Alert archive / New Jersey / Mesoscale Discussions in 2021
Mesoscale Discussion 1141
The Storm Prediction Center issued this mesoscale discussion at Jul 1, 2021, 4:16 PM EDT for 4 states. It was in force for 89 min.
The area
The outline as issued.
The facts
- Issued
- Jul 1, 2021, 4:16 PM EDT (20:16 UTC)
- Expired
- Jul 1, 2021, 5:45 PM EDT
- In force
- 89 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 331
All 23 counties
Kent County, DE, New Castle County, DE, Sussex County, DE, Caroline County, MD, Dorchester County, MD, Kent County, MD, Queen Anne's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Worcester County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Mercer County, NJ, Monmouth County, NJ, Ocean County, NJ, Salem County, NJ, Delaware County, PA, Philadelphia County, PA
The radar
The Dover AFB radar (KDOX), 34 km from the middle of the area, began a volume at 20:19 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 nearest sounding before it
Wallops Is Stn, VA (KWAL), launched 12:00Z, 8.3 hours before the alert went out and 126 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
- 1445 J/kg
- Mixed-layer CIN
- -95 J/kg
- Mixed-layer LCL
- 981 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 29 m²/s²
- 0-3 km storm-relative helicity
- 31 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
014
ACUS11 KWNS 012016
SWOMCD
SPC MCD 012016
NJZ000-PAZ000-MDZ000-DEZ000-VAZ000-012145-
Mesoscale Discussion 1141
NWS Storm Prediction Center Norman OK
0316 PM CDT Thu Jul 01 2021
Areas affected...Portions of the Delmarva Peninsula...far
southeastern PA...and southern NJ
Concerning...Severe Thunderstorm Watch 331...
Valid 012016Z - 012145Z
The severe weather threat for Severe Thunderstorm Watch 331
continues.
SUMMARY...The threat for mainly damaging wind gusts will continue to
shift eastward across the Delmarva Peninsula, far southeastern
Pennsylvania, and southern New Jersey this afternoon.
DISCUSSION...Multiple clusters of storms with a history of producing
measured severe wind gusts to 58 mph in DC, 66 mph in Annapolis MD,
and damaging wind gusts across central MD have moved eastward across
the Chesapeake Bay. The environment across the Delmarva Peninsula
and southern NJ ahead of this convection remains favorable in the
short term for strong to severe wind gusts capable of producing
mainly scattered tree damage, as low-level lapse rates are modestly
steepened. Latest radar imagery from KDOX shows swaths of strong
inbound velocities across the Eastern Shore of MD associated with
two separate clusters. Recent VWPs from KDOX and KDIX indicate 30-45
kt of west-southwesterly flow at mid levels, and organized multicell
clusters should remain the dominant storm mode as they continue
eastward towards the Atlantic Coast over the next couple of hours.
..Gleason.. 07/01/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PHI...AKQ...LWX...
LAT...LON 38007520 38017583 38347621 38957626 39307614 40307522
40387456 40327392 39687408 39187453 38767494 38367498
38007520SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 1, 11:45 AM EDT | Mesoscale Discussion | SPC | Kent, New Castle, Sussex | 2 hr |
| Jul 1, 12:46 PM EDT | Severe Thunderstorm Watch | SPC | Kent, New Castle, Sussex | 7 hr |
| Jul 1, 2:36 PM EDT | Mesoscale Discussion | SPC | Kent, New Castle | 84 min |
Nearby
Mesoscale Discussions in New Jersey, 2021Mesoscale Discussions in Maryland, 2021Mesoscale Discussions in Delaware, 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.