Alert archive / Iowa / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 175, NWS Des Moines, IA

August 26, 1990Allamakee County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Aug 26, 1990, 7:43 AM CDT for Allamakee County, Iowa. It was in force for 37 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Aug 26, 1990, 7:43 AM CDT (12:43 UTC)
Expired
Aug 26, 1990, 8:20 AM CDT
In force
37 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Allamakee County, IA

The radar

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

What was reported inside it

TimeReportWhereRemark
Aug 26, 7:50 AM CDTThunderstorm Wind 50Allamakee, IA

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Minneapolis, MN (KSTC), launched 12:00Z, 0.7 hours before the alert went out and 249 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 12:00Z on 1990-08-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 21 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, Minneapolis, MN at 12:00Z on 1990-08-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -132 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
21 J/kg
Mixed-layer CIN
-644 J/kg
Mixed-layer LCL
1569 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
-132 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

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KALO 261243
SVRALO
IAC005-261345-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING 
NATIONAL WEATHER SERVICE WATERLOO IA
743 AM CDT SUN AUG 26 1990

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 845 AM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTY

   IN THE NORTHEAST PART OF IOWA
      ALLAMAKEE

AT TIME 735 AM CDT WEATHER RADAR INDICATED A SEVERE THUNDERSTORM
IN THE NORTHERN PORTION OF ALLAMAKEE COUNTY. THE SEVERE
THUNDERSTORM WAS MOVING SOUTHEAST AT 20 MILES AN HOUR AND WILL
BE EFFECTING THE TOWNS OF WAUKON...LANSING AND HARPERS FERRY.

YOU SHOULD MOVE INSIDE A REINFORCED BUILDING.  STAY AWAY FROM
WINDOWS. DO NOT USE TELEPHONES OR ELECTRICAL APPLIANCES UNTIL
AFTER THE STORM PASSES.

SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES
WITH LITTLE OR NO ADVANCE WARNING.

JOHNSON

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, Aug 26, 4:48 AM CDT, 2 hours 55 minutes before
IAZALL-261030-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
445 AM CDT SUN AUG 26 1990

AN ISOLATED STRONG THUNDERSTORM WAS OVER NORTHWEST IOWA.  AT 428 AM...
THE THUNDERSTORM WAS 45 MILES SOUTHWEST OF FORT DODGE...OR JUST SOUTH-
WEST OF LAKE VIEW.  THIS STORM IS LIKELY PRODUCING EXTREMELY HEAVY
RAINS...PEA TO MARBLE SIZE HAIL AND WIND GUSTS OF 30 TO 40 MILES AN
HOUR.  THE STORM WAS MOVING NORTHEAST AT 20 MILES AN HOUR.   THE STORM
WILL BE MOVING THROUGH THE LAKE VIEW AREA TO AROUND ROCKWELL CITY BY
530 AM.

THIS STORM WAS PART OF A CLUSTER OF THUNDERSTORMS THAT WAS LOCATED
BETWEEN IDA GROVE AND JEFFERSON.  OTHER ISOLATED SHOWERS AND THUNDER-
STORMS WERE OVER WEST CENTRAL IOWA NEAR DENISON AND IN THE NORTHWEST
JUST SOUTHEAST OF SIOUX FALLS SOUTH DAKOTA.  THESE SHOWERS AND STORMS
WERE ALSO MOVING NORTHEAST AT 20 MILES AN HOUR.

THUNDERSTORMS WERE ALSO OCCURRING OVER SOUTHERN MINNISOTA...JUST NORTH
THE BORDER...NORTH OF MASON CITY.

DLF
Special weather statement, Aug 26, 5:48 AM CDT, 1 hour 55 minutes before
IAZALL-261130-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
545 AM CDT SUN AUG 26 1990

A CLUSTER OF STRONG THUNDERSTORMS WAS OVER NORTH CENTRAL AND NORTHWEST
IOWA.  AT 530 AM...THE THUNDERSTORMS WERE LOCATED FROM 10 MILES SOUTH OF
FORT DODGE TO ROCKWELL CITY...25 MILES SOUTHWEST OF FORT DODGE.  THE
CALHOUN COUNTY SHERIFFS OFFICE REPORTED THAT BRIEF HEAVY RAINS AND
WINDS UP TO 40 MILES AN HOUR OCCURRED WITH THE STORMS AS THE PASSED
OVER ROCKWELL CITY.

THE STORMS WERE MOVING NORTHEAST AT 20 MILES AN HOUR.   THE STORMS WILL
BE PASSING THROUGH MANSON AND FORT DODGE TO JUST SOUTH OF HUMBOLT AND
EAGLE GROVE BY 630 AM.  IN ADDITION TO THE HEAVY RAINS AND GUSTY WINDS
...SOME SMALL HAIL IS POSSIBLE FROM THESE STORMS.

ISOLATED THUNDERSTORMS WERE ALSO OVER SOUTHWEST IOWA...EAST OF COUNCIL
BLUFFS NEAR AVOCA AND IN NORTHWEST IOWA...SOUTHEAST OF SIOUX FALLS
SOUTH DAKOTA...NEAR SIBLEY.  THESE STORMS WERE AL+SO MOVING NORTHEAST
AT 20 MILES AN HOUR.

DLF
Special weather statement, Aug 26, 6:01 AM CDT, 1 hour 42 minutes before
IAZALL-262300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
600 AM CDT SUN AUG 26 1990

...HOT TEMPERATURES AND UNPLEASANT HUMIDITY WILL OCCUR ACROSS IOWA...

