Alert archive / Iowa / Flash Flood Warnings in 1993

Flash Flood Warning 50, NWS Des Moines, IA

July 8, 1993Sac County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jul 8, 1993, 6:33 AM CDT for Sac County, Iowa. It was in force for 117 min.

The area

The counties it named.

The facts

Issued
Jul 8, 1993, 6:33 AM CDT (11:33 UTC)
Expired
Jul 8, 1993, 8:30 AM CDT
In force
117 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Sac County, IA

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 11.6 hours before the alert went out and 158 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 1993-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 303 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, Omaha, NE at 00:00Z on 1993-07-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 101 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
303 J/kg
Mixed-layer CIN
-240 J/kg
Mixed-layer LCL
1249 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
101 m²/s²
0-3 km storm-relative helicity
194 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 081133
FFWDSM
IAC161-081330-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
633 AM CDT THU JUL 8 1993
 
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL  830 AM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION(S)...
 
IN WEST CENTRAL IOWA
 
   ...SAC COUNTY
 
AT 630 AM CDT...THUNDERSTORMS OVER EARLY IN SAC COUNTY...50 MILES WEST
OF FORT DODGE...PRODUCED AROUND 2 INCHES OF RAIN IN 20 MINUTES. THIS
SHOULD CAUSE FLASH FLOODING IN SAC COUNTY DURING THE NEXT FEW HOURS.
 
 
A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT.  MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES.  DO NOT
ATTEMPT TO CROSS BRIDGERS...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.

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, Jul 8, 4:41 AM CDT, 1 hour 52 minutes before
IAZALL-081040-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
441 AM CDT THU JUL 8 1993

...A FLASH FLOOD WATCH CONTINUES FOR SOUTHWEST IOWA UNTIL 11 AM CDT...

AT 427 AM CDT...A VERY STRONG THUNDERSTORM WAS OVER NORTHWEST IOWA.
THIS STORM WAS LOCATED 35 MILES SOUTHEAST OF SIOUX CITY IN MONONA
COUNTY.  THIS STORM HAS BEEN PRODUCING VERY HEAVY RAINS...FREQUENT
DANGEROUS LIGHTNING AND SMALL HAIL.

THIS STORM WAS PART OF A LARGER AREA OF SHOWERS AND STORMS OVER PARTS
OF WEST CENTRAL AND NORTHWEST IOWA.  THE PRECIPITATION WAS WEST OF A
LINE THAT EXTENDED FROM NEAR SPENCER SOUTH 40 MILES NORTHEAST OF
COUNCIL BLUFFS...NEAR EXIRA.

THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT AROUND 40 MILES AN HOUR.

FILLBACH
Special weather statement, Jul 8, 4:44 AM CDT, 1 hour 49 minutes before
IAZALL-081040-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
441 AM CDT THU JUL 8 1993

...A FLASH FLOOD WATCH CONTINUES FOR SOUTHWEST IOWA UNTIL 11 AM CDT...

AT 427 AM CDT...A VERY STRONG THUNDERSTORM WAS OVER NORTHWEST IOWA.
THIS STORM WAS LOCATED 35 MILES SOUTHEAST OF SIOUX CITY IN MONONA
COUNTY.  THIS STORM HAS BEEN PRODUCING VERY HEAVY RAINS...FREQUENT
DANGEROUS LIGHTNING AND SMALL HAIL.

THIS STORM WAS PART OF A LARGER AREA OF SHOWERS AND STORMS OVER PARTS
OF WEST CENTRAL AND NORTHWEST IOWA.  THE PRECIPITATION WAS WEST OF A
LINE THAT EXTENDED FROM NEAR SPENCER SOUTH 40 MILES NORTHEAST OF
COUNCIL BLUFFS...NEAR EXIRA.

THE SHOWERS AND STORMS WEREB MOVING NORTHEAST AT AROUND 40 MILES AN HOUR.

FILLBACH
Special weather statement, Jul 8, 5:50 AM CDT, 43 minutes before
IAZALL-081145-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
550 AM CDT THU JUL 8 1993

...A FLASH FLOOD WATCH CONTINUES FOR SOUTHWEST IOWA UNTIL 11 AM CDT...

AT 525 AM CDT...A VERY STRONG THUNDERSTORM WAS 30 MILES NORTHEAST OF
OMAHA NEAR HARLAN.  ANOTHER STORM WITH HEAVY RAIN WAS 30 MILES EAST-
SOUTHEAST OF SIOUX CITY JUST SOUTH OF IDA GROVE.  BRIEF TORRENTIAL RAIN
...DANGEROUS LIGHTNING...STRONG WIND GUSTS AND SMALL HAIL CAN BE
EXPECTED WITH THESE STRONG STORMS.

