Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 31, NWS Philadelphia/Mount Holly

April 13, 20204 states

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 13, 2020, 2:41 PM EDT for 4 states. It was in force for 64 min. 2 reports 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 13, 2020, 2:41 PM EDT (18:41 UTC)
Expired
Apr 13, 2020, 3:45 PM EDT
In force
64 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

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

The radar

The Dover AFB radar (KDOX), 94 km from the middle of the area, began a volume at 18:45 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 13, 3:39 PM EDTNON-TSTM WND GST 101 W Ashland, DEMESONET STATION AR506 HOCKESSIN.
Apr 13, 3:44 PM EDTTSTM WND DMG1 Nw Pilesgrove Twp, NJLARGE LIMB DOWN ON POINTERS AUBURN ROAD. TIME ESTIMATED FROM RADAR.

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

The watch it was issued in

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

IssuedProductOfficeLasted
Apr 13, 11:33 AM EDTTornado WatchSPC5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.7 hours before the alert went out and 156 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 2020-04-13Temperature 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 2020-04-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 487 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
712 m above ground
0-6 km bulk shear
75 kt
0-1 km storm-relative helicity
487 m²/s²
0-3 km storm-relative helicity
684 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

323 
WUUS51 KPHI 131841
SVRPHI
DEC003-MDC015-NJC015-033-PAC029-045-131945-
/O.NEW.KPHI.SV.W.0031.200413T1841Z-200413T1945Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
241 PM EDT Mon Apr 13 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  New Castle County in northern Delaware...
  Cecil County in northeastern Maryland...
  Western Salem County in southern New Jersey...
  Northwestern Gloucester County in southern New Jersey...
  Southern Chester County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 345 PM EDT.

* At 239 PM EDT, severe thunderstorms were located along a line
  extending from Churchtown to Severn, moving east at 40 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Wilmington, Newark, Middletown, West Chester, Elkton, Calvert,
  Chester, Pennsville, Coatesville, Westtown, Smyrna, Carneys Point,
  Downingtown, Folcroft, Swarthmore, Elsmere, Paulsboro, Kennett
  Square, New Castle and Penns Grove.

People attending Covid-19 Drive through testing should seek safe
shelter immediately!

This includes the following highways...
 Interstate 295 in New Jersey between mile markers 0 and 17.
 Interstate 95 in Pennsylvania between mile markers 0 and 12.
 Interstate 95 in Maryland between mile markers 91 and 109.
 New Jersey Turnpike near exit 1.
 Interstate 95 in Delaware between mile markers 0 and 23.
 Interstate 476 in Pennsylvania between mile markers 0 and 7.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 600 PM EDT for central and
northern Delaware...northeastern Maryland...southern New Jersey...and
southeastern Pennsylvania.

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3972 7623 3973 7610 3976 7606 3987 7599
      3995 7600 4007 7593 4002 7578 3998 7535
      3987 7523 3945 7542 3932 7544 3936 7551
      3935 7556 3931 7558 3929 7576 3938 7577
      3938 7605 3943 7600 3952 7598 3955 7608
TIME...MOT...LOC 1839Z 285DEG 33KT 4012 7598 3914 7667 

HAIL...<.75IN
WIND...60MPH
 
$$

NC
2 follow-up statements
006 
WWUS51 KPHI 131919
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
319 PM EDT Mon Apr 13 2020

DEC003-MDC015-NJC015-033-PAC029-045-131945-
/O.CON.KPHI.SV.W.0031.000000T0000Z-200413T1945Z/
New Castle DE-Cecil MD-Salem NJ-Gloucester NJ-Chester PA-Delaware PA-
319 PM EDT Mon Apr 13 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM EDT
FOR NEW CASTLE...CECIL...WESTERN SALEM...NORTHWESTERN GLOUCESTER...
SOUTHEASTERN CHESTER AND DELAWARE COUNTIES...

At 318 PM EDT, severe thunderstorms were located along a line
extending from near Paoli to Overton, moving east at 40 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Wilmington, Newark, Middletown, West Chester, Elkton, Chester,
Pennsville, Westtown, Smyrna, Carneys Point, Folcroft, Swarthmore,
Elsmere, Paulsboro, Kennett Square, New Castle, Penns Grove, Salem,
North East and Woodstown.

People attending Covid-19 Drive through testing should seek safe
shelter immediately!

This includes the following highways...
 Interstate 295 in New Jersey between mile markers 0 and 17.
 Interstate 95 in Pennsylvania between mile markers 0 and 11.
 Interstate 95 in Maryland between mile markers 101 and 109.
 New Jersey Turnpike near exit 1.
 Interstate 95 in Delaware between mile markers 0 and 23.
 Interstate 476 in Pennsylvania between mile markers 0 and 7.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 600 PM EDT for central and
northern Delaware...northeastern Maryland...southern New Jersey...and
southeastern Pennsylvania.

