Alert archive / New Jersey / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 111, NWS Philadelphia/Mount Holly

July 20, 20177 counties in New Jersey; Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 20, 2017, 7:52 PM EDT for 7 counties in New Jersey; Bucks County, Pennsylvania. It was in force for 53 min. 2 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 20, 2017, 7:52 PM EDT (23:52 UTC)
Expired
Jul 20, 2017, 8:45 PM EDT
In force
53 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Burlington County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Ocean County, NJ, Somerset County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 44 km from the middle of the area, began a volume at 23:55 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

TimeReportWhereRemark
Jul 20, 8:07 PM EDTTSTM WND DMG1 S Marshalls Corner, NJTREE DOWN ON STATE HIGHWAY 31 SOUTHBOUND BETWEEN TITUS MILL ROAD AND WOODVILLE ROAD...FORCING A ROAD CLOSURE AND DETOURS. TIME ESTIMATED FROM RADAR.
Jul 20, 8:17 PM EDTTSTM WND DMGWeber Park, NJDOWNED TREE ON STATE HIGHWAY 31 NEAR OLDEN AVENUE. TIME ESTIMATED BY 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.

IssuedProductOfficeLasted
Jul 20, 5:03 PM EDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 11.9 hours before the alert went out and 174 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-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 2017-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 14 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2017-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 22 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
14 J/kg
Mixed-layer CIN
-148 J/kg
Mixed-layer LCL
1647 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
22 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

304 
WUUS51 KPHI 202352
SVRPHI
NJC005-019-021-023-025-029-035-PAC017-210045-
/O.NEW.KPHI.SV.W.0111.170720T2352Z-170721T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
752 PM EDT THU JUL 20 2017

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern Ocean County in southern New Jersey...
  Southeastern Hunterdon County in northwestern New Jersey...
  Mercer County in central New Jersey...
  Northeastern Burlington County in southern New Jersey...
  Southwestern Somerset County in northern New Jersey...
  Southwestern Monmouth County in central New Jersey...
  Southwestern Middlesex County in northern New Jersey...
  Southeastern Bucks County in southeastern Pennsylvania...

* Until 845 PM EDT

* At 752 PM EDT, a severe thunderstorm was located near Pennington,
  or 11 miles northwest of Trenton, moving southeast at 35 mph.

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. 

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

* This severe thunderstorm will be near,
  Hopewell around 755 PM EDT. 
  Pennington, Washington Crossing and Washington Crossing around 800 
  PM EDT. 
  Trenton, Princeton, Yardley, Lawrenceville and Woodside around 805 
  PM EDT. 
  Ewing and Levittown around 810 PM EDT. 
  Mercerville-Hamilton Square, White Horse and Edinburg around 815 
  PM EDT. 
  Bordentown and Windsor around 820 PM EDT. 
  Allentown and Crosswicks around 825 PM EDT. 
  Roosevelt, Imlaystown and Georgetown around 830 PM EDT. 

Other locations impacted by this severe thunderstorm include Country
Lake Estates, Hulmeville, Princeton Junction, Pemberton Heights,
Village Shires, New Egypt, Yardville-Groveville, Monmouth Junction,
Heathcote and Morrisville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 4035 7512 4054 7475 4018 7412 3979 7465
TIME...MOT...LOC 2352Z 314DEG 31KT 4037 7486 

HAIL...<.75IN
WIND...60MPH
 
$$

Robertson
1 follow-up statement
176 
WWUS51 KPHI 210016
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
816 PM EDT THU JUL 20 2017

NJC019-210025-
/O.CAN.KPHI.SV.W.0111.000000T0000Z-170721T0045Z/
Hunterdon NJ-
816 PM EDT THU JUL 20 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN HUNTERDON COUNTY
IS CANCELLED...
    
The severe thunderstorm which prompted the warning has weakened.
Therefore, the warning has been cancelled. However gusty winds and 
heavy rain are still possible with these thunderstorms.

A severe thunderstorm watch remains in effect until 1000 PM EDT for
southern, central and northern New Jersey...and southeastern
Pennsylvania.

LAT...LON 4028 7499 4033 7480 4046 7461 4018 7412
      3979 7465
TIME...MOT...LOC 0015Z 319DEG 29KT 4022 7471 

$$

NJC005-021-023-025-029-035-PAC017-210045-
/O.CON.KPHI.SV.W.0111.000000T0000Z-170721T0045Z/
Ocean NJ-Mercer NJ-Burlington NJ-Somerset NJ-Monmouth NJ-
Middlesex NJ-Bucks PA-
816 PM EDT THU JUL 20 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 845 PM EDT
FOR NORTHWESTERN OCEAN...MERCER...NORTHEASTERN BURLINGTON...SOUTH
CENTRAL SOMERSET...SOUTHWESTERN MONMOUTH...SOUTHWESTERN MIDDLESEX AND
SOUTHEASTERN BUCKS COUNTIES...

At 815 PM EDT, a severe thunderstorm was located over
Mercerville-Hamilton Square, or over Trenton, moving southeast at 35
mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

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

This severe storm will be near...
  Bordentown and Windsor around 820 PM EDT. 
  Allentown and Crosswicks around 825 PM EDT. 
  Georgetown, Imlaystown and Columbus around 830 PM EDT. 
  Cream Ridge and Jobstown around 835 PM EDT. 
  Wrightstown and Six Flags Theme Park around 840 PM EDT. 
  Woodruff, Browns Mills and Cassville around 845 PM EDT. 

Other locations impacted by this severe thunderstorm include Country
Lake Estates, Concordia, Fieldsboro, Princeton Junction, Woodbourne,
Princeton North, Pemberton Heights, New Egypt, Yardville-Groveville
and Englishtown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 4028 7499 4033 7480 4046 7461 4018 7412
      3979 7465
TIME...MOT...LOC 0015Z 319DEG 29KT 4022 7471 

HAIL...<.75IN
WIND...60MPH
 
$$

Robertson

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 3:43 AM EDTHeat AdvisoryPHIAtlantic, Burlington, Cape May, Cumberland, Hunterdon, Middlesex and 4 more15 hr
Jul 20, 6:22 PM EDTSevere Thunderstorm WarningPHIWarren53 min
Jul 20, 6:24 PM EDTSevere Thunderstorm WarningPHIHunterdon, Morris, Sussex, Warren66 min
Jul 20, 7:00 PM EDTSevere Thunderstorm WarningPHIHunterdon, Mercer, Somerset, Warren60 min
Jul 20, 7:31 PM EDTSpecial Weather StatementPHIMorris29 min
Jul 20, 7:56 PM EDTSpecial Weather StatementPHIMiddlesex, Monmouth, Somerset49 min
Jul 20, 5:35 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe55 min
Jul 20, 5:37 PM EDTSevere Thunderstorm WarningPHIMonroe53 min

Nearby

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