THESE STORMS WERE PART OF A LARGER AREA OF NUMEROUS SHOWERS AND
THUNDERSTORMS IN WESTERN IOWA.  THE AREA WAS 100 MILES WIDE AND WEST OF
A LINE FROM 40 MILES WEST MASON CITY NEAR ALGONA TO 50 MILES NORTHWEST
LAMONI NEAR CORNING.

MOVEMENT WAS NORTHEAST AT 40 MILES AN HOUR.
/
BURKE
Special weather statement, Jul 8, 5:52 AM CDT, 41 minutes before
IAZALL-081145-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
550 AM CDT THU JUL 8 1993

...A FLASH FLOOD WATCH CONTINUES FOR SOUTHWEST IOWA UNTIL 11 AM CDT...

AT 525 AM CDT...A VERY STRONG THUNDERSTORM WAS 30 MILES NORTHEAST OF
OMAHA NEAR HARLAN.  ANOTHER STORM WITH HEAVY RAIN WAS 30 MILES EAST-
SOUTHEAST OF SIOUX CITY JUST SOUTH OF IDA GROVE.  BRIEF TORRENTIAL RAIN
...DANGEROUS LIGHTNING...STRONG WIND GUSTS AND SMALL HAIL CAN BE
EXPECTED WITH THESE STRONG STORMS.

THESE STORMS WERE PART OF A LARGER AREA OF NUMEROUS SHOWERS AND
THUNDERSTORMS IN WESTERN IOWA.  THE AREA WAS 100 MILES WIDE AND WEST OF
A LINE FROM 40 MILES WEST MASON CITY NEAR ALGONA TO 50 MILES NORTHWEST
LAMONI NEAR CORNING.

MOVEMENT WAS NORTHEAST AT 40 MILES AN HOUR.
/
BURKE
Special weather statement, Jul 8, 6:20 AM CDT, 13 minutes before
IAZALL-081245-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
620 AM CDT THU JUL 8 1993

...A LINE OF STORMS WITH HEAVY RAIN WILL MOVE THROUGH DES MOINES SOON...

THUNDERSTORMS WILL ROAR THROUGH WEST DES MOINES AROUND 7 AM AND ACROSS
THE DES MOINES METROPLEX BETWEEN 7 AND 9 AM.  LOCAL STREET FLOODING IS
LIKELY DUE TO BRIEF TORRENTIAL RAIN.  FREQUENT DANGEROUS LIGHTNING...
SMALL HAIL...AND WIND GUSTS TO 45 MILES AN HOUR WILL ACCOMPANY THE
STRONGEST STORMS.

IF YOU ARE THREATENED BY A STRONG DOWNBURST...TAKE COVER AND USE CAUTION
IF YOU WILL BE OUT THIS MORNING.  NEVER DRIVE INTO FLOWING WATER.  THE
SAFEST PLACE DURING A STRONG THUNDERSTORM IS INSIDE A STURDY SHELTER.

BURKE
Special weather statement, Jul 8, 6:23 AM CDT, 10 minutes before
IAZALL-081245-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
620 AM CDT THU JUL 8 1993

...A LINE OF STORMS WITH HEAVY RAIN WILL MOVE THROUGH DES MOINES SOON...

THUNDERSTORMS WILL ROAR THROUGH WEST DES MOINES AROUND 7 AM AND ACROSS
THE DES MOINES METROPLEX BETWEEN 7 AND 9 AM.  LOCAL STREET FLOODING IS
LIKELY DUE TO BRIEF TORRENTIAL RAIN.  FREQUENT DANGEROUS LIGHTNING...
SMALL HAIL...AND WIND GUSTS TO 45 MILES AN HOUR WILL ACCOMPANY THE
STRONGEST STORMS.

IF YOU ARE THREATENED BY A STRONG DOWNBURST...TAKE COVER AND USE CAUTION
IF YOU WILL BE OUT THIS MORNING.  NEVER DRIVE INTO FLOWING WATER.  THE
SAFEST PLACE DURING A STRONG THUNDERSTORM IS INSIDE A STURDY SHELTER.

BU>RKE

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 8, 7:54 AM CDTFlash Flood WarningDMXDallas66 min
Jul 8, 6:19 PM CDTSevere Thunderstorm WarningDMXCrawford41 min

Nearby

Flash Flood Warnings in Iowa, 1993Every flash flood warning in 1993

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.