Alert archive / Montana / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 25, NWS Missoula, MT

July 21, 2001Ravalli County, Montana

NWS Missoula, MT issued this severe thunderstorm warning at Jul 21, 2001, 5:26 PM MDT for Ravalli County, Montana. It was in force for 49 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 21, 2001, 5:26 PM MDT (23:26 UTC)
Expired
Jul 21, 2001, 6:15 PM MDT
In force
49 min
Issued by
NWS Missoula, MT
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Ravalli County, MT

The nearest sounding before it

Spokane, WA (KOTX), launched 12:00Z, 11.4 hours before the alert went out and 270 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 12:00Z on 2001-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 69 joules per kilogram.LCLLFCEL10008507005003002001001 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 12:00Z on 2001-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 8 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
69 J/kg
Mixed-layer CIN
-159 J/kg
Mixed-layer LCL
905 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
13 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 212328
SVRMSO
MTC081-220015-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
526 PM MDT SAT JUL 21 2001

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN RAVALLI COUNTY IN WEST CENTRAL MONTANA

* UNTIL 615 PM MDT

* AT 526 PM MDT...RADAR INDICATED A SEVERE THUNDERSTORM 5 MILES 
SOUTH OF SULA...MOVING NORTHEAST AT 25 MPH.

* THE SEVERE THUNDERSTORM WILL MOVE EAST OF SULA BY 545 PM MDT.

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS AND HAIL...ALONG WITH
FREQUENT LIGHTNING AND HEAVY RAIN. FOR YOUR PROTECTION...GO INDOORS
AND STAY AWAY FROM WINDOWS. IF YOU ARE CAUGHT OUTSIDE...kMOVE TO A
WELL PROTECTED AREA.


LAT...LON 4575 11413 4571 11388 4615 11380 4618 11408

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 21, 1:50 PM MDT, 3 hours 36 minutes earlier.

Area forecast discussion, Jul 21, 1:50 PM MDT, 3 hours 36 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
150 PM MDT SAT JUL 21 2001

.SHORT TERM...AVN HANDLING EJECTING SHORTWAVE MOVING INTO SOUTHEAST
OREGON AT BASE OF TROUGH BETTER THAN 12Z ETA. THIS FEATURE HOLDS
TOGETHER INTO THE LATE EVENING TO ENHANCE CONVECTION CURRENTLY FIRING
OVER SOUTHERN ZONES. PWATS DOWN FROM YESTERDAY AND STILL A LITTLE
UNCERTAIN ABOUT MODEL DIFFERENCES THIS EVENING...SO NO FLASH FLOOD
WATCH PLANNED. WITH DRIER AIR AROUND CLOUDBASE LEVEL AND LOWER
WETBULB ZEROES...WILL THROW IN MENTION OF GUSTY WINDS AND HAIL FOR
SOME AREAS. MORE DISORGANIZED SHORTWAVE ENERGY DROPPING DOWN FROM
SOUTHWEST CANADA WILL KEEP SHOWERS AND A FEW THUNDERSTORMS GOING
THROUGH THE MORNING ACROSS THE NORTHERN ZONES. FOR THE REMAINDER OF
THE SHORT TERM...STILL DEALING WITH TROUGH FOR CONTINUED INSTABILITY
AND WEAK DYNAMICS SUPPORTING SHOWERS AND THUNDERSTORMS. LITTLE BETTER
CHANCE IN NORTHWEST MONTANA TOMORROW AS NORTHERN WAVE AXIS DROPS
THROUGH...SO WILL GO CATEGORICAL CONVECTIVE WORDING THERE...OTHERWISE
ISOLATED TO SCATTERED ACROSS THE BOARD. SIGLER

.EXTENDED...WEAK TROUGH LIFTS NORTH DAY3/4 (TUE/WED) WITH RISING
HEIGHTS AND WARMING TREND. WILL KEEP SLIGHT CHANCE POPS MENTIONED
THROUGH DAY5 (THU) WITH MODELS ADVERTISING GENERAL TROFINESS OVER
REGION. UPPER RIDGE OVER THE 4-CORNERS AREA RE-ESTABLISHING ITSELF
TOWARD THE END OF THE PERIOD...FOR TYPICAL WARM DRY CONDITIONS. MSJ

.MSO...NONE.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 8:53 PM MDTSevere Thunderstorm WarningMSOMineral, Missoula52 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.