Special Weather Statement, NWS Pocatello, ID

Area Forecast Discussion
National Weather Service Pocatello ID
325 AM MDT Fri Aug 6 2021

.SHORT TERM (Today - Sunday)...
A low pressure trough/attendant cold front will cross SE ID today.
The combination of clouds, ongoing showers, and the front will keep
high temps confined to a refreshing 70-80 degrees, while dynamics
associated with the trough/front will continue to trigger a few
showers/t-storms this AM, and another round of showers/t-storms this
afternoon/eve with the best potential generally NE of a line from
Shoshone, to American Falls, to Montpelier. Once again, a few of the
stronger cells/lines may produce gusty winds, small hail, and heavy
downpours, and an isolated severe t-storm cannot be ruled out.
Overall organization may be limited by a lack of wind shear, but
instability is looking plentiful on forecast soundings. Drier
conditions are expected Sat, before a stronger low pressure system
brushes by to our north Sun. Resultant breezy conditions are likely
Sun, with isolated t-storms north/east of the Snake Plain. - 01

.LONG TERM...
The area looks mostly dry in the extended outside of maybe some
isolated high elevation PoPs into mid-week and even this looks
pretty slim at this point. On Monday, an upper low looks to move
across Montana with cooler air in place across eastern Idaho. As
this feature departs to the east, high pressure looks to build back
over the area. Still some disagreement amongst the guidance as to
the strength of the ridge, and overall placement, but this is to be
expected this far out. Temperatures will start the period on the
cooler side of normal by around 10 degrees but will gradually
moderate back to around normal values by mid-week and eventually
above normal by the end of the forecast period with things remaining
mostly dry. McKaughan

&&

.AVIATION...
Another round of showers and thunderstorms are expected today before
things dry out for the weekend. Gusty winds remain the primary
concern with gusts around 40 kts possible in and around tstms. Non-
convective winds will be breezier today behind the FROPA sustained
in the 15-20 kt range at times at KBYI, KPIH, KIDA and KDIJ with
gusts in the 20-30 kt range likely. Precip should begin to clear the
area by late evening with VFR likely to prevail outside of any
SHRA/TSTMs. McKaughan

&&

.FIRE WEATHER...
Today will be noticeably cooler than Thursday with temperatures 10
to 15 degrees below normal. This in turn will create much higher
minimum RHs during the afternoon hours. Additionally, another round
of showers and thunderstorms is expected today through the late
evening before things start to dry out for the weekend and for much
of next week. The next storm to impact the area will be Sunday into
Monday. Increasing winds are definitely expected, but humidities
should remain high enough to preclude any Red Flag Warnings even if
fuels were to be more receptive. The question remains on the risk of
thunderstorms. It does look like we should see some development
along the Montana border Sunday especially in Lemhi County. The
current forecast keeps that around through Monday, but trends are
toward moving that out later Sunday and Monday is storm-free, as is
much of next week. McKaughan

&&

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

Special Weather Statement
National Weather Service Pocatello ID
733 AM MDT Fri Aug 6 2021

IDZ054-058-062-061400-
Marsh and Arbon Highlands ID-Blackfoot Mountains ID-
Lower Snake River Plain ID-
733 AM MDT Fri Aug 6 2021

...A strong thunderstorm will impact portions of northwestern
Caribou, north central Bannock, south central Bonneville and
southeastern Bingham Counties through 800 AM MDT...

At 733 AM MDT, Doppler radar was tracking a strong thunderstorm over
Fort Hall Mount Putnam, or 12 miles west of Chesterfield Reservoir,
moving northeast at 30 mph.

HAZARD...Winds in excess of 30 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Pocatello, Chesterfield Reservoir, northern Blackfoot Reservoir,
Chubbuck, Inkom, Portneuf Gap, Fort Hall Mount Putnam, Fort Hall
Putnam Lodge, Cutthroat Trout Campground and Trail Creek Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4274 11233 4295 11251 4329 11170 4305 11152
TIME...MOT...LOC 1333Z 240DEG 49KT 4293 11220

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...30 MPH

GK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE POCATELLO ID
737 AM MDT FRI AUG 6 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0736 AM     HAIL             2 E CHUBBUCK            42.92N 112.42W
08/06/2021  M0.70 INCH       BANNOCK            ID   NWS EMPLOYEE

            HAIL UP TO DIME SIZE REPORTED.

