Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Missoula, MT

August 1, 2021Flathead County, Montana

NWS Missoula, MT issued this special weather statement at Aug 1, 2021, 6:46 PM MDT for Flathead County, Montana. It was in force for 29 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 1, 2021, 6:46 PM MDT (00:46 UTC)
Expired
Aug 1, 2021, 7:15 PM MDT
In force
29 min
Issued by
NWS Missoula, MT

County Flathead County, MT

The radar

The Missoula radar (KMSX), 146 km from the middle of the area, began a volume at 00:50 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, 0.8 hours before the alert went out and 183 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 2021-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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 2021-08-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -16 square meters per square second.1939Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1384 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
-16 m²/s²
0-3 km storm-relative helicity
23 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

683 
WWUS85 KMSO 020046
SPSMSO

Special Weather Statement
National Weather Service Missoula MT
646 PM MDT Sun Aug 1 2021
 
MTZ002-003-020115-
Flathead/Mission Valleys MT-West Glacier Region MT-
646 PM MDT Sun Aug 1 2021

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL FLATHEAD COUNTY UNTIL 715
PM MDT...

At 645 PM MDT, Doppler radar was tracking a strong thunderstorm near
Columbia Falls, or 15 miles north of Evergreen, moving north at 20
mph.

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

Locations impacted include...
Kalispell, Evergreen, Whitefish, Columbia Falls, West Glacier, Martin
City, Coram, Hungry Horse and La Salle.

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.

&&

LAT...LON 4820 11409 4826 11436 4860 11431 4848 11385
TIME...MOT...LOC 0045Z 194DEG 19KT 4844 11414 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 1, 6:30 PM MDTAreal Flood AdvisoryMSOFlathead, Lake3 hr
Aug 1, 6:33 PM MDTAreal Flood AdvisoryMSOFlathead3 hr
Aug 1, 6:40 PM MDTAreal Flood AdvisoryMSOSilver Bow10 min
Aug 1, 6:49 PM MDTFlash Flood WarningMSOSilver Bow97 min
Aug 2, 10:09 AM MDTFlash Flood WatchMSODeer Lodge, Silver Bow9 hr
Aug 2, 2:18 PM MDTSpecial Weather StatementMSOFlathead42 min
Aug 2, 2:21 PM MDTSpecial Weather StatementMSODeer Lodge, Powell54 min
Aug 2, 2:54 PM MDTSpecial Weather StatementMSOSilver Bow51 min
Aug 2, 3:05 PM MDTSpecial Weather StatementMSOFlathead55 min
Aug 2, 5:59 PM MDTDense Fog AdvisoryMSOFlathead, Lake, Sanders17 hr
Aug 1, 6:30 PM MDTFlash Flood WarningMSOLemhi3 hr
Aug 1, 7:22 PM MDTAreal Flood AdvisoryMSOIdaho113 min
Aug 1, 7:53 PM MDTAreal Flood AdvisoryMSOIdaho112 min
Aug 1, 7:59 PM MDTAreal Flood WarningMSOLemhi3 hr
Aug 1, 8:15 PM MDTAreal Flood AdvisoryMSOIdaho2 hr
Aug 1, 10:01 PM MDTAreal Flood AdvisoryMSOIdaho119 min

Nearby

Special Weather Statements in Montana, 2021Every special weather statement 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.