Alert archive / New Jersey / Special Weather Statements in 2021

Special Weather Statement, NWS Philadelphia/Mount Holly

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

NWS Philadelphia/Mount Holly issued this special weather statement at Jul 17, 2021, 12:55 PM EDT for Hunterdon County, New Jersey; Bucks County, Pennsylvania. It was in force for 50 min. 4 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, 12:55 PM EDT (16:55 UTC)
Expired: Jul 17, 2021, 1:45 PM EDT
In force: 50 min
Issued by: NWS Philadelphia/Mount Holly

Counties Hunterdon County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 69 km from the middle of the area, began a volume at 16:57 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, 1:08 PM EDT	TSTM WND DMG	3 E Gardenville, PA	SEVERAL LARGE TREES AND NUMEROUS BRANCHES DOWN WITH POWER OUTAGES.
Jul 17, 1:15 PM EDT	TSTM WND DMG	2 W Stockton, NJ	TREE DOWN ON NJ ROUTE 29, ALL LANES AND RIGHT SHOULDER CLOSED.
Jul 17, 1:15 PM EDT	TSTM WND DMG	Sergeantsville, NJ	REPORTS OF TREES DOWN AROUND DELAWARE TOWNSHIP. TIME ESTIMATED FROM RADAR.
Jul 17, 1:35 PM EDT	TSTM WND DMG	Raritan Twp, NJ	REPORTS OF TREES DOWN AROUND RARITAN TOWNSHIP.

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, 4.9 hours before the alert went out and 191 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.

387 
WWUS81 KPHI 171655
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
1255 PM EDT Sat Jul 17 2021

NJZ009-015-PAZ103>106-171745-
Hunterdon-Mercer-Lower Bucks-Upper Bucks-Eastern Montgomery-Western
Montgomery-
1255 PM EDT Sat Jul 17 2021

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN HUNTERDON...
NORTHWESTERN MERCER...CENTRAL MONTGOMERY AND CENTRAL BUCKS
COUNTIES...

At 1255 PM EDT, a strong thunderstorm was located over Lumberville,
or 18 miles northwest of Trenton, moving northeast at 55 mph.

Wind gusts up to 40 mph and pea size hail are possible with this
storm.

Locations impacted include...
Lansdale, Perkasie, Doylestown, Byram, Souderton, Bedminster,
Flemington, Chalfont, Tinicum, Hatfield, New Hope, Dublin, Hopewell,
Stockton, Fricks, Lumberville, Sergeantsville, Pipersville,
Gardenville and Sand Brook.

This includes Northeast Extension between mile markers 25 and 35.
 
If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4016 7529 4029 7544 4059 7487 4047 7477
      4041 7474 4040 7474
TIME...MOT...LOC 1655Z 238DEG 48KT 4039 7504 

$$

Davis

The office that day

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

Issued	Product	Office	Counties	Lasted
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, 7:01 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Somerset	44 min
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
Jul 17, 7:36 PM EDT	Special Weather Statement	PHI	Kent	39 min
Jul 17, 7:59 PM EDT	Severe Thunderstorm Warning	PHI	Kent	46 min
Jul 17, 5:09 PM EDT	Special Weather Statement	PHI	Kent	51 min
Jul 17, 5:54 PM EDT	Special Weather Statement	PHI	Kent, Queen Anne's	36 min

Nearby

Special Weather Statements in New Jersey, 2021 Special Weather Statements in Pennsylvania, 2021 Every special weather statement 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.