Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Missoula, MT

August 5, 2021Powell County, Montana

NWS Missoula, MT issued this special weather statement at Aug 5, 2021, 6:21 PM MDT for Powell County, Montana. It was in force for 39 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 5, 2021, 6:21 PM MDT (00:21 UTC)
Expired
Aug 5, 2021, 7:00 PM MDT
In force
39 min
Issued by
NWS Missoula, MT
Hail
0.50 in
Wind
50

County Powell County, MT

The radar

The Missoula radar (KMSX), 82 km from the middle of the area, began a volume at 00:25 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

Great_falls, MT (KTFX), launched 00:00Z, 0.4 hours before the alert went out and 186 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, Great_falls, MT at 00:00Z on 2021-08-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 49 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, Great_falls, MT at 00:00Z on 2021-08-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 48 square meters per square second.19395878Sfc1 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
49 J/kg
Mixed-layer CIN
-233 J/kg
Mixed-layer LCL
3223 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
48 m²/s²
0-3 km storm-relative helicity
99 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

894 
WWUS85 KMSO 060021
SPSMSO

Special Weather Statement
National Weather Service Missoula MT
621 PM MDT Thu Aug 5 2021
 
MTZ007-043-060100-
Butte/Blackfoot Region MT-Potomac/Seeley Lake Region MT-
621 PM MDT Thu Aug 5 2021

...A strong thunderstorm will impact portions of northeastern Granite
and central Powell Counties through 700 PM MDT...

At 621 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles northeast of Drummond, moving north at 55 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around 
         unsecured objects. Minor damage to outdoor objects is 
         possible.

Locations impacted include...
Drummond, Ovando, Jens, Helmville and New Chicago. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4659 11295 4664 11321 4717 11312 4718 11305
      4718 11280 4715 11279 4683 11280 4683 11267
TIME...MOT...LOC 0021Z 197DEG 49KT 4674 11301 

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 5, 8:08 PM MDTSpecial Weather StatementMSO52 min
Aug 5, 9:12 PM MDTSpecial Weather StatementMSO48 min
Aug 6, 1:13 AM MDTSpecial Weather StatementMSORavalli47 min
Aug 6, 2:46 PM MDTFire Weather WatchMSOBeaverhead, Deer Lodge, Granite, Jefferson, Madison, Powell and 1 more22 hr
Aug 5, 9:20 PM MDTSpecial Weather StatementMSOIdaho40 min
Aug 5, 9:24 PM MDTSpecial Weather StatementMSOClearwater36 min
Aug 5, 9:38 PM MDTSpecial Weather StatementMSOIdaho52 min
Aug 6, 5:32 PM MDTSpecial Weather StatementMSOLemhi43 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.