Alert archive / Delaware / Flash Flood Warnings in 2008

Flash Flood Warning 31, NWS Philadelphia/Mount Holly

August 15, 2008Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 15, 2008, 3:42 PM EDT for Sussex County, Delaware. It was in force for 4 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
Aug 15, 2008, 3:42 PM EDT (19:42 UTC)
Expired
Aug 15, 2008, 7:47 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 28 km from the middle of the area, began a volume at 19:43 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

Wallops Is Stn, VA (KWAL), launched 12:00Z, 7.7 hours before the alert went out and 90 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, Wallops Is Stn, VA at 12:00Z on 2008-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1087 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, Wallops Is Stn, VA at 12:00Z on 2008-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 square meters per square second.1939587897Sfc1 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
1087 J/kg
Mixed-layer CIN
-41 J/kg
Mixed-layer LCL
657 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
50 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.9

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 151942
FFWPHI
DEC005-160045-
/O.NEW.KPHI.FF.W.0031.080815T1942Z-080816T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
342 PM EDT FRI AUG 15 2008

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EAST CENTRAL SUSSEX COUNTY IN SOUTHERN DELAWARE...

* UNTIL 845 PM EDT

* AT 339 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED FLASH
  FLOODING FROM A THUNDERSTORM OVER THE WARNED AREA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO REHOBOTH
  BEACH AND LEWES

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

LAT...LON 3858 7539 3878 7524 3880 7516 3879 7514
      3879 7511 3881 7509 3880 7508 3874 7506
      3872 7507 3866 7505 3866 7506 3855 7505

$$

SZATKOWSKI
1 follow-up statement
000 
WGUS71 KPHI 152347
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
747 PM EDT FRI AUG 15 2008

DEC005-152357-
/O.CAN.KPHI.FF.W.0031.000000T0000Z-080816T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX DE-
747 PM EDT FRI AUG 15 2008

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR EAST CENTRAL SUSSEX
COUNTY...

THE STORMS HAVE MOVED OUT OF THE WARNING AREA AND RAINFALL HAS 
ENDED. 

LAT...LON 3858 7539 3878 7524 3880 7516 3879 7514
      3879 7511 3881 7509 3880 7508 3874 7506
      3872 7507 3866 7505 3866 7506 3855 7505

$$

SZATKOWSKI

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 15, 3:11 PM EDTSevere Thunderstorm WarningPHISussex64 min
Aug 15, 4:16 PM EDTSevere Thunderstorm WarningPHISussex74 min
Aug 15, 5:24 PM EDTFlash Flood WarningPHISussex2 hr

Nearby

Flash Flood Warnings in Delaware, 2008Every flash flood warning in 2008

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.