Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 166, NWS Philadelphia/Mount Holly

July 22, 2020New Castle County, Delaware; 4 counties in Pennsylvania; Gloucester County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 22, 2020, 5:33 PM EDT for New Castle County, Delaware; 4 counties in Pennsylvania; Gloucester County, New Jersey. It was in force for 57 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
Jul 22, 2020, 5:33 PM EDT (21:33 UTC)
Expired
Jul 22, 2020, 6:30 PM EDT
In force
57 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties New Castle County, DE, Gloucester County, NJ, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 102 km from the middle of the area, began a volume at 21:32 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
Jul 22, 6:02 PM EDTTSTM WND DMG1 Se Roxborough, PADOWNED TREE NEAR THE INTERSTATE 76 AND MONTGOMERY DRIVE INTERCHANGE. 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
Jul 22, 2:57 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.6 hours before the alert went out and 183 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 2020-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 248 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 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 2020-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 square meters per square second.1939Sfc1 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
248 J/kg
Mixed-layer CIN
-214 J/kg
Mixed-layer LCL
1163 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
44 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

535 
WUUS51 KPHI 222133
SVRPHI
DEC003-NJC015-PAC029-045-091-101-222230-
/O.NEW.KPHI.SV.W.0166.200722T2133Z-200722T2230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
533 PM EDT Wed Jul 22 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northern New Castle County in northern Delaware...
  Northwestern Gloucester County in southern New Jersey...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Southeastern Chester County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 630 PM EDT.

* At 533 PM EDT, severe thunderstorms were located along a line
  extending from Paoli to near Kennett Square to Pleasant Hill,
  moving east at 25 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Philadelphia, Wilmington, Newark, West Chester, Chester, Yeadon,
  Westtown, Folcroft, Swarthmore, Elsmere, Kennett Square, Narberth,
  East Lansdowne, Rockledge, Newport, Arden, Darby Township, Stanton,
  Cheyney and Morris Park.

This includes the following highways...
 Interstate 95 in Pennsylvania between mile markers 0 and 13, and
between mile markers 22 and 23.
 Interstate 95 in Delaware between mile markers 3 and 23.
 Interstate 76 in Pennsylvania between mile markers 335 and 348.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 476 in Pennsylvania between mile markers 0 and 13.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

To report severe weather, contact your nearest law enforcement
agency. They will send your report to the National Weather Service
office in Mount Holly NJ.

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

&&

LAT...LON 3976 7585 3985 7572 3999 7559 4011 7501
      3993 7516 3978 7542 3978 7544 3975 7547
      3961 7571 3970 7579 3972 7579 3972 7582
TIME...MOT...LOC 2133Z 254DEG 20KT 4004 7552 3988 7564 3969 7590 

HAIL...0.75IN
WIND...60MPH
 
$$

MPS
2 follow-up statements
805 
WWUS51 KPHI 222206 RRA
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
606 PM EDT Wed Jul 22 2020

PAC029-222216-
/O.CAN.KPHI.SV.W.0166.000000T0000Z-200722T2230Z/
Chester PA-
606 PM EDT Wed Jul 22 2020

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CHESTER COUNTY IS
CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1000 PM EDT for
northern Delaware...southern New Jersey...and southeastern
Pennsylvania.

LAT...LON 3988 7551 4003 7540 4011 7502 3991 7518
      3978 7541 3978 7544 3975 7547 3963 7568
      3962 7573 3969 7578
TIME...MOT...LOC 2206Z 270DEG 18KT 4005 7531 3989 7543 3970 7569 

$$

DEC003-NJC015-PAC045-091-101-222230-
/O.CON.KPHI.SV.W.0166.000000T0000Z-200722T2230Z/
New Castle DE-Gloucester NJ-Montgomery PA-Philadelphia PA-
Delaware PA-
606 PM EDT Wed Jul 22 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM EDT
FOR NORTHERN NEW CASTLE...NORTHWESTERN GLOUCESTER...SOUTHEASTERN
MONTGOMERY...WESTERN PHILADELPHIA AND DELAWARE COUNTIES...

At 606 PM EDT, severe thunderstorms were located along a line
extending from Bryn Mawr to near Lima to near Pike Creek, moving east
at 20 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Philadelphia, Wilmington, Newark, Chester, Yeadon, Folcroft,
Swarthmore, Elsmere, Narberth, East Lansdowne, Rockledge, Newport,
Arden, Darby Township, Stanton, Morris Park, Talleyville, Elam, Bryn
Mawr and Trout Lake.

This includes the following highways...
 Interstate 95 in Pennsylvania between mile markers 0 and 14, and
near mile marker 22.
 Interstate 95 in Delaware between mile markers 3 and 23.
 Interstate 76 in Pennsylvania between mile markers 335 and 349.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 476 in Pennsylvania between mile markers 0 and 13.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Mount Holly NJ.

