Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 32, NWS Philadelphia/Mount Holly

April 28, 20116 counties in Pennsylvania; 5 counties in New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 28, 2011, 10:57 AM EDT for 6 counties in Pennsylvania; 5 counties in New Jersey. It was in force for 63 min. 3 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: Apr 28, 2011, 10:57 AM EDT (14:57 UTC)
Expired: Apr 28, 2011, 12:00 PM EDT
In force: 63 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Somerset County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Chester County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 75 km from the middle of the area, began a volume at 14:59 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
Apr 28, 11:00 AM EDT	FUNNEL CLOUD	Alexandria Twp, NJ	A FUNNEL CLOUD SPOTTED IN ALEXANDRIA TOWNSHIP.
Apr 28, 11:10 AM EDT	TSTM WND DMG	Alexandria Twp, NJ	TREES AND POWER LINES DOWN.
Apr 28, 11:50 AM EDT	HAIL 0.25	Whitehouse Station, NJ

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
Apr 28, 9:45 AM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 3.0 hours before the alert went out and 164 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: 211 J/kg
Mixed-layer CIN: -85 J/kg
Mixed-layer LCL: 513 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 346 m²/s²
0-3 km storm-relative helicity: 324 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

845
WUUS51 KPHI 281457
SVRPHI
NJC019-021-023-035-041-PAC011-017-029-077-091-095-281600-
/O.NEW.KPHI.SV.W.0032.110428T1457Z-110428T1600Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1057 AM EDT THU APR 28 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
NORTHWESTERN MERCER COUNTY IN CENTRAL NEW JERSEY...
SOUTHEASTERN BERKS COUNTY IN EASTERN PENNSYLVANIA...
SOUTHEASTERN LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
SOUTH CENTRAL NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
NORTHWESTERN MIDDLESEX COUNTY IN NORTHERN NEW JERSEY...
SOMERSET COUNTY IN NORTHERN NEW JERSEY...
THIS INCLUDES THE CITY OF SOMERVILLE...
HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...
SOUTHERN WARREN COUNTY IN NORTHWEST NEW JERSEY...
BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
NORTHEASTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL NOON EDT

* AT 1055 AM EDT...THE PUBLIC REPORTED A SEVERE THUNDERSTORM CAPABLE
OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS
LOCATED NEAR POTTSTOWN...OR 18 MILES SOUTHEAST OF READING...AND
MOVING NORTHEAST AT 60 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
SPRING MOUNT...SCHWENKSVILLE AND GREEN LANE AROUND 1105 AM EDT...
SOUDERTON AND HATFIELD AROUND 1110 AM EDT...
PERKASIE AND FRICKS AROUND 1115 AM EDT...
BEDMINSTER...DUBLIN AND ROBESONIA AROUND 1120 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 400 PM EDT
THURSDAY AFTERNOON FOR NORTHERN DELAWARE AND NORTHEASTERN MARYLAND
AND NEW JERSEY AND EASTERN PENNSYLVANIA.

LAT...LON 4056 7453 4052 7451 4036 7478 4006 7571
4030 7583 4080 7485 4078 7489 4073 7483
4071 7474 4075 7456 4070 7451 4065 7453
4067 7446 4065 7445 4061 7442
TIME...MOT...LOC 1456Z 241DEG 52KT 4023 7560

HEAVENER

1 follow-up statement

794 
WWUS51 KPHI 281525
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1125 AM EDT THU APR 28 2011

PAC011-029-091-281536-
/O.CAN.KPHI.SV.W.0032.000000T0000Z-110428T1600Z/
CHESTER PA-MONTGOMERY PA-BERKS PA-
1125 AM EDT THU APR 28 2011

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN BERKS...NORTHERN
MONTGOMERY AND NORTH CENTRAL CHESTER COUNTIES IS CANCELLED...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 400 PM EDT
THURSDAY AFTERNOON FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW
JERSEY AND EASTERN PENNSYLVANIA.

LAT...LON 4056 7453 4052 7451 4036 7478 4031 7516
      4051 7542 4080 7485 4078 7489 4073 7483
      4071 7474 4073 7456 4070 7451 4065 7453
      4064 7452 4067 7446 4061 7442
TIME...MOT...LOC 1526Z 241DEG 52KT 4044 7510

$$

NJC019-021-023-035-041-PAC017-077-095-281600-
/O.CON.KPHI.SV.W.0032.000000T0000Z-110428T1600Z/
WARREN NJ-HUNTERDON NJ-SOMERSET NJ-MERCER NJ-MIDDLESEX NJ-LEHIGH PA-
NORTHAMPTON PA-BUCKS PA-
1125 AM EDT THU APR 28 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL NOON EDT FOR
NORTHERN BUCKS...SOUTH CENTRAL NORTHAMPTON...EXTREME SOUTHEASTERN
LEHIGH...NORTHWESTERN MIDDLESEX...NORTHWESTERN MERCER...SOMERSET...
HUNTERDON AND SOUTHWESTERN WARREN COUNTIES...

AT 1124 AM EDT...THE PUBLIC REPORTED A SEVERE THUNDERSTORM CAPABLE OF
PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED
NEAR PIPERSVILLE...OR 19 MILES SOUTH OF EASTON...MOVING NORTHEAST AT
60 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  SAND BROOK AND SERGEANTSVILLE BY 1135 AM EDT...
  FLEMINGTON AND CLOVERHILL BY 1140 AM EDT...
  WHITE HOUSE STATION BY 1145 AM EDT...
  BRIDGEWATER AND RARITAN BY 1150 AM EDT...
  FAR HILLS...MARTINSVILLE AND SOMERVILLE BY 1155 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 400 PM EDT
THURSDAY AFTERNOON FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW
JERSEY AND EASTERN PENNSYLVANIA.

