Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 30, NWS Philadelphia/Mount Holly

April 13, 2020Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 13, 2020, 1:27 PM EDT for Chester County, Pennsylvania. It was in force for 33 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
Apr 13, 2020, 1:27 PM EDT (17:27 UTC)
Expired
Apr 13, 2020, 2:00 PM EDT
In force
33 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 114 km from the middle of the area, began a volume at 17:27 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.

IssuedProductOfficeLasted
Apr 13, 11:33 AM EDTTornado WatchSPC5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.5 hours before the alert went out and 185 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.

355 
WUUS51 KPHI 131727
SVRPHI
PAC029-131800-
/O.NEW.KPHI.SV.W.0030.200413T1727Z-200413T1800Z/

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

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Chester County in southeastern Pennsylvania...

* Until 200 PM EDT.

* At 127 PM EDT, a severe thunderstorm was located over Parkesburg,
  or 14 miles southeast of New Holland, moving northeast at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  West Chester, Pottstown, Phoenixville, Coatesville, Downingtown,
  Kennett Square, Oxford, Royersford, Parkesburg, West Grove, Honey
  Brook, Elverson, Homeville, Glen Roy, Cochranville, Pughtown, Mount
  Vernon, Marshallton, Lionville-Marchwood and Valley Forge.

This includes Pennsylvania Turnpike between exits 312 and 320.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 600 PM EDT for northern
Delaware...and southeastern Pennsylvania.

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

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

&&

LAT...LON 3987 7599 3995 7600 4004 7593 4010 7594
      4025 7567 4020 7555 4015 7552 4016 7550
      4014 7551 4013 7546 4009 7545 4009 7541
      3975 7576 3973 7608 3974 7609
TIME...MOT...LOC 1727Z 229DEG 40KT 3993 7594 

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

NC
2 follow-up statements
632 
WWUS51 KPHI 131746
SVSPHI

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

PAC029-131800-
/O.CON.KPHI.SV.W.0030.000000T0000Z-200413T1800Z/
Chester PA-
146 PM EDT Mon Apr 13 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM EDT
FOR CHESTER COUNTY...

At 145 PM EDT, a severe thunderstorm was located over Glenmoore, or
10 miles northwest of West Chester, moving northeast at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
West Chester, Pottstown, Phoenixville, Coatesville, Downingtown,
Kennett Square, Oxford, Royersford, Parkesburg, West Grove, Honey
Brook, Elverson, Homeville, Cochranville, Pughtown, Mount Vernon,
Marshallton, Lionville-Marchwood, Valley Forge and Glenmoore.

This includes Pennsylvania Turnpike between exits 312 and 320.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 600 PM EDT for southeastern
Pennsylvania.

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

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

&&

LAT...LON 3987 7599 3995 7600 4004 7593 4010 7591
      4025 7567 4020 7555 4015 7552 4016 7550
      4014 7551 4013 7546 4009 7545 4009 7541
      3983 7573 3976 7602 3981 7603
TIME...MOT...LOC 1745Z 229DEG 40KT 4007 7573 

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

NC
522 
WWUS51 KPHI 131751
SVSPHI

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

PAC029-131801-
/O.EXP.KPHI.SV.W.0030.000000T0000Z-200413T1800Z/
Chester PA-
151 PM EDT Mon Apr 13 2020

...THE SEVERE THUNDERSTORM WARNING FOR CHESTER COUNTY WILL EXPIRE AT
200 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with this thunderstorm.

A Tornado Watch remains in effect until 600 PM EDT for 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 3987 7599 3995 7600 4004 7593 4010 7591
      4025 7567 4020 7555 4015 7552 4016 7550
      4014 7551 4013 7546 4009 7545 4009 7541
      3983 7573 3976 7602 3981 7603
TIME...MOT...LOC 1751Z 229DEG 40KT 4007 7574 

$$

NC

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 13, 6:11 AM EDTAreal Flood AdvisoryPHIBerks, Chester, Delaware, Montgomery4 hr
Apr 13, 6:48 AM EDTAreal Flood AdvisoryPHIDelaware, Montgomery, Philadelphia4 hr
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, 1:47 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, 2:41 PM EDTSevere Thunderstorm WarningPHIChester, Delaware64 min
Apr 13, 4:35 PM EDTAreal Flood WarningPHIMontgomery2 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.