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

&&

LAT...LON 3988 7551 4003 7540 4011 7502 3991 7518
      3978 7541 3978 7544 3975 7547 3963 7568
      3962 7573 3969 7578
TIME...MOT...LOC 2206Z 270DEG 18KT 4005 7531 3989 7543 3970 7569 

HAIL...0.75IN
WIND...60MPH
 
$$

MPS
250 
WWUS51 KPHI 222220
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
620 PM EDT Wed Jul 22 2020

DEC003-NJC015-PAC045-091-101-222230-
/O.EXP.KPHI.SV.W.0166.000000T0000Z-200722T2230Z/
New Castle DE-Gloucester NJ-Montgomery PA-Philadelphia PA-
Delaware PA-
620 PM EDT Wed Jul 22 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN NEW CASTLE...
NORTHWESTERN GLOUCESTER...SOUTHEASTERN MONTGOMERY...WESTERN
PHILADELPHIA AND DELAWARE COUNTIES WILL EXPIRE AT 630 PM EDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 1000 PM EDT for
northern Delaware...southern New Jersey...and southeastern
Pennsylvania.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.

LAT...LON 3988 7551 4003 7540 4011 7502 3991 7518
      3978 7541 3978 7544 3975 7547 3963 7568
      3962 7573 3969 7578
TIME...MOT...LOC 2220Z 254DEG 20KT 4007 7522 3991 7534 3972 7560 

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 10:14 PM EDTSpecial Weather StatementPHIKent46 min
Jul 21, 10:21 PM EDTSevere Thunderstorm WarningPHIKent54 min
Jul 22, 5:23 PM EDTSevere Thunderstorm WarningPHIKent, Sussex52 min
Jul 22, 5:54 PM EDTSevere Thunderstorm WarningPHIKent, New Castle51 min
Jul 21, 8:45 PM EDTSpecial Weather StatementPHIBerks30 min
Jul 21, 9:20 PM EDTSpecial Weather StatementPHIMontgomery25 min
Jul 22, 1:36 PM EDTSpecial Weather StatementPHICarbon24 min
Jul 22, 1:58 PM EDTSpecial Weather StatementPHIMonroe32 min
Jul 22, 2:10 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton50 min
Jul 22, 3:29 PM EDTSpecial Weather StatementPHILebanon46 min
Jul 22, 3:39 PM EDTSevere Thunderstorm WarningPHIBerks51 min
Jul 22, 4:01 PM EDTSevere Thunderstorm WarningPHIChester22 min
Jul 22, 4:10 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh, Northampton65 min
Jul 22, 4:25 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery50 min
Jul 22, 4:38 PM EDTSevere Thunderstorm WarningPHIChester52 min
Jul 22, 4:49 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Carbon, Lehigh, Monroe, Northampton56 min
Jul 22, 5:09 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Delaware, Lehigh, Montgomery and 1 more66 min
Jul 22, 5:16 PM EDTSevere Thunderstorm WarningPHIBucks, Monroe, Northampton59 min
Jul 22, 5:23 PM EDTAreal Flood AdvisoryPHINorthampton3 hr
Jul 22, 5:40 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia65 min
Jul 21, 10:57 PM EDTSpecial Marine WarningPHI63 min
Jul 22, 3:04 PM EDTSevere Thunderstorm WarningPHISussex30 min
Jul 22, 3:18 PM EDTSpecial Weather StatementPHIMorris, Warren42 min
Jul 22, 3:50 PM EDTSevere Thunderstorm WarningPHIHunterdon, Morris, Sussex, Warren29 min
Jul 22, 4:33 PM EDTSpecial Weather StatementPHIMorris57 min
Jul 22, 4:56 PM EDTSevere Thunderstorm WarningPHIHunterdon, Morris, Somerset49 min
Jul 22, 5:49 PM EDTSpecial Marine WarningPHI86 min
Jul 22, 6:04 PM EDTSevere Thunderstorm WarningPHIHunterdon, Middlesex, Morris, Somerset, Sussex, Warren60 min
Jul 22, 6:12 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Gloucester, Salem48 min
Jul 22, 6:17 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean, Somerset52 min
Jul 22, 6:46 PM EDTSevere Thunderstorm WarningPHIAtlantic, Camden, Cape May, Cumberland, Gloucester, Salem44 min
Jul 22, 6:47 PM EDTSpecial Marine WarningPHI28 min
Jul 22, 6:52 PM EDTAreal Flood AdvisoryPHIMiddlesex, Somerset113 min
Jul 22, 6:52 PM EDTSpecial Marine WarningPHI41 min
Jul 22, 7:20 PM EDTSpecial Marine WarningPHI55 min
Jul 22, 7:23 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 1 more52 min
Jul 22, 7:58 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Camden, Ocean47 min
Jul 22, 7:59 PM EDTSpecial Marine WarningPHI61 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2020Severe Thunderstorm Warnings in Delaware, 2020Severe Thunderstorm Warnings in New Jersey, 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.