TYPICAL AUGUST WEATHER IS EXPECTED OVER THE STATE FROM MIDDAY INTO THE
EVENING HOURS AS TEMPERATURES CLIMB INTO THE UPPER 80S TO MIDDLE 90S.
THE COMBINATION OF HEAT AND HUMIDITY WILL PRODUCE HEAT INDICES IN THE
UPPER 90S IN EXTREME NORTHEAST IOWA TO AROUND 107 DEGREES IN THE
SOUTHWEST QUARTER.

PEOPLE WORKING OUT-OF-DOORS...THOSE LIVING IN UN-AIRCONDITIONED SPACES
...THE ELDERLY...AND PEOPLE IN POOR HEALTH SHOULD TAKE PRECAUTIONS.
PROLONGED EXPOSURE TO THESE CONDITIONS OR STRENUOUS PHYSICAL ACTIVITY
CAN LEAD TO HEAT EXHAUSTION OR POSSIBLE HEAT STROKE.

PEOPLE ATTENDING OUTDOOR EVENTS SUCH AS THE IOWA STATE FAIR SHOULD
WEAR LIGHT-COLORED...LOOSE-FITTING CLOTHING...HAVE PROTECTION FROM THE
SUN AND DRINK PLENTY OF NON-ALCOHOLIC LIQUIDS.

SLIGHTLY HIGHER HEA;T INDICES ARE EXPECTED MONDAY.

MYERS
Special weather statement, Aug 26, 6:50 AM CDT, 53 minutes before
IAZALL-261230-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
645 AM CDT SUN AUG 26 1990

AN ISOLATED INTENSE THUNDERSTOM WAS OVER NORTH CENTRAL IOWA.  AT 535 AM
...THE STORM WAS LOCATED NORTH OF FORT DODGE...JUST SOUTH OF HUMBOLT.
HAIL...WINDS UPTO 40 MILES AN HOUR AND EXTREMELY HEAVY RAINS WILL
OCCUR WITH THIS STORM AS IT MOVES NORTHEAST AT 30 MILES AN HOUR.  BY
730 AM THE STORM WILL BE LOCATED SOUTH OF MASON CITY NEAR BELMOND.

OTHER ISOLATED THUNDERSTORMS WITH VERY HEAVY RAINS WERE LOCATED IN
NORTH CENTRAL IOWA...SOUTHWEST OF MASON CITY NEAR BRITT AND JUST SOUTH-
WEST OF FORT DODGE.   IN WEST CENTRAL IOWA...AN ISOLATED THUNDERSTORM
WITH VERY HEAVY RAIdNS WAS LOCATED 70 MILES WEST OF DES MOINES NEAR
AUDUBON.

THESE STORMS WERE ALSO MOVING NORTHEAST AT 30 MILES AN HOUR.

DLF
Special weather statement, Aug 26, 7:35 AM CDT, 8 minutes before
IAZ002-003-007-261330-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WATERLOO IA
730 AM CDT SUN AUG 26 1990

AT 725 AM CDT A STRONG THUNDERSTORM WAS LOCATED IN THE NORTHERN
HALF OF ALLAMAKEE COUNTY IN EXTREME NORTHEAST IOWA.
THIS THUNDERSTORM CAN PRODUCE EXTREMELY HEAVY RAINS...HAIL AND
WIND GUSTS TO 40 TO 50 MILES AN HOUR. THE STORM WAS MOVING SOUTHEAST
AT 20 MILES AN HOUR AND WILL EFFECT THE TOWNS OF LANSING...NEW ALBIN
AND HARPERS FERRY ALONG THE MISSISSIPPI RIVER BETWEEN 730 AND 800 AM CDT.

ANOTHER STRONG THUNDERSTORM WAS BETWEEN BELMOND AND DOWS...50 MILES
NORTHWEST OF WATERLOO. THIS STORM IS MOVING EAST AT 20 MILES AN HOUR AND
CAN PRODUCE HAIL...EXTREMELY HEAVY RAINS AND GUSTY SURFACE WIND AS IT ENTERS
WESTERN FRANKLIN COUNTY AROUND 745 AM.

JOHNSON
Special weather statement, Aug 26, 7:35 AM CDT, 8 minutes before
IAZALL-261330-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
735 AM CDT SUN AUG 26 1990

AT 725 AM CDT...AN INTENSE THUNDERSTORM WAS LOCATED OVER NORTH CENTRAL
IOWA...BETWEEN CLARION AND BELMOND...OR ABOUT 35 MILES SOUTHWEST OF
MASON CITY.  THIS THUNDERSTORM ALONG WITH BRIEF VERY HEAVY RAINFALL
COULD ALSO PRODUCE SOME HAIL AND BRIEF STRONG GUSTY WIND AS IT MOVES
NORTHEAST AT 25 MILES AN HOUR.

OVER THE REMAINDER OF NORTH CENTRAL AND CENTRAL IOWA...SCATTERED
SHOWERS AND THUNDERSTORMS WERE LOCATED OVER ABOUT A 40 MILE WIDE AREA
FROM 15 MILES NORTHEAST OF MASON CITY...TO NEAR EXIRA...OR 60 MILES
WEST OF DES MOINES.  THESE SHOWERS AND THUNDERSTORMS WERE MOVING
NORTHEAST AT 25 MILES AN HOUR.

SCATTERED SHOWERS AND THUNDERSTORMS WERE ALSO MOVING RAPIDLY ACROSS
THE EXTREME NORTHEAST CORNER OF IOWA.  THESE SHOWERS AND STORMS WERE
MOVING EAST AT 40 MILES AN HOUR.

WPM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 26, 6:35 AM CDTSevere Thunderstorm WarningDMXHumboldt18 min
Aug 26, 6:35 AM CDTSevere Thunderstorm WarningDMXWright30 min
Aug 26, 7:04 AM CDTSevere Thunderstorm WarningDMXWright31 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1990Every severe thunderstorm 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.