Alert archive / Iowa / Flash Flood Warnings in 2016

Flash Flood Warning 31, NWS Des Moines, IA

September 21, 2016Bremer County, Iowa

NWS Des Moines, IA issued this flash flood warning at Sep 21, 2016, 8:54 PM CDT for Bremer County, Iowa. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 21, 2016, 8:54 PM CDT (01:54 UTC)
Expired
Sep 22, 2016, 3:00 AM CDT
In force
6 hr
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Flood severity
None

County Bremer County, IA

The radar

The La Crosse radar (KARX), 149 km from the middle of the area, began a volume at 01:57 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

Davenport, (KDVN), launched 00:00Z, 1.9 hours before the alert went out and 201 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, Davenport, at 00:00Z on 2016-09-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 560 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, Davenport, at 00:00Z on 2016-09-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 113 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
560 J/kg
Mixed-layer CIN
-186 J/kg
Mixed-layer LCL
1439 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
113 m²/s²
0-3 km storm-relative helicity
249 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

347 
WGUS53 KDMX 220154
FFWDMX
IAC017-220800-
/O.NEW.KDMX.FF.W.0031.160922T0154Z-160922T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
854 PM CDT WED SEP 21 2016

THE NATIONAL WEATHER SERVICE IN DES MOINES  HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  BREMER COUNTY IN NORTHEASTERN IOWA...

* UNTIL 300 AM CDT THURSDAY.

* AT 853 PM CDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING
  HEAVY RAIN ACROSS THE WARNED AREA. UPWARDS OF 6 PLUS INCHES OF
  RAIN HAVE FALLEN IN AREAS TO THE WEST AND NORTHWEST AND HAVE BEGUN
  TO MOVE INTO THE WARNED AREA WHERE 2 PLUS INCHES HAVE ALREADY
  FALLEN IN PLACES. FLASH FLOODING IS EXPECTED TO BEGIN SHORTLY.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  WAVERLY...SUMNER...TRIPOLI...READLYN...PLAINFIELD...FREDERIKA AND
  WAVERLY MUNICIPAL AIRPORT.

ADDITIONAL RAINFALL AMOUNTS OF 4 OR MORE INCHES ARE POSSIBLE IN THE
WARNED AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

&&

LAT...LON 4274 9255 4291 9255 4291 9208 4264 9208

$$

CURTIS
1 follow-up statement
309 
WGUS73 KDMX 220424
FFSDMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
1124 PM CDT WED SEP 21 2016

IAC017-220800-
/O.CON.KDMX.FF.W.0031.000000T0000Z-160922T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BREMER IA-
1124 PM CDT WED SEP 21 2016

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 300 AM CDT FOR
NORTHWESTERN BREMER COUNTY...

AT 1120 PM CDT...THE THREAT FOR FLASH FLOODING CONTINUES ACROSS THE
WARNED AREA. UPWARDS OF FIVE INCHES OF RAIN FELL OVER NORTHWEST
BREMER COUNTY THIS EVENING. THIS WILL LEAD TO EXTREMELY RAPID RISES
ON AREA STREAMS AND IN LOW AREAS PRONE TO FLOODING. ADDITIONAL HEAVY
RAINFALL IS ALSO FORECAST TONIGHT WHICH MAY EXACERBATE THE FLOODING
CONDITIONS.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
TRIPOLI...PLAINFIELD AND FREDERIKA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...FARMLAND...AND OTHER LOW LYING
SPOTS.

&&

LAT...LON 4274 9255 4291 9255 4291 9218 4281 9226

$$

SKOW

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 21, 7:05 PM CDTSevere Thunderstorm WarningDMXCerro Gordo55 min
Sep 21, 7:16 PM CDTTornado WarningDMXCerro Gordo13 min
Sep 21, 7:43 PM CDTTornado WarningDMXBremer, Butler47 min
Sep 21, 8:26 PM CDTSpecial Weather StatementDMXBremer64 min
Sep 21, 9:05 PM CDTSpecial Weather StatementDMXBremer40 min
Sep 21, 9:39 PM CDTRiver Flood WarningDMXBlack Hawk, Bremer, Butler5 days
Sep 21, 9:40 PM CDTRiver Flood WarningDMXBlack Hawk8 days
Sep 21, 9:41 PM CDTRiver Flood WarningDMXBlack Hawk, Bremer, Butler6 days
Sep 21, 9:50 PM CDTRiver Flood WarningDMXCerro Gordo, Floyd, Worth4 days
Sep 21, 10:51 PM CDTAreal Flood WarningDMXCerro Gordo, Franklin, Worth48 hr
Sep 22, 3:05 AM CDTAreal Flood WarningDMXBremer24 hr
Sep 22, 4:13 AM CDTFlash Flood WarningDMXCerro Gordo, Hancock6 hr
Sep 22, 7:00 AM CDTFlash Flood WarningDMXButler4 hr
Sep 22, 10:22 AM CDTRiver Flood WarningDMXWright6 days
Sep 22, 11:23 AM CDTAreal Flood WarningDMXBremer, Butler24 hr

Nearby

Flash Flood Warnings in Iowa, 2016Every flash flood warning in 2016

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.