Alert archive / Montana / Flash Flood Warnings in 1991

Flash Flood Warning 1, NWS Missoula, MT

May 18, 1991Lewis and Clark County, Teton County, Montana

NWS Missoula, MT issued this flash flood warning at May 18, 1991, 7:42 PM MDT for Lewis and Clark County, Teton County, Montana. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
May 18, 1991, 7:42 PM MDT (01:42 UTC)
Expired
May 18, 1991, 11:45 PM MDT
In force
4 hr
Issued by
NWS Missoula, MT
Area
Whole counties

Counties Lewis and Clark County, MT, Teton County, MT

The nearest sounding before it

Great Falls, MT (KGTF), launched 00:00Z, 1.7 hours before the alert went out and 76 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 1991-05-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 189 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, Great Falls, MT at 00:00Z on 1991-05-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 143 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
189 J/kg
Mixed-layer CIN
-83 J/kg
Mixed-layer LCL
1231 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
143 m²/s²
0-3 km storm-relative helicity
229 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

The office that day

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

IssuedProductOfficeCountiesLasted
May 18, 8:57 PM MDTFlash Flood WarningMSOLewis and Clark, Pondera, Teton6 hr
May 18, 8:57 PM MDTFlash Flood WarningMSOGlacier6 hr

Nearby

Flash Flood Warnings in Montana, 1991Every flash flood warning in 1991

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.