Alert archive / Montana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 4, NWS Missoula, MT

July 7, 2021Flathead County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Jul 7, 2021, 7:48 PM MDT for Flathead County, Montana. It was in force for 27 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 7, 2021, 7:48 PM MDT (01:48 UTC)
Expired
Jul 7, 2021, 8:15 PM MDT
In force
27 min
Issued by
NWS Missoula, MT
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Flathead County, MT

The radar

The Missoula radar (KMSX), 200 km from the middle of the area, began a volume at 01:50 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.

The nearest sounding before it

Spokane, WA (KOTX), launched 00:00Z, 1.8 hours before the alert went out and 221 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Spokane, WA at 00:00Z on 2021-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 10 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 00:00Z on 2021-07-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -22 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
10 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
3130 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
-22 m²/s²
0-3 km storm-relative helicity
1 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

128 
WUUS55 KMSO 080148
SVRMSO
MTC029-080215-
/O.NEW.KMSO.SV.W.0004.210708T0148Z-210708T0215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Missoula MT
748 PM MDT Wed Jul 7 2021

The National Weather Service in Missoula has issued a

* Severe Thunderstorm Warning for...
  North central Flathead County in northwestern Montana...

* Until 815 PM MDT.

* At 748 PM MDT, a severe thunderstorm was located 21 miles northwest
  of West Glacier, or 38 miles north of Evergreen, moving northeast
  at 35 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* This severe thunderstorm will remain over mainly rural areas of
  north central Flathead County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4894 11404 4891 11401 4889 11406 4885 11399
      4883 11400 4882 11395 4885 11391 4884 11388
      4885 11385 4884 11381 4885 11379 4881 11376
      4879 11377 4872 11370 4865 11417 4883 11434
      4896 11403
TIME...MOT...LOC 0148Z 236DEG 29KT 4878 11419 

HAIL...1.00IN
WIND...60MPH
 
$$
3 follow-up statements
376 
WWUS55 KMSO 080157
SVSMSO

Severe Weather Statement
National Weather Service Missoula MT
757 PM MDT Wed Jul 7 2021

MTC029-080215-
/O.CON.KMSO.SV.W.0004.000000T0000Z-210708T0215Z/
Flathead MT-
757 PM MDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM MDT
FOR NORTH CENTRAL FLATHEAD COUNTY...

At 756 PM MDT, a severe thunderstorm was located 22 miles north of
West Glacier, or 41 miles north of Evergreen, moving northeast at 35
mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

This severe thunderstorm will remain over mainly rural areas of north
central Flathead County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4894 11404 4891 11401 4889 11406 4885 11399
      4883 11400 4882 11395 4885 11391 4884 11388
      4885 11385 4884 11381 4885 11379 4881 11376
      4879 11377 4872 11370 4867 11406 4883 11423
      4896 11403
TIME...MOT...LOC 0156Z 236DEG 29KT 4882 11410 

HAIL...0.75IN
WIND...60MPH
 
$$
163 
WWUS55 KMSO 080206
SVSMSO

Severe Weather Statement
National Weather Service Missoula MT
806 PM MDT Wed Jul 7 2021

MTC029-080215-
/O.CON.KMSO.SV.W.0004.000000T0000Z-210708T0215Z/
Flathead MT-
806 PM MDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM MDT
FOR NORTH CENTRAL FLATHEAD COUNTY...

At 806 PM MDT, a severe thunderstorm was located 25 miles north of
West Glacier, or 45 miles north of Evergreen, moving northeast at 35
mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

This severe thunderstorm will remain over mainly rural areas of north
central Flathead County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4885 11391 4884 11388 4885 11385 4884 11381
      4885 11379 4881 11376 4879 11377 4872 11370
      4868 11400 4876 11408 4882 11395
TIME...MOT...LOC 0206Z 236DEG 29KT 4887 11400 

HAIL...<.75IN
WIND...60MPH
 
$$
138 
WWUS55 KMSO 080211
SVSMSO

Severe Weather Statement
National Weather Service Missoula MT
811 PM MDT Wed Jul 7 2021

MTC029-080221-
/O.EXP.KMSO.SV.W.0004.000000T0000Z-210708T0215Z/
Flathead MT-
811 PM MDT Wed Jul 7 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL FLATHEAD COUNTY
WILL EXPIRE AT 815 PM MDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds and heavy rain are still possible with this thunderstorm.

LAT...LON 4885 11391 4884 11388 4885 11385 4884 11381
      4885 11379 4881 11376 4879 11377 4872 11370
      4868 11400 4876 11408 4882 11395
TIME...MOT...LOC 0211Z 236DEG 29KT 4887 11400 

$$

The office that day

Everything else NWS Missoula, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 7, 7:41 PM MDTSpecial Weather StatementMSOFlathead34 min
Jul 8, 7:08 AM MDTRed Flag WarningMSOBeaverhead, Deer Lodge, Granite, Jefferson, Madison, Powell and 1 more14 hr

Nearby

Severe Thunderstorm Warnings in Montana, 2021Every severe thunderstorm warning in 2021

Sources

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.