Alert archive / Iowa / Flash Flood Warnings in 1998

Flash Flood Warning 22, NWS Des Moines, IA

June 24, 1998Hamilton County, Webster County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jun 24, 1998, 12:34 AM CDT for Hamilton County, Webster County, Iowa. It was in force for 4 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 24, 1998, 12:34 AM CDT (05:34 UTC)
Expired: Jun 24, 1998, 4:30 AM CDT
In force: 4 hr
Issued by: NWS Des Moines, IA
Area: Whole counties

Counties Hamilton County, IA, Webster County, IA

The radar

The Des Moines radar (KDMX), 77 km from the middle of the area, began a volume at 05:37 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 00:00Z, 5.6 hours before the alert went out and 273 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 901 J/kg
Mixed-layer CIN: -26 J/kg
Mixed-layer LCL: 1105 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 212 m²/s²
0-3 km storm-relative helicity: 335 m²/s²
Significant tornado parameter: 1.4
Supercell composite: 8.6

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 240534
FFWDSM
IAC079-187-240930-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1234 AM CDT WED JUN 24 1998

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  HAMILTON COUNTY IN CENTRAL IOWA
  WEBSTER COUNTY IN CENTRAL IOWA

* UNTIL 430 AM CDT

* AT 1230 AM CDT... NATIONAL WEATHER SERVICE DOPPLER RADAR
  INDICATED THUNDERSTORMS WITH VERY HEAVY RAIN ACROSS WEBSTER AND
  HAMILTON COUNTIES MOVING EAST AT 20 MPH.

* DOPPLER RADAR ESTIMATES RAINFALL OF 2 TO 3 INCHES ACROSS WEBSTER
  COUNTY WITH 1 TO 2 INCHES IN HAMILTON COUNTY. WITH RAINFALL RATES
  OF 1 TO 2 INCHES AN HOUR EXPECTED FOR ANOTHER HOUR OR TWO...FLASH
  FLOODING CAN BE EXPECTED IN URBAN AREAS AS WELL AS STREAMS ACROSS
  THESE COUNTIES.

SOME STREAMS AFFECTED INCLUDE...
  THE TRIBUTARIES OF THE DES MOINES RIVER IN WEBSTER COUNTY AS WELL
  AS THE HEADWATERS OF THE SOUTH SKUNK RIVER AND ITS TRIBUTARIES IN
  HAMILTON COUNTY.  IN ADDITION...THE HEADWATERS OF SQUAW CREEK
  IN HAMILTON COUNTY.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGER OF FLOODING.

COGIL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 23, 8:59 PM CDT	Severe Thunderstorm Warning	DMX	Sac	46 min
Jun 23, 9:25 PM CDT	Severe Thunderstorm Warning	DMX	Crawford	30 min
Jun 23, 9:47 PM CDT	Tornado Warning	DMX	Sac	33 min
Jun 23, 9:52 PM CDT	Tornado Warning	DMX	Calhoun	33 min
Jun 23, 10:08 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun, Carroll	47 min
Jun 23, 10:17 PM CDT	Severe Thunderstorm Warning	DMX	Webster	33 min
Jun 23, 10:19 PM CDT	Flash Flood Warning	DMX	Palo Alto	3 hr
Jun 23, 10:38 PM CDT	Severe Thunderstorm Warning	DMX	Humboldt	32 min
Jun 23, 10:41 PM CDT	Flash Flood Warning	DMX	Kossuth	4 hr
Jun 23, 10:41 PM CDT	Flash Flood Warning	DMX	Sac	4 hr
Jun 23, 10:54 PM CDT	Flash Flood Warning	DMX	Pocahontas	4 hr
Jun 23, 11:20 PM CDT	Flash Flood Warning	DMX	Crawford	4 hr
Jun 23, 11:31 PM CDT	Flash Flood Warning	DMX	Winnebago	4 hr
Jun 23, 11:34 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Franklin, Worth	31 min
Jun 23, 11:53 PM CDT	Flash Flood Warning	DMX	Calhoun	4 hr
Jun 23, 11:56 PM CDT	Severe Thunderstorm Warning	DMX	Butler	34 min
Jun 24, 2:35 AM CDT	Flash Flood Warning	DMX	Sac	4 hr
Jun 24, 2:50 AM CDT	Flash Flood Warning	DMX	Crawford	4 hr

Nearby

Flash Flood Warnings in Iowa, 1998 Every 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.