Alert archive / New Jersey / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 169, NWS Philadelphia/Mount Holly

August 18, 2017Bucks County, Montgomery County, Philadelphia County, Pennsylvania; 4 counties in New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 18, 2017, 5:54 PM EDT for Bucks County, Montgomery County, Philadelphia County, Pennsylvania; 4 counties in New Jersey. It was in force for 66 min. 6 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: Aug 18, 2017, 5:54 PM EDT (21:54 UTC)
Expired: Aug 18, 2017, 7:00 PM EDT
In force: 66 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Burlington County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Bucks County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 48 km from the middle of the area, began a volume at 21:54 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
Aug 18, 5:54 PM EDT	TSTM WND DMG	Warwick Twp, PA	CREEK ROAD AT OLD YORK ROAD CLOSED FROM A DOWNED TREE IN WIRES. TIME ESTIMATED BY RADAR.
Aug 18, 6:15 PM EDT	TSTM WND GST 60	Yardley, PA	PUBLIC REPORT OF HIGH WINDS AND FLOODING OF LOW WATER CROSSINGS IN YARDLEY. TIME ESTIMATED FROM RADAR.
Aug 18, 6:15 PM EDT	HAIL 0.75	Yardley, PA
Aug 18, 6:32 PM EDT	TSTM WND DMG	Falls Twp, PA	WIRES DOWN IN SEVERAL LOCATIONS.
Aug 18, 6:45 PM EDT	TSTM WND DMG	Bordentown Twp, NJ	DOWNED TREE ON US 206 BETWEEN DUNNS MILL ROAD AND US 130 INTERSECTION. ALL LANES CLOSED. TIME ESTIMATED FROM RADAR.
Aug 18, 6:45 PM EDT	TSTM WND DMG	Mechanicsville, NJ	TREES DOWN NEAR THE WATERFRONT IN PERTH AMBOY AND SOUTH AMBOY. SCATTERED WIRES AND POWER LINES DOWN THROUGHOUT THE COUNTY.

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
Aug 18, 2:27 PM EDT	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 9.9 hours before the alert went out and 171 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1073 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 147 m²/s²
0-3 km storm-relative helicity: 215 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted.

401 
WUUS51 KPHI 182154
SVRPHI
NJC005-021-023-025-PAC017-091-101-182300-
/O.NEW.KPHI.SV.W.0169.170818T2154Z-170818T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
554 PM EDT FRI AUG 18 2017

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Mercer County in central New Jersey...
  Northwestern Burlington County in southern New Jersey...
  Southwestern Monmouth County in central New Jersey...
  Southern Middlesex County in northern New Jersey...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Southeastern Bucks County in southeastern Pennsylvania...
  Northern Philadelphia County in southeastern Pennsylvania...

* Until 700 PM EDT

* At 554 PM EDT, severe thunderstorms were located along a line
  extending from near New Hope to Narberth, moving east at 35 mph.

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

  SOURCE...Radar indicated. 

  IMPACT...Expect damage to trees and power lines. 

* Locations impacted include...
  Philadelphia, Trenton, Old Bridge, Bensalem, East Brunswick, South
  Brunswick, Sayreville, North Brunswick, Ewing, Princeton, Florence,
  Burlington, Bristol, Riverside, Hatboro, Jamesburg, Hightstown,
  Jenkintown, Narberth and Bordentown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4011 7451 3998 7528 4002 7533 4033 7505
      4035 7486 4037 7486 4040 7474 4037 7472
      4039 7463 4037 7461 4042 7458 4046 7450
      4051 7426
TIME...MOT...LOC 2154Z 252DEG 32KT 4031 7502 4003 7525 

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

SFJ

2 follow-up statements

398 
WWUS51 KPHI 182227
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
627 PM EDT FRI AUG 18 2017

NJC005-021-023-025-PAC017-091-101-182300-
/O.CON.KPHI.SV.W.0169.000000T0000Z-170818T2300Z/
Mercer NJ-Burlington NJ-Monmouth NJ-Middlesex NJ-Montgomery PA-
Bucks PA-Philadelphia PA-
627 PM EDT FRI AUG 18 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 700 PM EDT
FOR MERCER...NORTHWESTERN BURLINGTON...SOUTHWESTERN MONMOUTH...
SOUTHERN MIDDLESEX...SOUTHEASTERN MONTGOMERY...SOUTHEASTERN BUCKS AND
NORTHERN PHILADELPHIA COUNTIES...

At 626 PM EDT, severe thunderstorms were located along a line
extending from Kingston to Burlington, moving east at 40 mph.

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

SOURCE...Radar indicated. 

IMPACT...Expect damage to trees and power lines. 

Locations impacted include...
Philadelphia, Trenton, Old Bridge, Bensalem, East Brunswick, South
Brunswick, Sayreville, North Brunswick, Ewing, Princeton, Florence,
Burlington, Bristol, Jamesburg, Hightstown, Bordentown, Cranbury,
Pennington, Beverly and Rockledge.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 this storm. Move indoors
immediately. Remember...if you can hear thunder...you are close
enough to be struck by lightning.

