Alert archive / Pennsylvania / Special Weather Statements in 2012

Special Weather Statement, NWS Philadelphia/Mount Holly

August 27, 2012Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Aug 27, 2012, 5:08 AM EDT for Chester County, Pennsylvania. It was in force for 52 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 27, 2012, 5:08 AM EDT (09:08 UTC)
Expired
Aug 27, 2012, 6:00 AM EDT
In force
52 min
Issued by
NWS Philadelphia/Mount Holly

County Chester County, PA

The radar

The Dover AFB radar (KDOX), 118 km from the middle of the area, began a volume at 09:08 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, 9.1 hours before the alert went out and 149 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 2012-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 225 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 2012-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 120 square meters per square second.1939Sfc1 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
225 J/kg
Mixed-layer CIN
-13 J/kg
Mixed-layer LCL
648 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
120 m²/s²
0-3 km storm-relative helicity
189 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.3

Open this sounding in Storm Lab

The text

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

741 
WWUS81 KPHI 270908
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
508 AM EDT MON AUG 27 2012

MDZ008-PAZ067-271000-
CECIL MD-CHESTER PA-
508 AM EDT MON AUG 27 2012

...AN AREA OF SHOWERS PRODUCING HEAVY RAINFALL WILL AFFECT CECIL AND
CHESTER COUNTIES...

AT 504 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED AN
AREA OF SHOWERS PRODUCING HEAVY RAINFALL 18 MILES WEST OF NEWARK...
MOVING NORTHEAST AT 25 MPH. THE SHOWERS WILL BE NEAR RISING SUN...
FARMINGTON...ZION AROUND 510 AM...CALVERT...PLEASANT HILL AROUND 515
AM...GLEN ROY...LOMBARD...BLAKE AROUND 520 AM...OXFORD AND MOUNT
VERNON AROUND 530 AM.

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

A FEW RUMBLES OF THUNDER ARE ALSO POSSIBLE.

LAT...LON 3973 7620 3974 7610 3988 7600 3996 7600
      4003 7594 4011 7595 4013 7590 4001 7559
      3954 7603 3954 7607 3956 7610 3958 7608
      3963 7616 3965 7616 3970 7621

$$

ROBERTSON

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 27, 10:07 AM EDTSpecial Weather StatementPHISomerset23 min
Aug 27, 10:25 AM EDTSpecial Weather StatementPHIMiddlesex, Somerset35 min
Aug 27, 10:34 AM EDTSpecial Weather StatementPHICamden, Mercer26 min
Aug 27, 10:57 AM EDTSpecial Weather StatementPHIUnion33 min
Aug 27, 11:03 AM EDTSpecial Weather StatementPHIUnion12 min
Aug 27, 11:12 AM EDTSpecial Weather StatementPHIBurlington, Camden48 min
Aug 27, 11:32 AM EDTSpecial Weather StatementPHIMiddlesex28 min
Aug 27, 11:54 AM EDTSpecial Weather StatementPHIAtlantic36 min
Aug 27, 12:03 PM EDTSpecial Weather StatementPHIMiddlesex, Monmouth42 min
Aug 27, 12:30 PM EDTAreal Flood AdvisoryPHIAtlantic, Burlington, Ocean2 hr
Aug 27, 12:50 PM EDTSpecial Weather StatementPHIMonmouth40 min
Aug 27, 1:12 PM EDTSpecial Marine WarningPHI80 min
Aug 27, 1:32 PM EDTSpecial Weather StatementPHIAtlantic, Ocean58 min
Aug 27, 2:28 PM EDTAreal Flood AdvisoryPHIBurlington, Mercer, Middlesex, Monmouth2 hr
Aug 27, 3:28 PM EDTAreal Flood AdvisoryPHIHunterdon, Mercer, Somerset69 min
Aug 27, 3:59 PM EDTAreal Flood AdvisoryPHIHunterdon, Middlesex, Morris, Somerset, Sussex72 min
Aug 27, 6:41 AM EDTSpecial Weather StatementPHIChester, Montgomery49 min
Aug 27, 8:25 AM EDTSpecial Weather StatementPHIBucks, Delaware, Montgomery, Philadelphia65 min
Aug 27, 10:00 AM EDTSpecial Weather StatementPHIPhiladelphia30 min
Aug 27, 11:46 AM EDTAreal Flood AdvisoryPHISussex119 min
Aug 27, 1:40 PM EDTAreal Flood AdvisoryPHISussex57 min
Aug 26, 8:44 PM EDTSpecial Weather StatementPHICaroline91 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.