Alert archive / Iowa / Flash Flood Warnings in 1990

Flash Flood Warning 25, NWS Des Moines, IA

July 12, 1990Polk County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jul 12, 1990, 6:36 AM CDT for Polk County, Iowa. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Jul 12, 1990, 6:36 AM CDT (11:36 UTC)
Expired
Jul 12, 1990, 9:45 AM CDT
In force
3 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

County Polk County, IA

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

Omaha, NE (KOAX), launched 00:00Z, 11.6 hours before the alert went out and 236 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, Omaha, NE at 00:00Z on 1990-07-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Omaha, NE at 00:00Z on 1990-07-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -21 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3580 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
-21 m²/s²
0-3 km storm-relative helicity
53 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 KDSM 121138
FFWDSM
IAC153-121445-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
636 AM CDT THU JUL 12 1990
 
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL  945 AM CDT
FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN CENTRAL IOWA
          ...EASTERN POLK
 
AT 635 AM CDT...LAW ENFORCEMENT OFFICIALS REPORTED EXTENSIVE STREET
FLOODING IN SECTIONS OF DOWNTOWN DES MOINES. WATER WAS REPORTED UP TO
CAR WINDOW LEVEL IN SOME AREAS. AT THE SAME TIME...RADAR INDICATED
THUNDERSTORMS WITH HEAVY RAIN OVER THE EASTERN HALF OF POLK COUNTY.
THE STORMS WERE MOVING SOUTH AROUND 10 MILES AN HOUR.
 
 
A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT.  MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES.  DO NOT
ATTEMPT TO CROSS BRIDGES...DIPS...OR LOW SPOTS IF WATER COVERS
THE ROADWAY.  NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL
ONE...ON FOOT.  TO ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.
 
BIKLE

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

Local storm report, Jul 12, 1:03 AM CDT, 5 hours 33 minutes before
LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
103 AM CDT THU JUL 12 1990

...REPORTS FROM THE LATE AFTERNOON OF THE 11TH...

TIME CDT      EVENT

504 PM        A TORNADO TOUCHED DOWN BRIEFLY 2-3 MILES SOUTHEAST OF
              JEWELL. /HAMILTON COUNTY/

504 PM        A COLD AIR FUNNEL WAS OBSERVED 21/2 MILES WEST OF STORY
              CITY. /STORY COUNTY/

530 PM        A TORNADO TOUCHED DOWN BRIEFLY SOUTH OF UNION. /HARDIN
              COUNTY/

SCHUMACHER

Nearby

Flash Flood Warnings in Iowa, 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.