Alert archive / Delaware / Flash Flood Warnings in 2015

Flash Flood Warning 39, NWS Philadelphia/Mount Holly

July 20, 2015Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 20, 2015, 4:00 PM EDT for Sussex 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 20, 2015, 4:00 PM EDT (20:00 UTC)
Expired: Jul 20, 2015, 7:00 PM EDT
In force: 3 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), 47 km from the middle of the area, began a volume at 20:03 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, 8.0 hours before the alert went out and 70 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: 1657 J/kg
Mixed-layer CIN: -44 J/kg
Mixed-layer LCL: 1114 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: -8 m²/s²
0-3 km storm-relative helicity: 8 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

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

994 
WGUS51 KPHI 202000
FFWPHI
DEC005-202300-
/O.NEW.KPHI.FF.W.0039.150720T2000Z-150720T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
400 PM EDT MON JUL 20 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN SUSSEX COUNTY IN SOUTHERN DELAWARE...

* UNTIL 700 PM EDT
    
* AT 400 PM EDT...DOPPLER RADAR INDICATED A THUNDERSTORM PRODUCING 
  HEAVY RAIN ACROSS THE WARNED AREA. UP TO THREE INCHES OF RAIN HAVE 
  ALREADY FALLEN. FLASH FLOODING IS EXPECTED TO BEGIN SHORTLY. UP TO 
  ANOTHER INCH OF RAIN MAY FALL BEFORE THE STORM MOVES SOUTH OF THE 
  AREA. 

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  SOUTH BETHANY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

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

PLEASE REPORT FLOODING TO YOUR LOCAL LAW ENFORCEMENT AGENCY WHEN YOU
CAN DO SO SAFELY.

&&

LAT...LON 3854 7507 3854 7505 3845 7505 3845 7516

$$

GAINES

2 follow-up statements

500 
WGUS71 KPHI 202106
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
506 PM EDT MON JUL 20 2015

DEC005-202300-
/O.CON.KPHI.FF.W.0039.000000T0000Z-150720T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX DE-
506 PM EDT MON JUL 20 2015

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 700 PM EDT FOR
SOUTHEASTERN SUSSEX COUNTY...

AT 502 PM EDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCED THREE 
TO FOUR INCHES OF RAIN EARLIER THIS AFTERNOON ACROSS THE WARNING 
AREA. 

FLASH FLOODING WILL MAINLY BE CONFINED TO THE FENWICK ISLAND AREA. 
NUMEROUS REPORTS OF MINOR FLOODING HAVE BEEN RECEIVED.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...


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

PLEASE REPORT FLOODING TO YOUR LOCAL LAW ENFORCEMENT AGENCY WHEN YOU
CAN DO SO SAFELY.

&&

LAT...LON 3850 7505 3845 7505 3845 7516

$$

GAINES

448 
WGUS71 KPHI 202257
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
657 PM EDT MON JUL 20 2015

DEC005-202306-
/O.EXP.KPHI.FF.W.0039.000000T0000Z-150720T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX DE-
657 PM EDT MON JUL 20 2015

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN SUSSEX COUNTY WILL EXPIRE
AT 700 PM EDT...

ANY FLOOD WATERS ARE RECEDEDING...AND ARE NO LONGER EXPECTED TO POSE 
A THREAT TO LIFE OR PROPERTY. PLEASE CONTINUE TO HEED ANY ROAD 
CLOSURES.

LAT...LON 3850 7505 3845 7505 3845 7516

$$

GAINES

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 3:21 PM EDT	Areal Flood Advisory	PHI	Sussex	3 hr
Jul 20, 3:32 PM EDT	Special Weather Statement	PHI	Sussex	13 min

Nearby

Flash Flood Warnings in Delaware, 2015 Every flash flood warning in 2015

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.