Alert archive / New Jersey / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 109, NWS Philadelphia/Mount Holly

July 20, 2017Monroe County, Northampton County, Pennsylvania; 4 counties in New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 20, 2017, 6:24 PM EDT for Monroe County, Northampton County, Pennsylvania; 4 counties in New Jersey. It was in force for 66 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, 6:24 PM EDT (22:24 UTC)
Expired
Jul 20, 2017, 7:30 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 Hunterdon County, NJ, Morris County, NJ, Sussex County, NJ, Warren County, NJ, Monroe County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 132 km from the middle of the area, began a volume at 22:26 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, 6:53 PM EDTTSTM WND DMG1 N Marshfield Station, NJDOWNED TREE ON US HIGHWAY 46 WESTBOUND SOUTH OF COLUMBIA. TIME APPROXIMATED FROM RADAR.
Jul 20, 7:01 PM EDTTSTM WND DMGMount Bethel, PATREES AND WIRES DOWN IN UPPER AND LOWER MOUNT BETHEL TOWNSHIPS.

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, 10.4 hours before the alert went out and 163 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.

064 
WUUS51 KPHI 202224
SVRPHI
NJC019-027-037-041-PAC089-095-202330-
/O.NEW.KPHI.SV.W.0109.170720T2224Z-170720T2330Z/

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

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Morris County in northern New Jersey...
  Northeastern Hunterdon County in northwestern New Jersey...
  Sussex County in northwestern New Jersey...
  Warren County in northwestern New Jersey...
  Central Monroe County in northeastern Pennsylvania...
  Northeastern Northampton County in eastern Pennsylvania...

* Until 730 PM EDT

* At 623 PM EDT, severe thunderstorms were located along a line
  extending from Shohola to near Werry Lake to Pocono Pines, moving
  southeast at 35 mph.

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. 

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

* Severe thunderstorms will be near,
  Werry Lake and Echo Lake around 635 PM EDT. 
  Millbrook, Flatbrookville and Paradise Valley around 640 PM EDT. 
  Port Jervis, Blairstown, Milford, Five Points, Analomink and 
  Hernyville around 645 PM EDT. 
  Montague around 650 PM EDT. 
  Newton, East Stroudsburg, High Point and Stormville around 655 PM 
  EDT. 
  Bangor, Pen Argyl, Delaware Water Gap, Andover, Greendell, 
  Delaware Water Gap and Allamuchy-Panther Valley around 700 PM EDT. 
  Hackettstown, East Bangor, Columbia and Lake Mohawk around 705 PM 
  EDT. 
  Hopatcong, Stanhope and Sussex around 710 PM EDT. 

Other locations impacted by these severe thunderstorms include
Portland, Cresco, Marshalls Creek, Arlington Heights, Roseto, White
Meadow Lake, Hidden Lake, Beattyestown, Stroudsburg and Bartonsville.

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 4120 7437 4109 7450 4104 7450 4105 7445
      4102 7443 4101 7439 4076 7452 4068 7504
      4113 7557 4118 7518 4124 7513 4115 7515
      4114 7509 4108 7503 4116 7490 4132 7480
      4136 7470
TIME...MOT...LOC 2223Z 306DEG 29KT 4149 7494 4114 7511 4110 7548 

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

Robertson
3 follow-up statements
285 
WWUS51 KPHI 202250
SVSPHI

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

NJC019-027-037-041-PAC089-095-202330-
/O.CON.KPHI.SV.W.0109.000000T0000Z-170720T2330Z/
Morris NJ-Hunterdon NJ-Sussex NJ-Warren NJ-Monroe PA-Northampton PA-
650 PM EDT THU JUL 20 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR MORRIS...NORTHEASTERN HUNTERDON...SUSSEX...WARREN...SOUTHEASTERN
MONROE AND NORTHEASTERN NORTHAMPTON COUNTIES...

At 649 PM EDT, severe thunderstorms were located along a line
extending from Matamoras to near Greendell to near Stormville, moving
southeast at 35 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

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

These severe storms will be near...
  Newton and Five Points around 655 PM EDT. 
  Greendell, High Point and Allamuchy-Panther Valley around 700 PM 
  EDT. 
  Hackettstown, Andover and Lake Mohawk around 705 PM EDT. 
  Hopatcong, Stanhope and Sussex around 710 PM EDT. 
  Mount Arlington, Hamburg, Netcong, Belvidere, Hope, Vernon Valley 
  and Budd Lake around 715 PM EDT. 
  Oxford, Chester, Succasunna-Kenvil, Succasunna and Highland Lake 
  around 720 PM EDT. 
  Dover, Wharton, Washington, Rockaway, Victory Gardens, Brass 
  Castle, Pleasant Valley and Great Meadows-Vienna around 725 PM 
  EDT. 
  Morris Plains, Mendham, Glen Gardner, Hampton, Califon, Upper 
  Greenwood Lake, Beatyestown and Long Valley around 730 PM EDT. 

