Alert archive / Delaware / Flash Flood Warnings in 2011

Flash Flood Warning 12, NWS Philadelphia/Mount Holly

July 19, 2011Kent County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 19, 2011, 4:12 PM EDT for Kent County, Delaware. 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 outline as issued.

The facts

Issued: Jul 19, 2011, 4:12 PM EDT (20:12 UTC)
Expired: Jul 19, 2011, 7:15 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Kent County, DE

The radar

The Dover AFB radar (KDOX), 28 km from the middle of the area, began a volume at 20:13 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 8.2 hours before the alert went out and 64 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: 1090 J/kg
Mixed-layer CIN: -43 J/kg
Mixed-layer LCL: 1062 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 68 m²/s²
0-3 km storm-relative helicity: 101 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 2.6

Open this sounding in Storm Lab

The text

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

315 
WGUS51 KPHI 192012
FFWPHI
DEC001-192315-
/O.NEW.KPHI.FF.W.0012.110719T2012Z-110719T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
412 PM EDT TUE JUL 19 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHERN KENT COUNTY IN CENTRAL DELAWARE...

* UNTIL 715 PM EDT

* AT 408 PM EDT...THUNDERSTORMS WITH HEAVY RAIN HAVE DROPPED
  A DOPPLER RADAR ESTIMATE OF 3 TO 4 INCHES OF RAIN IN AND 
  AROUND VIOLA AND WOODSIDE. AN ADDITIONAL INCH OF RAIN IS
  POSSIBLE AND THIS WOULD START STREAM FLOODING IN THE AREA.
 
* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  HAZLETTVILLE...WOODSIDE...VIOLA...RISING SUN AND CAMDEN

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.

FLOODING IS OCCURRING OR IS IMMINENT. MOST FLOOD RELATED DEATHS OCCUR
IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS WATER COVERED BRIDGES...
DIPS...OR LOW WATER CROSSINGS. NEVER TRY TO CROSS A FLOWING STREAM...
EVEN A SMALL ONE...ON FOOT. TO ESCAPE RISING WATER MOVE UP TO HIGHER
GROUND.

&&

LAT...LON 3913 7567 3914 7551 3896 7544 3891 7563

$$

TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 19, 6:02 AM EDT	Heat Advisory	PHI	New Castle	13 hr
Jul 19, 2:13 PM EDT	Special Weather Statement	PHI	Kent, New Castle, Sussex	92 min
Jul 19, 2:29 PM EDT	Excessive Heat Warning	PHI	Kent, New Castle, Sussex	5 days
Jul 19, 2:43 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	92 min
Jul 19, 3:45 PM EDT	Areal Flood Advisory	PHI	Kent, Sussex	3 hr
Jul 19, 4:25 PM EDT	Special Weather Statement	PHI	Kent, Sussex	80 min
Jul 19, 4:40 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	32 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; radar from the NEXRAD Level II archive.