Alert archive / Pennsylvania / Special Weather Statements in 2011

Special Weather Statement, NWS Philadelphia/Mount Holly

March 6, 2011Chester County, Delaware County, Montgomery County, Pennsylvania; Cecil County, Maryland; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this special weather statement at Mar 6, 2011, 3:14 PM EST for Chester County, Delaware County, Montgomery County, Pennsylvania; Cecil County, Maryland; New Castle County, Delaware. It was in force for 61 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
Mar 6, 2011, 3:14 PM EST (20:14 UTC)
Expired
Mar 6, 2011, 4:15 PM EST
In force
61 min
Issued by
NWS Philadelphia/Mount Holly

Counties New Castle County, DE, Cecil County, MD, Chester County, PA, Delaware County, PA, Montgomery County, PA

The radar

The Dover AFB radar (KDOX), 102 km from the middle of the area, began a volume at 20:13 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, 8.2 hours before the alert went out and 175 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 12:00Z on 2011-03-06Temperature 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 12:00Z on 2011-03-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 341 square meters per square second.1939587897Sfc1 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
465 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
341 m²/s²
0-3 km storm-relative helicity
335 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.

371 
WWUS81 KPHI 062014
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
314 PM EST SUN MAR 6 2011

DEZ001-MDZ008-NJZ016-017-PAZ067>071-062115-
BUCKS PA-CECIL MD-CHESTER PA-DELAWARE PA-GLOUCESTER NJ-MONTGOMERY PA-
NEW CASTLE DE-PHILADELPHIA PA-SALEM NJ-
314 PM EST SUN MAR 6 2011

...HEAVY RAIN WILL AFFECT BUCKS...CECIL...CHESTER...DELAWARE... 
GLOUCESTER...MONTGOMERY...NEW CASTLE...PHILADELPHIA AND SALEM 
COUNTIES...

AT 306 PM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED AN 
AREA OF HEAVY RAIN ACROSS NORTHEAST MARYLAND...MOVING NORTH AT 45 
MPH. THE AREA OF HEAVY RAIN WILL AFFECT HOCKESSIN...KENNETT SQUARE 
WEST CHESTER...WEST GOSHEN...SCHWENKSVILLE...SPRING MOUNT...TELFORD 
AND SOUDERTON.

THE HEAVY RAIN COULD RESULT IN PONDING WATER ON ROADS AND QUICKLY 
FILL ROADSIDE DITCHES AND SMALL STREAMS.

LAT...LON 4037 7554 4030 7506 3962 7549 3961 7548
      3962 7549 3957 7552 3958 7556 3954 7555
      3948 7558 3933 7567 3952 7599 3953 7600
      3955 7605

$$

HAYES

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 6, 3:30 AM ESTCoastal Flood StatementPHIBurlington, Camden, Gloucester, Salem17 hr
Mar 6, 3:37 AM ESTWinter Weather AdvisoryPHISussex, Warren28 hr
Mar 6, 4:41 PM ESTAreal Flood AdvisoryPHISussex, Warren4 hr
Mar 6, 5:01 PM ESTAreal Flood AdvisoryPHIHunterdon, Morris, Somerset12 hr
Mar 6, 5:33 PM ESTAreal Flood AdvisoryPHIBurlington, Camden, Gloucester, Mercer, Salem4 hr
Mar 6, 5:54 PM ESTSpecial Weather StatementPHIBurlington, Camden66 min
Mar 6, 6:00 PM ESTAreal Flood WarningPHISussex, Warren6 hr
Mar 6, 6:17 PM ESTAreal Flood WarningPHIMorris32 hr
Mar 6, 6:30 PM ESTAreal Flood AdvisoryPHIAtlantic, Camden, Cape May, Cumberland, Middlesex, Monmouth and 2 more4 hr
Mar 6, 2:19 PM ESTAreal Flood AdvisoryPHIBerks, Carbon, Lehigh, Monroe, Northampton6 hr
Mar 6, 3:32 PM ESTAreal Flood WarningPHIBerks, Monroe41 days
Mar 6, 4:55 PM ESTAreal Flood WarningPHICarbon, Lehigh, Northampton12 hr

Nearby

Special Weather Statements in Pennsylvania, 2011Special Weather Statements in Maryland, 2011Special Weather Statements in Delaware, 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.