Alert archive / Montana / Flash Flood Warnings in 2001

Flash Flood Warning 8, NWS Missoula, MT

July 21, 2001Ravalli County, Montana

NWS Missoula, MT issued this flash flood warning at Jul 21, 2001, 8:00 PM MDT for Ravalli County, Montana. It was in force for 2 hr. 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, 8:00 PM MDT (02:00 UTC)
Expired
Jul 21, 2001, 10:00 PM MDT
In force
2 hr
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 00:00Z, 2.0 hours before the alert went out and 232 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 2001-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 64 joules per kilogram.LCLEL10008507005003002001001 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 2001-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 22 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
64 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
2067 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
22 m²/s²
0-3 km storm-relative helicity
54 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 
WGUS55 KMSO 220202
FFWMSO

MTC081-220400-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
800 PM MDT SAT JUL 21 2001

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS REISSUED A

* FLASH FLOOD WARNING FOR THE SLEEPING CHILD CREEK...LITTLE SLEEPING
  CHILD CREEK...AND SKALKAHO CREEK... 
  IN EASTERN RAVALLI COUNTY IN WEST CENTRAL MONTANA 

* UNTIL 1000 PM MDT

* AT 800 PM MDT...RADAR INDICATED A STRONG THUNDERSTORM WITH VERY HEAVY 
  RAINFALL 10 MILES EAST OF HAMILTON...MOVING NORTH AT 20 MPH.
  THIS STORM WILL MOVE ACROSS THE SLEEPING CHILD CREEK...LITTLE 
  SLEEPING CHILD CREEK...AND SKALKAHO CREEK AREAS CREATING MORE 
  WATER RUNOFF AND POSSIBLE MUDSLIDES. 

THE RIVER GAGE ON LAIRD CREEK NEAR SULA JUMPED TO 8.59 FEET AT 
730 PM MDT. FLOODING AND MUDSLIDES HAD BEEN REPORTED IN THIS AREA 
EARLIER...HOWEVER WATER IS RECEDING AS OF 800 PM MDT. 

A FLASH FLOOD WARNING MEANS FLOODING IS IMMINENT OR OCCURRING. IF YOU
ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY. RESIDENTS
LIVING ALONG RIVERS AND CREEKS SHOULD TAKE IMMEDIATE PRECAUTIONS TO
PROTECT LIFE AND PROPERTY. DO NOT CROSS FLOODED ROADWAYS.

CAMPING SHOULD BE AVOIDED ALONG CREEKS OR STREAMS DURING THREATENING
RAINS. EVEN SMALL STREAMS CAN BE DEADLY TORRENTS OF WATER DURING A
FLASH FLOOD.

LAT...LON 4613 11413 4609 11387 4700 11345 4707 11396

What forecasters said that day

The local office's own words before this flash flood 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 flash flood warning went out at Jul 21, 1:50 PM MDT, 6 hours 10 minutes earlier.

Area forecast discussion, Jul 21, 1:50 PM MDT, 6 hours 10 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 21, 6:10 PM MDTFlash Flood WarningMSORavalli110 min
Jul 21, 6:30 PM MDTSevere Thunderstorm WarningMSOGranite, Ravalli45 min
Jul 21, 6:53 PM MDTFlash Flood WarningMSORavalli112 min
Jul 21, 7:08 PM MDTSevere Thunderstorm WarningMSORavalli52 min

Nearby

Flash Flood Warnings in Montana, 2001Every flash flood 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.