Alert archive / Delaware / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 145, NWS Philadelphia/Mount Holly

July 27, 2009Sussex County, Delaware; Cape May County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 27, 2009, 4:25 PM EDT for Sussex County, Delaware; Cape May County, New Jersey. It was in force for 54 min. 5 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 27, 2009, 4:25 PM EDT (20:25 UTC)
Expired: Jul 27, 2009, 5:19 PM EDT
In force: 54 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Sussex County, DE, Cape May County, NJ

The radar

The Dover AFB radar (KDOX), 48 km from the middle of the area, began a volume at 20:26 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.

What was reported inside it

Time	Report	Where	Remark
Jul 27, 4:35 PM EDT	TSTM WND DMG	Wildwood, NJ	LIFE GUARD STANDS BLEW OVER, LIFE GUARD BOATS BLEW DOWN BEACH AND PORTABLE TOILETS OVERTURNED.
Jul 27, 4:45 PM EDT	HAIL 0.75	Erma, NJ	PENNY SIZE HAIL.
Jul 27, 4:45 PM EDT	HAIL 0.75	Rio Grande, NJ	PENNY SIZE HAIL IN RIO GRANDE.
Jul 27, 4:50 PM EDT	HAIL 1	Green Creek, NJ	NICKEL TO QUARTER SIZE HAIL IN GREEN CREEK, RIO GRANDE AND WHITESBORO.
Jul 27, 4:54 PM EDT	HAIL 1	Cape May Court House, NJ	QUARTER SIZE HAIL IN MAYVILLE.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 8.4 hours before the alert went out and 111 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: 1088 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 729 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 115 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 2.0

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 272025
SVRPHI
DEC005-NJC009-272145-
/O.NEW.KPHI.SV.W.0145.090727T2025Z-090727T2145Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
425 PM EDT MON JUL 27 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL SUSSEX COUNTY IN SOUTHERN DELAWARE...
  CAPE MAY COUNTY IN SOUTHERN NEW JERSEY...

* UNTIL 545 PM EDT

* AT 423 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING PENNY SIZE
  HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE
  LOCATED ALONG A LINE EXTENDING FROM NORTH WILDWOOD TO 11 MILES
  SOUTHWEST OF NORTH CAPE MAY...OR ALONG A LINE EXTENDING FROM 9
  MILES NORTHEAST OF CAPE MAY TO 13 MILES WEST OF CAPE MAY...AND
  MOVING NORTHEAST AT 20 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  NORTH CAPE MAY AROUND 440 PM EDT...
  STONE HARBOR AROUND 450 PM EDT...
  RIO GRANDE AROUND 500 PM EDT...
  SCOTCH BONNET AROUND 510 PM EDT...
  GREEN CREEK AROUND 515 PM EDT...
  AVALON AROUND 520 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

STORMS ALONG THE SHORE TODAY HAVE HAD A HISTORY OF PRODUCING 
DAMAGING WINDS AND LARGE DAMAGING HAIL. SEEK SHELTER 
NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS

PLEASE GET OFF THE BEACH AT THE FIRST SIGN OF THREATENING WEATHER.
THESE STORMS HAVE BEEN PROLIFIC LIGHTNING PRODUCERS ALSO.

&&

LAT...LON 3881 7533 3888 7525 3885 7522 3893 7499
      3902 7496 3911 7490 3916 7492 3927 7478
      3927 7458 3912 7470 3907 7471 3902 7479
      3898 7480
TIME...MOT...LOC 2024Z 233DEG 16KT 3901 7475 3890 7513

$$ 

TFG

3 follow-up statements

000 
WWUS51 KPHI 272040
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
440 PM EDT MON JUL 27 2009

DEC005-272048-
/O.CAN.KPHI.SV.W.0145.000000T0000Z-090727T2145Z/
SUSSEX DE-
440 PM EDT MON JUL 27 2009

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL SUSSEX COUNTY IS
CANCELLED...

THE SEVERE STORMS HAVE MOVED INTO DELAWARE BAY AND CAPE MAY COUNTY.

LAT...LON 3891 7503 3893 7499 3902 7496 3911 7490
      3916 7492 3927 7478 3927 7458 3912 7470
      3907 7471 3902 7479 3898 7480
TIME...MOT...LOC 2038Z 227DEG 18KT 3907 7468 3897 7502

$$

NJC009-272145-
/O.CON.KPHI.SV.W.0145.000000T0000Z-090727T2145Z/
CAPE MAY NJ-
440 PM EDT MON JUL 27 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM EDT
FOR CAPE MAY COUNTY...

AT 438 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER
SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS
WERE LOCATED ALONG A LINE EXTENDING FROM AVALON TO CAPE MAY POINT...
OR ALONG A LINE EXTENDING FROM 15 MILES NORTHEAST OF CAPE MAY TO 7
MILES WEST OF CAPE MAY...MOVING NORTHEAST AT 20 MPH. THE MOST 
INTENSE STORM IN THE LINE WAS OVER CAPE MAY AND HAIL HAS ALREADY BEEN
REPORTED WITH THAT STORM.

