Alert archive / Pennsylvania / Special Weather Statements in 2011

Special Weather Statement, NWS Philadelphia/Mount Holly

April 28, 20114 states

NWS Philadelphia/Mount Holly issued this special weather statement at Apr 28, 2011, 6:12 AM EDT for 4 states. It was in force for 63 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: Apr 28, 2011, 6:12 AM EDT (10:12 UTC)
Expired: Apr 28, 2011, 7:15 AM EDT
In force: 63 min
Issued by: NWS Philadelphia/Mount Holly

Counties New Castle County, DE, Cecil County, MD, Kent County, MD, Gloucester County, NJ, Salem County, NJ, Chester County, PA, Delaware County, PA, Philadelphia County, PA

The radar

The Dover AFB radar (KDOX), 84 km from the middle of the area, began a volume at 10:12 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 00:00Z, 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-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: 1143 J/kg
Mixed-layer CIN: -34 J/kg
Mixed-layer LCL: 834 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 283 m²/s²
0-3 km storm-relative helicity: 353 m²/s²
Significant tornado parameter: 1.8
Supercell composite: 14.0

Open this sounding in Storm Lab

The text

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

283 
WWUS81 KPHI 281012
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
612 AM EDT THU APR 28 2011

DEZ001-MDZ008-012-015-NJZ016>018-021-PAZ067-068-070-071-281115-
CAMDEN NJ-CECIL MD-CHESTER PA-CUMBERLAND NJ-DELAWARE PA-GLOUCESTER NJ-
KENT MD-MONTGOMERY PA-NEW CASTLE DE-PHILADELPHIA PA-QUEEN ANNE'S MD-
SALEM NJ-
612 AM EDT THU APR 28 2011

...STRONG THUNDERSTORMS WILL AFFECT CAMDEN...CECIL...CHESTER...
CUMBERLAND...DELAWARE...GLOUCESTER...KENT...MONTGOMERY...NEW
CASTLE...PHILADELPHIA...QUEEN ANNE'S AND SALEM COUNTIES...

AT 605 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 24 MILES NORTH OF
BALTIMORE TO 10 MILES NORTHEAST OF BALTIMORE TO 11 MILES SOUTHEAST OF
BALTIMORE...MOVING EAST AT 45 MPH. THE THUNDERSTORMS WILL BE NEAR
MOUNT VERNON...HOMEVILLE AROUND 630 AM...MARSHALLTON...COCHRANVILLE
AROUND 645 AM...WEST DEPTFORD...BRYN MAWR AROUND 700 AM...SOUTH
PHILADELPHIA AND ROXBOROUGH AROUND 715 AM.

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

WIND GUSTS TO 50 MPH ARE POSSIBLE WITH THESE STORMS...AS WELL AS 
SMALL HAIL.

LAT...LON 3932 7619 3942 7602 3951 7599 3953 7600
      3956 7610 3972 7624 3976 7609 3991 7601
      4016 7516 3983 7508 3948 7514 3939 7545
      3946 7555 3950 7557 3957 7553 3958 7556
      3946 7558 3942 7553 3937 7551 3914 7628

