Alert archive / Pennsylvania / Special Weather Statements in 2011

Special Weather Statement, NWS Philadelphia/Mount Holly

September 28, 2011Chester County, Delaware County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Sep 28, 2011, 3:20 PM EDT for Chester County, Delaware County, Montgomery County, Pennsylvania. It was in force for 55 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
Sep 28, 2011, 3:20 PM EDT (19:20 UTC)
Expired
Sep 28, 2011, 4:15 PM EDT
In force
55 min
Issued by
NWS Philadelphia/Mount Holly

Counties Chester County, PA, Delaware County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 118 km from the middle of the area, began a volume at 19:20 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 7.3 hours before the alert went out and 65 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, Phillips Aaf/Abe, MD at 12:00Z on 2011-09-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 822 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, Phillips Aaf/Abe, MD at 12:00Z on 2011-09-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 34 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
822 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
526 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
34 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

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

146 
WWUS81 KPHI 281920
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
320 PM EDT WED SEP 28 2011

DEZ001-PAZ060-067-068-070-282015-
BERKS PA-CHESTER PA-DELAWARE PA-MONTGOMERY PA-NEW CASTLE DE-
320 PM EDT WED SEP 28 2011

...A CLUSTER OF SHOWERS AND STRONG THUNDERSTORMS WILL AFFECT 
BERKS...CHESTER...DELAWARE...MONTGOMERY AND NEW CASTLE COUNTIES...

AT 315 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A 
CLUSTER OF SHOWERS AND STRONG THUNDERSTORMS 3 MILES SOUTH OF WEST 
CHESTER...MOVING NORTH AT 25 MPH. THE SHOWERS AND THUNDERSTORMS WILL 
BE NEAR EXTON...WEST GOSHEN AROUND 330 PM...CHESTER SPRINGS... 
LIONVILLE AROUND 345 PM...SOUTH POTTSTOWN...CEDARVILLE AROUND 400 
PM...STOWE AND POTTSTOWN AROUND 415 PM.

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

WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH ANY 
THUNDERSTORMS. 

LAT...LON 3983 7604 3987 7601 3996 7600 4003 7595
      4011 7595 4014 7590 4019 7598 4038 7594
      4035 7537 4028 7527 3983 7538 3976 7547
      3972 7548 3974 7606

$$

HAYES

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 27, 11:53 PM EDTCoastal Flood StatementPHIBurlington, Camden, Gloucester, Salem4 hr
Sep 28, 1:54 AM EDTSpecial Weather StatementPHIBurlington, Camden, Gloucester, Hunterdon, Mercer, Morris and 4 more51 min
Sep 28, 3:56 AM EDTFlash Flood WatchPHIHunterdon, Morris, Somerset, Sussex, Warren39 hr
Sep 28, 4:09 AM EDTSpecial Weather StatementPHIHunterdon, Morris, Somerset, Warren51 min
Sep 28, 4:10 AM EDTCoastal Flood AdvisoryPHIAtlantic, Burlington, Cape May, Cumberland, Middlesex, Monmouth and 1 more7 hr
Sep 28, 4:49 AM EDTAreal Flood WarningPHIHunterdon, Morris, Warren7 hr
Sep 28, 5:45 AM EDTRiver Flood WarningPHIHunterdon, Somerset22 hr
Sep 28, 6:29 AM EDTFlash Flood WarningPHISussex, Warren7 hr
Sep 28, 9:17 AM EDTSpecial Weather StatementPHISussex58 min
Sep 28, 10:02 AM EDTCoastal Flood StatementPHIBurlington, Camden, Gloucester, Salem8 hr
Sep 28, 12:00 PM EDTAreal Flood WarningPHIHunterdon, Morris, Somerset, Warren6 hr
Sep 28, 3:29 PM EDTCoastal Flood StatementPHIAtlantic, Burlington, Cape May, Cumberland, Monmouth, Ocean9 hr
Sep 28, 5:58 PM EDTAreal Flood WarningPHIHunterdon, Morris, Somerset, Sussex, Warren26 hr
Sep 27, 8:16 PM EDTAreal Flood WarningPHICarbon, Monroe3 hr
Sep 28, 4:38 AM EDTAreal Flood WarningPHIBucks3 hr
Sep 28, 5:45 AM EDTSpecial Weather StatementPHIMontgomery60 min
Sep 28, 11:15 AM EDTSpecial Weather StatementPHIBerks60 min
Sep 28, 12:24 PM EDTSpecial Weather StatementPHILehigh51 min
Sep 28, 3:59 PM EDTSpecial Weather StatementPHIBerks, Chester, Delaware, Montgomery61 min
Sep 28, 4:21 PM EDTSpecial Weather StatementPHICarbon54 min
Sep 28, 4:33 PM EDTAreal Flood AdvisoryPHIBerks, Chester, Montgomery2 hr
Sep 28, 4:36 PM EDTFlash Flood WarningPHIBerks, Chester3 hr
Sep 28, 4:48 PM EDTSpecial Weather StatementPHINorthampton57 min
Sep 28, 4:59 PM EDTAreal Flood AdvisoryPHIBucks, Northampton3 hr
Sep 28, 5:02 PM EDTSpecial Weather StatementPHIBerks, Lehigh58 min
Sep 28, 5:12 PM EDTSpecial Weather StatementPHILehigh63 min
Sep 28, 5:29 PM EDTSpecial Weather StatementPHICarbon61 min
Sep 28, 5:32 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh, Northampton58 min
Sep 28, 5:42 PM EDTAreal Flood AdvisoryPHIBerks, Bucks, Carbon, Lehigh, Monroe, Montgomery and 1 more3 hr
Sep 28, 6:31 PM EDTSpecial Weather StatementPHINorthampton59 min
Sep 28, 6:35 PM EDTAreal Flood WarningPHIBucks2 hr
Sep 28, 6:41 PM EDTFlash Flood WarningPHICarbon, Lehigh, Monroe, Northampton3 hr
Sep 28, 7:44 PM EDTAreal Flood WarningPHIChester3 hr
Sep 28, 8:30 AM EDTSpecial Weather StatementPHICaroline, Cecil, Kent, Queen Anne's, Talbot2 hr
Sep 28, 9:32 AM EDTAreal Flood AdvisoryPHICaroline, Kent, Queen Anne's, Talbot3 hr
Sep 28, 10:05 AM EDTSpecial Weather StatementPHICaroline40 min
Sep 28, 1:40 PM EDTSpecial Weather StatementPHICaroline, Kent, Queen Anne's65 min
Sep 28, 1:58 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's62 min
Sep 28, 2:14 PM EDTAreal Flood AdvisoryPHICaroline, Queen Anne's, Talbot2 hr
Sep 28, 2:59 PM EDTSpecial Weather StatementPHICecil61 min
Sep 28, 3:54 PM EDTSpecial Weather StatementPHICecil66 min
Sep 28, 9:10 AM EDTSpecial Weather StatementPHISussex35 min
Sep 28, 10:45 AM EDTSpecial Weather StatementPHIKent60 min
Sep 28, 1:31 PM EDTSpecial Weather StatementPHISussex59 min
Sep 28, 2:41 PM EDTSpecial Weather StatementPHIKent64 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.