Alert archive / Iowa / Flash Flood Warnings in 1998

Flash Flood Warning 8, NWS Des Moines, IA

June 18, 1998Polk County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jun 18, 1998, 2:16 PM CDT for Polk 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 18, 1998, 2:16 PM CDT (19:16 UTC)
Expired
Jun 18, 1998, 5:30 PM CDT
In force
3 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

County Polk County, IA

The radar

The Des Moines radar (KDMX), 13 km from the middle of the area, began a volume at 19:19 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

Omaha, NE (KOAX), launched 12:00Z, 7.3 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 12:00Z on 1998-06-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 245 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 1998-06-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -105 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
245 J/kg
Mixed-layer CIN
-251 J/kg
Mixed-layer LCL
1451 m above ground
0-6 km bulk shear
67 kt
0-1 km storm-relative helicity
-105 m²/s²
0-3 km storm-relative helicity
-51 m²/s²
Significant tornado parameter
0.0
Supercell composite
-1.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 181915
FFWDSM
IAC153-182220-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
216 PM CDT THU JUN 18 1998

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  POLK COUNTY IN CENTRAL IOWA

* UNTIL 530 PM CDT

* AT 200 PM CDT... NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  THUNDERSTORM WITH VERY HEAVY RAIN OVER POLK COUNTY... MOVING
  NORTHEAST AT 35 MPH WITH MORE STORMS MOVING INTO THE AREA.

* HEAVY RAINS OF 2 TO 5 INCHES WITH MORE RAIN OCCURRING
  AT THIS TIME WILL CONTINUE WILL CAUSE WIDESPREAD FLOODING
  AND THE RAPID RISE OF CREEKS AND STREAMS.

SOME STREAMS AFFECTED INCLUDE...
  JORDAN CREEK
  WALNUT CR`EEK
  FOUR MILE CREEK

MOVE TO HIGHER GROUND IF FLOOD WATERS THREATEN.

FORSTER

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 18, 9:31 AM CDT, 4 hours 45 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-182200-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
931 AM CDT THU JUN 18 1998

HAZARD--SEVERE THUNDERSTORMS WITH HAIL 1 INCH OR LARGER...
HEAVY RAINS AND DAMAGING WINDS.  AN ISOLATED TORNADO IS ALSO
POSSIBLE.

AREA OF CONCERN AND TIMING DETAILS--

THROUGH NOON--ALONG AND EAST OF A FORT DODGE-ATLANTIC LINE.
NOON TO 800 PM--MAINLY SOUTHEAST OF A FORT DODGE--CRESTON LINE.

METEOROLOGICAL COMMENTS--A COLD FRONT WILL BE THE FOCUS OF
THUNDERSTORM DEVELOPMENT THROUGH THE DAY.  AT 900 AM...THE
FRONT WAS LOCATED FROM NEAR SIOUX CITY TO JUST SOUTH OF OMAHA
INTO SOUTH CENTRAL KANSAS.  A WARM FRONT LOCATED NEAR I-80 WILL
ALSO MOVE NORTH TODAY PROVIDING ANOTHER FOCUS FOR CONVERGENCE.
WARM...UNSTABLE AND VERY MOIST AIR SOUTH OF THIS FRONT AND IS
EXPECTED TO PROVIDE PLENTY OF BUOYANCY FOR STRONG UPDRAFTS FOR
SEVERE THUNDERSTORMS TODAY.  A 100 KNOT SOUTHWESTERLY JET STREAM
WILL BE PUSHING NORTHEAST FROM THE TEXAS PANHANDLE TODAY
INTERSECTING 40 KNOT SOUTHERLY FLOW IN THE LOWEST 5000 FEET.  THIS
WILL CREATE FAVORABLE SHEAR FOR THE MAINTENANCE OF ROTATING
UPDRAFTS AND SEVERE STORMS.  ISOLATED SUPERCELLS ARE POSSIBLE...BUT
AT THIS TIME A SQUALL LINE IS EXPECTED TO FORM EVENTUALLY ALONG THE
COLD FRONT THIS AFTERNOON...SPREADING EASTWARD TOWARD EVENING.

