Alert archive / Pennsylvania / Special Weather Statements in 2011

Special Weather Statement, NWS Philadelphia/Mount Holly

May 23, 2011Delaware County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at May 23, 2011, 5:35 PM EDT for Delaware County, Philadelphia 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
May 23, 2011, 5:35 PM EDT (21:35 UTC)
Expired
May 23, 2011, 6:30 PM EDT
In force
55 min
Issued by
NWS Philadelphia/Mount Holly

Counties Delaware County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 86 km from the middle of the area, began a volume at 21:37 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, 9.6 hours before the alert went out and 81 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 2011-05-23Temperature 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, Phillips Aaf/Abe, MD at 12:00Z on 2011-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -35 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
530 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
-35 m²/s²
0-3 km storm-relative helicity
11 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.

077 
WWUS81 KPHI 232135
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
535 PM EDT MON MAY 23 2011

DEZ001-NJZ016>019-PAZ068>071-232230-
BUCKS PA-CAMDEN NJ-DELAWARE PA-GLOUCESTER NJ-MONTGOMERY PA-
NEW CASTLE DE-NORTHWESTERN BURLINGTON NJ-PHILADELPHIA PA-SALEM NJ-
535 PM EDT MON MAY 23 2011

...A STRONG THUNDERSTORM WILL AFFECT BUCKS...BURLINGTON...CAMDEN...
DELAWARE...GLOUCESTER...MONTGOMERY...NEW CASTLE...PHILADELPHIA AND
SALEM COUNTIES...

AT 529 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 4 MILES WEST OF WILMINGTON...MOVING NORTHEAST AT
30 MPH. THE THUNDERSTORM WILL BE NEAR CHELSEA...TALLEYVILLE AROUND
545 PM...MEDIA...UPPER PROVIDENCE TOWNSHIP AROUND 600 PM...ARDMORE...
NARBERTH AROUND 615 PM...CHESTNUT HILL AND WYNDMOOR AROUND 630 PM.

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

WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THIS STORM.

LAT...LON 4001 7494 3969 7551 3978 7570 3984 7564
      3984 7560 3988 7561 3999 7545 4000 7546
      4002 7542 4004 7543 4007 7537 4007 7541
      4010 7543 4025 7530

$$

HEAVENER

The office that day

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

IssuedProductOfficeCountiesLasted
May 23, 11:07 AM EDTSpecial Weather StatementPHIAtlantic53 min
May 23, 7:58 PM EDTTornado WarningPHIHunterdon, Warren32 min
May 23, 5:47 PM EDTSpecial Weather StatementPHIBerks43 min
May 23, 6:21 PM EDTSpecial Weather StatementPHIBerks, Chester, Montgomery54 min
May 23, 6:30 PM EDTSpecial Weather StatementPHICarbon, Northampton60 min
May 23, 7:22 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Monroe, Northampton38 min
May 23, 7:30 PM EDTTornado WarningPHICarbon, Lehigh, Monroe, Northampton30 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.