&&

JKEYES

Special Weather Statement
National Weather Service Pocatello ID
811 AM MDT Fri Aug 6 2021

IDZ058>063-061500-
Franklin/Eastern Oneida Region ID-Bear Lake Valley ID-
Bear River Range ID-Marsh and Arbon Highlands ID-Caribou Range ID-
Blackfoot Mountains ID-
811 AM MDT Fri Aug 6 2021

...A strong thunderstorm will impact portions of southeastern
Caribou, southeastern Bannock, central Franklin and northern Bear
Lake Counties through 900 AM MDT...

At 811 AM MDT, Doppler radar was tracking a strong thunderstorm near
Oneida Narrows Reservoir, or 10 miles southeast of Swanlake, moving
northeast at 30 mph.

HAZARD...Winds in excess of 30 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Preston, Montpelier, Georgetown, Oneida Narrows Reservoir, Thatcher,
Oxford, Bern, Ovid, Georgetown Summit, Liberty, Clear Creek Ranger
Station, Mink Creek, Riverdale, Emmigrant Summit, Smokey Canyon Mine
and Bennington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4209 11190 4229 11204 4275 11104 4237 11105
TIME...MOT...LOC 1411Z 240DEG 49KT 4225 11182

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...30 MPH

GK

Special Weather Statement
National Weather Service Pocatello ID
1016 AM MDT Fri Aug 6 2021

IDZ072-073-061700-
Sawtooth/Stanley Basin ID-Sun Valley Region ID-
1016 AM MDT Fri Aug 6 2021

...Strong thunderstorms will impact portions of west central Custer
and northwestern Blaine Counties through 1100 AM MDT...

At 1016 AM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles west of Stanley to 15 miles southeast
of Atlanta. Movement was northwest at 135 mph.

HAZARD...Pea size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible.

Locations impacted include...
Galena Lodge, Redfish Lake, Galena Summit and Smiley Creek Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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

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

&&

LAT...LON 4420 11515 4420 11489 4367 11449 4367 11468
      4374 11467 4381 11471 4379 11476 4379 11485
      4382 11485 4386 11499 4387 11497 4396 11499
      4398 11497 4401 11498 4402 11503 4404 11505
      4407 11504 4409 11500 4412 11505 4415 11502
TIME...MOT...LOC 1616Z 143DEG 117KT 4421 11508 4368 11485

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...<30 MPH

GK

Special Weather Statement
National Weather Service Pocatello ID
1127 AM MDT Fri Aug 6 2021

IDZ068-070>075-061815-
Challis/Pahsimeroi Valleys ID-Frank Church Wilderness ID-
Sawtooth/Stanley Basin ID-Wood River Foothills ID-
Big Lost Highlands/Copper Basin ID-Sun Valley Region ID-
Lost River Valleys ID-
1127 AM MDT Fri Aug 6 2021

...A strong thunderstorm will impact portions of south central Custer
and northwestern Blaine Counties through 1215 PM MDT...

At 1127 AM MDT, Doppler radar was tracking a strong thunderstorm 7
miles north of Ketchum, moving southeast at 20 mph.

HAZARD...Winds in excess of 30 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Hailey, Ketchum, Sun Valley, Galena Lodge, Galena Summit, Livingston
Mill, Copper Basin Airport and Twin Bridges Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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.

&&

LAT...LON 4425 11444 4373 11370 4347 11438 4373 11468
      4374 11467 4375 11469 4381 11470 4381 11474
      4380 11476 4384 11480
TIME...MOT...LOC 1727Z 317DEG 35KT 4380 11442

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...30 MPH

GK

Special Weather Statement
National Weather Service Pocatello ID
1224 PM MDT Fri Aug 6 2021

IDZ068-070>075-061930-
Challis/Pahsimeroi Valleys ID-Frank Church Wilderness ID-
Sawtooth/Stanley Basin ID-Wood River Foothills ID-
Big Lost Highlands/Copper Basin ID-Sun Valley Region ID-
Lost River Valleys ID-
1224 PM MDT Fri Aug 6 2021

...A strong thunderstorm will impact portions of southeastern Custer,
north central Blaine and west central Butte Counties through 130 PM
MDT...

At 1223 PM MDT, Doppler radar was tracking a strong thunderstorm 15
miles east of Sun Valley, moving southeast at 20 mph.

HAZARD...Winds in excess of 30 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Hailey, Ketchum, Sun Valley, Grouse, Little Wood Reservoir, Bellevue,
Herd Lake, Garfield Ranger Station, Copper Basin Airport and Twin
Bridges Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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.

&&

LAT...LON 4402 11458 4419 11408 4360 11349 4335 11428
TIME...MOT...LOC 1823Z 317DEG 49KT 4376 11404

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...30 MPH

GK