Alert archive / Montana / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 24, NWS Missoula, MT

July 20, 2001Mineral County, Missoula County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Jul 20, 2001, 8:53 PM MDT for Mineral County, Missoula County, Montana. It was in force for 52 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued
Jul 20, 2001, 8:53 PM MDT (02:53 UTC)
Expired
Jul 20, 2001, 9:45 PM MDT
In force
52 min
Issued by
NWS Missoula, MT
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Mineral County, MT, Missoula County, MT

The nearest sounding before it

Spokane, WA (KOTX), launched 00:00Z, 2.9 hours before the alert went out and 170 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 2001-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 257 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 00:00Z on 2001-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 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
257 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
2144 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS55 KMSO 210253
SVRMSO

MTC061-063-210345-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
853 PM MDT FRI JUL 20 2001

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN MINERAL COUNTY IN WEST CENTRAL MONTANA
  SOUTHWESTERN MISSOULA COUNTY IN WEST CENTRAL MONTANA

* UNTIL 945 PM MDT

* AT 853 PM MDT...RADAR INDICATED A SEVERE THUNDERSTORM 21 MILES
  SOUTHWEST OF FRENCHTOWN...OR 28 MILES WEST OF MISSOULA...MOVING
  NORTHEAST AT 40 MPH.

* THE SEVERE THUNDERSTORM WILL BE...
  3 MILES SOUTHEAST OF FRENCHTOWN AT 920 PM MDT

DAMAGING WINDS IN EXCESS OF 55 MPH ARE LIKELY WITH THIS SEVERE
THUNDERSTORM. LARGE HAIL IS POSSIBLE...ALONG WITH FREQUENT LIGHTNING
AND HEAVY RAIN. FOR YOUR PROTECTION...GO INDOORS AND STAY AWAY FROM
WINDOWS. IF YOU ARE CAUGHT OUTSIDE...MOVE TO A WELL PROTECTED AREA.


LAT...LON 4686 11479 4670 11464 4691 11404 4705 11423

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Missoula, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 20, 8:44 PM MDT, 9 minutes earlier.

Area forecast discussion, Jul 20, 8:44 PM MDT, 9 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
844 PM MDT FRI JUL 20 2001

WILL UPDATE ZONES AND SFPMSO TO EXTEND FLASH FLOOD WATCH FOR THE
SEVERELY BURNED AREAS OF SOUTHERN RAVALLI COUNTY IN WEST CENTRAL
MONTANA THROUGH 7 AM SATURDAY. UPPER LOW CENTER LOCATED OVER THE
CENTRAL WASHINGTON-OREGON BORDER SHOULD CONTINUE TO TRIGGER TSTMS...
SOME SEVERE...OVER THE CWA TONIGHT. AROUND 7 PM THE TOWN OF
COTTONWOOD NEAR GRANGEVILLE REPORTED 1 INCH HAIL. CWA BECOMES UNDER
THE FAVORABLE LEFT FRONT SIDE OF UPPER LOW OVERNIGHT. STRONG
300/700 MB CONVERGENT/DIVERGENT COUPLET ASSOCIATED LEFT FRONT
QUADRANT OF H3 70 KNOT JET DEVELOPS OVER CENTRAL ZONES AROUND 06Z.
NEW ETA LITTLE FURTHER NORTH WITH THIS COUPLET SO WILL BUMP POPS UP
OVER NORTHWEST MONTANA. WITH FLASH FLOODING HAVING ALREADY OCCURRED
OVER AREAS SOUTHERN RAVALLI COUNTY EARLIER TODAY AND WITH GROUND
ALREADY SATURATED...WILL NOT TAKE MUCH PCPN TO TRIGGER MORE FLASH
FLOODING. HARMER

.MSO...FLASH FLOOD WATCH FOR SOUTHERN RAVALLI COUNTY THROUGH 7 AM
SATURDAY.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 5:26 PM MDTSevere Thunderstorm WarningMSORavalli49 min
Jul 21, 5:34 PM MDTFlash Flood WarningMSORavalli116 min

Nearby

Severe Thunderstorm Warnings in Montana, 2001Every severe thunderstorm warning in 2001

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.