Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 301, NWS Philadelphia/Mount Holly

August 1, 2019Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 1, 2019, 3:24 PM EDT for Chester County, Pennsylvania. It was in force for 66 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: Aug 1, 2019, 3:24 PM EDT (19:24 UTC)
Expired: Aug 1, 2019, 4:30 PM EDT
In force: 66 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Chester County, PA

The radar

The Dover AFB radar (KDOX), 122 km from the middle of the area, began a volume at 19:24 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 nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.4 hours before the alert went out and 154 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: 353 J/kg
Mixed-layer CIN: -134 J/kg
Mixed-layer LCL: 1030 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: 23 m²/s²
0-3 km storm-relative helicity: 53 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

561 
WUUS51 KPHI 011924
SVRPHI
PAC029-012030-
/O.NEW.KPHI.SV.W.0301.190801T1924Z-190801T2030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
324 PM EDT Thu Aug 1 2019

The National Weather Service in Mount Holly NJ has issued a

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

* Until 430 PM EDT.

* At 323 PM EDT, a severe thunderstorm was located over Gap, or 9
  miles southeast of New Holland, moving southeast at 10 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Minor damage to vehicles is possible. Wind damage to 
           roofs, siding, trees, and power lines is possible.

* Locations impacted include...
  Coatesville, Oxford, Parkesburg, West Grove, Homeville, Glen Roy,
  Cochranville, Mount Vernon, Marshallton, Atglen, South Coatesville,
  Christiana, Modena and Thorndale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to large hail and damaging winds, frequent cloud to 
ground lightning is occurring. Move indoors immediately. Remember, 
if you can hear thunder, you are close enough to be struck by 
lightning.

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

&&

LAT...LON 3974 7612 3973 7610 3974 7610 3976 7606
      3981 7603 3983 7604 3987 7599 3992 7600
      3994 7598 3995 7600 4007 7593 3995 7565
      3972 7593 3972 7613
TIME...MOT...LOC 1923Z 319DEG 11KT 3999 7600 

HAIL...1.00IN
WIND...60MPH
 
$$

Gorse

2 follow-up statements

610 
WWUS51 KPHI 011953
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
353 PM EDT Thu Aug 1 2019

PAC029-012030-
/O.CON.KPHI.SV.W.0301.000000T0000Z-190801T2030Z/
Chester PA-
353 PM EDT Thu Aug 1 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM EDT
FOR SOUTHWESTERN CHESTER COUNTY...

At 353 PM EDT, a severe thunderstorm was located over Cochranville,
or 14 miles northwest of Newark, moving southeast at 10 mph.

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

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Oxford, Parkesburg, West Grove, Homeville, Glen Roy, Mount Vernon,
Cochranville, Atglen, South Coatesville and Christiana.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

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

&&

LAT...LON 3974 7612 3973 7610 3974 7610 3976 7606
      3981 7603 3983 7604 3987 7599 3992 7600
      3994 7598 3995 7600 4004 7595 3990 7571
      3972 7593 3972 7613
TIME...MOT...LOC 1953Z 320DEG 8KT 3986 7590 

HAIL...1.00IN
WIND...60MPH
 
$$

Gorse

139 
WWUS51 KPHI 012016
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
416 PM EDT Thu Aug 1 2019

PAC029-012030-
/O.CON.KPHI.SV.W.0301.000000T0000Z-190801T2030Z/
Chester PA-
416 PM EDT Thu Aug 1 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM EDT
FOR SOUTHWESTERN CHESTER COUNTY...

At 416 PM EDT, a severe thunderstorm was located over Kemblesville,
or 8 miles northwest of Newark, moving south at 15 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...
Oxford, West Grove, Glen Roy and Mount Vernon. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

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

&&

LAT...LON 3974 7612 3973 7610 3974 7610 3976 7606
      3981 7603 3990 7571 3972 7593 3972 7613
TIME...MOT...LOC 2016Z 343DEG 14KT 3976 7588 

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

Gorse

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 1, 2:01 PM EDT	Special Weather Statement	PHI	Berks	29 min
Aug 1, 2:28 PM EDT	Special Weather Statement	PHI	Chester	47 min
Aug 1, 3:02 PM EDT	Coastal Flood Advisory	PHI	Bucks, Delaware, Philadelphia	12 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2019 Every severe thunderstorm warning in 2019

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.