Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 182, NWS Philadelphia/Mount Holly

July 24, 2020Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 24, 2020, 12:42 AM EDT for Bucks County, Montgomery County, Pennsylvania. It was in force for 48 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: Jul 24, 2020, 12:42 AM EDT (04:42 UTC)
Expired: Jul 24, 2020, 1:30 AM EDT
In force: 48 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Bucks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 75 km from the middle of the area, began a volume at 04:44 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

Brookhaven, NY (KOKX), launched 00:00Z, 4.7 hours before the alert went out and 213 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: 1702 J/kg
Mixed-layer CIN: -49 J/kg
Mixed-layer LCL: 797 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 111 m²/s²
0-3 km storm-relative helicity: 116 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 4.0

Open this sounding in Storm Lab

The text

As transmitted.

943 
WUUS51 KPHI 240442
SVRPHI
PAC017-091-240530-
/O.NEW.KPHI.SV.W.0182.200724T0442Z-200724T0530Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
1242 AM EDT Fri Jul 24 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Central Montgomery County in southeastern Pennsylvania...
  Central Bucks County in southeastern Pennsylvania...

* Until 130 AM EDT.

* At 1242 AM EDT, a severe thunderstorm was located over Chalfont, or
  18 miles north of Philadelphia, moving east at 55 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...
  Norristown, Lansdale, West Norriton, East Norriton, Doylestown,
  Hatboro, Souderton, Ambler, Collegeville, Chalfont, Trappe,
  Hatfield, Newtown, Langhorne, Schwenksville, Bryn Athyn, Ivyland,
  Fricks, Feasterville-Trevose and Richboro.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 330 and 350.
 Northeast Extension between mile markers 21 and 33.

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.

Frequent cloud to ground lightning is occurring with this storm, and
the storm will affect the beaches. For your safety, immediately move
off the beach and seek shelter indoors.

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

&&

LAT...LON 4009 7537 4024 7552 4041 7507 4016 7482
TIME...MOT...LOC 0442Z 247DEG 46KT 4028 7520 

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

Davis

2 follow-up statements

665 
WWUS51 KPHI 240458
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1258 AM EDT Fri Jul 24 2020

PAC017-091-240530-
/O.CON.KPHI.SV.W.0182.000000T0000Z-200724T0530Z/
Montgomery PA-Bucks PA-
1258 AM EDT Fri Jul 24 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 130 AM EDT
FOR EAST CENTRAL MONTGOMERY AND CENTRAL BUCKS COUNTIES...

At 1258 AM EDT, a severe thunderstorm was located near Richboro, or
14 miles west of Trenton, moving east at 30 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...
Lansdale, Doylestown, Hatboro, Chalfont, Hatfield, Newtown,
Langhorne, Ivyland, Fricks, Richboro, Langhorn, Gardenville,
Levittown, Feasterville-Trevose, Horsham, North Wales, New Britain,
Penndel, Langhorne Manor and Churchville.

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.

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 4020 7529 4032 7531 4041 7507 4016 7482
      4015 7490
TIME...MOT...LOC 0458Z 271DEG 25KT 4026 7504 

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

Staarmann

752 
WWUS51 KPHI 240522
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
122 AM EDT Fri Jul 24 2020

PAC017-091-240531-
/O.EXP.KPHI.SV.W.0182.000000T0000Z-200724T0530Z/
Montgomery PA-Bucks PA-
122 AM EDT Fri Jul 24 2020

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL MONTGOMERY AND
CENTRAL BUCKS COUNTIES WILL EXPIRE AT 130 AM EDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will 
be allowed to expire.  However, heavy rain is still possible with 
this thunderstorm.

Remember, a Severe Thunderstorm Warning still remains in effect for
Bucks County until 2:15 AM EDT.

LAT...LON 4020 7529 4032 7531 4041 7507 4016 7482
      4015 7490
TIME...MOT...LOC 0521Z 247DEG 46KT 4037 7470 

$$

Davis

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 23, 10:26 PM EDT	Severe Thunderstorm Warning	PHI	Chester	49 min
Jul 23, 10:44 PM EDT	Areal Flood Advisory	PHI	Chester	2 hr
Jul 23, 11:10 PM EDT	Areal Flood Advisory	PHI	Chester, Delaware	2 hr
Jul 23, 11:16 PM EDT	Severe Thunderstorm Warning	PHI	Delaware	44 min
Jul 23, 11:38 PM EDT	Special Weather Statement	PHI	Chester	37 min
Jul 23, 11:44 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	46 min
Jul 24, 12:24 AM EDT	Flash Flood Warning	PHI	Chester	114 min
Jul 24, 12:32 AM EDT	Special Weather Statement	PHI	Bucks, Montgomery	28 min
Jul 24, 1:13 AM EDT	Severe Thunderstorm Warning	PHI	Bucks	62 min
Jul 24, 10:43 AM EDT	Flash Flood Warning	PHI	Philadelphia	76 min
Jul 24, 1:43 PM EDT	Areal Flood Advisory	PHI	Bucks, Philadelphia	3 hr
Jul 24, 2:19 PM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery, Philadelphia	2 hr
Jul 24, 2:26 PM EDT	Flash Flood Warning	PHI	Bucks, Montgomery, Philadelphia	2 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2020 Every 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.