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3943 7600 3963 7594 3969 7595 3989 7580
      3999 7569 3998 7535 3989 7526 3988 7526
      3987 7523 3945 7542 3932 7544 3936 7551
      3935 7556 3931 7558 3929 7576 3938 7577
      3938 7605
TIME...MOT...LOC 1918Z 285DEG 33KT 4003 7553 3905 7622 

HAIL...<.75IN
WIND...60MPH
 
$$

NC
424 
WWUS51 KPHI 131943
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
343 PM EDT Mon Apr 13 2020

DEC003-MDC015-NJC015-033-PAC029-045-131953-
/O.EXP.KPHI.SV.W.0031.000000T0000Z-200413T1945Z/
New Castle DE-Cecil MD-Salem NJ-Gloucester NJ-Chester PA-Delaware PA-
343 PM EDT Mon Apr 13 2020

...THE SEVERE THUNDERSTORM WARNING FOR NEW CASTLE...CECIL...WESTERN
SALEM...NORTHWESTERN GLOUCESTER...SOUTHEASTERN CHESTER AND DELAWARE
COUNTIES WILL EXPIRE AT 345 PM EDT...
    
The storms which prompted the warning have exited the warned area. 
Therefore, the warning will be allowed to expire.  However, gusty 
winds and heavy rain are still possible with these thunderstorms.

A Tornado Watch remains in effect until 600 PM EDT for central and
northern Delaware...northeastern Maryland...southern New Jersey...and
southeastern Pennsylvania.

LAT...LON 3943 7600 3963 7594 3969 7595 3989 7580
      3999 7569 3998 7535 3989 7526 3988 7526
      3987 7523 3945 7542 3932 7544 3936 7551
      3935 7556 3931 7558 3929 7576 3938 7577
      3938 7605
TIME...MOT...LOC 1943Z 285DEG 33KT 3997 7526 3899 7595 

$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 13, 3:43 AM EDTCoastal Flood StatementPHISussex17 hr
Apr 13, 5:12 AM EDTSpecial Weather StatementPHIKent, New Castle33 min
Apr 13, 5:41 AM EDTSpecial Weather StatementPHINew Castle34 min
Apr 13, 5:44 AM EDTSpecial Weather StatementPHIKent, Sussex31 min
Apr 13, 6:11 AM EDTAreal Flood AdvisoryPHINew Castle4 hr
Apr 13, 6:17 AM EDTSpecial Weather StatementPHIKent, New Castle28 min
Apr 13, 6:42 AM EDTAreal Flood AdvisoryPHIKent, New Castle4 hr
Apr 13, 6:48 AM EDTAreal Flood AdvisoryPHINew Castle4 hr
Apr 13, 11:25 AM EDTRiver Flood WarningPHINew Castle4 hr
Apr 13, 12:13 PM EDTRiver Flood WarningPHINew Castle3 hr
Apr 13, 3:22 PM EDTSevere Thunderstorm WarningPHIKent, Sussex38 min
Apr 13, 3:26 PM EDTTornado WarningPHIKent13 min
Apr 13, 3:40 PM EDTSevere Thunderstorm WarningPHIKent65 min
Apr 13, 3:45 PM EDTTornado WarningPHIKent15 min
Apr 13, 4:28 AM EDTSpecial Weather StatementPHIKent, Queen Anne's32 min
Apr 13, 4:45 AM EDTSpecial Weather StatementPHICaroline, Talbot30 min
Apr 13, 2:50 PM EDTSevere Thunderstorm WarningPHICaroline, Kent, Queen Anne's, Talbot55 min
Apr 13, 8:03 AM EDTAreal Flood AdvisoryPHIBucks4 hr
Apr 13, 10:58 AM EDTRiver Flood WarningPHIChester6 hr
Apr 13, 11:09 AM EDTAreal Flood WarningPHIChester, Delaware3 hr
Apr 13, 12:29 PM EDTRiver Flood WarningPHIChester, Delaware12 hr
Apr 13, 1:01 PM EDTAreal Flood AdvisoryPHIBerks, Carbon, Lehigh, Monroe, Northampton4 hr
Apr 13, 1:07 PM EDTFlash Flood WarningPHIBerks, Carbon, Lehigh, Northampton4 hr
Apr 13, 1:27 PM EDTSevere Thunderstorm WarningPHIChester33 min
Apr 13, 1:47 PM EDTFlash Flood WarningPHIChester3 hr
Apr 13, 2:23 PM EDTAreal Flood WarningPHIMontgomery, Philadelphia4 hr
Apr 13, 2:37 PM EDTAreal Flood AdvisoryPHIBerks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more2 hr
Apr 13, 4:35 PM EDTAreal Flood WarningPHIMontgomery2 hr
Apr 13, 8:36 AM EDTAreal Flood AdvisoryPHIHunterdon, Middlesex, Morris, Somerset4 hr
Apr 13, 10:29 AM EDTAreal Flood WarningPHIHunterdon, Somerset7 hr
Apr 13, 3:52 PM EDTSpecial Marine WarningPHI23 min
Apr 13, 4:13 PM EDTSevere Thunderstorm WarningPHIAtlantic, Cape May, Cumberland31 min
Apr 13, 6:32 PM EDTSmall Craft AdvisoryPHI21 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2020Severe Thunderstorm Warnings in New Jersey, 2020Severe Thunderstorm Warnings in Delaware, 2020Every severe thunderstorm warning in 2020

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.