Alert archive / Iowa / Flash Flood Watches in 2021

Flash Flood Watch 5, NWS Des Moines, IA

August 12, 2021Appanoose County, Davis County, Iowa

NWS Des Moines, IA issued this flash flood watch at Aug 12, 2021, 1:30 PM CDT for Appanoose County, Davis County, Iowa. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Aug 12, 2021, 1:30 PM CDT (18:30 UTC)
Expired
Aug 12, 2021, 8:13 PM CDT
In force
7 hr
Issued by
NWS Des Moines, IA
Flood severity
None

Counties Appanoose County, IA, Davis County, IA

The radar

The Des Moines radar (KDMX), 142 km from the middle of the area, began a volume at 18:32 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 12:00Z, 6.5 hours before the alert went out and 204 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 12:00Z on 2021-08-12Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 2021-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 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
2463 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
27 m²/s²
0-3 km storm-relative helicity
71 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

301 
WGUS63 KDMX 121830
FFADMX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Des Moines IA
130 PM CDT Thu Aug 12 2021

IAZ096-097-130230-
/O.NEW.KDMX.FF.A.0005.210812T1830Z-210813T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Appanoose-Davis-
Including the cities of Centerville and Bloomfield
130 PM CDT Thu Aug 12 2021

...FLASH FLOOD WATCH IN EFFECT THROUGH FRIDAY MORNING...

The National Weather Service in Des Moines has issued a

* Flash Flood Watch for portions of south central Iowa and southeast 
  Iowa, including the following areas, in south central Iowa, 
  Appanoose. In southeast Iowa, Davis.

* Through Friday morning.

* Heavy rainfall of 2 to 5 inches fell over portions of the watch 
  area Thursday morning. Additional thunderstorms and heavy rainfall 
  are possible Thursday evening through early Friday morning which 
  may lead to flash flooding.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Martin
2 follow-up statements
970 
WGUS63 KDMX 122214
FFADMX

Flood Watch
National Weather Service Des Moines IA
514 PM CDT Thu Aug 12 2021

IAZ096-097-130615-
/O.CON.KDMX.FF.A.0005.000000T0000Z-210813T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Appanoose-Davis-
Including the cities of Centerville and Bloomfield
514 PM CDT Thu Aug 12 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY MORNING...

The Flash Flood Watch continues for

* Portions of south central Iowa and southeast Iowa, including the 
  following areas, in south central Iowa, Appanoose. In southeast 
  Iowa, Davis.

* Through Friday morning.

* 2 To 5 inches of rainfall occurred throughout the area this 
  morning. If additional thunderstorms produce heavy rainfall again, 
  Flash Flooding is possible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Krull
368 
WGUS63 KDMX 130113
FFADMX

Flood Watch
National Weather Service Des Moines IA
813 PM CDT Thu Aug 12 2021

IAZ096-097-130215-
/O.CAN.KDMX.FF.A.0005.000000T0000Z-210813T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Appanoose-Davis-
Including the cities of Centerville and Bloomfield
813 PM CDT Thu Aug 12 2021

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of south central Iowa and 
southeast Iowa, including the following areas, in south central 
Iowa, Appanoose. In southeast Iowa, Davis has been cancelled.

The Flood Watch is cancelled. Flooding is no longer expected to pose 
a threat. Please continue to heed remaining road closures.

$$

Krull

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 4:30 AM CDTSpecial Weather StatementDMXDecatur30 min
Aug 12, 4:58 AM CDTSpecial Weather StatementDMXDecatur47 min
Aug 12, 7:38 AM CDTSpecial Weather StatementDMXDavis52 min
Aug 12, 11:12 AM CDTFlash Flood WarningDMXAppanoose, Davis3 hr

Nearby

Flash Flood Watches in Iowa, 2021Every flash flood watch in 2021

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.