Alert archive / Iowa / Flash Flood Warnings in 1987

Flash Flood Warning 1, NWS Des Moines, IA

July 7, 1987Clarke County, Decatur County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jul 7, 1987, 8:16 AM CDT for Clarke County, Decatur County, Iowa. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Jul 7, 1987, 8:16 AM CDT (13:16 UTC)
Expired
Jul 7, 1987, 11:00 AM CDT
In force
3 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

Counties Clarke County, IA, Decatur County, IA

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 1.3 hours before the alert went out and 222 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 1987-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 1987-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3600 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
64 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 071318
FFWDSM
IAC039-053-071600-
<PQ<
BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
816 AM CDT TUE JUL 7 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING
EFFECTIVE UNTIL 1100 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTIES OF

SOUTH CENTRAL IOWA...
 CLARKE AND NORTHWEST DECATUR

A FLASH FLOOD WARNING MEANS FLOODING IS IMMINENT OR IS OCCURRING.
TAKE NECESSARY PRECAUTIONS IMMEDIATELY.

VERY HEAVY RAINS FELL OVER MOST OF CLARKE COUNTY AND NORTHWEST
DECATUR COUNTY IN SOUTH CENTRAL IOWA EARLY THIS MORNING.  AMOUNTS
RANGED ANYWHERE FROM 4 TO 6 INCHES.

WATER WAS REPORTED TO BE OVER ROADS IN MUCH OF CLARKE AND NORTH-
WEST DECATUR COUNTY.  SMALL CREEKS AND MANY FIELDS WERE FLOODED.

MORE HEAVY RAINS CAN BE EXPECTED IN THESE AREAS DURING THE DAY AS
PRECIPITATION NOW IN WESTERN IOWA WILL MOVE ACROSS THE SAME AREA.

SIGNIFICANT RISES CAN ALSO BE EXPECTED ON THE THOMPSON RIVER NEAR
DAVIS CITY.  A MORE SPECIFIC FORECAST WILL BE AVAILABLE LATER
THIS MORNING.

PEOPLE IN FLOOD PRONE OR LOW LYING AREAS SHOULD MOVE TO HIGHER GROUND
AT ONCE.  ACT QUICKLY..AS FLOOD WATERS OFTEN RISE RAPIDLY.

IF YOU ARE DRIVING..DO NOT TRY TO DRIVE THROUGH FLOOD WATERS OF
UNKNOWN DEPTH.  IF YOUR VEHICLE STALLS..ABANDON IT IMMEDIATELY
AND SEEK HIGHER GROUND.

DO NOT ATTEMPT TO CROSS A FLOWING STREAM ON FOOT WHERE THE WATER
IS ABOVE YOUR KNEES.

ADAMS/BAKER

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, Jul 7, 2:58 AM CDT, 5 hours 18 minutes before
<PQ<
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
257 AM CDT TUE JUL 7 1987

THE SEVERE THUNDERSTORM WARNING FOR CLAY AND BUENA VISTA COUNTIES OF
NORTHWEST IOWA WILL EXPIRE AT 300 AM CDT.

AT 250 AM CDT...RADAR INDICATED THAT THE STORMS OVER THESE RESPECTIVE
COUNTIES HAVE WEAKENED.  THEREFORE...THE WARNINGS WILL NOT BE RENEWED.

MOVEMENT OF THE STORMS HAS CONTINUED EAST AROUND 25 MILES AN HOUR.

BIKLE
Special weather statement, Jul 7, 5:46 AM CDT, 2 hours 30 minutes before
SPECIAL WEATHER STATEMENT         <PQ<
NATIONAL WEATHER SERVICE DES MOINES IA
540 AM CDT TUE JUL 7 1987

SEVERE THUNDERSTORM WATCH NUMBER 335 FOR A LARGE PART OF
WESTERN AND CENTRAL IOWA HAS &BEEN CANCELLED.  SHOWERS AND
THUNDERSTORMS WILL CONTINUE FOR THE NEXT SEVERAL HOURS BUT
THE THREAT OF SEVERE STORMS HAS ENDED.  LOCALLY HEAVY RAINS
WILL STILL BE POSSIBLE.

