Alert archive / New Jersey / Mesoscale Discussions in 2018

Mesoscale Discussion 784

June 18, 20185 states

The Storm Prediction Center issued this mesoscale discussion at Jun 18, 2018, 5:55 PM EDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 18, 2018, 5:55 PM EDT (21:55 UTC)
Expired: Jun 18, 2018, 8:00 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 37 counties

Hampden County, MA, Hampshire County, MA, Middlesex County, MA, Norfolk County, MA, Suffolk County, MA, Worcester County, MA, Bergen County, NJ, Essex County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex 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, 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, Lehigh County, PA, Monroe County, PA, Northampton County, PA, Pike County, PA, Schuylkill County, PA, Providence County, RI

The radar

The Brookhaven radar (KOKX), 97 km from the middle of the area, began a volume at 21:57 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, 9.9 hours before the alert went out and 97 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1413 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 122 m²/s²
0-3 km storm-relative helicity: 123 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

615 
ACUS11 KWNS 182155
SWOMCD
SPC MCD 182155 
MAZ000-RIZ000-CTZ000-NYZ000-NJZ000-PAZ000-190000-

Mesoscale Discussion 0784
NWS Storm Prediction Center Norman OK
0455 PM CDT Mon Jun 18 2018

Areas affected...Eastern Pennsylvania...northern New Jersey...far
southeast New York...Connecticut...northern Rhode
Island...Massachusetts

Concerning...Severe potential...Watch possible 

Valid 182155Z - 190000Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated damaging wind gusts and marginally severe hail
possible, especially in portions of New England. Convective trends
are being monitored for a WW.

DISCUSSION...Loosely organized clusters are in progress across
portions of New England down into the Hudson Valley. The ambient
environment is characterized by deep moisture, with PWAT values of
up to 2 inches in some locations, especially over New England. Rich
low-level moisture and strong surface heating is the main source of
buoyancy, given poor mid-level lapse rates (5.5 C/km on average). 

Given modest mid-level flow and associated effective bulk shear
along with modest instability, the severe threat is expected to be
isolated in extent. Marginally severe hail is possible, along with
damaging wind gusts induced by wet downbursts. As storms are driven
primarily by the strong surface heating, a decrease in coverage and
intensity is expected after sunset. Storms may also weaken as they
approach the marine layer situated near the coast.

A WW is currently not anticipated but convective trends will be
monitored

..Squitieri/Jirak/Guyer.. 06/18/2018

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

ATTN...WFO...BOX...OKX...ALY...PHI...BGM...CTP...

LAT...LON   40787689 40777636 41117547 41687443 42197355 42477230
            42517202 42667167 42687148 42667123 42617094 42577089
            42127111 41667179 41167316 40587388 40217454 40197517
            40417626 40787689

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 18, 7:05 PM EDT	Mesoscale Discussion	SPC	Essex	55 min
Jun 18, 12:19 PM EDT	Mesoscale Discussion	SPC	Cayuga, Chenango, Cortland, Essex, Fulton, Genesee and 22 more	116 min
Jun 18, 1:33 PM EDT	Severe Thunderstorm Watch	SPC	Cayuga, Erie, Genesee, Jefferson, Lewis, Livingston and 12 more	6 hr
Jun 18, 2:49 PM EDT	Severe Thunderstorm Watch	SPC	Albany, Clinton, Essex, Franklin, Fulton, Hamilton and 9 more	5 hr
Jun 18, 4:04 PM EDT	Mesoscale Discussion	SPC	Albany, Broome, Chemung, Chenango, Columbia, Cortland and 14 more	26 min

Nearby

Mesoscale Discussions in New Jersey, 2018 Mesoscale Discussions in New York, 2018 Mesoscale Discussions in Connecticut, 2018 Every mesoscale discussion in 2018

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.