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, 7:52 PM EDT for Chester County, Pennsylvania. It was in force for 23 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, 7:52 PM EDT (23:52 UTC)
Expired: Aug 11, 2012, 8:15 PM EDT
In force: 23 min
Issued by: NWS Philadelphia/Mount Holly

County Chester County, PA

The radar

The Dover AFB radar (KDOX), 111 km from the middle of the area, began a volume at 23:53 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, 11.9 hours before the alert went out and 154 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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.

925 
WWUS81 KPHI 112352
SPSPHI

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

MDZ008-PAZ067-120015-
CECIL MD-CHESTER PA-
752 PM EDT SAT AUG 11 2012

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

AT 746 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
ISOLATED...POTENTIALLY STRONG THUNDERSTORMS ALONG A LINE EXTENDING 
FROM 14 MILES WEST OF WEST CHESTER TO 22 MILES WEST OF 
NEWARK...MOVING NORTHEAST AT 20 MPH. THE THUNDERSTORMS WILL BE NEAR 
MODENA...SOUTH COATESVILLE AROUND 800 PM...BAY VIEW AND MARSHALLTON 
AROUND 815 PM.

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

THERE WILL BE LIGHTNING STRIKES IN THE PATH OF THESE STORMS.  

LAT...LON 3996 7587 4011 7546 3963 7590 3955 7608
      3956 7609 3958 7608 3963 7616

$$

FORECASTER:  DRAG

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 11, 11:51 AM EDT	Special Weather Statement	PHI	Sussex, Warren	54 min
Aug 11, 11:57 AM EDT	Special Weather Statement	PHI	Cape May, Cumberland	63 min
Aug 11, 1:06 PM EDT	Special Weather Statement	PHI	Cumberland	39 min
Aug 11, 1:38 PM EDT	Special Marine Warning	PHI		37 min
Aug 11, 1:45 PM EDT	Special Weather Statement	PHI	Cape May	45 min
Aug 11, 2:12 PM EDT	Special Weather Statement	PHI	Cape May	48 min
Aug 11, 2:35 PM EDT	Special Weather Statement	PHI	Cape May	25 min
Aug 11, 3:01 PM EDT	Special Weather Statement	PHI	Cape May	44 min
Aug 11, 3:10 PM EDT	Areal Flood Advisory	PHI	Atlantic, Cape May, Ocean	62 min
Aug 11, 3:25 PM EDT	Special Marine Warning	PHI		35 min
Aug 11, 4:04 PM EDT	Flash Flood Warning	PHI	Atlantic, Cape May	114 min
Aug 11, 5:20 PM EDT	Special Weather Statement	PHI	Atlantic	40 min
Aug 11, 6:42 PM EDT	Special Weather Statement	PHI	Salem	33 min
Aug 11, 6:49 PM EDT	Special Weather Statement	PHI	Morris	26 min
Aug 11, 6:52 PM EDT	Special Weather Statement	PHI	Somerset	23 min
Aug 11, 7:17 PM EDT	Special Weather Statement	PHI	Gloucester	28 min
Aug 11, 7:19 PM EDT	Special Weather Statement	PHI	Sussex	26 min
Aug 11, 7:56 PM EDT	Special Weather Statement	PHI	Mercer	34 min
Aug 11, 6:07 PM EDT	Special Weather Statement	PHI	Bucks	38 min
Aug 11, 6:11 PM EDT	Special Weather Statement	PHI	Chester	49 min
Aug 11, 7:33 PM EDT	Special Weather Statement	PHI	Bucks	27 min
Aug 11, 11:44 AM EDT	Special Weather Statement	PHI	Kent	61 min
Aug 11, 3:20 PM EDT	Special Weather Statement	PHI	Sussex	85 min
Aug 11, 4:21 PM EDT	Special Weather Statement	PHI	Sussex	39 min
Aug 11, 5:12 PM EDT	Special Weather Statement	PHI	Caroline	63 min
Aug 11, 7:09 PM EDT	Special Weather Statement	PHI	Kent	36 min

Nearby

Special Weather Statements in Pennsylvania, 2012 Every 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.