CORBETT
Special weather statement, Jul 7, 5:52 AM CDT, 2 hours 24 minutes before
TTAASE KDSM 071052

RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
545 AM CDT TUE JUL 7 1987

AT 530 AM...AN AREA OF THUNDERSTORMS WITH VERY HEAVY RAINS WAS LOCATED
IN CENTRAL AND LSOUTH LCENTRAL IOWA.  THE  HEAVIEST THUNDERSTORMS WERE
LOCATED IN SOUTH CENTRAL IOWA JUST NORTH OF MOUNT AYR...ABOUT 40 MILES
MILES SOUTHEAST OF DES MOINES.

LLGHT RAIN WITH A FEW SCATTERED THUNDERSTORMS WERE ALSO FALLING ON MOST
OF CENTRAL AND WEST CENTRAL IOWA...AS WELL AS A SMALL +PART OF NORTH
CENTRAL IOWA.

THESE STORMS WERE MOVING TO THE EAST AT 45 MILES AN HOUR.

SCOTT
Local storm report, Jul 7, 6:53 AM CDT, 1 hour 23 minutes before
LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
654 AM CDT TUE JUL 7 1987

...ALL EVENTS OCCURRED DURING THE MORNING OF JULY 7TH...

150   UNCONFIRMED FUNNEL CLOUD REPORTED BETWEEN ROYAL AND
      PETERSON IN SOUTHWEST CLAY COUNTY.

210   60 MILES AN HOUR WIND REPORTED AT MARATHON IN NORTHEAST
      BUENA VISTA COUNTY.

210   UNCONFIRMED TORNADO REPORTED AT TERRILL IN SOUTHEAST
      DICKINSON COUNTY.

245   62 MILES AN HOUR WIND REPORTED AT CARROLL IN CENTRAL
      CARROLL COUNTY.  RECEIVED REPORT OF THIS AT 545...THREE
      HOURS LATER.

UNK   UNCONFIRMED REPORT OF FUNNEL CLOUD NEAR THE JOHN DEERE PLANT
   EAST OF SAYLORVILLE RESERVOIR.  RECEIVED REPORT AT 4a43 AM CDT.

BIKLE
Local storm report, Jul 7, 6:56 AM CDT, 1 hour 20 minutes before
LOCAL STORM REPORT...CORRECTION
NATIONAL WEATHER SERVICE DES MOINES IA
656 AM CDT TUE JUL 7 1987

...ALL EVENTS OCCURRED DURING THE MORNING OF JULY 7TH...

150   UNCONFIRMED FUNNEL CLOUD REPORTED BETWEEN ROYAL AND
      PETERSON IN SOUTHWEST CLAY COUNTY.

210   60 MILES AN HOUR WIND REPORTED AT MARATHON IN NORTHEAST
      BUENA VISTA COUNTY.

210   UNCONFIRMED TORNADO REPORTED AT TERRILL IN SOUTHEAST
      DICKINSON COUNTY.

245   62 MILES AN HOUR WIND REPORTED AT CARROLL IN CENTRAL
      CARROLL COUNTY.  RECEIVED REPORT OF THIS AT 545...THREE
      HOURS LATER.

UNK   UNCONFIRMED REPORT OF FUNNEL CLOUD NEAR THE JOHN DEERE PLANT
   EAST OF SAYLORVILLE RESERVOIR IN POLkK COUNTY.  RECEIVED REPORT
   AT 443 AM CDT.

BIKLE

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 6, 7:27 PM CDTSevere Thunderstorm WarningDMXMahaska33 min
Jul 7, 2:06 AM CDTSevere Thunderstorm WarningDMXBuena Vista, Clay84 min

Nearby

Flash Flood Warnings in Iowa, 1987Every flash flood warning in 1987

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.