Alert archive / Iowa / Flash Flood Warnings in 1996

Flash Flood Warning 12, NWS Des Moines, IA

June 21, 1996Crawford County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jun 21, 1996, 6:47 AM CDT for Crawford 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 21, 1996, 6:47 AM CDT (11:47 UTC)
Expired
Jun 21, 1996, 10:00 AM CDT
In force
3 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

County Crawford County, IA

The radar

The Omaha radar (KOAX), 114 km from the middle of the area, began a volume at 11:46 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 00:00Z, 11.8 hours before the alert went out and 114 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 00:00Z on 1996-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2363 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, Omaha, NE at 00:00Z on 1996-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 112 square meters per square second.193958Sfc1 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
2363 J/kg
Mixed-layer CIN
-22 J/kg
Mixed-layer LCL
1424 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
276 m²/s²
Significant tornado parameter
2.1
Supercell composite
19.6

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 211147
FFWDSM
IAC047-211500-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
647 AM CDT FRI JUN 21 1996

* FLASH FLOOD WARNING FOR
  CRAWFORD COUNTY - WEST CENTRAL IOWA

* UNTIL 1000 AM CDT
 
* SOME STREAMS AFFECTED
    BOYER RIVER
    WEST FORK OF THE NISNABOTNA RIVER
    OTTER CREEK
    BIG CREEK

* CAUSE AND EFFECT
    UP TO 5 INCHES OF RAIN HAS FALLEN OVER THE COUNTY SINCE
    MIDNIGHT...WITH TWO-DAY TOTALS UP TO 9 INCHES.

* FORECAST CONDITIONS
    NUMEROUS HIGHWAYS WILL REMAIN FLOODED...INCLUDING HIGHWAY 30 AND
    141. EVACTUATIONS CONTINUE ALONG THE BOYER RIVER AS IT RISES
    OUT OF ITS BANKS. THE RAIN WILL END BY 900 AM...BUT RUNOFF WILL
    CONTINUE UNTIL LATER IN THE MORNING.

LEAVE FLOOD PRONE OR LOW LYING AREAS IMMEDIATELY. HEED THE ADVICE OF
EMERGENCY MANAGEMENT OFFICIALS AND EVACUATE IF YOU ARE TOLD TO DO SO.

PYTLAK

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 20, 7:58 PM CDTSevere Thunderstorm WarningDMXSac42 min
Jun 20, 8:13 PM CDTSevere Thunderstorm WarningDMXCalhoun, Pocahontas32 min
Jun 21, 1:04 AM CDTSevere Thunderstorm WarningDMXCrawford26 min
Jun 21, 1:30 AM CDTSevere Thunderstorm WarningDMXCalhoun30 min
Jun 21, 4:10 AM CDTFlash Flood WarningDMXCrawford3 hr
Jun 21, 4:13 AM CDTFlash Flood WarningDMXCarroll, Crawford3 hr

Nearby

Flash Flood Warnings in Iowa, 1996Every flash flood warning in 1996

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.