SEVERE THUNDERSTORMS WILL BE NEAR...
  RIO GRANDE BY 445 PM EDT...
  SCOTCH BONNET AND VILLAS BY 450 PM EDT...
  SCOTCH BONNET...WHITESBORO-BURLEIGH AND AVALON BY 455 PM EDT...
  GREEN CREEK BY 500 PM EDT...
  CAPE MAY COURT HOUSE BY 505 PM EDT...
  GOSHEN AND SEA ISLE CITY BY 520 PM EDT...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

STORMS ALONG THE SHORE TODAY HAVE HAD A HISTORY OF PRODUCING 
DAMAGING WINDS AND LARGE DAMAGING HAIL. SEEK SHELTER 
NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS

PLEASE GET OFF THE BEACH AT THE FIRST SIGN OF THREATENING WEATHER.
THESE STORMS HAVE BEEN PROLIFIC LIGHTNING PRODUCERS ALSO.

HEAVY RAIN WILL CAUSE PONDING OF WATER IN POOR DRAINAGE AREAS.


LAT...LON 3891 7503 3893 7499 3902 7496 3911 7490
      3916 7492 3927 7478 3927 7458 3912 7470
      3907 7471 3902 7479 3898 7480
TIME...MOT...LOC 2038Z 227DEG 18KT 3907 7468 3897 7502




$$
 

TFG

000 
WWUS51 KPHI 272055
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
455 PM EDT MON JUL 27 2009

NJC009-272145-
/O.CON.KPHI.SV.W.0145.000000T0000Z-090727T2145Z/
CAPE MAY NJ-
455 PM EDT MON JUL 27 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM EDT
FOR CAPE MAY COUNTY...

AT 451 PM EDT...A SEVERE THUNDERSTORM WAS REPORTED CAPABLE OF
PRODUCING HALF DOLLAR SIZE HAIL...AND DAMAGING WINDS TO 60 MPH.
THIS STORM WAS LOCATED NEAR WHITESBORO-BURLEIGH...OR 8 MILES NORTH
OF CAPE MAY...MOVING NORTHEAST AT 15 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  CAPE MAY COURT HOUSE BY 500 PM EDT...
  SCOTCH BONNET AND GOSHEN BY 505 PM EDT...
  GOSHEN BY 510 PM EDT...
  AVALON BY 515 PM EDT...
  SEA ISLE CITY BY 530 PM EDT...
  SEAVILLE BY 540 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS A HISTORY OF PRODUCING DESTRUCTIVE WINDS AND LARGE
DAMAGING HAIL. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY
AWAY FROM WINDOWS

HAIL UP TO QUARTER SIZE HAS BEEN REPORTED IN AND AROUND 
WHITESBORO WITH THIS STORM. THE CORE OF THE LARGEST HAIL IS STARTING
TO DESCEND IN THIS STORM AND EVEN SOME LARGER HAIL IS POSSIBLE
DURING THE NEXT 15 MINUTES. IF YOU ARE IN THE PATH OF
THE STORM...TAKE IMMEDIATE ACTION TO PROTECT LIFE AND PROPERTY.

FREQUENT LIGHTNING AND HEAVY DOWNPOURS ARE ALSO OCCURRING WITH 
THIS STORM.

&&

LAT...LON 3902 7479 3899 7482 3899 7486 3899 7490
      3903 7495 3911 7490 3916 7492 3927 7478
      3927 7458 3912 7470
TIME...MOT...LOC 2053Z 222DEG 14KT 3905 7484

$$
 
TFG

000 
WWUS51 KPHI 272119
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
519 PM EDT MON JUL 27 2009

NJC009-272127-
/O.CAN.KPHI.SV.W.0145.000000T0000Z-090727T2145Z/
CAPE MAY NJ-
519 PM EDT MON JUL 27 2009

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL CAPE MAY COUNTY IS
CANCELLED...

THE SEVERE THUNDERSTORM HAS MOVED OFFSHORE.

LAT...LON 3902 7479 3899 7482 3899 7486 3899 7490
      3903 7495 3911 7490 3916 7492 3927 7478
      3927 7458 3912 7470
TIME...MOT...LOC 2117Z 222DEG 14KT 3912 7476

$$
 
TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 27, 3:01 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	59 min
Jul 26, 8:16 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex	59 min
Jul 26, 9:57 PM EDT	Areal Flood Advisory	PHI	Mercer, Middlesex, Morris, Somerset	2 hr
Jul 27, 2:46 PM EDT	Special Marine Warning	PHI		89 min
Jul 27, 2:58 PM EDT	Special Marine Warning	PHI		92 min
Jul 27, 4:10 PM EDT	Special Marine Warning	PHI		2 hr
Jul 27, 6:25 PM EDT	Special Marine Warning	PHI		95 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2009 Severe Thunderstorm Warnings in New Jersey, 2009 Every severe thunderstorm warning in 2009

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.