PRECAUTIONS--EMERGENCY MANAGEMENT SHOULD PAY CLOSE ATTENTION TO
SHORT TERM FORECASTS AND FURTHER STATEMENTS TODAY.  SEVERE WEATHER
WATCHES MAY BE ISSUED LATER THIS MORNING OR EARLY AFTERNOON. SPOTTER
ACTIVATION WILL BE REQUIRED IN SEVERAL LOCATIONS. REPORT RAINFALL
AMOUNTS TO THE NATIONAL WEATHER SERVICE IF AVAILABLE.  A FLASH FLOOD
WATCH IS IN EFFECT TODAY.

KULA
Special weather statement, Jun 18, 9:31 AM CDT, 4 hours 45 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-182200-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
931 AM CDT THU JUN 18 1998

HAZARD--SEVERE THUNDERSTORMS WITH HAIL 1 INCH OR LARGER...
HEAVY RAINS AND DAMAGING WINDS.  AN ISOLATED TORNADO IS ALSO
POSSIBLE.

AREA OF CONCERN AND TIMING DETAILS--

THROUGH NOON--ALONG AND EAST OF A FORT DODGE-ATLANTIC LINE.
NOON TO 800 PM--MAINLY SOUTHEAST OF A FORT DODGE--CRESTON LINE.

METEOROLOGICAL COMMENTS--A COLD FRONT WILL BE THE FOCUS OF
THUNDERSTORM DEVELOPMENT THROUGH THE DAY.  AT 900 AM...THE
FRONT WAS LOCATED FROM NEAR SIOUX CITY TO JUST SOUTH OF OMAHA
INTO SOUTH CENTRAL KANSAS.  A WARM FRONT LOCATED NEAR I-80 WILL
ALSO MOVE NORTH TODAY PROVIDING ANOTHER FOCUS FOR CONVERGENCE.
WARM...UNSTABLE AND VERY MOIST AIR SOUTH OF THIS FRONT AND IS
EXPECTED TO PROVIDE PLENTY OF BUOYANCY FOR STRONG UPDRAFTS FOR
SEVERE THUNDERSTORMS TODAY.  A 100 KNOT SOUTHWESTERLY JET STREAM
WILL BE PUSHING NORTHEAST FROM THE TEXAS PANHANDLE TODAY
INTERSECTING 40 KNOT SOUTHERLY FLOW IN THE LOWEST 5000 FEET.  THIS
WILL CREATE FAVORABLE SHEAR FOR THE MAINTENANCE OF ROTATING
UPDRAFTS AND SEVERE STORMS.  ISOLATED SUPERCELLS ARE POSSIBLE...BUT
AT THIS TIME A SQUALL LINE IS EXPECTED TO FORM EVENTUALLY ALONG THE
COLD FRONT THIS AFTERNOON...SPREADING EASTWARD TOWARD EVENING.

PRECAUTIONS--EMERGENCY MANAGEMENT SHOULD PAY CLOSE ATTENTION TO
SHORT TERM FORECASTS AND FURTHER STATEMENTS TODAY.  SEVERE WEATHER
WATCHES MAY BE ISSUED LATER THIS MORNING OR EARLY AFTERNOON. SPOTTER
ACTIVATION WILL BE REQUIRED IN SEVERAL LOCATIONS. REPORT RAINFALL
AMOUNTS TO THE NATIONAL WEATHER SERVICE IF AVAILABLE.  A FLASH FLOOD
WATCH IS IN EFFECT TODAY.

KULA
Local storm report, Jun 18, 9:57 AM CDT, 4 hours 19 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
957 AM CDT THU JUN 18 1998

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0800 AM    CORYDON                   IA   WIND DAMAGE
06/18/98   WAYNE                          UTILITY POLES AND TREES
                                          DOWN, STRONG WINDS
Special weather statement, Jun 18, 12:59 PM CDT, 1 hour 17 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-190100-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
1259 PM CDT THU JUN 18 1998

HAZARD--SEVERE THUNDERSTORMS WITH DAMAGING WINDS ABOVE 60 MPH...HAIL
1 INCH OR LARGER AND HEAVY RAINS.  URBAN AND SMALL STREAM FLOODING
IS LIKELY WITH THE HEAVIEST STORMS.

AREA OF CONCERN AND TIMING DETAILS--

EAST OF A POCAHONTAS--AUDUBON--BEDFORD LINE...OR VIRTUALLY ALL OF
CENTRAL INTO EASTERN IOWA FROM NOW UNTIL 600 PM.

