Alert archive / Minnesota / Flash Flood Warnings in 1986

Flash Flood Warning 1, NWS Twin Cities, MN

September 21, 1986Olmsted County, Minnesota

NWS Twin Cities, MN issued this flash flood warning at Sep 21, 1986, 4:17 AM CDT for Olmsted County, Minnesota. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Sep 21, 1986, 4:17 AM CDT (09:17 UTC)
Expired
Sep 21, 1986, 7:00 AM CDT
In force
3 hr
Issued by
NWS Twin Cities, MN
Area
Whole counties

County Olmsted County, MN

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

Minneapolis, MN (KSTC), launched 00:00Z, 9.3 hours before the alert went out and 134 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, Minneapolis, MN at 00:00Z on 1986-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 1986-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 176 square meters per square second.193958Sfc1 km3 km6 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
531 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
176 m²/s²
0-3 km storm-relative helicity
228 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 KRST 210917
FFWRST
MNC109-211200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED 
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE ROCHESTER MN
417 AM CDT SUN SEP 21 1986

THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING 
EFFECTIVE UNTIL 700 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTY OF

SOUTHEAST MINNESOTA...OLMSTED

THIS WARNING INCLUDES THE CITY OF ROCHESTER AND THE STREAMS
OF SILVER AND CASCADE. HEAVY RAINS UP TO 5 INCHES FELL OVER
PORTIONS OF OLMSTED COUNTY LATE SATURDAY AND EARLY SUNDAY
MORNING. COMBINED WITH ALREADY SATURATED GROUND SMALL STREAM
FLOODING IS LIKELY IN PORTIONS OF OLMSTED COUNTY THIS EARLY
SUNDAY MORNING ESPECIALLY ON SILVER AND CASCADE CREEKS IN THE
CITY OF ROCHESTER

 A FLASH FLOOD WARNING MEANS FLOODING IN IMMINENT.......
 ........TAKE NECESSARY PRECAUTIONS IMMEDIATELY.........

 PERSONS IN LOW LYING AND FLOOD PRONE AREAS SHOULD SEEK HIGHER
 GROUND IMMEDIATELY. WE REPEAT..DO NOT TAKE THIS SITUATION LIGHTLY.

 MOTORISTS SHOULD BE PARTICULARY CAUTIOUS AND NOT ATTEMPT TO CROSS
 ROADWAYS COVERED WITH FAST MOVING WATER OR WATER OF AN UNKNOWN
 DEPTHS. PERSONS IN FLOOD PRONE AREAS SHOULD BE ALERT FOR FAST
 RISING WATER.

The office that day

Everything else NWS Twin Cities, MN issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 21, 12:45 AM CDTSevere Thunderstorm WarningMPXRedwood55 min

Nearby

Flash Flood Warnings in Minnesota, 1986Every flash flood warning in 1986

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.