Other locations impacted by these severe thunderstorms include
Portland, White Meadow Lake, Beattyestown, Stroudsburg, Shawnee,
Roseto, Bernardsville and Arlington Heights.

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 4069 7496 4095 7532 4106 7497 4134 7476
      4136 7470 4120 7437 4109 7450 4104 7450
      4105 7445 4102 7443 4101 7439 4076 7452
TIME...MOT...LOC 2249Z 306DEG 29KT 4137 7472 4102 7489 4098 7526 

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

Robertson
786 
WWUS51 KPHI 202312
SVSPHI

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

NJC037-PAC089-202321-
/O.CAN.KPHI.SV.W.0109.000000T0000Z-170720T2330Z/
Sussex NJ-Monroe PA-
712 PM EDT THU JUL 20 2017

...THE SEVERE THUNDERSTORM WARNING FOR SUSSEX AND SOUTHEASTERN MONROE
COUNTIES IS CANCELLED...

The storms which prompted the warning have weakened. Therefore, the 
warning has been cancelled. Showers and thunderstorms remain 
possible with heavy rain and gusty winds.

A severe thunderstorm watch remains in effect until 1000 PM EDT for
northern and northwestern New Jersey...and eastern Pennsylvania.

LAT...LON 4092 7477 4092 7476 4078 7451 4076 7452
      4076 7457 4074 7464 4069 7497 4084 7516
      4096 7484
TIME...MOT...LOC 2311Z 305DEG 24KT 4093 7479 4081 7509 

$$

NJC019-027-041-PAC095-202330-
/O.CON.KPHI.SV.W.0109.000000T0000Z-170720T2330Z/
Morris NJ-Hunterdon NJ-Warren NJ-Northampton PA-
712 PM EDT THU JUL 20 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR SOUTHWESTERN MORRIS...NORTHEASTERN HUNTERDON...CENTRAL WARREN AND
EAST CENTRAL NORTHAMPTON COUNTIES...

At 711 PM EDT, severe thunderstorms were located along a line
extending from near Allamuchy-Panther Valley to Belvidere, moving
southeast at 30 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

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

These severe storms will be near...
  Hackettstown, Allamuchy-Panther Valley and Beatyestown around 715 
  PM EDT. 
  Netcong, Budd Lake and Long Valley around 720 PM EDT. 
  Mendham, Glen Gardner, Chester, Hampton, Califon, Succasunna and 
  Succasunna-Kenvil around 730 PM EDT. 

Other locations impacted by these severe thunderstorms include
Beattyestown.

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...occasional 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 4092 7477 4092 7476 4078 7451 4076 7452
      4076 7457 4074 7464 4069 7497 4084 7516
      4096 7484
TIME...MOT...LOC 2311Z 305DEG 24KT 4093 7479 4081 7509 

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

Robertson
926 
WWUS51 KPHI 202329
SVSPHI

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

NJC019-027-041-PAC095-202338-
/O.EXP.KPHI.SV.W.0109.000000T0000Z-170720T2330Z/
Morris NJ-Hunterdon NJ-Warren NJ-Northampton PA-
729 PM EDT THU JUL 20 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN MORRIS...
NORTHEASTERN HUNTERDON...CENTRAL WARREN AND EAST CENTRAL NORTHAMPTON
COUNTIES WILL EXPIRE AT 730 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 
and heavy rain are still possible with these thunderstorms.

A severe thunderstorm watch remains in effect until 1000 PM EDT for
northern and northwestern New Jersey...and eastern Pennsylvania.

LAT...LON 4092 7477 4092 7476 4078 7451 4076 7452
      4076 7457 4074 7464 4069 7497 4084 7516
      4096 7484
TIME...MOT...LOC 2328Z 306DEG 29KT 4085 7465 4073 7495 

$$

Robertson

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 3:43 AM EDTHeat AdvisoryPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton15 hr
Jul 20, 5:35 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe55 min
Jul 20, 5:37 PM EDTSevere Thunderstorm WarningPHIMonroe53 min
Jul 20, 6:22 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh, Monroe, Northampton53 min
Jul 20, 7:00 PM EDTSevere Thunderstorm WarningPHIBucks, Carbon, Lehigh, Northampton60 min
Jul 20, 7:52 PM EDTSevere Thunderstorm WarningPHIBucks53 min
Jul 20, 7:31 PM EDTSpecial Weather StatementPHIMorris29 min
Jul 20, 7:56 PM EDTSpecial Weather StatementPHIMiddlesex, Monmouth, Somerset49 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.