&&

LAT...LON 4056 7453 4052 7451 4036 7478 4031 7516
      4051 7542 4080 7485 4078 7489 4073 7483
      4071 7474 4073 7456 4070 7451 4065 7453
      4064 7452 4067 7446 4061 7442
TIME...MOT...LOC 1526Z 241DEG 52KT 4044 7510

$$

HEAVENER

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 28, 4:24 AM EDT	Special Weather Statement	PHI	Berks, Carbon, Lehigh, Northampton	66 min
Apr 28, 4:36 AM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	54 min
Apr 28, 5:31 AM EDT	Special Weather Statement	PHI	Carbon, Monroe	59 min
Apr 28, 5:49 AM EDT	Special Weather Statement	PHI	Carbon	56 min
Apr 28, 5:58 AM EDT	Areal Flood Advisory	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	3 hr
Apr 28, 6:12 AM EDT	Special Weather Statement	PHI	Chester, Delaware, Philadelphia	63 min
Apr 28, 6:18 AM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	57 min
Apr 28, 6:23 AM EDT	Special Weather Statement	PHI	Berks, Chester, Lehigh, Montgomery	52 min
Apr 28, 6:56 AM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more	34 min
Apr 28, 7:06 AM EDT	Flash Flood Warning	PHI	Carbon, Monroe	6 hr
Apr 28, 7:35 AM EDT	Special Weather Statement	PHI	Bucks	55 min
Apr 28, 8:17 AM EDT	Special Weather Statement	PHI	Berks	58 min
Apr 28, 8:55 AM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	65 min
Apr 28, 8:59 AM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	4 hr
Apr 28, 9:11 AM EDT	Special Weather Statement	PHI	Carbon, Monroe	49 min
Apr 28, 9:33 AM EDT	Severe Thunderstorm Warning	PHI	Carbon, Lehigh, Monroe, Northampton	57 min
Apr 28, 10:00 AM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery	60 min
Apr 28, 10:25 AM EDT	Severe Thunderstorm Warning	PHI	Bucks, Carbon, Lehigh, Monroe, Northampton	50 min
Apr 28, 10:48 AM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Montgomery, Northampton	3 hr
Apr 28, 10:58 AM EDT	Tornado Warning	PHI	Bucks, Northampton	32 min
Apr 28, 11:11 AM EDT	Severe Thunderstorm Warning	PHI	Northampton	64 min
Apr 28, 12:03 PM EDT	Special Weather Statement	PHI	Montgomery, Philadelphia	57 min
Apr 28, 12:11 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery	31 min
Apr 28, 12:42 PM EDT	Special Weather Statement	PHI	Delaware	63 min
Apr 28, 12:45 PM EDT	Special Weather Statement	PHI	Bucks, Delaware, Montgomery, Philadelphia	60 min
Apr 28, 1:23 PM EDT	Areal Flood Advisory	PHI	Philadelphia	103 min
Apr 28, 9:00 AM EDT	Special Weather Statement	PHI	Monmouth	60 min
Apr 28, 9:02 AM EDT	Special Marine Warning	PHI		26 min
Apr 28, 10:10 AM EDT	Gale Warning	PHI		5 hr
Apr 28, 11:15 AM EDT	Areal Flood Advisory	PHI	Mercer, Middlesex, Morris, Somerset	4 hr
Apr 28, 11:22 AM EDT	Tornado Warning	PHI	Hunterdon, Morris, Sussex, Warren	23 min
Apr 28, 11:45 AM EDT	Tornado Warning	PHI	Morris	30 min
Apr 28, 12:06 PM EDT	Special Marine Warning	PHI		43 min
Apr 28, 12:29 PM EDT	Special Weather Statement	PHI	Camden, Gloucester, Salem	61 min
Apr 28, 12:34 PM EDT	Special Weather Statement	PHI	Cumberland	56 min
Apr 28, 12:38 PM EDT	Special Weather Statement	PHI	Hunterdon, Morris, Somerset	52 min
Apr 28, 1:13 PM EDT	Special Weather Statement	PHI	Atlantic, Cape May	62 min
Apr 28, 1:44 PM EDT	Special Marine Warning	PHI		91 min
Apr 28, 2:02 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester	41 min
Apr 28, 2:11 PM EDT	Areal Flood Advisory	PHI	Burlington, Monmouth, Ocean	94 min
Apr 28, 2:27 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Monmouth, Ocean	41 min
Apr 28, 2:42 PM EDT	Special Marine Warning	PHI		63 min
Apr 28, 2:55 PM EDT	Special Weather Statement	PHI	Monmouth	65 min
Apr 28, 5:04 PM EDT	Special Weather Statement	PHI	Cape May	56 min
Apr 28, 6:03 PM EDT	Special Marine Warning	PHI		57 min
Apr 28, 6:22 PM EDT	Special Weather Statement	PHI	Cape May	53 min
Apr 28, 6:37 PM EDT	Special Marine Warning	PHI		53 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2011 Severe Thunderstorm Warnings in New Jersey, 2011 Every severe thunderstorm warning in 2011

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.