Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 179, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 17, 2021, 1:05 PM EDT for Bucks County, Pennsylvania; Hunterdon County, Mercer County, New Jersey. It was in force for 40 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, 1:05 PM EDT (17:05 UTC)
- Expired
- Jul 17, 2021, 1:45 PM EDT
- In force
- 40 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 60.0 mph
Counties Hunterdon County, NJ, Mercer County, NJ, Bucks County, PA
The radar
The Philadelphia radar (KDIX), 61 km from the middle of the area, began a volume at 17:05 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, 5.1 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.
- 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
The text
As transmitted.
111
WUUS51 KPHI 171705
SVRPHI
NJC019-021-PAC017-171745-
/O.NEW.KPHI.SV.W.0179.210717T1705Z-210717T1745Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
105 PM EDT Sat Jul 17 2021
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Southeastern Hunterdon County in northwestern New Jersey...
Northwestern Mercer County in central New Jersey...
Central Bucks County in southeastern Pennsylvania...
* Until 145 PM EDT.
* At 105 PM EDT, a severe thunderstorm was located over Gardenville,
or 19 miles northwest of Trenton, moving northeast at 10 mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Minor damage to vehicles is possible. Wind damage to
roofs, siding, trees, and power lines is possible.
* Locations impacted include...
Princeton, Doylestown, Byram, Flemington, Tinicum, Clinton,
Pennington, New Hope, Hopewell, Stockton, Sergeantsville,
Gardenville, Lumberville, Sand Brook and Lambertville.
This includes Interstate 78 in New Jersey between mile markers 16 and
17.
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.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4034 7467 4029 7507 4037 7519 4065 7491
4038 7473 4037 7472 4038 7471
TIME...MOT...LOC 1705Z 229DEG 10KT 4037 7509
HAIL...1.00IN
WIND...60MPH
$$
Davis2 follow-up statements
951
WWUS51 KPHI 171722
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
122 PM EDT Sat Jul 17 2021
NJC019-021-PAC017-171745-
/O.CON.KPHI.SV.W.0179.000000T0000Z-210717T1745Z/
Hunterdon NJ-Mercer NJ-Bucks PA-
122 PM EDT Sat Jul 17 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 145 PM EDT
FOR SOUTHEASTERN HUNTERDON...NORTHWESTERN MERCER AND CENTRAL BUCKS
COUNTIES...
At 122 PM EDT, a severe thunderstorm was located over Lumberville, or
19 miles northwest of Trenton, moving northeast at 10 mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Minor damage to vehicles is possible. Wind damage to roofs,
siding, trees, and power lines is possible.
Locations impacted include...
Princeton, Doylestown, Byram, Flemington, Tinicum, Clinton,
Pennington, New Hope, Hopewell, Stockton, Sergeantsville,
Gardenville, Lumberville, Sand Brook and Lambertville.
This includes Interstate 78 in New Jersey between mile markers 16 and
17.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4034 7467 4029 7507 4037 7519 4065 7491
4038 7473 4037 7472 4038 7471
TIME...MOT...LOC 1722Z 229DEG 10KT 4040 7504
HAIL...1.00IN
WIND...60MPH
$$
JEO215
WWUS51 KPHI 171739
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
139 PM EDT Sat Jul 17 2021
NJC019-021-PAC017-171749-
/O.EXP.KPHI.SV.W.0179.000000T0000Z-210717T1745Z/
Hunterdon NJ-Mercer NJ-Bucks PA-
139 PM EDT Sat Jul 17 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN HUNTERDON...
NORTHWESTERN MERCER AND CENTRAL BUCKS COUNTIES WILL EXPIRE AT 145 PM
EDT...
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 will be allowed to expire. However gusty
winds and heavy rain are still possible with this thunderstorm.
A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
central, northern and northwestern New Jersey...and southeastern
Pennsylvania.
LAT...LON 4034 7467 4029 7507 4037 7519 4065 7491
4038 7473 4037 7472 4038 7471
TIME...MOT...LOC 1739Z 229DEG 10KT 4043 7500
$$
JEOThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| 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, 12:55 PM EDT | Special Weather Statement | PHI | Bucks | 50 min |
| Jul 17, 1:31 PM EDT | Areal Flood Advisory | PHI | Bucks | 97 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, 3:06 PM EDT | Severe Thunderstorm Warning | PHI | Carbon, Lehigh, Monroe, Northampton | 39 min |
| Jul 17, 5:13 PM EDT | Areal Flood Advisory | PHI | Bucks, Montgomery, Philadelphia | 4 hr |
| Jul 17, 5:25 PM EDT | Flash Flood Warning | PHI | Bucks | 6 hr |
| Jul 17, 5:30 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 19 min |
| Jul 17, 6:02 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 43 min |
| Jul 17, 6:39 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 51 min |
| Jul 17, 6:51 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 39 min |
| Jul 17, 7:01 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 44 min |
| Jul 17, 7:12 PM EDT | Areal Flood Advisory | PHI | Bucks, Philadelphia | 3 hr |
| Jul 17, 7:26 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 49 min |
| Jul 17, 7:36 PM EDT | Special Weather Statement | PHI | Carbon | 54 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, 3:09 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, 5:19 PM EDT | Tornado Warning | PHI | Hunterdon | 14 min |
| Jul 17, 5:52 PM EDT | Areal Flood Advisory | PHI | Somerset | 2 hr |
| Jul 17, 6:15 PM EDT | Flash Flood Warning | PHI | Morris, Somerset | 5 hr |
| Jul 17, 6:59 PM EDT | Small Craft Advisory | PHI | 7 hr |
Nearby
Severe Thunderstorm Warnings in New Jersey, 2021Severe Thunderstorm Warnings in Pennsylvania, 2021Every 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.