Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 173, NWS Philadelphia/Mount Holly

August 2, 20094 counties in Pennsylvania; Camden County, Gloucester County, Salem County, New Jersey; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 2, 2009, 10:53 AM EDT for 4 counties in Pennsylvania; Camden County, Gloucester County, Salem County, New Jersey; New Castle County, Delaware. It was in force for 67 min. 4 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: Aug 2, 2009, 10:53 AM EDT (14:53 UTC)
Expired: Aug 2, 2009, 12:00 PM EDT
In force: 67 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

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

The radar

The Philadelphia radar (KDIX), 69 km from the middle of the area, began a volume at 14:54 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
Aug 2, 11:00 AM EDT	TSTM WND DMG	Wilmington Manor, DE	SMALL BRANCHES DOWN IN WILMINGTON.
Aug 2, 11:00 AM EDT	HAIL 0.5	Wilmington, DE	DIME SIZE HAIL IN WILMINGTON.
Aug 2, 11:10 AM EDT	TSTM WND DMG	2 Sse Morris Park, PA	LARGE TREE LIMBS KNOCKED DOWN.
Aug 2, 11:20 AM EDT	TSTM WND DMG	Drexel Hill, PA	NUMEROUS TREES AND BRANCHES DOWN THROUGHOUT THE COUNTY.

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

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 2.9 hours before the alert went out and 209 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: 2636 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 482 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 50 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.4

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 021453
SVRPHI
DEC003-NJC007-015-033-PAC029-045-091-101-021600-
/O.NEW.KPHI.SV.W.0173.090802T1453Z-090802T1600Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1053 AM EDT SUN AUG 2 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEASTERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  THIS INCLUDES THE CITY OF WILMINGTON...
  EAST CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF PHILADELPHIA...
  CAMDEN COUNTY IN SOUTHERN NEW JERSEY...
  THIS INCLUDES THE CITY OF CAMDEN...
  NORTHERN GLOUCESTER COUNTY IN SOUTHERN NEW JERSEY...
  NORTHERN SALEM COUNTY IN SOUTHERN NEW JERSEY...

* UNTIL NOON EDT

* AT 1050 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  ASHLAND...OR 7 MILES NORTHEAST OF NEWARK...AND MOVING EAST AT 35
  MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  TALLEYVILLE AND WILMINGTON AROUND 1100 AM EDT...
  ELAM AROUND 1105 AM EDT...
  CHELSEA AROUND 1110 AM EDT...
  BECKETT AROUND 1115 AM EDT...
  CHESTER AROUND 1120 AM EDT...
  GIBBSTOWN AND FOLCROFT AROUND 1125 AM 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.

&&

LAT...LON 3956 7552 3958 7556 3955 7555 3953 7562
      3988 7571 4019 7517 4002 7501 3999 7507
      3998 7503 3994 7502 3991 7496 3979 7491
      3977 7489 3978 7481 3977 7480
TIME...MOT...LOC 1453Z 257DEG 32KT 3976 7565

$$
 
TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 2, 2:19 AM EDT	Flash Flood Watch	PHI	Berks, Carbon, Delaware, Lehigh, Monroe, Northampton and 1 more	13 hr
Aug 2, 3:29 AM EDT	Areal Flood Advisory	PHI	Berks	3 hr
Aug 2, 5:54 AM EDT	Areal Flood Advisory	PHI	Chester	3 hr
Aug 2, 7:34 AM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery, Philadelphia	3 hr
Aug 2, 7:51 AM EDT	Areal Flood Warning	PHI	Chester	4 hr
Aug 2, 9:04 AM EDT	Areal Flood Warning	PHI	Montgomery, Philadelphia	4 hr
Aug 2, 9:06 AM EDT	Flash Flood Warning	PHI	Berks, Carbon, Chester, Lehigh, Monroe, Northampton	4 hr
Aug 2, 10:08 AM EDT	Flash Flood Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	9 hr
Aug 2, 10:08 AM EDT	Severe Thunderstorm Warning	PHI	Chester	67 min
Aug 2, 10:24 AM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery	66 min
Aug 2, 11:14 AM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Montgomery, Northampton	61 min
Aug 2, 11:25 AM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	65 min
Aug 2, 11:48 AM EDT	Severe Thunderstorm Warning	PHI	Bucks	57 min
Aug 2, 11:51 AM EDT	Tornado Warning	PHI	Bucks	24 min
Aug 2, 12:33 PM EDT	River Flood Warning	PHI	Bucks	28 hr
Aug 2, 1:25 PM EDT	Areal Flood Warning	PHI	Montgomery, Philadelphia	6 hr
Aug 2, 4:06 PM EDT	Areal Flood Advisory	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	4 hr
Aug 2, 4:21 PM EDT	River Flood Warning	PHI	Chester	56 min
Aug 2, 4:22 PM EDT	Flash Flood Warning	PHI	Berks	2 hr
Aug 2, 6:15 PM EDT	Areal Flood Warning	PHI	Montgomery, Philadelphia	4 hr
Aug 2, 6:25 PM EDT	Areal Flood Warning	PHI	Philadelphia	4 hr
Aug 2, 8:48 AM EDT	Areal Flood Warning	PHI	Mercer	4 hr
Aug 2, 11:18 AM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	9 hr
Aug 2, 11:30 AM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Camden, Cape May, Cumberland, Gloucester, Salem	60 min
Aug 2, 11:33 AM EDT	Special Marine Warning	PHI		87 min
Aug 2, 12:13 PM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 3 more	3 hr
Aug 2, 12:23 PM EDT	Special Marine Warning	PHI		97 min
Aug 2, 12:27 PM EDT	Severe Thunderstorm Warning	PHI	Morris, Somerset	48 min
Aug 2, 12:45 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth	60 min
Aug 2, 12:49 PM EDT	River Flood Warning	PHI	Mercer	8 hr
Aug 2, 1:28 PM EDT	Special Marine Warning	PHI		92 min
Aug 2, 1:43 PM EDT	Severe Thunderstorm Warning	PHI	Cape May	47 min
Aug 2, 1:49 PM EDT	Special Marine Warning	PHI		86 min
Aug 2, 1:51 PM EDT	Special Marine Warning	PHI		84 min
Aug 2, 1:56 PM EDT	Special Marine Warning	PHI		2 hr
Aug 2, 1:59 PM EDT	River Flood Warning	PHI	Hunterdon, Somerset	13 hr
Aug 2, 4:16 PM EDT	River Flood Warning	PHI	Middlesex, Somerset	20 hr
Aug 2, 4:16 PM EDT	River Flood Warning	PHI	Middlesex, Somerset	22 hr
Aug 2, 10:32 AM EDT	Tornado Warning	PHI	New Castle	28 min
Aug 2, 10:39 AM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle	96 min
Aug 2, 12:53 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	67 min

Nearby

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