Alert archive / New Jersey / Mesoscale Discussions in 2021
Mesoscale Discussion 1209
The Storm Prediction Center issued this mesoscale discussion at Jul 9, 2021, 3:28 AM EDT for Atlantic County, Monmouth County, Ocean County, New Jersey; Richmond County, New York. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 9, 2021, 3:28 AM EDT (07:28 UTC)
- Expired
- Jul 9, 2021, 5:30 AM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Atlantic County, NJ, Monmouth County, NJ, Ocean County, NJ, Richmond County, NY
The radar
The Philadelphia radar (KDIX), 52 km from the middle of the area, began a volume at 07:30 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 00:00Z, 7.5 hours before the alert went out and 228 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
- 440 J/kg
- Mixed-layer CIN
- -10 J/kg
- Mixed-layer LCL
- 675 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 151 m²/s²
- 0-3 km storm-relative helicity
- 336 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 3.3
The text
As transmitted.
989
ACUS11 KWNS 090728
SWOMCD
SPC MCD 090728
NYZ000-NJZ000-090930-
Mesoscale Discussion 1209
NWS Storm Prediction Center Norman OK
0228 AM CDT Fri Jul 09 2021
Areas affected...coastal portions of New Jersey and into western
Long Island and vicinity
Concerning...Severe potential...Watch unlikely
Valid 090728Z - 090930Z
Probability of Watch Issuance...20 percent
SUMMARY...Risk for a brief/weak tornado or two continues near the
New Jersey coast. WW not anticipated at this time.
DISCUSSION...Latest radar loop shows that Elsa's center has moved
offshore east of Cape May, NJ, and is moving steadily
north-northeastward. To the north and northeast of the center, the
main convective band is likewise advancing northward, while embedded
cells feed westward into coastal portions of southern New Jersey.
Several of these cells continue to exhibit low-level rotation
offshore, per WSR-88D VWP data. Additionally, some slight increase
in cellular character -- and updraft intensity -- appears to have
occurred with the center of Elsa now over water. However, the
circulations continue to weaken quickly as they move onshore, and
given the poor thermodynamic environment onshore, this trend should
persist. Still, a brief/weak tornado or two will remain a
possibility over the next few hours for immediate coastal areas,
with this risk gradually spreading northward toward Long Island
through the 09Z to 10Z time frame.
..Goss/Hart.. 07/09/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OKX...PHI...
LAT...LON 39007338 39337380 39417424 39237473 39377492 39817457
40637417 40597366 39997266 39007338SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 8, 10:01 PM EDT | Mesoscale Discussion | SPC | Atlantic, Burlington, Cape May, Cumberland, Monmouth, Ocean | 59 min |
| Jul 9, 4:35 PM EDT | Mesoscale Discussion | SPC | Hunterdon, Morris, Somerset, Sussex, Warren | 115 min |
Nearby
Mesoscale Discussions in New Jersey, 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.