Alert archive / Pennsylvania / Special Weather Statements in 2011

Special Weather Statement, NWS Philadelphia/Mount Holly

March 21, 20114 states

NWS Philadelphia/Mount Holly issued this special weather statement at Mar 21, 2011, 6:12 AM EDT for 4 states. It was in force for 63 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Mar 21, 2011, 6:12 AM EDT (10:12 UTC)
Expired
Mar 21, 2011, 7:15 AM EDT
In force
63 min
Issued by
NWS Philadelphia/Mount Holly

Counties New Castle County, DE, Cecil County, MD, 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 10:16 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.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 10.2 hours before the alert went out and 192 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-pSkew-T log-p diagram, Wallops Is Stn, VA at 00:00Z on 2011-03-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 00:00Z on 2011-03-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 96 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
1228 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
96 m²/s²
0-3 km storm-relative helicity
197 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.

038 
WWUS81 KPHI 211012
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
612 AM EDT MON MAR 21 2011

DEZ001-MDZ008-NJZ016>018-021-PAZ067-070-071-211115-
CAMDEN NJ-CECIL MD-CHESTER PA-CUMBERLAND NJ-DELAWARE PA-GLOUCESTER NJ-
NEW CASTLE DE-PHILADELPHIA PA-SALEM NJ-
612 AM EDT MON MAR 21 2011

...A CLUSTER OF STRONG THUNDERSTORMS WILL AFFECT CAMDEN...CECIL... 
CHESTER...CUMBERLAND...DELAWARE...GLOUCESTER...NEW CASTLE... 
PHILADELPHIA AND SALEM COUNTIES...

AT 606 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A 
CLUSTER OF STRONG THUNDERSTORMS OVER SOUTH CENTRAL AND SOUTHEAST 
PENNSYLVANIA...MOVING EAST AT 40 MPH. THESE THUNDERSTORMS WILL BE 
NEAR MOUNT VERNON...OXFORD AROUND 630 AM...LADENBERG...NORTH STAR 
AROUND 645 AM...PENNS GROVE...WILMINGTON AROUND 700 AM...MULLICA 
HILL AND WENONAH AROUND 715 AM.

WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THESE STORMS...AS WELL AS PEA 
SIZED HAIL.

LAT...LON 3973 7623 3973 7615 3978 7607 3987 7601
      3996 7600 4007 7594 3991 7508 3934 7529
      3937 7542 3943 7548 3946 7555 3950 7557
      3958 7554 3958 7556 3946 7558 3940 7551
      3948 7601 3953 7599 3954 7607 3970 7624

$$

HAYES

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 21, 6:51 AM EDTSpecial Weather StatementPHICumberland, Gloucester, Salem54 min
Mar 21, 7:58 AM EDTSpecial Weather StatementPHIAtlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 2 more92 min

Nearby

Special Weather Statements in Pennsylvania, 2011Special Weather Statements in New Jersey, 2011Special Weather Statements in Maryland, 2011Every special weather statement 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.