Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2010

Severe Thunderstorm Warning 6, NWS Philadelphia/Mount Holly

April 8, 20104 states

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 8, 2010, 9:25 PM EDT for 4 states. It was in force for 37 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Apr 8, 2010, 9:25 PM EDT (01:25 UTC)
Expired
Apr 8, 2010, 10:02 PM EDT
In force
37 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

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

The radar

The Philadelphia radar (KDIX), 99 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.

What was reported inside it

TimeReportWhereRemark
Apr 8, 10:00 PM EDTTSTM WND DMG5 Ene Chelsea, PAWIRES DOWN IN THE ASTON TOWNSHIP AREA.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 1.4 hours before the alert went out and 184 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 2010-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 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 2010-04-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -20 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
2 J/kg
Mixed-layer CIN
-144 J/kg
Mixed-layer LCL
2005 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
-20 m²/s²
0-3 km storm-relative helicity
3 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.

579 
WUUS51 KPHI 090125
SVRPHI
DEC003-MDC015-NJC015-033-PAC029-045-090215-
/O.NEW.KPHI.SV.W.0006.100409T0125Z-100409T0215Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
925 PM EDT THU APR 8 2010

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEASTERN CECIL COUNTY IN NORTHEAST MARYLAND...
  THIS INCLUDES THE CITY OF ELKTON...
  NORTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  THIS INCLUDES THE CITIES OF...WILMINGTON...NEWARK...
  SOUTHEASTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF WEST CHESTER...
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHWESTERN GLOUCESTER COUNTY IN SOUTHERN NEW JERSEY...
  NORTHWESTERN SALEM COUNTY IN SOUTHERN NEW JERSEY...

* UNTIL 1015 PM EDT

* AT 920 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN
  EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR ELKTON...AND 
  MOVING NORTHEAST AT 60 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  NORTH STAR...PIKE CREEK...LADENBERG AND STANTON AROUND 930 PM
  EDT...
  ASHLAND...HOCKESSIN...KENNETT SQUARE AND ELSMERE AROUND 935 PM
  EDT...
  ELAM AND TALLEYVILLE AROUND 940 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF 
YOUR HOME OR BUSINESS. THIS STORM HAS THE POTENTIAL TO CAUSE 
SIGNIFICANT WIND DAMAGE. 

&&

LAT...LON 4009 7548 3997 7531 3976 7522 3966 7552
      3969 7552 3963 7559 3954 7585 3968 7600
TIME...MOT...LOC 0123Z 229DEG 52KT 3968 7582

$$

SZATKOWSKI
1 follow-up statement
861 
WWUS51 KPHI 090202
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1002 PM EDT THU APR 8 2010

DEC003-MDC015-NJC015-033-PAC029-045-090211-
/O.CAN.KPHI.SV.W.0006.000000T0000Z-100409T0215Z/
CECIL MD-SALEM NJ-GLOUCESTER NJ-DELAWARE PA-CHESTER PA-NEW CASTLE DE-
1002 PM EDT THU APR 8 2010

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN NEW CASTLE...
SOUTHEASTERN CHESTER...DELAWARE...NORTHWESTERN GLOUCESTER...NORTH
CENTRAL SALEM AND NORTHEASTERN CECIL COUNTIES IS CANCELLED...

THE SEVERE THUNDERSTORM HAS MOVED OUT OF THIS WARNING AREA AND THE 
THREAT OF SEVERE WEATHER HAS ENDED FOR THESE LOCATIONS.

LAT...LON 4009 7548 3997 7531 3976 7522 3966 7552
      3969 7552 3963 7559 3954 7585 3968 7600
TIME...MOT...LOC 0201Z 229DEG 52KT 4004 7528

$$

SZATKOWSKI

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 8, 9:56 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia28 min
Apr 8, 9:24 PM EDTSpecial Marine WarningPHI51 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2010Severe Thunderstorm Warnings in New Jersey, 2010Severe Thunderstorm Warnings in Delaware, 2010Every severe thunderstorm warning in 2010

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.