Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 74, NWS Philadelphia/Mount Holly

July 1, 2017Hunterdon County, Warren County, New Jersey; 6 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 1, 2017, 4:24 PM EDT for Hunterdon County, Warren County, New Jersey; 6 counties in Pennsylvania. It was in force for 51 min. 15 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 1, 2017, 4:24 PM EDT (20:24 UTC)
Expired: Jul 1, 2017, 5:15 PM EDT
In force: 51 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Possible
Hail: 1.0 in
Wind: 60.0 mph

Counties Hunterdon County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Chester County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 100 km from the middle of the area, began a volume at 20:24 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 1, 4:30 PM EDT	TSTM WND DMG	Birdsboro, PA	MULTIPLE TREES REPORTED DOWN
Jul 1, 4:30 PM EDT	TSTM WND DMG	Topton, PA	TREE REPORTED DOWN ON RAILROAD TRACKS IN TOPTON.
Jul 1, 4:35 PM EDT	TSTM WND DMG	1 Wnw Upper Hanover Twp, PA	SEVERAL LARGE BRANCHES DOWN. TIME ESTIMATED FROM RADAR.
Jul 1, 4:35 PM EDT	TSTM WND DMG	Mertztown, PA	TREE REPORTED DOWN IN MERTZTOWN.
Jul 1, 4:37 PM EDT	TSTM WND DMG	East Texas, PA	DOWNED TREES AND WIRES ON BROOKSIDE RD BETWEEN EAST TEXAS RD AND LOWER MACUNGIE RD
Jul 1, 4:40 PM EDT	TSTM WND DMG	Haines, PA	PARTIAL ROOF COLLAPSE OF A COMERCIAL BUILDING ON SCHANTZ RD. TIME ESTIMATED FROM RADAR.
Jul 1, 4:46 PM EDT	TSTM WND GST 59	S Allentown, PA	59 MPH GUST RECORDED IN SOUTH ALLENTOWN. SMALL BRANCHES COVERING SOME ROADWAYS.
Jul 1, 4:47 PM EDT	TSTM WND DMG	North Catasauqua, PA	MULTIPLE TREES AND POWER LINES REPORTED DOWN IN NORTH CATASAUQUA
Jul 1, 4:47 PM EDT	TSTM WND DMG	North Catasauqua, PA	MULTIPLE TREES AND POWER LINES REPORTED DOWN IN NORTH CATASAUQUA.
Jul 1, 4:47 PM EDT	HAIL 0.5	North Catasauqua, PA
Jul 1, 4:48 PM EDT	TSTM WND DMG	1 Sw Schoenersville, PA	SEVERAL REPORTS OF DAMAGE AT THE LEHIGH VALLEY INTERNALTIONAL AIRPORT. ONE PLANE OVERTURNED. ANOTHER PLANE LOST ITS NOSE GEAR AND ANOTHER PLANE WAS DAMAGED BY A FALLING TREE. ROOFING WAS STRIPPED OFF AND SKYLIGHTS WERE CRACKTED AT THE MAIN TERMINAL BUILDING.
Jul 1, 4:48 PM EDT	TSTM WND DMG	1 Sw Schoenersville, PA	SEVERAL REPORTS OF DAMAGE AT THE LEHIGH VALLEY INTERNATIONAL AIRPORT. ONE PLANE OVERTURNED. ANOTHER PLANE LOST ITS NOSE GEAR AND ANOTHER PLANE WAS DAMAGED BY A FALLING TREE. ROOFING WAS STRIPPED OFF AND SKYLIGHTS WERE CRACKED AT THE MAIN TERMINAL BUILDING.
Jul 1, 4:48 PM EDT	TSTM WND DMG	Allentown, PA	MULTIPLE PLANES OVER TURNED AND SPILLING FUEL AT THE LEHIGH VALLEY INTERNATIONAL AIRPORT.
Jul 1, 4:51 PM EDT	TSTM WND GST 64	Lehigh Valley Intl Airp, PA	64 MPH GUST RECORDED AT THE LEHIGH VALLEY INTERNATIONAL AIRPORT
Jul 1, 5:04 PM EDT	TSTM WND DMG	1 Nnw Finland, PA	DOWNED TREE ON TRUMBAUERSVILLE RD NEAR CARVERS HILL RD

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 1, 1:34 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.4 hours before the alert went out and 209 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: 160 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 564 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 105 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

As transmitted.

