Alert archive / Iowa / Flash Flood Warnings in 1998

Flash Flood Warning 14, NWS Des Moines, IA

June 20, 1998Winnebago County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jun 20, 1998, 2:06 PM CDT for Winnebago County, Iowa. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jun 20, 1998, 2:06 PM CDT (19:06 UTC)
Expired
Jun 20, 1998, 5:05 PM CDT
In force
3 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

County Winnebago County, IA

The radar

The Minneapolis radar (KMPX), 164 km from the middle of the area, began a volume at 19:08 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 7.1 hours before the alert went out and 164 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 1998-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 18 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 1998-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 416 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
18 J/kg
Mixed-layer CIN
-384 J/kg
Mixed-layer LCL
2049 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
416 m²/s²
0-3 km storm-relative helicity
589 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 201907
FFWDSM
IAC189-202205-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
206 PM CDT SAT JUN 20 1998

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WINNEBAGO COUNTY IN NORTH CENTRAL IOWA

* UNTIL 505 PM CDT

* AT 200 PM CDT...RADAR INDICATED A THUNDERSTORM WITH VERY HEAVY
  RAIN NEAR LAKE MILLS WITH ANOTHER STORM SOUTH OF BUFFALO CENTER...
  MOVING NORTHEAST AT 30 MPH.

* UPWARDS OF 3 INCHES OF RAIN HAS FALLEN OVER NORTHERN WINNEBAGO
  COUNTY WITH A SPOTTER NEAR SCARVILLE REPORTING 5 INCHES OF RAIN
  IN LESS THAN ONE HOUR. STREET FLOODING WAS REPORTED IN LAKE MILLS.

SOME STREAMS AFFECTED INCLUDE...
  LIME CREEK...BUFFALO CREEK AND AREAS AROUND LAKE MILLS

DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD!

JUNGBLUTH

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, Jun 20, 11:52 AM CDT, 2 hours 14 minutes before
IAZ004-005-015-023-024-033>037-044>050-057>062-070>075-081>086-
092>097-202200-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
1152 AM CDT SAT JUN 20 1998

HAZARD--SCATTERED THUNDERSTORMS...SOME CAPABLE OF PRODUCING HAIL UP
TO 2 INCHES IN DIAMETER...WINDS TO 80 MPH...AND RAINFALL AMOUNTS OF
1 TO 2 INCHES.

AREA OF CONCERN AND TIMING DETAILS--THE ENTIRE FORECAST AREA WILL BE
AFFECTED.  THE THREAT WILL LIKELY NOON TO 500 PM WEST OF A LINE FROM
MASON CITY TO ATLANTIC...AND FROM 500 PM UNTIL 1100 PM EAST
OF THAT.

METEOROLOGICAL COMMENTS--A DYNAMIC WEATHER SITUATION WILL DEVELOP
FROM MID AFTERNOON INTO THE EVENING. THUNDERSTORMS SHOULD FORM A
SOLID LINE ALONG A COLD FRONT AS IT SWEEPS ACROSS THE STATE BY SUNDAY
MORNING. AT MIDDAY THE COLD FRONT HAD PUSHED INTO THE NORTHWEST
COUNTIES OF IOWA WITH VERY WARM AND UNSTABLE AIR TO ITS EAST.  DEW
POINTS IN THE 70S ARE PRODUCING STRONG INSTABILITY ACROSS IOWA WITH
CAPE VALUES IN EXCESS OF 5000 J/KG AND LIFTED INDICES AROUND MINUS 12
DEGREES C.  ONLY A WARM LAYER OF AIR ALOFT AROUND 5000 FEET IS
HOLDING BACK THE THUNDERSTORMS AT THIS TIME...BUT THE INSTABILITY
WILL BE RELEASED AS THE COLD FRONT AND A MID-LEVEL JET STREAM MOVE
THROUGH.

TODAYS ENVIRONMENT IS MOST FAVORABLE FOR TORRENTIAL RAINS AND
DAMAGING STRAIGHT LINE WINDS...ALTHOUGH A BRIEF TORNADO AND LARGE
HAIL CANNOT BE RULED OUT DUE TO THE STRONG INSTABILITY. RAINFALL
RATES WILL BE HIGH...BUT THE PROGRESSIVE MOVEMENT OF THE LINE SHOULD
LIMIT MOST RAIN AMOUNTS TO THE 1 TO 2 INCH RANGE.

