Alert archive / New Jersey / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 78, NWS Philadelphia/Mount Holly

June 17, 2023Hunterdon County, Somerset County, Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 17, 2023, 3:40 PM EDT for Hunterdon County, Somerset County, Warren County, New Jersey. It was in force for 31 min. 10 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
Jun 17, 2023, 3:40 PM EDT (19:40 UTC)
Expired
Jun 17, 2023, 4:11 PM EDT
In force
31 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.88 in
Wind
60.0 mph

Counties Hunterdon County, NJ, Somerset County, NJ, Warren County, NJ

The radar

The Philadelphia radar (KDIX), 90 km from the middle of the area, began a volume at 19:40 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
Jun 17, 3:45 PM EDTHAIL 0.882 Sse Califon, NJ
Jun 17, 3:45 PM EDTHAIL 0.882 Sse Califon, NJ
Jun 17, 3:45 PM EDTHAIL 0.882 Sse Califon, NJ
Jun 17, 3:45 PM EDTHAIL 0.882 Sse Califon, NJ
Jun 17, 3:45 PM EDTHAIL 0.882 Sse Califon, NJ
Jun 17, 3:45 PM EDTHAIL 0.882 Sse Califon, NJ
Jun 17, 3:50 PM EDTHAIL 0.25Clinton, NJtime estimated from radar.
Jun 17, 3:50 PM EDTHAIL 0.25Clinton, NJtime estimated from radar.
Jun 17, 3:50 PM EDTHAIL 0.25Clinton, NJtime estimated from radar.
Jun 17, 3:50 PM EDTHAIL 0.25Clinton, NJtime estimated from radar.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 7.7 hours before the alert went out and 178 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 2023-06-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 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 2023-06-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 6 square meters per square second.1939Sfc1 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
20 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
658 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
6 m²/s²
0-3 km storm-relative helicity
24 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

852 
WUUS51 KPHI 171940
SVRPHI
NJC019-035-041-172030-
/O.NEW.KPHI.SV.W.0078.230617T1940Z-230617T2030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
340 PM EDT Sat Jun 17 2023

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Hunterdon County in northwestern New Jersey...
  Southwestern Warren County in northwestern New Jersey...
  Southwestern Somerset County in northern New Jersey...

* Until 430 PM EDT.

* At 339 PM EDT, a severe thunderstorm was located over Hampton, or
  11 miles east of Easton, moving southeast at 30 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Somerville, Bridgewater, Bound Brook, Manville, Washington,
  Flemington, High Bridge, Clinton, Harmony, Oxford, Glen Gardner,
  Hampton, Lebanon, Califon, Bloomsbury, Brass Castle, Flagtown,
  Pleasant Valley, Sergeantsville and Roxburg.

This includes the following highways...
 Interstate 78 in New Jersey between mile markers 5 and 28.
 Interstate 287 in New Jersey between mile markers 12 and 18.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to 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 4074 7517 4083 7502 4055 7452 4037 7490
TIME...MOT...LOC 1939Z 319DEG 26KT 4071 7500 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gorse
2 follow-up statements
480 
WWUS51 KPHI 171953
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
353 PM EDT Sat Jun 17 2023

NJC041-172001-
/O.CAN.KPHI.SV.W.0078.000000T0000Z-230617T2030Z/
Warren NJ-
353 PM EDT Sat Jun 17 2023

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN WARREN COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4037 7490 4064 7509 4070 7501 4069 7500
      4077 7491 4055 7452
TIME...MOT...LOC 1951Z 317DEG 31KT 4060 7486 

$$

NJC019-035-172030-
/O.CON.KPHI.SV.W.0078.000000T0000Z-230617T2030Z/
Hunterdon NJ-Somerset NJ-
353 PM EDT Sat Jun 17 2023

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM EDT
FOR HUNTERDON AND SOUTHWESTERN SOMERSET COUNTIES...

At 351 PM EDT, a severe thunderstorm was located near Lebanon, or 13 
miles west of Somerville, moving southeast at 35 mph. Nickel size 
hail was reported in parts of Hunterdon County.

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

SOURCE...Radar indicated.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Somerville, Bridgewater, Bound Brook, Manville, Flemington, High
Bridge, Clinton, Glen Gardner, Hampton, Lebanon, Califon, Flagtown,
Sergeantsville, Cloverhill, Annandale, White House Station, Sand
Brook, Raritan and South Bound Brook.

This includes the following highways...
 Interstate 78 in New Jersey between mile markers 8 and 28.
 Interstate 287 in New Jersey between mile markers 12 and 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with this storm. Move
indoors immediately. Lightning is one of nature's leading killers.
Remember, if you can hear thunder, you are close enough to be struck
by lightning.

&&

LAT...LON 4037 7490 4064 7509 4070 7501 4069 7500
      4077 7491 4055 7452
TIME...MOT...LOC 1951Z 317DEG 31KT 4060 7486 

HAIL THREAT...OBSERVED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gorse
956 
WWUS51 KPHI 172011
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
411 PM EDT Sat Jun 17 2023

NJC019-035-172020-
/O.CAN.KPHI.SV.W.0078.000000T0000Z-230617T2030Z/
Hunterdon NJ-Somerset NJ-
411 PM EDT Sat Jun 17 2023

...THE SEVERE THUNDERSTORM WARNING FOR HUNTERDON AND SOUTHWESTERN
SOMERSET COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.  However small hail and
gusty winds are still possible with this thunderstorm.

LAT...LON 4037 7490 4064 7509 4070 7501 4069 7500
      4077 7491 4055 7452
TIME...MOT...LOC 2008Z 319DEG 26KT 4049 7474 

$$

Gorse

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 17, 4:19 PM EDTSevere Thunderstorm WarningPHIMiddlesex, Monmouth, Somerset22 min
Jun 17, 4:55 PM EDTSpecial Marine WarningPHI50 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2023Every severe thunderstorm warning in 2023

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.