152 
WUUS51 KPHI 012024
SVRPHI
NJC019-041-PAC011-017-029-077-091-095-012115-
/O.NEW.KPHI.SV.W.0074.170701T2024Z-170701T2115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
424 PM EDT SAT JUL 1 2017

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Central Hunterdon County in northwestern New Jersey...
  Southwestern Warren County in northwestern New Jersey...
  Eastern Berks County in eastern Pennsylvania...
  Montgomery County in southeastern Pennsylvania...
  Lehigh County in eastern Pennsylvania...
  Northwestern Bucks County in southeastern Pennsylvania...
  Chester County in southeastern Pennsylvania...
  Southern Northampton County in eastern Pennsylvania...

* Until 515 PM EDT

* At 423 PM EDT, severe thunderstorms were located along a line
  extending from near Allentown to Topton to near Quarryville, moving
  east at 40 mph.

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

  SOURCE...Radar indicated. 

  IMPACT...Minor damage to vehicles is possible. Expect damage to 
           trees and power lines. 

* Locations impacted include...
  Allentown, Reading, Easton, West Chester, Bethlehem, Norristown,
  Pottstown, Phoenixville, Lansdale, West Norriton, Forks, East
  Norriton, Coatesville, Emmaus, Westtown, Wyomissing, Northampton,
  Quakertown, Perkasie and Doylestown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. These storms may cause serious injury and significant
property damage.

&&

LAT...LON 3987 7599 4011 7594 4014 7588 4025 7605
      4055 7592 4069 7562 4074 7478 4072 7472
      4068 7472 4055 7495 4002 7531 4006 7535
      4006 7536 3990 7558 3984 7559 3981 7570
      3972 7578 3973 7609
TIME...MOT...LOC 2023Z 265DEG 35KT 4063 7551 4052 7570 3988 7611 

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

SFJ

2 follow-up statements

440 
WWUS51 KPHI 012041
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
441 PM EDT SAT JUL 1 2017

NJC019-041-PAC011-017-029-077-091-095-012115-
/O.CON.KPHI.SV.W.0074.000000T0000Z-170701T2115Z/
Hunterdon NJ-Warren NJ-Berks PA-Montgomery PA-Lehigh PA-Bucks PA-
Chester PA-Northampton PA-
441 PM EDT SAT JUL 1 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM EDT
FOR CENTRAL HUNTERDON...SOUTHWESTERN WARREN...SOUTHEASTERN BERKS...
MONTGOMERY...SOUTHEASTERN LEHIGH...NORTHWESTERN BUCKS...CHESTER AND
SOUTHERN NORTHAMPTON COUNTIES...

At 441 PM EDT, severe thunderstorms were located along a line
extending from Old Orchard to Emmaus to Cochranville, moving east at
40 mph.

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

SOURCE...Radar indicated. 

IMPACT...Minor damage to vehicles is possible. Expect damage to 
         trees and power lines. 

Locations impacted include...
Allentown, Easton, West Chester, Bethlehem, Norristown, Pottstown,
Phoenixville, Lansdale, West Norriton, Forks, East Norriton,
Coatesville, Emmaus, Westtown, Northampton, Quakertown, Perkasie,
Doylestown, Byram and Wilson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. These storms may cause serious injury and significant
property damage.

&&

LAT...LON 3987 7599 4011 7594 4014 7588 4016 7591
      4020 7588 4069 7559 4074 7478 4072 7472
      4068 7472 4055 7495 4002 7531 4006 7535
      4006 7536 3990 7558 3984 7559 3981 7570
      3972 7578 3973 7609
TIME...MOT...LOC 2041Z 265DEG 35KT 4064 7530 4053 7549 3989 7590 

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

SFJ

909 
WWUS51 KPHI 012057
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
457 PM EDT SAT JUL 1 2017

NJC019-041-PAC011-017-029-077-091-095-012115-
/O.CON.KPHI.SV.W.0074.000000T0000Z-170701T2115Z/
Hunterdon NJ-Warren NJ-Berks PA-Montgomery PA-Lehigh PA-Bucks PA-
Chester PA-Northampton PA-
457 PM EDT SAT JUL 1 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM EDT
FOR CENTRAL HUNTERDON...SOUTHWESTERN WARREN...SOUTHEASTERN BERKS...
MONTGOMERY...SOUTHEASTERN LEHIGH...NORTHWESTERN BUCKS...CHESTER AND
SOUTHERN NORTHAMPTON COUNTIES...

