Alert archive / Connecticut / Mesoscale Discussions in 2007

Mesoscale Discussion 821

May 16, 20075 counties in Massachusetts; 9 counties in New York; Providence County, Rhode Island

The Storm Prediction Center issued this mesoscale discussion at May 16, 2007, 2:43 PM EDT for 5 counties in Massachusetts; 9 counties in New York; Providence County, Rhode Island. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: May 16, 2007, 2:43 PM EDT (18:43 UTC)
Expired: May 16, 2007, 4:15 PM EDT
In force: 92 min
Issued by: the Storm Prediction Center

Counties Berkshire County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Worcester County, MA, Columbia County, NY, Dutchess County, NY, Orange County, NY, Putnam County, NY, Rensselaer County, NY, Rockland County, NY, Suffolk County, NY, Ulster County, NY, Westchester County, NY, Providence County, RI

The radar

The Albany radar (KENX), 106 km from the middle of the area, began a volume at 18:43 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

Albany, NY (KALY), launched 12:00Z, 6.7 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-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: 210 J/kg
Mixed-layer CIN: -80 J/kg
Mixed-layer LCL: 969 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 183 m²/s²
0-3 km storm-relative helicity: 193 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
ACUS11 KWNS 161844
SWOMCD
SPC MCD 161843 
RIZ000-MAZ000-CTZ000-NYZ000-NHZ000-VTZ000-NJZ000-162015-

MESOSCALE DISCUSSION 0821
NWS STORM PREDICTION CENTER NORMAN OK
0143 PM CDT WED MAY 16 2007

AREAS AFFECTED...SRN NY...CT...MA

CONCERNING...TORNADO WATCH 277...

VALID 161843Z - 162015Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 277 CONTINUES.

A SEVERE THREAT WILL CONTINUE ACROSS SRN NEW ENGLAND AND SRN NEW
YORK THIS AFTERNOON. A TORNADO THREAT WILL EXIST WITH THE MOST
ORGANIZED STORMS. WIND DAMAGE AND ISOLATED LARGE HAIL MAY ALSO
ACCOMPANY THE STRONGER CELLS.

18Z SFC ANALYSIS CURRENTLY SHOWS A DUAL-CENTERED SFC LOW OVER ERN NY
AND WRN MA. A FRONTAL BOUNDARY MOVING SLOWLY SWWD EXTENDS SEWD FROM
THE LOW ACROSS SRN MA WITH A COLD FRONT EXTENDING SWWD FROM THE LOW
INTO ERN PA. SOUTH AND EAST OF THESE BOUNDARIES...OBJECTIVE ANALYSIS
STILL HAS SBCAPE VALUES AROUND 1000 J/KG AND THE WARM SECTOR REMAINS
SUFFICIENTLY UNSTABLE FOR SEVERE STORMS. CONVECTION CURRENTLY MOVING
NEWD ACROSS WRN MA AND NRN CT MAY INTERACT WITH THE BOUNDARY
BECOMING LOCALLY MORE INTENSE. OTHERWISE...NEW ACTIVITY MAY DEVELOP
ALONG A PRE-FRONTAL TROUGH ACROSS FAR SRN NY AND EXPAND EWD INTO WRN
MA AND WRN CT. VERTICAL SHEAR PROFILES ON WSR-88D VWPS AND LOW-LEVEL
SHEAR PROFILES SUGGEST THAT A SUPERCELL AND ISOLATED TORNADO THREAT
WILL CONTINUE FOR SEVERAL MORE HOURS. STEEP LOW-LEVEL LAPSE RATES
AND STRONG UNIDIRECTIONAL WINDS ON REGIONAL WSR-88D VWPS SHOULD BE
FAVORABLE FOR A FEW DAMAGE WIND GUSTS WITH ISOLATED LARGE HAIL
POSSIBLE AS WELL.

..BROYLES.. 05/16/2007

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BOX...OKX...ALY...BGM...

42937328 43057290 42727204 41867153 41247173 40687332
41147433 41937450

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 16, 11:57 AM EDT	Mesoscale Discussion	SPC		93 min
May 16, 12:32 PM EDT	Tornado Watch	SPC	Greater Bridgeport Planning Region, Capitol Planning Region, Northwest Hills Planning Region, Lower Connecticut River Valley Planning Region, Naugatuck Valley Planning Region, Southeastern Connecticut Planning Region and 1 more	6 hr
May 16, 1:26 PM EDT	Severe Thunderstorm Watch	SPC	Bronx, Kings, Nassau, New York, Queens, Richmond and 1 more	7 hr
May 16, 3:46 PM EDT	Mesoscale Discussion	SPC	Bronx, Kings, New York, Queens, Richmond	89 min

Nearby

Mesoscale Discussions in Connecticut, 2007 Mesoscale Discussions in New York, 2007 Mesoscale Discussions in Massachusetts, 2007 Every mesoscale discussion in 2007

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.