Alert archive / Iowa / Severe Thunderstorm Warnings in 1994

Severe Thunderstorm Warning 135, NWS Des Moines, IA

July 7, 1994Poweshiek County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jul 7, 1994, 6:48 PM CDT for Poweshiek County, Iowa. It was in force for 27 min.

The area

The counties it named.

The facts

Issued
Jul 7, 1994, 6:48 PM CDT (23:48 UTC)
Expired
Jul 7, 1994, 7:15 PM CDT
In force
27 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Poweshiek County, IA

The nearest sounding before it

Topeka, KS (KTOP), launched 12:00Z, 11.8 hours before the alert went out and 398 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, Topeka, KS at 12:00Z on 1994-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 777 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, Topeka, KS at 12:00Z on 1994-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -20 square meters per square second.193958Sfc1 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
777 J/kg
Mixed-layer CIN
-76 J/kg
Mixed-layer LCL
935 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-20 m²/s²
0-3 km storm-relative helicity
1 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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.

What forecasters said that day

The local office's own words before this severe thunderstorm 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 7, 5:45 PM CDT, 1 hour 3 minutes before
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Special weather statement, Jul 7, 5:46 PM CDT, 1 hour 2 minutes before
IAZALL-072340-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
545 PM CDT THU JUL 7 1994

...A TORNADO WATCH IS IN EFFECT FOR CENTRAL IOWA AND MUCH OF EASTERN
   IOWA UNTIL 800 PM CDT...
...A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR EXTREME EAST CENTRAL
   AND EXTREME NORTHEAST IOWA UNTIL 800 PM CDT...

AT 540 PM CDT...A 30 MILE WIDE LINE OF SHOWERS AND SCATTERED STRONG
THUNDERSTORMS EXTENDED FROM CENTRAL INTO NORTH CENTRAL IOWA. THE
STRONGEST STORMS WERE LOCATED FROM STORY CITY NORTH TO THE IOWA/
MINNESOTA BORDER NORTH OF MASON CITY. SEVERAL OF THE STORMS IN THIS
AREA WILL PRODUCE BRIEF VERY HEAVY RAIN...DEADLY LIGHTNING AND IN
SOME CASES WIND GUSTS OF 30 TO 40 MILES AN HOUR.

THE SOUTH END OF THIS AREA OF SHOWERS AND STORMS THAT EXTENDED FROM
NEAR AMES SOUTH THROUGH DES MOINES HAS WEAKENED CONSIDERABLY...
ALTHOUGH A BRIEF HEAVY SHOWER IS STILL POSSIBLE.

THE SHOWERS AND STORMS WERE MOVING NORhTHEAST AT 25 MILES AN HOUR.

BARLOW
Special weather statement, Jul 7, 6:06 PM CDT, 42 minutes before
IAZ038-080010-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WATERLOO IA
606 PM CDT THU JUL 7 1994

...A TORNADO WATCH REMAINS IN EFFECT UNTIL 8PM...
...A FLASH FLOOD WATCH IS ALSO IN EFFECT FOR TONIGHT...

AT 600PM...WEATHER SERVICE RADAR IN WATERLOO WAS SHOWING VERY STRONG
THUNDERSTORMS LOCATED 25 MILES SOUTHWEST OF WATERLOO OR JUST WEST OF
GRUNDY CENTER.  THESE THUNDERSTORMS WERE PRODUCING INTENSE RAINFALL AND
WILL MOST LIKELY PRODUCE STREET FLOODING AND SOME FLOODING ON SMALL
STREAMS.  THE GROUND HAS ALREADY BEEN SATURATED IN THIS AREA FROM
THUNDERSTORMS EARLIER IN THE AFTERNOON AND ANY ADDITIONAL HEAVY
RAINFALL WILL LIKELY CAUSE FLOODING.

IF FLASH FLOODING IS OBSERVED...ACT QUICKLY.  MOVE TO ESCAPE FLOOD
WATERS.  DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS
RISING.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE WATER COVERS THE
ROADWAY.  THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO
CROSS SAFELY.  VEHICLES CAUGHT IN RISING WATER SHOULD BE ABANDONED
QUICKLY.  MOVE TO HIGHER GROUND.

AREA RESIDENTS SHOULD MONITOR THE LATEST WEATHER CONDITIONS AND IF
HEAVY RAINS OR FLOODING ARE OBSERVED...BE PREPARED TO MOVE TO
HIGHER GROUND.

LINDENBERG
Special weather statement, Jul 7, 6:07 PM CDT, 41 minutes before
IAZ038-080010-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WATERLOO IA
606 PM CDT THU JUL 7 1994

...A TORNADO WATCH REMAINS IN EFFECT UNTIL 8PM...
...A FLASH FLOOD WATCH IS ALSO IN EFFECT FOR TONIGHT...