At 456 PM EDT, severe thunderstorms were located along a line
extending from Bloomsbury to Springtown to near Marshallton, moving
east at 40 mph.

HAZARD...65 mph wind gusts and quarter size hail. 

SOURCE...Trained weather spotters. 

IMPACT...Minor damage to vehicles is possible. Expect damage to 
         trees and power lines. 

Locations impacted include...
Allentown, Easton, West Chester, Bethlehem, Norristown, Pottstown,
Phoenixville, Lansdale, West Norriton, Forks, East Norriton,
Coatesville, Emmaus, Westtown, Northampton, Quakertown, Perkasie,
Doylestown, Byram and Wilson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. These storms may cause serious injury and significant
property damage.

&&

LAT...LON 3987 7599 4011 7594 4014 7588 4016 7591
      4020 7588 4069 7559 4074 7478 4072 7472
      4068 7472 4055 7495 4002 7531 4006 7535
      4006 7536 3990 7558 3984 7559 3981 7570
      3972 7578 3973 7609
TIME...MOT...LOC 2056Z 265DEG 35KT 4065 7510 4054 7529 3990 7571 

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

SFJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 30, 9:48 PM EDT	Special Weather Statement	PHI	Middlesex	42 min
Jun 30, 9:55 PM EDT	Special Weather Statement	PHI	Middlesex	20 min
Jun 30, 10:32 PM EDT	Special Weather Statement	PHI	Middlesex	28 min
Jul 1, 9:48 AM EDT	Marine Dense Fog Advisory	PHI		5 hr
Jul 1, 5:00 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Warren	4 hr
Jul 1, 5:01 PM EDT	Severe Thunderstorm Warning	PHI	Camden, Gloucester, Salem	44 min
Jul 1, 5:08 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Morris, Somerset, Warren	52 min
Jul 1, 5:10 PM EDT	Special Marine Warning	PHI		95 min
Jul 1, 5:29 PM EDT	Special Weather Statement	PHI	Sussex	31 min
Jul 1, 5:30 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester	4 hr
Jul 1, 5:35 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester, Mercer, Salem	40 min
Jul 1, 5:41 PM EDT	Special Weather Statement	PHI	Atlantic, Cape May, Cumberland, Salem	34 min
Jul 1, 5:50 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset, Sussex and 1 more	40 min
Jul 1, 6:07 PM EDT	Special Weather Statement	PHI	Burlington, Camden, Gloucester, Mercer	23 min
Jul 1, 6:17 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	4 hr
Jul 1, 6:22 PM EDT	Special Weather Statement	PHI	Middlesex, Monmouth, Morris	23 min
Jul 1, 6:33 PM EDT	Special Weather Statement	PHI	Burlington, Camden, Cumberland, Gloucester	27 min
Jul 1, 6:59 PM EDT	Special Marine Warning	PHI		61 min
Jul 1, 7:01 PM EDT	Special Weather Statement	PHI	Atlantic, Burlington, Ocean	29 min
Jun 30, 8:09 PM EDT	Special Weather Statement	PHI	Montgomery	51 min
Jun 30, 8:32 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Lehigh, Montgomery	118 min
Jun 30, 9:17 PM EDT	Special Weather Statement	PHI	Bucks	43 min
Jul 1, 2:38 PM EDT	Special Weather Statement	PHI	Berks	52 min
Jul 1, 3:22 PM EDT	Special Weather Statement	PHI	Berks, Carbon	23 min
Jul 1, 3:24 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	3 hr
Jul 1, 3:41 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh, Northampton	49 min
Jul 1, 4:05 PM EDT	Special Weather Statement	PHI	Chester	40 min
Jul 1, 4:20 PM EDT	Flash Flood Warning	PHI	Berks, Lehigh	4 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2017 Severe Thunderstorm Warnings in New Jersey, 2017 Every severe thunderstorm warning in 2017

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.