Severe Thunderstorm Watch 346

Issued

Jul 7, 2021, 3:03 PM MDT (21:03 UTC)

Expired

Jul 7, 2021, 10:50 PM MDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

1.5 in

Strongest gust expected

65 kt

The Billings radar (KBLX), 139 km from the middle of the area, began a volume at 21:05 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Two or more tornadoes

10%

One or more EF2 to EF5 tornadoes

2%

Ten or more severe wind reports

50%

One or more gusts of 65 knots or more

40%

Ten or more severe hail reports

40%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 1183 Severe potential...watch possibleJul 7, 2:03 PM MDT
• Mesoscale Discussion 1189 Severe thunderstorm watch 346Jul 7, 5:48 PM MDT

401 
WWUS20 KWNS 072101
SEL6  
SPC WW 072101
MTZ000-080500-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 346
NWS Storm Prediction Center Norman OK
305 PM MDT Wed Jul 7 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Central and Eastern Montana

* Effective this Wednesday afternoon and evening from 305 PM
  until 1100 PM MDT.

* Primary threats include...
  Scattered damaging winds and isolated significant gusts to 75
    mph possible
  Scattered large hail events to 1.5 inches in diameter possible

SUMMARY...Storms will continue to develop and intensify within
multiple corridors across western into central Montana through late
afternoon and early evening. Severe hail will be the main concern
initially, but severe-caliber wind gust potential will likely
increase through early evening as storms tend to organize and
cluster as they move generally eastward.

The severe thunderstorm watch area is approximately along and 80
statute miles north and south of a line from 10 miles west northwest
of Helena MT to 120 miles east northeast of Billings MT. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU6).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 342...WW 343...WW
344...WW 345...

AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
29020.

...Guyer

Severe Thunderstorm Watches in Montana, 2021Every severe thunderstorm watch in 2021

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.