Alert archive / Pennsylvania / Special Weather Statements in 2012

Special Weather Statement, NWS Philadelphia/Mount Holly

August 11, 2012Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Aug 11, 2012, 6:11 PM EDT for Chester County, Pennsylvania. It was in force for 49 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
Aug 11, 2012, 6:11 PM EDT (22:11 UTC)
Expired
Aug 11, 2012, 7:00 PM EDT
In force
49 min
Issued by
NWS Philadelphia/Mount Holly

County Chester County, PA

The radar

The Dover AFB radar (KDOX), 127 km from the middle of the area, began a volume at 22:12 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 12:00Z, 10.2 hours before the alert went out and 157 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 12:00Z on 2012-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2012-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -38 square meters per square second.1939587897Sfc1 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
0 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
-38 m²/s²
0-3 km storm-relative helicity
108 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.3

Open this sounding in Storm Lab

The text

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

574 
WWUS81 KPHI 112211
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
611 PM EDT SAT AUG 11 2012

MDZ008-PAZ067-112300-
CECIL MD-CHESTER PA-
611 PM EDT SAT AUG 11 2012

...STRONG THUNDERSTORMS WILL AFFECT CECIL AND CHESTER COUNTIES...

AT 607 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 21 MILES SOUTH OF
LANCASTER TO 26 MILES WEST OF NEWARK...MOVING NORTHEAST AT 30 MPH.
THE THUNDERSTORMS WILL BE NEAR ROCK SPRINGS...RICHARDSMERE AROUND 615
PM...GLEN ROY AROUND 630 PM...MOUNT VERNON...HOMEVILLE AROUND 645
PM...PARKESBURG AND HONEY BROOK AROUND 700 PM.

VERY HEAVY RAIN WILL FALL FROM THESE STORMS...AND WILL CAUSE WATER TO
POND ON ROADS AND QUICKLY FILL POOR DRAINAGE AREAS.

WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THESE STORMS.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THESE STORMS. DO
NOT SEEK SHELTER UNDER TREES WHEN LIGHTNING THREATENS...MOVE INDOORS
WHEN A THUNDERSTORM APPROACHES.

LAT...LON 3974 7610 3983 7602 3985 7603 3988 7600
      3996 7600 4003 7594 4010 7594 4013 7590
      4006 7580 3968 7609 3963 7615 3972 7623

$$

FORECASTER:  DRAG

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 11:51 AM EDTSpecial Weather StatementPHISussex, Warren54 min
Aug 11, 11:57 AM EDTSpecial Weather StatementPHICape May, Cumberland63 min
Aug 11, 1:06 PM EDTSpecial Weather StatementPHICumberland39 min
Aug 11, 1:38 PM EDTSpecial Marine WarningPHI37 min
Aug 11, 1:45 PM EDTSpecial Weather StatementPHICape May45 min
Aug 11, 2:12 PM EDTSpecial Weather StatementPHICape May48 min
Aug 11, 2:35 PM EDTSpecial Weather StatementPHICape May25 min
Aug 11, 3:01 PM EDTSpecial Weather StatementPHICape May44 min
Aug 11, 3:10 PM EDTAreal Flood AdvisoryPHIAtlantic, Cape May, Ocean62 min
Aug 11, 3:25 PM EDTSpecial Marine WarningPHI35 min
Aug 11, 4:04 PM EDTFlash Flood WarningPHIAtlantic, Cape May114 min
Aug 11, 5:20 PM EDTSpecial Weather StatementPHIAtlantic40 min
Aug 11, 6:42 PM EDTSpecial Weather StatementPHISalem33 min
Aug 11, 6:49 PM EDTSpecial Weather StatementPHIMorris26 min
Aug 11, 6:52 PM EDTSpecial Weather StatementPHISomerset23 min
Aug 11, 7:17 PM EDTSpecial Weather StatementPHIGloucester28 min
Aug 11, 7:19 PM EDTSpecial Weather StatementPHISussex26 min
Aug 11, 7:56 PM EDTSpecial Weather StatementPHIMercer34 min
Aug 11, 6:07 PM EDTSpecial Weather StatementPHIBucks38 min
Aug 11, 7:33 PM EDTSpecial Weather StatementPHIBucks27 min
Aug 11, 7:52 PM EDTSpecial Weather StatementPHIChester23 min
Aug 11, 11:44 AM EDTSpecial Weather StatementPHIKent61 min
Aug 11, 3:20 PM EDTSpecial Weather StatementPHISussex85 min
Aug 11, 4:21 PM EDTSpecial Weather StatementPHISussex39 min
Aug 11, 5:12 PM EDTSpecial Weather StatementPHICaroline63 min
Aug 11, 7:09 PM EDTSpecial Weather StatementPHIKent36 min

Nearby

Special Weather Statements in Pennsylvania, 2012Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.