METEOROLOGICAL COMMENTS--A COLD FRONT WAS APPROACHING A STORM LAKE--
AUDUBON--SHENANDOAH LINE AND WILL PUSH EAST THIS AFTERNOON.  THE
FIRST ROUND OF STORMS WHICH PRODUCED SEVERE WEATHER IN CENTRAL IOWA
WAS AFFECTING AREAS OF NORTH CENTRAL IOWA NORTH OF WEBSTER CITY UP
TOWARDS MASON CITY.  NEWER DEVELOPMENT WAS TAKING PLACE RAPIDLY
IN CENTRAL AND SOUTH CENTRAL IOWA FROM BOONE THROUGH CRESTON.  OTHER
STORMS MOVING INTO TAYLOR AND RINGGOLD COUNTIES FROM MISSOURI WILL
MOVE NORTHEAST AT 50 MPH ALSO.  ANY ONE OF THESE STORMS IS CAPABLE
OF SEVERE WEATHER.

PRECAUTIONS--EMERGENCY MANAGEMENT SHOULD PAY CLOSE ATTENTION TO
SHORT TERM FORECASTS AND FURTHER WARNINGS.   SPOTTER ACTIVATION WILL
BE REQUIRED IN SEVERAL LOCATIONS.  REPORT RAINFALL AMOUNTS TO THE
NATIONAL WEATHER SERVICE IF AVAILABLE.  A FLASH FLOOD WATCH IS ALSO
IN EFFECT TODAY.

KULA

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 18, 3:35 AM CDTSevere Thunderstorm WarningDMXEmmet30 min
Jun 18, 9:12 AM CDTSevere Thunderstorm WarningDMXAdair, Cass, Guthrie33 min
Jun 18, 10:05 AM CDTSevere Thunderstorm WarningDMXWebster35 min
Jun 18, 10:41 AM CDTSevere Thunderstorm WarningDMXMarion34 min
Jun 18, 10:45 AM CDTSevere Thunderstorm WarningDMXBoone, Webster35 min
Jun 18, 10:54 AM CDTSevere Thunderstorm WarningDMXPolk31 min
Jun 18, 11:06 AM CDTSevere Thunderstorm WarningDMXJasper34 min
Jun 18, 11:12 AM CDTSevere Thunderstorm WarningDMXWarren33 min
Jun 18, 11:15 AM CDTSevere Thunderstorm WarningDMXMarshall, Story35 min
Jun 18, 11:21 AM CDTSevere Thunderstorm WarningDMXMarion34 min
Jun 18, 11:22 AM CDTSevere Thunderstorm WarningDMXPolk33 min
Jun 18, 11:36 AM CDTSevere Thunderstorm WarningDMXJasper34 min
Jun 18, 11:40 AM CDTSevere Thunderstorm WarningDMXBoone35 min
Jun 18, 11:43 AM CDTSevere Thunderstorm WarningDMXHardin32 min
Jun 18, 11:50 AM CDTSevere Thunderstorm WarningDMXMarshall, Story30 min
Jun 18, 12:01 PM CDTSevere Thunderstorm WarningDMXHamilton, Webster34 min
Jun 18, 12:55 PM CDTSevere Thunderstorm WarningDMXWinnebago, Worth30 min
Jun 18, 1:30 PM CDTSevere Thunderstorm WarningDMXDallas, Polk35 min
Jun 18, 1:33 PM CDTSevere Thunderstorm WarningDMXUnion32 min
Jun 18, 1:56 PM CDTTornado WarningDMXWarren34 min
Jun 18, 1:59 PM CDTFlash Flood WarningDMXDallas3 hr
Jun 18, 2:09 PM CDTSevere Thunderstorm WarningDMXPolk31 min
Jun 18, 2:16 PM CDTTornado WarningDMXPolk34 min
Jun 18, 2:19 PM CDTFlash Flood WarningDMXStory3 hr
Jun 18, 2:35 PM CDTFlash Flood WarningDMXMadison3 hr
Jun 18, 3:03 PM CDTSevere Thunderstorm WarningDMXMahaska, Marion32 min
Jun 18, 3:12 PM CDTSevere Thunderstorm WarningDMXPoweshiek28 min
Jun 18, 3:16 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Tama34 min
Jun 18, 3:34 PM CDTSevere Thunderstorm WarningDMXDavis, Wapello31 min
Jun 18, 5:04 PM CDTFlash Flood WarningDMXPolk, Story2 hr

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.