Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 290, NWS Philadelphia/Mount Holly

July 31, 20195 counties in Pennsylvania; Hunterdon County, Mercer County, Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 31, 2019, 3:24 PM EDT for 5 counties in Pennsylvania; Hunterdon County, Mercer County, Somerset County, New Jersey. It was in force for 51 min. 3 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 31, 2019, 3:24 PM EDT (19:24 UTC)
Expired: Jul 31, 2019, 4:15 PM EDT
In force: 51 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Hunterdon County, NJ, Mercer County, NJ, Somerset County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 76 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.

What was reported inside it

Time	Report	Where	Remark
Jul 31, 3:24 PM EDT	TSTM WND DMG	2 Ne Plymouth Meeting, PA	TREES BLOWN DOWN.
Jul 31, 3:24 PM EDT	TSTM WND DMG	Lafayette Hill, PA	LARGE TREE LIMBS DOWNED IN LAFAYETTE HILL. TIME ESTIMATED FROM RADAR.
Jul 31, 3:25 PM EDT	TSTM WND DMG	Lafayette Hill, PA	MULTIPLE TREES AND LIMBS DOWN. 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.

Issued	Product	Office	Lasted
Jul 31, 1:17 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 7.4 hours before the alert went out and 218 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: 885 J/kg
Mixed-layer CIN: -80 J/kg
Mixed-layer LCL: 1207 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 28 m²/s²
0-3 km storm-relative helicity: 33 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

As transmitted.

198 
WUUS51 KPHI 311924
SVRPHI
NJC019-021-035-PAC017-029-045-091-101-312015-
/O.NEW.KPHI.SV.W.0290.190731T1924Z-190731T2015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
324 PM EDT Wed Jul 31 2019

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Hunterdon County in northwestern New Jersey...
  Northwestern Mercer County in central New Jersey...
  Southwestern Somerset County in northern New Jersey...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Central Bucks County in southeastern Pennsylvania...
  Southeastern Chester County in southeastern Pennsylvania...
  Central Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 415 PM EDT.

* At 323 PM EDT, severe thunderstorms were located along a line
  extending from Sand Brook to Plymouth Meeting to Marshallton,
  moving southeast 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...
  Philadelphia, West Chester, Ewing, Norristown, West Norriton, East
  Norriton, Westtown, Doylestown, Byram, Downingtown, Conshohocken,
  Hatboro, Ambler, Flemington, Jenkintown, Narberth, Chalfont, East
  Lansdowne, Pennington and Rockledge.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

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

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

&&

LAT...LON 4014 7533 4054 7500 4047 7467 4001 7508
      3983 7560 3996 7583
TIME...MOT...LOC 1923Z 292DEG 13KT 4047 7494 4012 7525 3998 7568 

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

MPS

1 follow-up statement

132 
WWUS51 KPHI 312006
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
406 PM EDT Wed Jul 31 2019

NJC019-021-035-PAC017-029-045-091-101-312015-
/O.EXP.KPHI.SV.W.0290.000000T0000Z-190731T2015Z/
Hunterdon NJ-Mercer NJ-Somerset NJ-Montgomery PA-Bucks PA-Chester PA-
Philadelphia PA-Delaware PA-
406 PM EDT Wed Jul 31 2019

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN HUNTERDON...
NORTHWESTERN MERCER...SOUTHWESTERN SOMERSET...SOUTHEASTERN
MONTGOMERY...CENTRAL BUCKS...SOUTHEASTERN CHESTER...CENTRAL
PHILADELPHIA AND DELAWARE COUNTIES WILL EXPIRE AT 415 PM EDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.  However gusty
winds and heavy rain are still possible with these thunderstorms.