&&

LAT...LON 4011 7451 3999 7524 4033 7485 4040 7474
      4037 7472 4039 7463 4037 7461 4042 7458
      4046 7450 4051 7426
TIME...MOT...LOC 2226Z 259DEG 34KT 4036 7463 4008 7486 

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

SFJ

553 
WWUS51 KPHI 182251
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
651 PM EDT FRI AUG 18 2017

NJC005-021-023-025-PAC017-091-101-182301-
/O.EXP.KPHI.SV.W.0169.000000T0000Z-170818T2300Z/
Mercer NJ-Burlington NJ-Monmouth NJ-Middlesex NJ-Montgomery PA-
Bucks PA-Philadelphia PA-
651 PM EDT FRI AUG 18 2017

...THE SEVERE THUNDERSTORM WARNING FOR MERCER...NORTHWESTERN
BURLINGTON...SOUTHWESTERN MONMOUTH...SOUTHERN MIDDLESEX...
SOUTHEASTERN MONTGOMERY...SOUTHEASTERN BUCKS AND NORTHERN
PHILADELPHIA COUNTIES WILL EXPIRE AT 700 PM EDT...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore the warning will be allowed to expire.  However gusty winds
are still possible with these thunderstorms.

A severe thunderstorm watch remains in effect until 900 PM EDT for
southern, central and northern New Jersey...and southeastern
Pennsylvania.

LAT...LON 4011 7451 3999 7524 4033 7485 4040 7474
      4037 7472 4039 7463 4037 7461 4042 7458
      4046 7450 4051 7426
TIME...MOT...LOC 2251Z 252DEG 32KT 4043 7436 4015 7459 

$$

SFJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 18, 3:39 AM EDT	Flash Flood Watch	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more	18 hr
Aug 18, 4:48 AM EDT	Areal Flood Advisory	PHI	Berks, Lehigh, Northampton	4 hr
Aug 18, 2:10 PM EDT	Areal Flood Advisory	PHI	Berks, Carbon, Lehigh	4 hr
Aug 18, 2:21 PM EDT	Special Weather Statement	PHI	Berks	24 min
Aug 18, 2:33 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	42 min
Aug 18, 3:14 PM EDT	Special Weather Statement	PHI	Berks, Lehigh	31 min
Aug 18, 3:15 PM EDT	Areal Flood Advisory	PHI	Berks	4 hr
Aug 18, 3:19 PM EDT	Special Weather Statement	PHI	Northampton	26 min
Aug 18, 3:37 PM EDT	Special Weather Statement	PHI	Carbon	38 min
Aug 18, 3:43 PM EDT	Special Weather Statement	PHI	Berks	32 min
Aug 18, 3:45 PM EDT	Areal Flood Advisory	PHI	Carbon, Lehigh, Monroe, Northampton	4 hr
Aug 18, 3:46 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh, Montgomery, Northampton	44 min
Aug 18, 4:02 PM EDT	Flash Flood Warning	PHI	Berks	4 hr
Aug 18, 4:24 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Montgomery	51 min
Aug 18, 4:29 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	61 min
Aug 18, 4:57 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Montgomery	3 hr
Aug 18, 5:03 PM EDT	Severe Thunderstorm Warning	PHI	Chester	42 min
Aug 18, 5:11 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	49 min
Aug 18, 5:20 PM EDT	Areal Flood Advisory	PHI	Bucks, Delaware, Montgomery, Philadelphia	3 hr
Aug 18, 5:39 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Philadelphia	66 min
Aug 18, 6:38 PM EDT	Special Weather Statement	PHI	Delaware, Philadelphia	37 min
Aug 18, 3:41 AM EDT	Small Craft Advisory	PHI		18 hr
Aug 18, 10:51 AM EDT	Special Weather Statement	PHI	Ocean	54 min
Aug 18, 11:19 AM EDT	Areal Flood Advisory	PHI	Burlington, Ocean	116 min
Aug 18, 11:28 AM EDT	Special Weather Statement	PHI	Ocean	47 min
Aug 18, 5:08 PM EDT	Special Weather Statement	PHI	Hunterdon, Warren	37 min
Aug 18, 5:42 PM EDT	Special Weather Statement	PHI	Hunterdon	33 min
Aug 18, 5:46 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Somerset	44 min
Aug 18, 5:50 PM EDT	Special Marine Warning	PHI		55 min
Aug 18, 6:13 PM EDT	Special Weather Statement	PHI	Middlesex, Somerset	32 min
Aug 18, 6:20 PM EDT	Areal Flood Advisory	PHI	Middlesex, Somerset	3 hr
Aug 18, 6:23 PM EDT	Special Weather Statement	PHI	Somerset	37 min
Aug 18, 6:41 PM EDT	Special Marine Warning	PHI		64 min
Aug 18, 6:43 PM EDT	Areal Flood Advisory	PHI	Monmouth, Ocean	3 hr
Aug 18, 6:48 PM EDT	Special Weather Statement	PHI	Cumberland, Gloucester, Salem	27 min
Aug 18, 6:53 PM EDT	Special Weather Statement	PHI	Middlesex, Monmouth	52 min
Aug 18, 6:54 PM EDT	Special Weather Statement	PHI	Burlington, Camden, Gloucester	51 min
Aug 18, 6:58 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Ocean	29 min
Aug 18, 7:00 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth, Ocean	60 min
Aug 18, 7:19 PM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Cape May, Cumberland, Ocean, Salem	3 hr
Aug 18, 7:25 PM EDT	Special Weather Statement	PHI	Atlantic	50 min
Aug 18, 7:34 PM EDT	Special Weather Statement	PHI	Cape May	26 min
Aug 18, 7:39 PM EDT	Special Marine Warning	PHI		66 min
Aug 18, 7:43 PM EDT	Special Weather Statement	PHI	Burlington, Ocean	47 min
Aug 18, 7:44 PM EDT	Special Marine Warning	PHI		61 min
Aug 18, 7:49 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Cape May, Cumberland, Gloucester	35 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2017 Severe Thunderstorm Warnings in Pennsylvania, 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.