Alert archive / New York / Mesoscale Discussions in 2007

Mesoscale Discussion 813

May 15, 20077 counties in Massachusetts; 12 counties in New York; Providence County, Rhode Island

The Storm Prediction Center issued this mesoscale discussion at May 15, 2007, 6:35 PM EDT for 7 counties in Massachusetts; 12 counties in New York; Providence County, Rhode Island. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued
May 15, 2007, 6:35 PM EDT (22:35 UTC)
Expired
May 15, 2007, 7:30 PM EDT
In force
55 min
Issued by
the Storm Prediction Center

Counties Berkshire County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Middlesex County, MA, Norfolk County, MA, Worcester County, MA, Albany County, NY, Chenango County, NY, Columbia County, NY, Cortland County, NY, Delaware County, NY, Greene County, NY, Madison County, NY, Montgomery County, NY, Otsego County, NY, Rensselaer County, NY, Schenectady County, NY, Schoharie County, NY, Providence County, RI

The radar

The Albany radar (KENX), 55 km from the middle of the area, began a volume at 22:36 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, 10.6 hours before the alert went out and 45 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, Albany, NY at 12:00Z on 2007-05-15Temperature 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, Albany, NY at 12:00Z on 2007-05-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 342 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
1392 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
342 m²/s²
0-3 km storm-relative helicity
400 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 152235
SWOMCD
SPC MCD 152235 
MAZ000-NHZ000-RIZ000-CTZ000-VTZ000-NYZ000-152330-

MESOSCALE DISCUSSION 0813
NWS STORM PREDICTION CENTER NORMAN OK
0535 PM CDT TUE MAY 15 2007

AREAS AFFECTED...SRN NY AND SRN NEW ENGLAND

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 152235Z - 152330Z

ISOLATED SEVERE TSTMS WITH DAMAGING WINDS WILL BE POSSIBLE THE NEXT
COUPLE OF HOURS ACROSS SRN NEW ENGLAND.  SEVERE STORM
COVERAGE/INTENSITY APPEARS MARGINAL FOR A SEVERE THUNDERSTORM
WATCH...BUT WILL CONTINUE TO MONITOR THIS AREA.

A SMALL BOWING SEGMENT HAS EVOLVED OVER CENTRAL MA AND IS MOVING TO
THE ESE AT ROUGHLY 50 KT.  MODIFIED RUC SOUNDINGS FOR THE AREA NEAR
AND IN ADVANCE OF THIS CONVECTION SHOWS A DEEP SURFACE-BASED MIXED
LAYER AND VERY MARGINAL INSTABILITY.  GIVEN THE 40-50 KT WNWLY FLOW
AROUND 3 KM AGL AND THE STEEP L0W-LEVEL LAPSE RATES...SOME OF THE
STORMS MAY PRODUCE STRONG/DAMAGING OUTFLOW WINDS.  HOWEVER...THE
LEADING CONVECTION WILL ENCOUNTER THE COOLER MARINE AIR MASS BY 23Z
WHICH SHOULD RESULT IN WEAKENING OF THE CONVECTION.  OTHER ISOLATED
STORMS COULD FORM UPSTREAM FROM SRN NY INTO WRN MA AND CT...AND THIS
CONVECTION COULD ALSO PRODUCE STRONG OUTFLOW WINDS.  THIS AREA WILL
CONTINUE TO BE MONITORED FOR THE POSSIBILITY OF A SEVERE
THUNDERSTORM WATCH...THOUGH THE SITUATION APPEARS TO BE SOMEWHAT
MARGINAL ATTM.

..THOMPSON.. 05/15/2007

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

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

42197109 41967133 41787173 41747259 41907361 42047477
42047531 42197577 42387609 42857619 43217580 43087497
42897378 42827231 42737126 42637103

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 15, 2:27 PM EDTMesoscale DiscussionSPCBerkshire, Franklin, Hampshire93 min

Nearby

Mesoscale Discussions in New York, 2007Mesoscale Discussions in Massachusetts, 2007Mesoscale Discussions in Connecticut, 2007Every 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.