Alert archive / New Jersey / Special Weather Statements in 2012

Special Weather Statement, NWS Philadelphia/Mount Holly

April 21, 20124 states

NWS Philadelphia/Mount Holly issued this special weather statement at Apr 21, 2012, 8:41 PM EDT for 4 states. It was in force for 109 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: Apr 21, 2012, 8:41 PM EDT (00:41 UTC)
Expired: Apr 21, 2012, 10:30 PM EDT
In force: 109 min
Issued by: NWS Philadelphia/Mount Holly

All 27 counties

Kent County, DE, New Castle County, DE, Sussex County, DE, Caroline County, MD, Cecil County, MD, Queen Anne's County, MD, Talbot County, MD, Camden County, NJ, Cumberland County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 86 km from the middle of the area, began a volume at 00:43 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 21, 8:48 PM EDT	TSTM WND DMG	Willistown, PA	PROPERTY DAMAGE ON SUGARTOWN ROAD. PARTIAL ROOF COLLAPSE OF ONE BLDG.
Apr 21, 9:05 PM EDT	TSTM WND DMG	Ambler, PA	ABOUT A DOZEN LARGE TREES UP TO 70 FT KNOCKED DOWN ALONG A PARK ENTRANCE ON THE AMBLER AND UPPER DUBLIN TOWNSHIP BORDER.
Apr 21, 9:07 PM EDT	HAIL 0.75	Green Lane, PA
Apr 21, 9:15 PM EDT	TSTM WND DMG	The Woodlands, PA	TREES DOWN IN HORSHAM TOWNSHIP.
Apr 21, 10:07 PM EDT	TSTM WND DMG	Lebanon, NJ	WIRE DOWN

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 0.7 hours before the alert went out and 196 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 670 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: -123 m²/s²
0-3 km storm-relative helicity: -75 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.

056 
WWUS81 KPHI 220041
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
841 PM EDT SAT APR 21 2012

DEZ001>003-MDZ008-012-015-019-020-NJZ001-007>010-012-015>019-021-
PAZ055-060>062-067>071-220230-
BERKS PA-BUCKS PA-CAMDEN NJ-CAROLINE MD-CECIL MD-CHESTER PA-
CUMBERLAND NJ-DELAWARE PA-GLOUCESTER NJ-HUNTERDON NJ-INLAND SUSSEX DE-
KENT DE-KENT MD-LEHIGH PA-MERCER NJ-MIDDLESEX NJ-MONROE PA-
MONTGOMERY PA-MORRIS NJ-NEW CASTLE DE-NORTHAMPTON PA-
NORTHWESTERN BURLINGTON NJ-PHILADELPHIA PA-QUEEN ANNE'S MD-SALEM NJ-
SOMERSET NJ-SUSSEX NJ-TALBOT MD-WARREN NJ-
841 PM EDT SAT APR 21 2012

...THUNDERSTORMS AND A COLD FRONT...

SCATTERED THUNDERSTORMS ACROSS EASTERN PENNSYLVANIA...NORTHWEST NEW 
JERSEY AND MUCH OF THE DELMARVA WERE OCCURRING WITH AND BEHIND A 
SHARP COLD FRONT THIS EVENING. AS OF 835 PM EDT...THE FRONT HAD 
MOVED INTO NORTHWESTERN NEW JERSEY...MOST OF EASTERN PENNSYLVANIA 
AND WAS MOVING INTO THE DELMARVA FROM CHESAPEAKE BAY. IT WILL CLEAR 
THE ATLANTIC COAST DURING THE REMAINDER OF THE EVENING.  

THE STRONGER THUNDERSTORMS...WHICH WERE SCATTERED FROM ABOUT 20 
MILES WEST OF PHILADELPHIA DOWN TO ABOUT 20 MILES SOUTHWEST OF 
GEORGETOWN AT 835 PM...WERE CAPABLE OF GENERATING WIND GUSTS TO AROUND 
40 MPH...DANGEROUS CLOUD TO GROUND LIGHTNING AND HEAVY DOWNPOURS. 

GUSTY WINDS OUTSIDE OF THUNDERSTORMS WERE ASSOCIATED WITH THE FRONT 
AND THE COLDER AIR BEHIND IT. TEMPERATURES BEHIND THE FRONT OVER 
MUCH OF MARYLAND AND PENNSYLVANIA HAD DROPPED IN EXCESS OF 20 
DEGREES OVER THE COURSE OF A FEW HOURS. 

IF YOU ARE OUTSIDE THIS EVENING AND HEAR THUNDER...PLEASE MOVE 
INDOORS. 

LAT...LON 3845 7569 3868 7576 3857 7604 3876 7640
      3943 7600 3972 7623 4014 7589 4032 7616
      4082 7547 4124 7545 4109 7502 4136 7469
      4121 7437 4067 7445 4056 7420 4018 7462
      3918 7500 3948 7558 3883 7520 3845 7541

$$

MPD

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 21, 9:38 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Hunterdon, Mercer, Middlesex, Monmouth, Morris and 2 more	67 min
Apr 22, 3:45 AM EDT	Wind Advisory	PHI	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 5 more	20 hr
Apr 22, 4:14 AM EDT	Coastal Flood Advisory	PHI	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 4 more	20 hr
Apr 21, 8:45 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	30 min

Nearby

Special Weather Statements in New Jersey, 2012 Special Weather Statements in Pennsylvania, 2012 Special Weather Statements in Maryland, 2012 Every special weather statement in 2012

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.