Alert archive / Connecticut / Mesoscale Discussions in 2021

Mesoscale Discussion 1943

November 12, 2021Suffolk County, New York

The Storm Prediction Center issued this mesoscale discussion at Nov 12, 2021, 12:24 PM EST for Suffolk County, New York. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued
Nov 12, 2021, 12:24 PM EST (17:24 UTC)
Expired
Nov 12, 2021, 2:00 PM EST
In force
96 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
20%

County Suffolk County, NY

The radar

The Brookhaven radar (KOKX), 56 km from the middle of the area, began a volume at 17:27 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, 5.4 hours before the alert went out and 56 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 2021-11-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 191 joules per kilogram.LCLLFCEL10008507005003002001001 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 2021-11-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 262 square meters per square second.1939587897Sfc1 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
191 J/kg
Mixed-layer CIN
-19 J/kg
Mixed-layer LCL
601 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
262 m²/s²
0-3 km storm-relative helicity
370 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.9

Open this sounding in Storm Lab

The text

As transmitted.

714 
ACUS11 KWNS 121725
SWOMCD
SPC MCD 121724 
CTZ000-NYZ000-121900-

Mesoscale Discussion 1943
NWS Storm Prediction Center Norman OK
1124 AM CST Fri Nov 12 2021

Areas affected...eastern Long Island...CT

Concerning...Severe potential...Watch unlikely 

Valid 121724Z - 121900Z

Probability of Watch Issuance...20 percent

SUMMARY...The threat for isolated wind damage cannot be ruled out
over the next hour or so as a rotating convective cluster moves
north over eastern Long Island and into CT.

DISCUSSION...KOKX radar imagery has shown a long-lived rotating
cluster of convection moving north from the shelf waters of the
Atlantic to the south coast of eastern Long Island.  The KOKX VAD
wind profile shows intense flow fields with an enlarged hodograph. 
The main limiting factors are scant buoyancy and very weak lapse
rates.  Nonetheless, the storm-scale forcing associated with the
hybrid rotating cluster of convection may enable the risk for
damaging gusts to be realized on a localized basis, as the
convection moves north from eastern Long Island into CT over the
next 1-2 hours.

..Smith/Hart.. 11/12/2021

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

ATTN...WFO...BOX...OKX...

LAT...LON   40777285 41747245 41917216 41657199 40807252 40777285

Nearby

Mesoscale Discussions in Connecticut, 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.