235 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL CARIBOU...SOUTH
CENTRAL BONNEVILLE AND SOUTHEASTERN BINGHAM COUNTIES UNTIL 115 PM
MDT...

At 1234 PM MDT, Doppler radar was tracking a strong thunderstorm 10
miles north of Chesterfield, or 11 miles northeast of Chesterfield
Reservoir, moving east at 15 mph.

Half inch hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Blackfoot Reservoir, Henry and Cutthroat Trout Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

If on or near Chesterfield Reservoir, Move to safe shelter now! Do
not be caught on or near the water. Gusty winds and choppy waves are
likely.

&&

LAT...LON 4298 11192 4310 11191 4311 11148 4289 11150
TIME...MOT...LOC 1834Z 272DEG 12KT 4302 11182

TAX

Special Weather Statement
National Weather Service Pocatello ID
1237 PM MDT Mon Aug 2 2021

IDZ063-064-021930-
Big Hole Mountains ID-Caribou Range ID-
1237 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN BONNEVILLE COUNTY
UNTIL 130 PM MDT...

At 1237 PM MDT, Doppler radar was tracking a strong thunderstorm near
Alpine, moving north at 20 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Palisades Reservoir, Irwin, Alpine Campground and Alpine Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

If on or near Palisades Reservoir, Move to safe shelter now! Do not
be caught on or near the water. Gusty winds and choppy waves are
likely.

&&

LAT...LON 4305 11105 4310 11127 4339 11124 4336 11104
      4306 11104
TIME...MOT...LOC 1837Z 193DEG 18KT 4313 11113

TAX