Alert archive / New Jersey / Mesoscale Discussions in 2021
Mesoscale Discussion 1198
The Storm Prediction Center issued this mesoscale discussion at Jul 8, 2021, 1:44 PM EDT for 15 counties in New Jersey; 10 counties in New York; 13 counties in Pennsylvania. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 8, 2021, 1:44 PM EDT (17:44 UTC)
- Expired
- Jul 8, 2021, 4:15 PM EDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
All 38 counties
Bergen County, NJ, Burlington County, NJ, Camden 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, 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, Westchester County, NY, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Delaware County, PA, Lancaster County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA, Pike County, PA, Schuylkill County, PA
The radar
The Philadelphia radar (KDIX), 72 km from the middle of the area, began a volume at 17:46 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.
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 12:00Z, 5.7 hours before the alert went out and 152 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.
787
ACUS11 KWNS 081745
SWOMCD
SPC MCD 081744
NYZ000-CTZ000-NJZ000-PAZ000-DEZ000-MDZ000-082015-
Mesoscale Discussion 1198
NWS Storm Prediction Center Norman OK
1244 PM CDT Thu Jul 08 2021
Areas affected...eastern Pennsylvania and New Jersey northeastward
into southern New England
Concerning...Severe potential...Watch possible
Valid 081744Z - 082015Z
Probability of Watch Issuance...60 percent
SUMMARY...Storms are expected to increase in coverage over the next
few hours, from southern New York into eastern Pennsylvania and New
Jersey, and localized wind damage and hail will be possible.
DISCUSSION...Storms are regenerating along the southwestern flank of
an ongoing cluster of storms, now extending from northern NJ across
southern NY and into western CT. A very moist and unstable air mass
exists in this area, with further heating expected. Shear is
marginal for long lived/organized severe, but isolated severe cells
will be possible with wind or hail threat due to robust
thermodynamics. The most favorable shear currently extends from
northern NJ into southern NY and into western CT with effective SRH
over 100 m2/s2, and a brief tornado is possible. Additional cells
may eventually develop upstream into PA later this afternoon, and
the entire area will be monitored for watch potential, dependent on
storm coverage.
..Jewell/Guyer.. 07/08/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BOX...OKX...ALY...PHI...BGM...CTP...LWX...
LAT...LON 40027380 39707534 39677605 39967659 40397644 40957610
41657450 41707286 41437256 40807289 40027380SPC 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, 2:09 PM EDT | Severe Thunderstorm Watch | SPC | Greater Bridgeport Planning Region, Capitol Planning Region, Northwest Hills Planning Region, Lower Connecticut River Valley Planning Region, Naugatuck Valley Planning Region, Southeastern Connecticut Planning Region and 1 more | 7 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
Mesoscale Discussions in New Jersey, 2021Mesoscale Discussions in Pennsylvania, 2021Mesoscale Discussions in New York, 2021Every mesoscale discussion 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.