Alert archive / Montana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 11, NWS Missoula, MT

August 4, 2021Lake County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Aug 4, 2021, 8:03 PM MDT for Lake 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
Aug 4, 2021, 8:03 PM MDT (02:03 UTC)
Expired
Aug 4, 2021, 8:30 PM MDT
In force
27 min
Issued by
NWS Missoula, MT
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

County Lake County, MT

The radar

The Missoula radar (KMSX), 83 km from the middle of the area, began a volume at 02:05 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.

The nearest sounding before it

Spokane, WA (KOTX), launched 00:00Z, 2.1 hours before the alert went out and 171 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 2021-08-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 502 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 2021-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 square meters per square second.193958Sfc1 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
502 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
3045 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
58 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

081 
WUUS55 KMSO 050203
SVRMSO
MTC047-050230-
/O.NEW.KMSO.SV.W.0011.210805T0203Z-210805T0230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Missoula MT
803 PM MDT Wed Aug 4 2021

The National Weather Service in Missoula has issued a

* Severe Thunderstorm Warning for...
  Central Lake County in northwestern Montana...

* Until 830 PM MDT.

* At 803 PM MDT, a severe thunderstorm was located over Kings Point,
  or near Polson, moving east at 25 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* Locations impacted include...
  Kings Point and Finley Point. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If on or near Flathead Lake, get away from the water and move 
indoors or inside a vehicle. Remember, lightning can strike out to 
15 miles from the parent thunderstorm. If you can hear thunder, you 
are close enough to be struck by lightning. Move to safe shelter 
now!  Do not be caught on the water in a thunderstorm.

&&

LAT...LON 4776 11423 4783 11421 4784 11396 4773 11395
TIME...MOT...LOC 0203Z 275DEG 21KT 4779 11415 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$
4 follow-up statements
410 
WWUS55 KMSO 050205
SVSMSO

Severe Weather Statement
National Weather Service Missoula MT
805 PM MDT Wed Aug 4 2021

MTC047-050230-
/O.CON.KMSO.SV.W.0011.000000T0000Z-210805T0230Z/
Lake MT-
805 PM MDT Wed Aug 4 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM MDT
FOR CENTRAL LAKE COUNTY...

At 805 PM MDT, a severe thunderstorm was located over Kings Point, or
near Polson, moving east at 25 mph.

HAZARD...Ping pong ball size hail.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect damage 
         to roofs, siding, windows, and vehicles.

Locations impacted include...
Kings Point and Finley Point. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If on or near Flathead Lake, get away from the water and move 
indoors or inside a vehicle. remember, lightning can strike out to 
15 miles from the parent thunderstorm. If you can hear thunder, you 
are close enough to be struck by lightning. Move to safe shelter 
now!  Do not be caught on the water in a thunderstorm.

&&

LAT...LON 4776 11422 4782 11419 4784 11396 4773 11395
TIME...MOT...LOC 0205Z 275DEG 21KT 4779 11413 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.50 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$
876 
WWUS55 KMSO 050215
SVSMSO

Severe Weather Statement
National Weather Service Missoula MT
815 PM MDT Wed Aug 4 2021

MTC047-050230-
/O.CON.KMSO.SV.W.0011.000000T0000Z-210805T0230Z/
Lake MT-
815 PM MDT Wed Aug 4 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM MDT
FOR CENTRAL LAKE COUNTY...

At 815 PM MDT, a severe thunderstorm was located near Kings Point, or
8 miles northeast of Polson, moving east at 25 mph.

HAZARD...Ping pong ball size hail.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect damage 
         to roofs, siding, windows, and vehicles.

Locations impacted include...
Finley Point.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If on or near Flathead Lake, get away from the water and move 
indoors or inside a vehicle. remember, lightning can strike out to 
15 miles from the parent thunderstorm. If you can hear thunder, you 
are close enough to be struck by lightning. Move to safe shelter 
now!  Do not be caught on the water in a thunderstorm.

&&

LAT...LON 4775 11413 4781 11413 4783 11396 4773 11395
TIME...MOT...LOC 0215Z 275DEG 21KT 4778 11404 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.50 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$
781 
WWUS55 KMSO 050219
SVSMSO

Severe Weather Statement
National Weather Service Missoula MT
819 PM MDT Wed Aug 4 2021

MTC047-050230-
/O.CON.KMSO.SV.W.0011.000000T0000Z-210805T0230Z/
Lake MT-
819 PM MDT Wed Aug 4 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM MDT
FOR NORTHEASTERN LAKE COUNTY...

At 819 PM MDT, a severe thunderstorm was located near Kings Point, or
9 miles northeast of Polson, moving east at 25 mph.

HAZARD...Golf ball size hail.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect damage 
         to roofs, siding, windows, and vehicles.

Locations impacted include...
Finley Point.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows.

If on or near Flathead Lake, get away from the water and move 
indoors or inside a vehicle. remember, lightning can strike out to 
15 miles from the parent thunderstorm. If you can hear thunder, you 
are close enough to be struck by lightning. Move to safe shelter 
now!  Do not be caught on the water in a thunderstorm.

&&

LAT...LON 4775 11409 4781 11410 4783 11396 4773 11395
TIME...MOT...LOC 0219Z 275DEG 21KT 4778 11401 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$
086 
WWUS55 KMSO 050227
SVSMSO

Severe Weather Statement
National Weather Service Missoula MT
827 PM MDT Wed Aug 4 2021

MTC047-050237-
/O.EXP.KMSO.SV.W.0011.000000T0000Z-210805T0230Z/
Lake MT-
827 PM MDT Wed Aug 4 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN LAKE COUNTY WILL
EXPIRE AT 830 PM MDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.


LAT...LON 4775 11409 4781 11410 4783 11396 4773 11395
TIME...MOT...LOC 0227Z 275DEG 21KT 4778 11399 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 4, 6:21 PM MDTSpecial Weather StatementMSOFlathead24 min
Aug 4, 6:31 PM MDTSpecial Weather StatementMSOLake14 min
Aug 4, 7:57 PM MDTSpecial Weather StatementMSOLake18 min
Aug 4, 8:26 PM MDTSevere Thunderstorm Warning Considerable damage threatMSOLake34 min
Aug 5, 2:27 PM MDTSpecial Weather StatementMSOMineral, Ravalli33 min
Aug 5, 3:20 PM MDTSpecial Weather StatementMSOGranite, Ravalli55 min
Aug 5, 4:12 PM MDTSpecial Weather StatementMSODeer Lodge, Silver Bow48 min
Aug 5, 4:19 PM MDTSpecial Weather StatementMSORavalli56 min
Aug 5, 5:03 PM MDTSevere Thunderstorm WarningMSOPowell42 min

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.