Special Weather Statement, NWS Pocatello, ID

Area Forecast Discussion
National Weather Service Pocatello ID
125 PM MDT Mon Aug 2 2021

.SHORT TERM...Tonight through Wednesday.

An upper level trough and associated surface front/dry line will
pass through central and east Idaho this afternoon. This will be the
focus for additional thunderstorms this afternoon. Precipitable
water values remain extraordinarily high, around 1.25 inches.
Surface dew points remain in the low to mid 60s. So heavy rain is
almost certain with thunderstorms once again this afternoon and
evening. Flash flood watches remain in effect for the high
country. Isolated flooding remains possible in the Snake Plain,
but mainly concerned with street flooding there, higher threat
along the bench areas.Isolated severe storms can't be entirely
ruled out with strong winds possible as well.

Models show convection ending this evening as the dry line/front
passes into Wyoming. Tuesday and Wednesday looks much drier with
lower dew points. Still moist by Idaho standards, but looking at dew
points in the upper 40s to around 50 as opposed to the current low
to mid 60s we are currently enjoying. Isolated heat of the day
variety thunderstorms are possible Tuesday and Wednesday. Wednesday
is a slightly better chance over the central mountains as a weak
upper level trough enters the region.

13

.LONG TERM...Thursday through Monday. A storm will @see across
eastern Idaho Thursday, with a better chance of showers and
thunderstorms. These storms won't be tapping into deep monsoon
moisture, but we can't rule out a few storms producing locally heavy
rain because of recent rainfall and moisture. The storm track shifts
north through the weekend. We could see some showers and storms
closer to the Montana border, but most of the area will be dry and
breezy. Keyes

&&

.AVIATION...Showers and thunderstorms will be potentially impacting
TAF sites this afternoon and evening. Just like the past few days,
we could see MVFR/IFR weather due to heavy rain and low visibility.
We should see things ending west to east overnight. At the moment,
we don't think we will have fog or stratus issues just due to all of
the recent rainfall...but it might be something we need to monitor.
Tomorrow should be VFR with no storms expected. Keyes

&&

.FIRE WEATHER...Showers and thunderstorms and the risk of heavy
rainfall and debris flows will end overnight from west to east. We
could see a few very isolated storms tomorrow across mainly the
central mountains and near the Wyoming border, but the risk is very
low (around 10% at most). There is an increasing chance in the
central mountains later Wednesday, expanding everything heading into
Thursday. These storms will be more of a mix of wet and dry, as
monsoon moisture won't be around. That said, with all of the recent
rainfall...it's possible enough moisture is there to produce a few
locally heavy rainers. The storm track shifts north heading into the
weekend. While showers and storms are possible closer to the Montana
border, the main issue may become gusty winds across most of central
and eastern Idaho with a drier airmass moving in. Keyes

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 9 PM MDT this evening for IDZ056>074.

&&

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

IDZ053-022230-
Upper Snake River Plain ID-
341 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN BONNEVILLE COUNTY
UNTIL 430 PM MDT...

At 340 PM MDT, Doppler radar was tracking a strong thunderstorm over
I-15, Ucon, or near Rigby, moving east at 15 to 20 mph.

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

Locations impacted include...
Osgood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4351 11210 4356 11213 4360 11203 4355 11200
TIME...MOT...LOC 2140Z 251DEG 36KT 4358 11195

TW

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

IDZ062-022230-
Blackfoot Mountains ID-
345 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL CARIBOU COUNTY UNTIL
430 PM MDT...

At 344 PM MDT, Doppler radar was tracking a strong thunderstorm near
Grace, or 10 miles east of Lava Hot Springs, moving northeast at 10
mph.

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

This storm will remain over mainly rural areas of west central
Caribou County.

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. Also, look for reduced visibilities due to heavy rain.

&&

LAT...LON 4260 11186 4271 11191 4275 11175 4261 11169
TIME...MOT...LOC 2144Z 247DEG 7KT 4264 11181

TW

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

IDZ062-063-022230-
Caribou Range ID-Blackfoot Mountains ID-
350 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL CARIBOU COUNTY UNTIL
430 PM MDT...

At 349 PM MDT, Doppler radar was tracking a strong thunderstorm near
Soda Springs, moving east at 15 to 20 mph.

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

Locations impacted include...
North Soda Springs and Diamond Creek 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. Expect low visibilities while driving in heavy rain.

&&

LAT...LON 4266 11171 4277 11175 4290 11118 4267 11111
TIME...MOT...LOC 2149Z 263DEG 8KT 4272 11155

TW

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

IDZ059-022245-
Franklin/Eastern Oneida Region ID-
358 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL FRANKLIN COUNTY UNTIL 445
PM MDT...

At 357 PM MDT, Doppler radar was tracking a strong thunderstorm near
Preston, moving east at 15 to 20 mph.

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

Locations impacted include...
Riverdale.

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. Expect low visibilities while driving through storms.

&&

LAT...LON 4213 11195 4218 11195 4221 11181 4212 11179
TIME...MOT...LOC 2157Z 263DEG 8KT 4217 11187

TW

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

IDZ058-059-022245-
Franklin/Eastern Oneida Region ID-Marsh and Arbon Highlands ID-
404 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN ONEIDA AND SOUTH
CENTRAL BANNOCK COUNTIES UNTIL 445 PM MDT...

At 402 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles north of Malad, moving east at 15 to 20 mph.

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

Locations impacted include...
Malad Pass.

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. Heavy rain will create reduced visibilities while driving.

&&

LAT...LON 4229 11234 4244 11238 4248 11225 4230 11221
TIME...MOT...LOC 2202Z 263DEG 8KT 4233 11227

TW

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

IDZ057-059-022300-
Franklin/Eastern Oneida Region ID-Raft River Region ID-
411 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN ONEIDA COUNTY UNTIL
500 PM MDT...

At 410 PM MDT, Doppler radar was tracking a strong thunderstorm near
Holbrook Summit, or 14 miles north of Snowville, moving east at 10
to 15 mph.

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

Locations impacted include...
Holbrook.

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. Expect low visibilities during heavy rain.

&&

LAT...LON 4213 11284 4221 11285 4224 11259 4211 11257
TIME...MOT...LOC 2210Z 263DEG 8KT 4217 11274

TW