Alert archive / Delaware / Flash Flood Warnings in 2011

Flash Flood Warning 15, NWS Philadelphia/Mount Holly

July 31, 2011Kent County, New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 31, 2011, 3:33 PM EDT for Kent County, New Castle County, Delaware. 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 outline as issued.

The facts

Issued: Jul 31, 2011, 3:33 PM EDT (19:33 UTC)
Expired: Jul 31, 2011, 5:55 PM EDT
In force: 2 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Kent County, DE, New Castle County, DE

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 7.6 hours before the alert went out and 150 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2108 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -22 m²/s²
0-3 km storm-relative helicity: 22 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.

806 
WGUS51 KPHI 311933
FFWPHI
DEC001-003-312330-
/O.NEW.KPHI.FF.W.0015.110731T1933Z-110731T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
333 PM EDT SUN JUL 31 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHERN KENT COUNTY IN CENTRAL DELAWARE...
  THIS INCLUDES THE CITY OF DOVER...
  SOUTHWESTERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...

* UNTIL 730 PM EDT

* AT 327 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  THAT THUNDERSTORMS CONTINUE TO FORM AND MOVE ACROSS NORTHERN 
  DELAWARE. STORM TOTALS HAVE REACHED AROUND TWO INCHES AND THE
  POTENTIAL EXISTS FOR AN ADDITIONAL ONE TO TWO INCHES OF RAIN.
  THE SMYRNA RIVER AND SNOWS BRANCH ARE THE MOST LIKELY WATERWAYS
  TO FLOOD.
 
* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO WOODLAND
  BEACH...GREEN SPRING...DELANEY CORNER...SMYRNA...CLAYTON AND
  CHESWOLD

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

&&

LAT...LON 3933 7577 3935 7567 3937 7550 3932 7543
      3924 7538 3920 7538 3916 7540 3912 7575

$$

TFG/GTH

1 follow-up statement

550 
WGUS71 KPHI 312155
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
555 PM EDT SUN JUL 31 2011

DEC001-003-312203-
/O.CAN.KPHI.FF.W.0015.000000T0000Z-110731T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
KENT DE-NEW CASTLE DE-
555 PM EDT SUN JUL 31 2011

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR SOUTHWESTERN NEW
CASTLE AND NORTHERN KENT COUNTIES...

NO ONGOING FLOODING IS OCCURRING AND WHAT IS LEFT OF THE  
THUNDERSTORMS THAT EARLIER PRODUCED THE HEAVY RAIN HAVE MOVED 
INTO DELAWARE BAY.
 
LAT...LON 3933 7577 3935 7567 3937 7550 3932 7543
      3924 7538 3920 7538 3916 7540 3912 7575

$$
 
TFG

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 31, 2:09 PM EDT	Special Weather Statement	PHI	Kent	66 min
Jul 31, 2:35 PM EDT	Areal Flood Advisory	PHI	Kent	115 min
Jul 31, 2:45 PM EDT	Special Weather Statement	PHI	Kent	90 min
Jul 31, 3:58 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle	36 min
Jul 31, 4:36 PM EDT	Special Weather Statement	PHI	Kent	84 min
Jul 31, 4:56 PM EDT	Special Weather Statement	PHI	Sussex	64 min

Nearby

Flash Flood Warnings in Delaware, 2011 Every flash flood warning in 2011

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.