Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 124, NWS Philadelphia/Mount Holly

July 6, 20215 counties in Pennsylvania; Burlington County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 6, 2021, 5:11 PM EDT for 5 counties in Pennsylvania; Burlington County, New Jersey. It was in force for 49 min. 10 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: Jul 6, 2021, 5:11 PM EDT (21:11 UTC)
Expired: Jul 6, 2021, 6:00 PM EDT
In force: 49 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Burlington County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 80 km from the middle of the area, began a volume at 21:13 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

Time	Report	Where	Remark
Jul 6, 5:16 PM EDT	HAIL 1	Eagleville, PA
Jul 6, 5:20 PM EDT	HAIL 0.7	Trooper, PA	TRAINED SPOTTER ESTIMATES PEA TO DIME SIZED HAIL OCCURRING IN EAGLEVILLE.
Jul 6, 5:25 PM EDT	HAIL 0.75	1 E East Norriton, PA	SOCIAL MEDIA.
Jul 6, 5:26 PM EDT	HAIL 0.7	1 N Bridgeport, PA
Jul 6, 5:30 PM EDT	TSTM WND DMG	1 N Plymouth Twp, PA	LARGE TREE BRANCH DOWN ON JEFFERSON AVENUE. TIME ESTIMATED FROM RADAR.
Jul 6, 5:54 PM EDT	HAIL 1	Ardmore, PA	PEA TO QUARTER SIZE HAIL. REPORT VIA SOCIAL MEDIA. TIME ESTIMATED FROM RADAR.
Jul 6, 6:00 PM EDT	HAIL 0.88	Phoenixville, PA	REPORT VIA SOCIAL MEDIA.
Jul 6, 6:00 PM EDT	HAIL 1	1 E Phoenixville, PA	REPORT VIA SOCIAL MEDIA.
Jul 6, 6:06 PM EDT	TSTM WND DMG	1 Nw West Norriton, PA	LARGE TREE DOWN AT THE JEFFERSONVILLE GOLF COURSE. TIME ESTIMATED FROM RADAR.
Jul 6, 6:06 PM EDT	HAIL 1	Wynnewood, PA

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.

Issued	Product	Office	Lasted
Jul 6, 1:32 PM EDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 9.2 hours before the alert went out and 222 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: 230 J/kg
Mixed-layer CIN: -195 J/kg
Mixed-layer LCL: 1202 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 139 m²/s²
0-3 km storm-relative helicity: 184 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

472 
WUUS51 KPHI 062111
SVRPHI
NJC005-PAC017-029-045-091-101-062200-
/O.NEW.KPHI.SV.W.0124.210706T2111Z-210706T2200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
511 PM EDT Tue Jul 6 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern Burlington County in southern New Jersey...
  Southern Montgomery County in southeastern Pennsylvania...
  South central Bucks County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...
  Northeastern Delaware County in southeastern Pennsylvania...

* Until 600 PM EDT.

* At 510 PM EDT, a severe thunderstorm was located over Valley Forge,
  or 13 miles northeast of West Chester, 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...
  Philadelphia, Bensalem, Norristown, Phoenixville, Lansdale, West
  Norriton, East Norriton, Riverside, Conshohocken, Palmyra, Hatboro,
  Ambler, Collegeville, Royersford, Jenkintown, Narberth, Trappe,
  Beverly, Rockledge and Newtown.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 318 and 354.
 Northeast Extension between mile markers 21 and 29.
 Interstate 95 in Pennsylvania between mile markers 26 and 38.
 Interstate 76 in Pennsylvania between mile markers 327 and 341.
 Interstate 476 in Pennsylvania between mile markers 9 and 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4021 7558 4031 7493 4000 7489 3997 7557
TIME...MOT...LOC 2110Z 262DEG 26KT 4012 7547 

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

Fitzsimmons

1 follow-up statement

235 
WWUS51 KPHI 062134
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
534 PM EDT Tue Jul 6 2021

NJC005-PAC017-029-045-091-101-062200-
/O.CON.KPHI.SV.W.0124.000000T0000Z-210706T2200Z/
Burlington NJ-Montgomery PA-Bucks PA-Chester PA-Philadelphia PA-
Delaware PA-
534 PM EDT Tue Jul 6 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM EDT
FOR NORTHWESTERN BURLINGTON...SOUTHERN MONTGOMERY...SOUTH CENTRAL
BUCKS...NORTHEASTERN CHESTER...PHILADELPHIA AND NORTHEASTERN DELAWARE
COUNTIES...

At 533 PM EDT, trained spotters reported wind damage and quarter 
sized hail from severe thunderstorms located near Ambler, or 11 
miles northwest of Philadelphia, moving east at 30 mph.

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

SOURCE...Trained weather spotters.

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

Locations impacted include...
Philadelphia, Bensalem, Norristown, Phoenixville, Lansdale, West
Norriton, East Norriton, Riverside, Conshohocken, Palmyra, Hatboro,
Ambler, Collegeville, Royersford, Jenkintown, Narberth, Trappe,
Beverly, Rockledge and Newtown.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 318 and 354.
 Northeast Extension between mile markers 21 and 29.
 Interstate 95 in Pennsylvania between mile markers 26 and 38.
 Interstate 76 in Pennsylvania between mile markers 327 and 341.
 Interstate 476 in Pennsylvania between mile markers 9 and 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should seek shelter inside a well-built structure and away from
windows.

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

&&

LAT...LON 4021 7558 4031 7493 4000 7489 3997 7557
TIME...MOT...LOC 2133Z 262DEG 26KT 4014 7525 

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

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 6, 4:23 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	52 min
Jul 6, 4:29 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	76 min
Jul 6, 5:08 PM EDT	Special Weather Statement	PHI	Carbon	37 min
Jul 6, 5:15 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe, Northampton	60 min
Jul 6, 5:34 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	41 min
Jul 6, 5:55 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	65 min
Jul 6, 6:13 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	31 min
Jul 6, 6:41 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	64 min
Jul 6, 7:01 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	59 min
Jul 6, 7:50 PM EDT	Special Weather Statement	PHI	Lehigh	25 min
Jul 6, 3:53 AM EDT	Small Craft Advisory	PHI		22 hr
Jul 6, 5:46 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	59 min
Jul 6, 6:17 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Middlesex, Monmouth, Somerset	58 min
Jul 6, 6:33 PM EDT	Special Marine Warning	PHI		117 min
Jul 6, 7:59 PM EDT	Severe Thunderstorm Warning	PHI	Mercer, Middlesex, Monmouth, Ocean, Somerset	61 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2021 Severe Thunderstorm Warnings in New Jersey, 2021 Every severe thunderstorm warning in 2021

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.