Alert archive / New Jersey / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 164, NWS Philadelphia/Mount Holly

July 31, 2009Gloucester County, Salem County, New Jersey; Chester County, Delaware County, Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 31, 2009, 4:03 PM EDT for Gloucester County, Salem County, New Jersey; Chester County, Delaware County, Pennsylvania; New Castle County, Delaware. It was in force for 57 min. 1 report 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 31, 2009, 4:03 PM EDT (20:03 UTC)
Expired: Jul 31, 2009, 5:00 PM EDT
In force: 57 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties New Castle County, DE, Gloucester County, NJ, Salem County, NJ, Chester County, PA, Delaware County, PA

The radar

The Dover AFB radar (KDOX), 94 km from the middle of the area, began a volume at 20:05 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 31, 4:20 PM EDT	TSTM WND DMG	Beckett, NJ	TREES REPORTED DOWN IN LOGAN TOWNSHIP.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 31, 1:18 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.1 hours before the alert went out and 181 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: 276 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 888 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: -25 m²/s²
0-3 km storm-relative helicity: 18 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.3

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 312003
SVRPHI
DEC003-NJC015-033-PAC029-045-312100-
/O.NEW.KPHI.SV.W.0164.090731T2003Z-090731T2100Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
403 PM EDT FRI JUL 31 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  THIS INCLUDES THE CITIES OF...WILMINGTON...NEWARK...
  SOUTH CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTHERN DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  WESTERN GLOUCESTER COUNTY IN SOUTHERN NEW JERSEY...
  NORTHERN SALEM COUNTY IN SOUTHERN NEW JERSEY...
  THIS INCLUDES THE CITY OF SALEM...

* UNTIL 500 PM EDT

* AT 403 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
  DESTRUCTIVE WINDS IN EXCESS OF 70 MPH.  THIS STORM WAS LOCATED 8
  MILES WEST OF GLASGOW...OR NEAR ELKTON...AND MOVING EAST AT 40 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  NEWARK AND GLASGOW AROUND 415 PM EDT...
  BEAR AND PIKE CREEK AROUND 420 PM EDT...
  STANTON AROUND 425 PM EDT...
  WILMINGTON MANOR...NEWPORT...NEW CASTLE AND ELSMERE AROUND 430 PM
  EDT...
  WILMINGTON AROUND 435 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED SOME WEAK ROTATION WITHIN THIS STORM.
WHILE NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A
TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A
STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT FRIDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND
EASTERN PENNSYLVANIA.

&&

LAT...LON 3997 7532 3958 7513 3955 7553 3957 7553
      3958 7556 3957 7555 3955 7556 3953 7578
      3980 7579
TIME...MOT...LOC 2004Z 252DEG 34KT 3962 7588

$$

IOVINO

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 31, 2:13 PM EDT	Flash Flood Warning	PHI	Sussex	4 hr
Jul 31, 2:36 PM EDT	Flash Flood Warning	PHI	Hunterdon, Morris, Sussex, Warren	4 hr
Jul 31, 4:08 PM EDT	Flash Flood Warning	PHI	Burlington, Camden, Gloucester, Salem	3 hr
Jul 31, 4:23 PM EDT	Special Marine Warning	PHI		67 min
Jul 31, 4:31 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester, Salem	59 min
Jul 31, 4:39 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 2 more	96 min
Jul 31, 4:56 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer, Middlesex, Monmouth, Morris, Somerset	114 min
Jul 31, 5:07 PM EDT	Flash Flood Warning	PHI	Atlantic, Burlington, Camden, Cumberland, Gloucester, Salem	3 hr
Jul 31, 5:10 PM EDT	Tornado Warning	PHI	Burlington, Ocean	21 min
Jul 31, 5:14 PM EDT	Special Marine Warning	PHI		2 hr
Jul 31, 5:15 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Ocean	60 min
Jul 31, 5:16 PM EDT	Special Marine Warning	PHI		119 min
Jul 31, 5:31 PM EDT	Flash Flood Warning	PHI	Burlington, Monmouth, Ocean	4 hr
Jul 31, 5:48 PM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Cape May, Cumberland, Ocean	3 hr
Jul 31, 3:04 PM EDT	Flash Flood Warning	PHI	Bucks, Chester, Montgomery	3 hr
Jul 31, 3:36 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	54 min
Jul 31, 3:40 PM EDT	Severe Thunderstorm Warning	PHI	Chester	65 min
Jul 31, 4:12 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle, Sussex	73 min
Jul 31, 4:36 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	54 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2009 Severe Thunderstorm Warnings in Pennsylvania, 2009 Severe Thunderstorm Warnings in Delaware, 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.