AT 600PM...WEATHER SERVICE RADAR IN WATERLOO WAS SHOWING VERY STRONG
THUNDERSTORMS LOCATED 25 MILES SOUTHWEST OF WATERLOO OR JUST WEST OF
GRUNDY CENTER.  THESE THUNDERSTORMS WERE PRODUCING INTENSE RAINFALL AND
WILL MOST LIKELY PRODUCE STREET FLOODING AND SOME FLOODING ON SMALL
STREAMS.  THE GROUND HAS ALREADY BEEN SATURATED IN THIS AREA FROM
THUNDERSTORMS EARLIER IN THE AFTERNOON AND ANY ADDITIONAL HEAVY
RAINFALL WILL LIKELY CAUSE FLOODING.

IF FLASH FLOODING IS OBSERVED...ACT QUICKLY.  MOVE TO ESCAPE FLOOD
WATERS.  DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS
RISING.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE WATER COVERS THE
ROADWAY.  THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO
CROSS SAFELY.  VEHICLES CAUGHT IN RISING WATER SHOULD BE ABANDONED
QUICKLY.  MOVE TO HIGHER GROUND.

AREA RESIDENTS SHOULD MONITOR THE LATEST WEATHER CONDITIONS AND IF
HEAVY RAINS OR FLOODING ARE OBSERVED...BE PREPARED TO MOVE TO
HIGHER GROUND.

LINDENBERG
Special weather statement, Jul 7, 6:24 PM CDT, 24 minutes before
IAZ025-IAZ036-080015-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
625 PM CDT THU JUL 7 1994

...THE STRONGEST STORMS SHIFT INTO NORTH CENTRAL IOWA...

AT 615 PM CDT...DOPPLER RADAR INDICATED THAT SHOWERS AND THUNDERSTORMS
WERE BECOMING MORE NUMEROUS OVER NORTH CENTRAL AND NORTHEAST IOWA...
WHILE A NARROW BAND OF SHOWERS AND THUNDERSTORMS WAS REFORMING EAST
AND SOUTHEAST OF DES MOINES.

THE STRONGEST STORMS WERE LOCATED NEAR CONRAD...10 MILES NORTH OF
MARHSALLTOWN AND NEAR OSAGE...20 MILES NORTHEAST OF MASON CITY. THESE
STORMS WILL PRODUCE BRIEF VERY HEAVY RAIN...ALONG WITH DEADLY LIGHTNING
AND POSSIBLY WIND GUSTS OF 30 TO 40 MILES AN HOUR.

THE LEADING EDGE OF THE SHOWERS AND STORMS EXTENDED FROM KNOXVILLE
NORTH THROUGH MARSHALLTOWN TO CHARLES CITY AND THEN NORTH INTO SOUTHERN
MINNEOSTA. ISOLATED THUNDERSTORMS WERE LOCATED OVER NORTHEAST IOWA.

THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT 25 MILES AN HOUR.R

BARLOW
Special weather statement, Jul 7, 6:31 PM CDT, 17 minutes before
IAZ025-IAZ036-080015-

SPECIAL WEATHER STATEMENT...CORRECTED 3RD PARAGRAPH
NATIONAL WEATHER SERVICE DES MOINES IA
625 PM CDT THU JUL 7 1994

...THE STRONGEST STORMS SHIFT INTO NORTH CENTRAL IOWA...

AT 615 PM CDT...DOPPLER RADAR INDICATED THAT SHOWERS AND THUNDERSTORMS
WERE BECOMING MORE NUMEROUS OVER NORTH CENTRAL AND NORTHEAST IOWA...
WHILE A NARROW BAND OF SHOWERS AND THUNDERSTORMS WAS REFORMING EAST
AND SOUTHEAST OF DES MOINES.

THE STRONGEST STORMS WERE LOCATED NEAR CONRAD...10 MILES NORTH OF
MARHSALLTOWN AND NEAR OSAGE...20 MILES NORTHEAST OF MASON CITY. THESE
STORMS WILL PRODUCE BRIEF VERY HEAVY RAIN...ALONG WITH DEADLY LIGHTNING
AND POSSIBLY WIND GUSTS OF 30 TO 40 MILES AN HOUR.

THE LEADING EDGE OF THE SHOWERS AND STORMS EXTENDED FROM KNOXVILLE
NORTH THROUGH MARSHALLTOWN TO CHARLES CITY AND THEN NORTH INTO SOUTHERN
MINNESOTA. ISOLATED THUNDERSTORMS WERE LOCATED OVER NORTHEAST IOWA
BETWEEN OSAGE AND DECORAH.

THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT 25 MILES AN HOUR.

BARLOW

Nearby

Severe Thunderstorm Warnings in Iowa, 1994Every severe thunderstorm warning in 1994

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.