Alert archive / South Dakota / Flash Flood Warnings in 1990

Flash Flood Warning 1, NWS Aberdeen, SD

August 1, 1990Lyman County, South Dakota

NWS Aberdeen, SD issued this flash flood warning at Aug 1, 1990, 7:06 PM CDT for Lyman County, South Dakota. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
Aug 1, 1990, 7:06 PM CDT (00:06 UTC)
Expired
Aug 1, 1990, 11:15 PM CDT
In force
4 hr
Issued by
NWS Aberdeen, SD
Area
Whole counties

County Lyman County, SD

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Aberdeen, SD (KHON), launched 00:00Z, 0.1 hours before the alert went out and 160 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, Aberdeen, SD at 00:00Z on 1990-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 94 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, Aberdeen, SD at 00:00Z on 1990-08-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 135 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
94 J/kg
Mixed-layer CIN
-122 J/kg
Mixed-layer LCL
2165 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
135 m²/s²
0-3 km storm-relative helicity
361 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 
TTAA00 KHON 020006
FFWHON
SDC085-020415-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED 
FLASH FLOOD WARNING 
NATIONAL WEATHER SERVICE HURON SD 
706 PM CDT WED AUG 1 1990

THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING 
EFFECTIVE UNTIL 1115 PM CDT FOR PEOPLE IN THE FOLLOWING COUNTY

   IN THE CENTRAL PART OF SOUTH DAKOTA
      NORTHEAST LYMAN

SOME OF THE CITIES INCLUDED IN THIS WARNING ARE LOWER BRULE AND
KENNEBEC.

 AT 700 PM CDT...RADAR INDICATED A STATIONARY THUNDERSTORMS WITH
VERY HEAVY RAIN 10 MILES WEST OF LOWER BRULE OR 40 MILES SOUTHEAST
OF PIERRE.

A FLASH FLOOD WARNING MEANS FLASH FLOODING IS OCCURING OR IS
IMMINENT. ACT QUICKLY TO SAVE YOURSELF. GET OUT OF LOWLAND AREAS
SUBJECT TO FLOODING. AVOID ALREADY FLOODED AREAS. DO NOT ATTEMPT TO
FORD INUNDATED ROADS. WHEN YOU ARE OUT OF IMMEDIATE DANGER TUNE IN
AREA RADIO AND TELEVISION STATIONS FOR ADDITIONAL INFORMATION.

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.

In the hours before

Special weather statement, Aug 1, 6:11 PM CDT, 55 minutes before
SDZNNN-DDHHMM-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ABERDEEN SD
610 PM CDT WED AUG 1 1990

...SEVERE THUNDERSTORM WATCH FOR PORTIONS OF NORTH CENTRAL SOUTH
   DAKOTA UNTILL 11 PM CDT...

AT 6 PM CDT SKIES WERE MOSTLY SUNNY OVER THE GLACIAL LAKES REGION AND
CLOUDY ELSEWHERE. SOME SPOTTY SHOWERS CONTINUE OVER THE UPPER JAMES
RIVER VALLEY.

DURING THE EVENING HOURS THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER
MOST OF NORTHERN SOUTH DAKOTA WITH SOME IN THE WATCH AREA BECOMING
SEVERE. TEMPERATURES WILL DROP SLOWLY INTO THE LOWER 80S FROM THE
JAMES RIVER WESTWARD BY SUNSET AND IN THE LOWER 70S IN THE NORTHEAST.
LAKE WIND ADVISORY REMAINS IN EFFECT FRO THE JAMES RIVER AND GLACIAL
ALAKES REGION UNTILL SUNSET.
 STUDNICKA
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Special weather statement, Aug 1, 7:02 PM CDT, 4 minutes before
SDZ002-003-004-005-011-020100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ABERDEEN SD
702 PM CDT WED AUG 1 1990

...SEVERE THUNDERSTORM WATCH FOR PORTIONS OF NORTH CENTRAL SOUTH
   DAKOTA UNTILL 11 PM CDT...

AT 7 PM CDT SKIES WERE MOSTLY CLOUDY TO CLOUDY ACROSS ALL OF NORTHERN
SOUTH DAKOTA. SOME SHOWERS AND THUNDERSHOWERS HAVE DEVELOPED OVER THE
FAR NORTHWEST PORTIONS IN AND AROUND THE LEMMON AREA.

DURING THE EVENING HOURS THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER
MOST OF NORTHERN SOUTH DAKOTA WITH SOME IN THE WATCH AREA BECOMING
SEVERE. TEMPERATURES WILL DROP SLOWLY INTO THE LOWER 80S FROM THE
JAMES RIVER WESTWARD BY SUNSET AND IN THE LOWER 70S IN THE NORTHEAST.
LAKE WIND ADVISORY REMAINS IN EFFECT FROM THE JAMES RIVER AND GLACIAL
LAKES REGION UNTIL SUNSET.
 STUDNICKA
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Nearby

Flash Flood Warnings in South Dakota, 1990Every flash flood warning in 1990

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.