PRECAUTIONS -PEOPLE WITH WEATHER SENSITIVE ACTIVITIES OR INTERESTS
SHOULD KEEP WATCH FOR FURTHER UPDATES. THE WEATHER SITUATION COULD
CHANGE QUICKLY LATER THIS AFTERNOON AND SEVERE WEATHER WATCHES ARE
LIKELY ACROSS MUCH OF IOWA. SPOTTER ACTIVATION WILL LIKELY BE
REQUIRED SO MONITOR SHORT TERM FORECASTS FOR TIMING INTO ANY SPECIFIC
AREA. PROLONGED HEAVY RAINS ARE NOT EXPECTED...BUT DUE TO SATURATED
GROUND AND HIGH WATER LEVELS...SMALL STREAM FLOODING AND PONDING OF
WATER IS POSSIBLE.

JUNGBLUTH
Special weather statement, Jun 20, 11:52 AM CDT, 2 hours 14 minutes before
IAZ004-005-015-023-024-033>037-044>050-057>062-070>075-081>086-
092>097-202200-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
1152 AM CDT SAT JUN 20 1998

HAZARD--SCATTERED THUNDERSTORMS...SOME CAPABLE OF PRODUCING HAIL UP
TO 2 INCHES IN DIAMETER...WINDS TO 80 MPH...AND RAINFALL AMOUNTS OF
1 TO 2 INCHES.

AREA OF CONCERN AND TIMING DETAILS--THE ENTIRE FORECAST AREA WILL BE
AFFECTED.  THE THREAT WILL LIKELY NOON TO 500 PM WEST OF A LINE FROM
MASON CITY TO ATLANTIC...AND FROM 500 PM UNTIL 1100 PM EAST
OF THAT.

METEOROLOGICAL COMMENTS--A DYNAMIC WEATHER SITUATION WILL DEVELOP
FROM MID AFTERNOON INTO THE EVENING. THUNDERSTORMS SHOULD FORM A
SOLID LINE ALONG A COLD FRONT AS IT SWEEPS ACROSS THE STATE BY SUNDAY
MORNING. AT MIDDAY THE COLD FRONT HAD PUSHED INTO THE NORTHWEST
COUNTIES OF IOWA WITH VERY WARM AND UNSTABLE AIR TO ITS EAST.  DEW
POINTS IN THE 70S ARE PRODUCING STRONG INSTABILITY ACROSS IOWA WITH
CAPE VALUES IN EXCESS OF 5000 J/KG AND LIFTED INDICES AROUND MINUS 12
DEGREES C.  ONLY A WARM LAYER OF AIR ALOFT AROUND 5000 FEET IS
HOLDING BACK THE THUNDERSTORMS AT THIS TIME...BUT THE INSTABILITY
WILL BE RELEASED AS THE COLD FRONT AND A MID-LEVEL JET STREAM MOVE
THROUGH.

TODAYS ENVIRONMENT IS MOST FAVORABLE FOR TORRENTIAL RAINS AND
DAMAGING STRAIGHT LINE WINDS...ALTHOUGH A BRIEF TORNADO AND LARGE
HAIL CANNOT BE RULED OUT DUE TO THE STRONG INSTABILITY. RAINFALL
RATES WILL BE HIGH...BUT THE PROGRESSIVE MOVEMENT OF THE LINE SHOULD
LIMIT MOST RAIN AMOUNTS TO THE 1 TO 2 INCH RANGE.

PRECAUTIONS -PEOPLE WITH WEATHER SENSITIVE ACTIVITIES OR INTERESTS
SHOULD KEEP WATCH FOR FURTHER UPDATES. THE WEATHER SITUATION COULD
CHANGE QUICKLY LATER THIS AFTERNOON AND SEVERE WEATHER WATCHES ARE
LIKELY ACROSS MUCH OF IOWA. SPOTTER ACTIVATION WILL LIKELY BE
REQUIRED SO MONITOR SHORT TERM FORECASTS FOR TIMING INTO ANY SPECIFIC
AREA. PROLONGED HEAVY RAINS ARE NOT EXPECTED...BUT DUE TO SATURATED
GROUND AND HIGH WATER LEVELS...SMALL STREAM FLOODING AND PONDING OF
WATER IS POSSIBLE.

JUNGBLUTH

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 20, 2:48 PM CDTSevere Thunderstorm WarningDMXHancock32 min

Nearby

Flash Flood Warnings in Iowa, 1998Every flash flood warning in 1998

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; radar from the NEXRAD Level II archive.