Alert archive / New Jersey / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 351
The Storm Prediction Center issued this severe thunderstorm watch at Jul 8, 2021, 2:09 PM EDT for 4 states. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 8, 2021, 2:09 PM EDT (18:09 UTC)
- Expired
- Jul 8, 2021, 9:00 PM EDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 43 counties
Capitol Planning Region, CT, Greater Bridgeport Planning Region, CT, Lower Connecticut River Valley Planning Region, CT, Naugatuck Valley Planning Region, CT, Northeastern Connecticut Planning Region, CT, Northwest Hills Planning Region, CT, Southeastern Connecticut Planning Region, CT, Bergen County, NJ, Essex County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Passaic County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Bronx County, NY, Dutchess County, NY, Kings County, NY, Nassau County, NY, New York County, NY, Orange County, NY, Putnam County, NY, Queens County, NY, Richmond County, NY, Rockland County, NY, Suffolk County, NY, Ulster County, NY, Westchester County, NY, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 124 km from the middle of the area, began a volume at 18:11 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 SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 5%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
19 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 8, 2:11 PM EDT | Severe Thunderstorm Warning | OKX | Bergen, Passaic | 49 min |
| Jul 8, 2:26 PM EDT | Severe Thunderstorm Warning | PHI | Monmouth, Ocean | 21 min |
| Jul 8, 2:29 PM EDT | Severe Thunderstorm Warning | PHI | Hunterdon, Morris, Somerset, Warren | 46 min |
| Jul 8, 3:03 PM EDT | Severe Thunderstorm Warning | PHI | Hunterdon, Middlesex, Morris, Somerset | 42 min |
| Jul 8, 3:15 PM EDT | Flash Flood Warning | OKX | Greater Bridgeport Planning Region | 3 hr |
| Jul 8, 3:53 PM EDT | Flash Flood Warning | OKX | Bergen, Essex, Hudson | 3 hr |
| Jul 8, 4:02 PM EDT | Severe Thunderstorm Warning | PHI | Monmouth | 31 min |
| Jul 8, 4:06 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Montgomery | 39 min |
| Jul 8, 4:25 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 50 min |
| Jul 8, 4:43 PM EDT | Severe Thunderstorm Warning | PHI | Middlesex, Somerset | 16 min |
| Jul 8, 4:45 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Bucks, Lehigh, Montgomery, Northampton | 45 min |
| Jul 8, 4:51 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 54 min |
| Jul 8, 5:06 PM EDT | Flash Flood Warning | OKX | Bergen | 3 hr |
| Jul 8, 5:16 PM EDT | Severe Thunderstorm Warning | OKX | Nassau, Suffolk | 44 min |
| Jul 8, 5:21 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 39 min |
| Jul 8, 5:34 PM EDT | Severe Thunderstorm Warning | PHI | Hunterdon, Morris, Sussex, Warren | 41 min |
| Jul 8, 6:06 PM EDT | Severe Thunderstorm Warning | PHI | Hunterdon | 39 min |
| Jul 8, 6:09 PM EDT | Severe Thunderstorm Warning | PHI | Hunterdon, Morris, Somerset, Sussex | 51 min |
| Jul 8, 6:16 PM EDT | Severe Thunderstorm Warning | PHI | Hunterdon, Morris, Sussex, Warren | 44 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 12:00Z, 6.2 hours before the alert went out and 127 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
- 973 J/kg
- Mixed-layer CIN
- -77 J/kg
- Mixed-layer LCL
- 751 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 60 m²/s²
- 0-3 km storm-relative helicity
- 93 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.3
The text
As transmitted.
566 WWUS20 KWNS 081806 SEL1 SPC WW 081806 CTZ000-NJZ000-NYZ000-PAZ000-CWZ000-090100- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 351 NWS Storm Prediction Center Norman OK 210 PM EDT Thu Jul 8 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Connecticut Northern and central New Jersey Southeast New York Eastern Pennsylvania Coastal Waters * Effective this Thursday afternoon and evening from 210 PM until 900 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Scattered severe thunderstorms including a few supercells should continue to develop and spread east-northeastward across the region, particularly in vicinity of an effective boundary. Damaging winds and severe hail are the primary concerns, although a tornado cannot be ruled out. The severe thunderstorm watch area is approximately along and 55 statute miles north and south of a line from 30 miles west southwest of Allentown PA to 15 miles north northeast of Groton CT. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 349...WW 350... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 24025. ...Guyer
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 8, 12:00 AM EDT | Mesoscale Discussion | SPC | 60 min | |
| Jul 8, 1:44 PM EDT | Mesoscale Discussion | SPC | 3 hr | |
| Jul 8, 4:36 PM EDT | Mesoscale Discussion | SPC | 114 min | |
| Jul 8, 1:31 PM EDT | Mesoscale Discussion | SPC | Cattaraugus, Chautauqua, Erie, Wyoming | 2 hr |
Nearby
Severe Thunderstorm Watches in New Jersey, 2021Severe Thunderstorm Watches in New York, 2021Severe Thunderstorm Watches in Pennsylvania, 2021Every severe thunderstorm watch 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.