$$

HAYES

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 28, 6:56 AM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Warren	34 min
Apr 28, 7:35 AM EDT	Special Weather Statement	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset, Sussex and 1 more	55 min
Apr 28, 9:00 AM EDT	Special Weather Statement	PHI	Monmouth	60 min
Apr 28, 9:02 AM EDT	Special Marine Warning	PHI		26 min
Apr 28, 10:10 AM EDT	Gale Warning	PHI		5 hr
Apr 28, 10:25 AM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Sussex, Warren	50 min
Apr 28, 10:48 AM EDT	Areal Flood Advisory	PHI	Hunterdon, Sussex, Warren	3 hr
Apr 28, 10:57 AM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Somerset, Warren	63 min
Apr 28, 10:58 AM EDT	Tornado Warning	PHI	Hunterdon, Warren	32 min
Apr 28, 11:11 AM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	64 min
Apr 28, 11:15 AM EDT	Areal Flood Advisory	PHI	Mercer, Middlesex, Morris, Somerset	4 hr
Apr 28, 11:22 AM EDT	Tornado Warning	PHI	Hunterdon, Morris, Sussex, Warren	23 min
Apr 28, 11:45 AM EDT	Tornado Warning	PHI	Morris	30 min
Apr 28, 12:06 PM EDT	Special Marine Warning	PHI		43 min
Apr 28, 12:29 PM EDT	Special Weather Statement	PHI	Camden, Gloucester, Salem	61 min
Apr 28, 12:34 PM EDT	Special Weather Statement	PHI	Cumberland	56 min
Apr 28, 12:38 PM EDT	Special Weather Statement	PHI	Hunterdon, Morris, Somerset	52 min
Apr 28, 12:42 PM EDT	Special Weather Statement	PHI	Gloucester, Salem	63 min
Apr 28, 1:13 PM EDT	Special Weather Statement	PHI	Atlantic, Cape May	62 min
Apr 28, 1:23 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Cumberland, Gloucester, Salem	103 min
Apr 28, 1:44 PM EDT	Special Marine Warning	PHI		91 min
Apr 28, 2:02 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester	41 min
Apr 28, 2:11 PM EDT	Areal Flood Advisory	PHI	Burlington, Monmouth, Ocean	94 min
Apr 28, 2:27 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Monmouth, Ocean	41 min
Apr 28, 2:42 PM EDT	Special Marine Warning	PHI		63 min
Apr 28, 2:55 PM EDT	Special Weather Statement	PHI	Monmouth	65 min
Apr 28, 5:04 PM EDT	Special Weather Statement	PHI	Cape May	56 min
Apr 28, 6:03 PM EDT	Special Marine Warning	PHI		57 min
Apr 28, 6:22 PM EDT	Special Weather Statement	PHI	Cape May	53 min
Apr 28, 6:37 PM EDT	Special Marine Warning	PHI		53 min
Apr 28, 4:24 AM EDT	Special Weather Statement	PHI	Berks, Carbon, Lehigh, Northampton	66 min
Apr 28, 4:36 AM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	54 min
Apr 28, 5:31 AM EDT	Special Weather Statement	PHI	Carbon, Monroe	59 min
Apr 28, 5:49 AM EDT	Special Weather Statement	PHI	Carbon	56 min
Apr 28, 5:58 AM EDT	Areal Flood Advisory	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	3 hr
Apr 28, 6:18 AM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	57 min
Apr 28, 6:23 AM EDT	Special Weather Statement	PHI	Berks, Chester, Lehigh, Montgomery	52 min
Apr 28, 7:06 AM EDT	Flash Flood Warning	PHI	Carbon, Monroe	6 hr
Apr 28, 8:17 AM EDT	Special Weather Statement	PHI	Berks	58 min
Apr 28, 8:55 AM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	65 min
Apr 28, 8:59 AM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	4 hr
Apr 28, 9:11 AM EDT	Special Weather Statement	PHI	Carbon, Monroe	49 min
Apr 28, 9:33 AM EDT	Severe Thunderstorm Warning	PHI	Carbon, Lehigh, Monroe, Northampton	57 min
Apr 28, 10:00 AM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery	60 min
Apr 28, 12:03 PM EDT	Special Weather Statement	PHI	Montgomery, Philadelphia	57 min
Apr 28, 12:11 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery	31 min
Apr 28, 12:45 PM EDT	Special Weather Statement	PHI	Bucks, Delaware, Montgomery, Philadelphia	60 min
Apr 28, 9:55 AM EDT	River Flood Warning	PHI	Cecil, Harford	66 hr
Apr 28, 11:32 AM EDT	Special Weather Statement	PHI	Caroline, Queen Anne's, Talbot	58 min
Apr 28, 11:37 AM EDT	Severe Thunderstorm Warning	PHI	Caroline, Cecil, Kent, Queen Anne's	53 min
Apr 28, 5:38 PM EDT	Severe Thunderstorm Warning	PHI	Caroline	39 min

Nearby

Special Weather Statements in Pennsylvania, 2011 Special Weather Statements in New Jersey, 2011 Special Weather Statements in Maryland, 2011 Every 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.