Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 190, NWS Philadelphia/Mount Holly

July 17, 2021Hunterdon County, Somerset County, New Jersey; Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 17, 2021, 7:01 PM EDT for Hunterdon County, Somerset County, New Jersey; Bucks County, Pennsylvania. It was in force for 44 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 17, 2021, 7:01 PM EDT (23:01 UTC)
Expired: Jul 17, 2021, 7:45 PM EDT
In force: 44 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Hunterdon County, NJ, Somerset County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 81 km from the middle of the area, began a volume at 23:01 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 17, 7:05 PM EDT	TSTM WND DMG	Lumberville, PA	SEVERAL TREES BLOWN DOWN NEAR THE INTERSECTION OF FLEECY DALE ROAD AND RIVER ROAD.
Jul 17, 7:35 PM EDT	TSTM WND DMG	1 Wsw Clinton, NJ	TREE DOWN ON INTERSTATE 78. TIME ESTIMATED FROM 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.

Issued	Product	Office	Lasted
Jul 17, 1:13 PM EDT	Severe Thunderstorm Watch	SPC	10 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 11.0 hours before the alert went out and 172 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: 1203 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 1054 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 46 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

As transmitted.

011 
WUUS51 KPHI 172301
SVRPHI
NJC019-035-PAC017-172345-
/O.NEW.KPHI.SV.W.0190.210717T2301Z-210717T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
701 PM EDT Sat Jul 17 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Central Hunterdon County in northwestern New Jersey...
  Northwestern Somerset County in northern New Jersey...
  Central Bucks County in southeastern Pennsylvania...

* Until 745 PM EDT.

* At 700 PM EDT, severe thunderstorms were located along a line
  extending from near Clinton to Gardenville, moving northeast at 20
  mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Byram, Flemington, Tinicum, High Bridge, Clinton, Peapack And
  Gladstone, Glen Gardner, Frenchtown, Lebanon, Califon, Stockton,
  Sergeantsville, Pipersville, Erwinna, Annandale, Gardenville, White
  House Station, Lumberville and Sand Brook.

This includes Interstate 78 in New Jersey between mile markers 13 and
26.
 
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 these storms. Move indoors
immediately. Remember, if you can hear thunder, you are close enough
to be struck by lightning.

&&

LAT...LON 4035 7502 4036 7520 4070 7495 4073 7474
      4072 7472 4074 7467 4074 7464
TIME...MOT...LOC 2300Z 230DEG 17KT 4058 7487 4037 7510 

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

JEO

1 follow-up statement

641 
WWUS51 KPHI 172339
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
739 PM EDT Sat Jul 17 2021

NJC019-035-PAC017-172349-
/O.EXP.KPHI.SV.W.0190.000000T0000Z-210717T2345Z/
Hunterdon NJ-Somerset NJ-Bucks PA-
739 PM EDT Sat Jul 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL HUNTERDON...
NORTHWESTERN SOMERSET AND CENTRAL BUCKS COUNTIES WILL EXPIRE AT 745
PM EDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
northern and northwestern New Jersey...and southeastern Pennsylvania.

LAT...LON 4035 7502 4036 7520 4070 7495 4073 7474
      4072 7472 4074 7467 4074 7464
TIME...MOT...LOC 2339Z 230DEG 17KT 4058 7487 4037 7510 

$$

JEO

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 12:55 PM EDT	Special Weather Statement	PHI	Hunterdon	50 min
Jul 17, 1:05 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer	40 min
Jul 17, 1:31 PM EDT	Areal Flood Advisory	PHI	Hunterdon	97 min
Jul 17, 1:50 PM EDT	Special Marine Warning	PHI		40 min
Jul 17, 1:56 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Somerset, Warren	36 min
Jul 17, 2:02 PM EDT	Areal Flood Advisory	PHI	Monmouth, Ocean	92 min
Jul 17, 2:56 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Somerset	49 min
Jul 17, 3:06 PM EDT	Severe Thunderstorm Warning	PHI	Warren	39 min
Jul 17, 3:09 PM EDT	Tornado Warning	PHI	Middlesex	21 min
Jul 17, 3:38 PM EDT	Areal Flood Advisory	PHI	Middlesex	40 min
Jul 17, 3:51 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex	24 min
Jul 17, 4:55 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Somerset	50 min
Jul 17, 5:13 PM EDT	Areal Flood Advisory	PHI	Hunterdon	4 hr
Jul 17, 5:19 PM EDT	Tornado Warning	PHI	Hunterdon	14 min
Jul 17, 5:25 PM EDT	Flash Flood Warning	PHI	Hunterdon	6 hr
Jul 17, 5:30 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Warren	19 min
Jul 17, 5:52 PM EDT	Areal Flood Advisory	PHI	Somerset	2 hr
Jul 17, 6:02 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Somerset	43 min
Jul 17, 6:15 PM EDT	Flash Flood Warning	PHI	Morris, Somerset	5 hr
Jul 17, 6:39 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	51 min
Jul 17, 6:51 PM EDT	Severe Thunderstorm Warning	PHI	Burlington	39 min
Jul 17, 6:59 PM EDT	Small Craft Advisory	PHI		7 hr
Jul 17, 7:12 PM EDT	Areal Flood Advisory	PHI	Mercer, Somerset	3 hr
Jul 17, 7:26 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	49 min
Jul 16, 8:14 PM EDT	Special Weather Statement	PHI	Montgomery	31 min
Jul 16, 8:41 PM EDT	Special Weather Statement	PHI	Bucks	34 min
Jul 16, 9:07 PM EDT	Special Weather Statement	PHI	Lehigh	23 min
Jul 16, 9:29 PM EDT	Special Weather Statement	PHI	Lehigh	31 min
Jul 16, 10:21 PM EDT	Special Weather Statement	PHI	Lehigh	24 min
Jul 17, 2:30 PM EDT	Special Weather Statement	PHI	Berks	45 min
Jul 17, 2:36 PM EDT	Severe Thunderstorm Warning	PHI	Berks	39 min
Jul 17, 7:36 PM EDT	Special Weather Statement	PHI	Carbon	54 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2021 Severe Thunderstorm Warnings in Pennsylvania, 2021 Every severe thunderstorm warning in 2021

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.