Alert archive / Pennsylvania / Special Weather Statements in 2012

Special Weather Statement, NWS Philadelphia/Mount Holly

October 19, 2012Chester County, Delaware County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Oct 19, 2012, 9:24 PM EDT for Chester County, Delaware County, Montgomery County, Pennsylvania. It was in force for 96 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
Oct 19, 2012, 9:24 PM EDT (01:24 UTC)
Expired
Oct 19, 2012, 11:00 PM EDT
In force
96 min
Issued by
NWS Philadelphia/Mount Holly

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

The radar

The Philadelphia radar (KDIX), 105 km from the middle of the area, began a volume at 01:26 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, 1.4 hours before the alert went out and 202 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 2012-10-20Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 00:00Z on 2012-10-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 square meters per square second.1939587897117Sfc1 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
1810 m above ground
0-6 km bulk shear
57 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
167 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.

278 
WWUS81 KPHI 200124
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
924 PM EDT FRI OCT 19 2012

DEZ001-MDZ008-PAZ067-068-070-200300-
CECIL MD-CHESTER PA-DELAWARE PA-MONTGOMERY PA-NEW CASTLE DE-
924 PM EDT FRI OCT 19 2012

...STRONG THUNDERSTORMS WILL AFFECT CECIL...CHESTER...DELAWARE...
MONTGOMERY AND NEW CASTLE COUNTIES...

AT 921 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 13 MILES SOUTH OF
READING TO 12 MILES WEST OF WEST CHESTER TO 5 MILES NORTHWEST OF
NEWARK...MOVING NORTHEAST AT 25 MPH. THE THUNDERSTORMS WILL BE NEAR
KEMBLESVILLE...APPLETON AROUND 930 PM...PUGHTOWN...CEDARVILLE AROUND
945 PM...WESTTOWN...ELAM AROUND 1000 PM...EAST GREENVILLE...
CONCORDVILLE AROUND 1015 PM...TROUT LAKE AND NEWTOWN SQUARE AROUND
1030 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.

LAT...LON 4013 7591 4025 7569 4045 7553 4038 7541
      4029 7531 3995 7530 3953 7591

$$

FORECASTER: HEAVENER

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 19, 9:36 PM EDTSmall Craft Advisory for Hazardous SeasPHI18 hr
Oct 19, 10:15 PM EDTSpecial Weather StatementPHIWarren60 min
Oct 20, 3:16 PM EDTSmall Craft AdvisoryPHI12 hr
Oct 19, 8:31 PM EDTSpecial Weather StatementPHIBerks44 min
Oct 19, 8:42 PM EDTSevere Thunderstorm WarningPHIBerks63 min
Oct 19, 8:59 PM EDTTornado WarningPHIBerks31 min
Oct 19, 10:00 PM EDTAreal Flood AdvisoryPHIChester, Delaware63 min
Oct 19, 10:27 PM EDTSpecial Weather StatementPHIBucks, Montgomery63 min
Oct 19, 10:36 PM EDTSpecial Weather StatementPHICaroline54 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.