Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2014

Severe Thunderstorm Warning 3, NWS Philadelphia/Mount Holly

February 21, 2014Chester County, Delaware County, Pennsylvania; New Castle County, Delaware; Cecil County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Feb 21, 2014, 12:32 PM EST for Chester County, Delaware County, Pennsylvania; New Castle County, Delaware; Cecil County, Maryland. It was in force for 58 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: Feb 21, 2014, 12:32 PM EST (17:32 UTC)
Expired: Feb 21, 2014, 1:30 PM EST
In force: 58 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

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

The radar

The Philadelphia radar (KDIX), 113 km from the middle of the area, began a volume at 17:31 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Feb 21, 10:39 AM EST	Tornado Watch	SPC	5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.5 hours before the alert went out and 179 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: 572 m above ground
0-6 km bulk shear: 65 kt
0-1 km storm-relative helicity: 456 m²/s²
0-3 km storm-relative helicity: 447 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

540 
WUUS51 KPHI 211732
SVRPHI
DEC003-MDC015-PAC029-045-211830-
/O.NEW.KPHI.SV.W.0003.140221T1732Z-140221T1830Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1232 PM EST FRI FEB 21 2014

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  NORTHERN CECIL COUNTY IN NORTHEAST MARYLAND...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 130 PM EST

* AT 1226 PM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS. THESE SEVERE STORMS EXTENDED FROM
  HOLTWOOD TO SCARBORO TO HICKORY TO PLEASANT HILLS TO GUNPOWDER...
  MOVING NORTHEAST AT 60 MPH. THESE STORMS ARE CAPABLE OF PRODUCING
  ONE INCH DIAMETER HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. 

* SEVERE THUNDERSTORMS WILL BE NEAR...
  ROCK SPRINGS AND OCTORARO AROUND 1235 PM EST...
  MOUNT VERNON AND GLEN ROY AROUND 1240 PM EST...
  OXFORD AND HOMEVILLE AROUND 1245 PM EST...
  PARKESBURG AND ZION AROUND 1250 PM EST...
  HONEY BROOK AND WEST GROVE AROUND 1255 PM EST...
  GLENMOORE AND ELVERSON AROUND 100 PM EST...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. IF A TORNADO
IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY INSIDE A
STRONG BUILDING...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS LINE OF
SEVERE THUNDERSTORMS. WHEN THUNDER ROARS...MOVE INDOORS! REMEMBER...
IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY
LIGHTNING.

THE HEAVY RAIN ASSOCIATED WITH THIS LINE MAY CAUSE MINOR FLOODING IN 
AREAS OF DEEP SNOW PACK AND CLOGGED STORM DRAINS.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 500 PM EST FRIDAY AFTERNOON
FOR DELAWARE AND NORTHEASTERN MARYLAND.

&&

LAT...LON 3973 7614 3979 7605 3988 7599 4011 7595
      4024 7570 4024 7560 4015 7553 4016 7550
      4014 7551 4012 7546 4009 7546 4007 7537
      4003 7533 3982 7538 3976 7546 3972 7548
      3950 7599 3955 7603 3954 7608 3972 7623
TIME...MOT...LOC 1730Z 240DEG 52KT 3984 7623 3972 7619
          3964 7626 3953 7629 3944 7636

$$

FORECASTER: HEAVENER

1 follow-up statement

519 
WWUS51 KPHI 211816
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
116 PM EST FRI FEB 21 2014

DEC003-MDC015-211826-
/O.CAN.KPHI.SV.W.0003.000000T0000Z-140221T1830Z/
NEW CASTLE DE-CECIL MD-
116 PM EST FRI FEB 21 2014

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN CECIL AND NORTHERN
NEW CASTLE COUNTIES IS CANCELLED...

THE STORM THAT PROMPTED THE SEVERE THUNDERSTORM WARNING HAS MOVED OUT
OF THE AREA...THEREFORE THE SEVERE THUNDERSTORM WARNING HAS BEEN
CANCELLED.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 500 PM EST FRIDAY AFTERNOON
FOR DELAWARE AND NORTHEASTERN MARYLAND. A TORNADO WATCH ALSO REMAINS
IN EFFECT UNTIL 500 PM EST FRIDAY AFTERNOON FOR NEW JERSEY AND
SOUTHEAST PENNSYLVANIA.

LAT...LON 3990 7598 4011 7595 4024 7570 4024 7564
      4022 7561 4024 7560 4015 7553 4016 7550
      4013 7550 4012 7546 4009 7546 4007 7537
      4003 7533 3994 7535 3982 7567 3972 7581
      3979 7605
TIME...MOT...LOC 1816Z 228DEG 49KT 4008 7569 3978 7577

$$

PAC029-045-211830-
/O.CON.KPHI.SV.W.0003.000000T0000Z-140221T1830Z/
DELAWARE PA-CHESTER PA-
116 PM EST FRI FEB 21 2014

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 130 PM EST
FOR CHESTER AND NORTHWESTERN DELAWARE COUNTIES...

AT 111 PM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING ONE INCH
DIAMETER HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THESE STORMS
WERE LOCATED ALONG A LINE EXTENDING FROM THORNDALE TO KEMBLESVILLE...
MOVING NORTHEAST AT 55 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
KENILWORTH AND CEDARVILLE AROUND 125 PM EST...
WESTTOWN AND MALVERN AROUND 130 PM EST...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. IF A TORNADO
IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY
STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 500 PM EST FRIDAY AFTERNOON
FOR DELAWARE AND NORTHEASTERN MARYLAND. A TORNADO WATCH ALSO REMAINS
IN EFFECT UNTIL 500 PM EST FRIDAY AFTERNOON FOR NEW JERSEY AND
SOUTHEAST PENNSYLVANIA.

&&

LAT...LON 3990 7598 4011 7595 4024 7570 4024 7564
      4022 7561 4024 7560 4015 7553 4016 7550
      4013 7550 4012 7546 4009 7546 4007 7537
      4003 7533 3994 7535 3982 7567 3972 7581
      3979 7605
TIME...MOT...LOC 1816Z 228DEG 49KT 4008 7569 3978 7577

$$

FORECASTER: MEOLA

The office that day

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

Issued	Product	Office	Counties	Lasted
Feb 21, 4:27 AM EST	Dense Fog Advisory	PHI	Berks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more	11 hr
Feb 21, 12:15 PM EST	Special Weather Statement	PHI	Chester	60 min
Feb 21, 1:37 PM EST	Areal Flood Advisory	PHI	Chester	4 hr
Feb 21, 1:53 PM EST	Areal Flood Advisory	PHI	Bucks, Montgomery	4 hr
Feb 21, 12:55 PM EST	Severe Thunderstorm Warning	PHI	Kent, Sussex	65 min
Feb 21, 1:43 PM EST	Areal Flood Advisory	PHI	Kent	4 hr
Feb 21, 12:38 PM EST	Special Weather Statement	PHI	Caroline, Talbot	67 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2014 Severe Thunderstorm Warnings in Delaware, 2014 Severe Thunderstorm Warnings in Maryland, 2014 Every severe thunderstorm warning in 2014

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.