Alert archive / Iowa / Flash Flood Warnings in 1998
Flash Flood Warning 32, NWS Des Moines, IA
NWS Des Moines, IA issued this flash flood warning at Aug 20, 1998, 6:56 PM CDT for Hamilton County, Iowa. It was in force for 2 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
- Aug 20, 1998, 6:56 PM CDT (23:56 UTC)
- Expired
- Aug 20, 1998, 9:00 PM CDT
- In force
- 2 hr
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Hamilton County, IA
The radar
The Des Moines radar (KDMX), 73 km from the middle of the area, began a volume at 23:57 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, 11.9 hours before the alert went out and 250 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.
- Mixed-layer CAPE
- 1044 J/kg
- Mixed-layer CIN
- -153 J/kg
- Mixed-layer LCL
- 1552 m above ground
- 0-6 km bulk shear
- 12 kt
- 0-1 km storm-relative helicity
- 25 m²/s²
- 0-3 km storm-relative helicity
- 87 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KDSM 202356 FFWDSM IAC079-210200- BULLETIN - EAS ACTIVATION REQUESTED FLASH FLOOD WARNING NATIONAL WEATHER SERVICE DES MOINES IA 656 PM CDT THU AUG 20 1998 THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A * FLASH FLOOD WARNING FOR... NORTHERN HAMILTON COUNTY IN CENTRAL IOWA * UNTIL 900 PM CDT * AT 655 PM CDT... NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A THUNDERSTORM WITH VERY HEAVY RAIN NEAR WEBSTER CITY... MOVING EAST AT ONLY 5 MPH. * UP TO 6 INCHES OF RAIN CAN BE EXPECTED. SERIOUS FLASH FLOODING HAS BEGUN IN WEBSTER CITY. SOME STREAMS AFFECTED INCLUDE... WHITE FOX CREEK BUCK CREEK HEADWATERS OF THE SOUTH SKUNK RIVER HEADWATERS OF BOONE RIVER DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD! PYTLAK
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, Aug 20, 3:47 PM CDT, 3 hours 9 minutes before
IAZ044>046-057-058-070-071-081-082-092-093-210000- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 347 PM CDT THU AUG 20 1998 ADVISORY INFORMATION--A HEAT ADVISORY REMAINS IN EFFECT UNTIL EARLY EVENING FOR SOUTHWEST IOWA. RECENT REPORTS--HEAT INDICES WERE IN THE 105 TO 115 DEGREE RANGE THROUGHOUT SOUTHWEST IOWA. EVEN IN CENTRAL IOWA...HEAT INDICES HAVE CLIMBED TO AROUND 105 DEGREES THIS AFTERNOON. TEMPERATURES WERE TOPPING OUT IN THE MID 90S BUT DEWPOINTS WERE NEAR 80 DEGREES. SLOW COOLING IS NOT EXPECTED TO OCCUR UNTIL AFTER 700 PM. PRECAUTIONS--DELAY ANY OUTDOOR ACTIVITIES UNTIL LATER THIS EVENING. IF YOU MUST BE OUTSIDE AIR CONDITIONING...TAKE APPROPRIATE PRECAUTIONS. PYTLAK
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.