A severe thunderstorm watch remains in effect until 900 PM EDT for
northern Delaware...central, northern and northwestern 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 4014 7533 4054 7500 4047 7467 4001 7508
      3983 7560 3996 7583
TIME...MOT...LOC 2005Z 292DEG 13KT 4041 7476 4006 7507 3992 7550 

$$

MPS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 30, 10:45 PM EDT	Special Weather Statement	PHI	Berks	45 min
Jul 30, 11:38 PM EDT	Special Weather Statement	PHI	Lehigh	52 min
Jul 31, 12:06 AM EDT	Special Weather Statement	PHI	Carbon	39 min
Jul 31, 3:28 AM EDT	Flash Flood Watch	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	17 hr
Jul 31, 1:02 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	28 min
Jul 31, 1:14 PM EDT	Areal Flood Advisory	PHI	Bucks, Delaware, Montgomery, Philadelphia	3 hr
Jul 31, 1:19 PM EDT	Flash Flood Warning	PHI	Bucks, Delaware, Philadelphia	5 hr
Jul 31, 1:30 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Delaware, Montgomery, Philadelphia	45 min
Jul 31, 1:46 PM EDT	Flash Flood Warning	PHI	Bucks	3 hr
Jul 31, 2:11 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	49 min
Jul 31, 2:27 PM EDT	Areal Flood Advisory	PHI	Berks, Chester, Montgomery	3 hr
Jul 31, 2:32 PM EDT	Areal Flood Advisory	PHI	Bucks, Delaware, Philadelphia	3 hr
Jul 31, 2:46 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	44 min
Jul 31, 3:49 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Delaware, Montgomery, Philadelphia	41 min
Jul 31, 4:36 PM EDT	Areal Flood Advisory	PHI	Bucks, Monroe, Northampton	4 hr
Jul 31, 4:52 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	38 min
Jul 31, 4:58 PM EDT	Flash Flood Warning	PHI	Monroe	4 hr
Jul 31, 1:43 PM EDT	Special Marine Warning	PHI		62 min
Jul 31, 1:49 PM EDT	Special Marine Warning	PHI		86 min
Jul 31, 1:57 PM EDT	Special Weather Statement	PHI	Ocean	33 min
Jul 31, 2:21 PM EDT	Areal Flood Advisory	PHI	Ocean	4 hr
Jul 31, 2:23 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth	52 min
Jul 31, 2:29 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Monmouth, Ocean	46 min
Jul 31, 2:29 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	46 min
Jul 31, 2:53 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth	52 min
Jul 31, 3:00 PM EDT	Areal Flood Advisory	PHI	Monmouth, Ocean	3 hr
Jul 31, 3:05 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	40 min
Jul 31, 3:06 PM EDT	Special Marine Warning	PHI		54 min
Jul 31, 3:20 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Middlesex, Morris, Somerset	40 min
Jul 31, 3:24 PM EDT	Flash Flood Warning	PHI	Monmouth	4 hr
Jul 31, 3:39 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Middlesex, Morris, Somerset, Sussex, Warren	4 hr
Jul 31, 3:39 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	51 min
Jul 31, 3:48 PM EDT	Flash Flood Warning	PHI	Ocean	2 hr
Jul 31, 3:51 PM EDT	Special Marine Warning	PHI		54 min
Jul 31, 3:58 PM EDT	Severe Thunderstorm Warning	PHI	Morris, Somerset	17 min
Jul 31, 5:02 PM EDT	Special Weather Statement	PHI	Atlantic	28 min
Jul 31, 5:16 PM EDT	Special Weather Statement	PHI	Atlantic	44 min
Jul 31, 5:27 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Cumberland, Ocean, Salem	48 min
Jul 31, 5:41 PM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 2 more	3 hr
Jul 31, 5:44 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	25 min
Jul 31, 5:51 PM EDT	Special Marine Warning	PHI		54 min
Jul 31, 5:55 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Ocean	35 min
Jul 31, 5:57 PM EDT	Special Marine Warning	PHI		63 min
Jul 31, 6:05 PM EDT	Special Marine Warning	PHI		55 min
Jul 31, 6:41 PM EDT	Special Marine Warning	PHI		64 min
Jul 31, 6:53 PM EDT	Special Marine Warning	PHI		54 min
Jul 31, 7:36 PM EDT	Special Marine Warning	PHI		54 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2019 Severe Thunderstorm Warnings in New Jersey, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.