Alert archive / New Jersey / Mesoscale Discussions in 2021

Mesoscale Discussion 303

March 28, 20214 states

The Storm Prediction Center issued this mesoscale discussion at Mar 28, 2021, 7:05 PM EDT for 4 states. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued
Mar 28, 2021, 7:05 PM EDT (23:05 UTC)
Expired
Mar 28, 2021, 9:00 PM EDT
In force
115 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 69
All 21 counties

New Castle County, DE, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Essex County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Union County, NJ, Richmond County, NY, Bucks County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 39 km from the middle of the area, began a volume at 23:08 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

Brookhaven, NY (KOKX), launched 12:00Z, 11.1 hours before the alert went out and 180 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.

Skew-T log-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 2021-03-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2021-03-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 165 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
666 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
165 m²/s²
0-3 km storm-relative helicity
285 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

783 
ACUS11 KWNS 282305
SWOMCD
SPC MCD 282305 
NJZ000-NYZ000-PAZ000-DEZ000-290100-

Mesoscale Discussion 0303
NWS Storm Prediction Center Norman OK
0605 PM CDT Sun Mar 28 2021

Areas affected...New Jersey...Delaware....eastern Maryland

Concerning...Severe Thunderstorm Watch 69...

Valid 282305Z - 290100Z

The severe weather threat for Severe Thunderstorm Watch 69
continues.

SUMMARY...Strong to severe wind gusts remain possible over the next
1-2 hours, mainly over New Jersey.

DISCUSSION...Radar shows relatively high reflectively now entering
western New Jersey, with a few severe gusts measured recently near
Wilmington Delaware. This strongly forced, low-topped line of
convection will likely maintain strength as it moves across central
New Jersey, until reaching the Atlantic Coast where a cooler
boundary layer exists. Observed VWP wind magnitudes of 50-60 kt near
1 km AGL suggest similar gusts will be possible.

..Jewell.. 03/28/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...OKX...PHI...

LAT...LON   40917458 40837430 40757416 40597405 40347400 39817404
            39457422 39217451 39067493 39137536 39497565 39767574
            40027563 40277534 40577514 40757503 40877477 40917458

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 28, 1:24 PM EDTMesoscale DiscussionSPCKent, Sussex2 hr
Mar 28, 5:05 PM EDTSevere Thunderstorm WatchSPCKent, New Castle, Sussex4 hr

Nearby

Mesoscale Discussions in New Jersey, 2021Mesoscale Discussions in Pennsylvania, 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.