Alert archive / Pennsylvania / Special Weather Statements in 2011

Special Weather Statement, NWS Philadelphia/Mount Holly

June 28, 2011Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Jun 28, 2011, 9:36 PM EDT for Delaware County, Pennsylvania. It was in force for 54 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
Jun 28, 2011, 9:36 PM EDT (01:36 UTC)
Expired
Jun 28, 2011, 10:30 PM EDT
In force
54 min
Issued by
NWS Philadelphia/Mount Holly

County Delaware County, PA

The radar

The Dover AFB radar (KDOX), 117 km from the middle of the area, began a volume at 01:37 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

Washington/Dulle, VA (KIAD), launched 00:00Z, 1.6 hours before the alert went out and 169 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, Washington/Dulle, VA at 00:00Z on 2011-06-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 256 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 00:00Z on 2011-06-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 square meters per square second.193958Sfc1 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
256 J/kg
Mixed-layer CIN
-89 J/kg
Mixed-layer LCL
1187 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
94 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.8

Open this sounding in Storm Lab

The text

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

169 
WWUS81 KPHI 290136
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
936 PM EDT TUE JUN 28 2011

DEZ001-PAZ067-070-290230-
CHESTER PA-DELAWARE PA-NEW CASTLE DE-
936 PM EDT TUE JUN 28 2011

...A STRONG THUNDERSTORM WILL AFFECT CHESTER...DELAWARE AND NEW
CASTLE COUNTIES...

AT 936 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 13 MILES NORTHWEST OF NEWARK...MOVING EAST AT 25
TO 30 MPH. THE THUNDERSTORM WILL BE NEAR WEST GROVE...TOUGHKENAMON 
AROUND 945 PM...KENNETT SQUARE...MARSHALLTON AROUND 1000 PM... 
CHEYNEY...GRADYVILLE AROUND 1015 PM...UPPER PROVIDENCE TOWNSHIP AND 
LIMA AROUND 1030 PM. 

VERY HEAVY RAIN WILL FALL FROM THIS STORM...AND WILL CAUSE WATER TO
POND ON ROADS AND QUICKLY FILL ROADSIDE DITCHES AND SMALL STREAMS.

GUSTY WINDS AND SMALL HAIL ARE ALSO POSSIBLE WITH THIS STORM ALONG 
WITH DANGEROUS CLOUD TO GROUND LIGHTNING.

LAT...LON 3977 7609 3978 7607 3985 7603 3988 7600
      4008 7542 3993 7527 3982 7541 3980 7562
      3972 7610

$$

RPW

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 29, 12:48 AM EDTSpecial Weather StatementPHISussex, Warren87 min
Jun 29, 1:02 AM EDTSpecial Weather StatementPHIAtlantic58 min
Jun 29, 2:09 AM EDTSpecial Weather StatementPHIMonmouth, Ocean96 min
Jun 29, 2:15 AM EDTSpecial Marine WarningPHI60 min
Jun 28, 8:31 PM EDTSpecial Weather StatementPHIMontgomery44 min
Jun 28, 8:36 PM EDTSpecial Weather StatementPHIBerks39 min
Jun 28, 9:57 PM EDTSpecial Weather StatementPHICarbon, Lehigh, Monroe, Northampton93 min
Jun 28, 9:05 PM EDTSpecial Weather StatementPHIKent, Queen Anne's55 min

Nearby

Special Weather Statements in Pennsylvania, 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.