Alert archive / Connecticut / Mesoscale Discussions in 2020

Mesoscale Discussion 608

May 15, 20208 counties in Massachusetts; 5 counties in New York; 5 counties in Rhode Island

The Storm Prediction Center issued this mesoscale discussion at May 15, 2020, 9:09 PM EDT for 8 counties in Massachusetts; 5 counties in New York; 5 counties in Rhode Island. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
May 15, 2020, 9:09 PM EDT (01:09 UTC)
Expired
May 15, 2020, 10:15 PM EDT
In force
66 min
Issued by
the Storm Prediction Center

Counties Bristol County, MA, Essex County, MA, Hampden County, MA, Middlesex County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA, Worcester County, MA, Dutchess County, NY, Orange County, NY, Putnam County, NY, Rockland County, NY, Westchester County, NY, Bristol County, RI, Kent County, RI, Newport County, RI, Providence County, RI, Washington County, RI

The radar

The Brookhaven radar (KOKX), 99 km from the middle of the area, began a volume at 01:11 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 00:00Z, 1.2 hours before the alert went out and 99 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 00:00Z on 2020-05-16Temperature 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 00:00Z on 2020-05-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 129 square meters per square second.19395878Sfc1 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
1367 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
129 m²/s²
0-3 km storm-relative helicity
309 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

954 
ACUS11 KWNS 160110
SWOMCD
SPC MCD 160109 
MAZ000-RIZ000-NHZ000-CTZ000-NYZ000-NJZ000-PAZ000-160215-

Mesoscale Discussion 0608
NWS Storm Prediction Center Norman OK
0809 PM CDT Fri May 15 2020

Areas affected...portions of southern New
York...Massachusetts...Connecticut...and Rhode Island

Concerning...Tornado Watch 187...

Valid 160109Z - 160215Z

The severe weather threat for Tornado Watch 187 continues.

SUMMARY...Although damaging winds remain possible in the near term,
a gradual weakening trend is expected over the next hour as a line
of storm moves towards the Atlantic coast.

DISCUSSION...Radar trends from KONX and KENX show a gradual
weakening trend in the squall line that is progressing across
southern NY, and into MA and CT, including areas south of WW 187.
This trend is expected to continue as this line of storms moves into
an environment characterized by more maritime influences with
temperatures in the 60s and dewpoints in the 50s along the Atlantic
coast and as diurnal cooling continues to help stabilize the inland
boundary layer. However, recent GOES IR imagery has shown some
individual storms and segments of the line cooling aloft in
conjunction with an uptake in lightning activity, suggesting
periodic and transient intensification, and thus a damaging wind
threat, remains possible in the near term.

..Moore.. 05/16/2020

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

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

LAT...LON   41847339 42307233 42757137 42687086 42057053 41367141
            41267252 40917377 41157439 41347475 41597466 41717437
            41847339

Nearby

Mesoscale Discussions in Connecticut, 2020Mesoscale Discussions in Massachusetts, 2020Mesoscale Discussions in New York, 2020Every mesoscale discussion in 2020

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.