Alert archive / Vermont / Mesoscale Discussions in 2012

Mesoscale Discussion 2096

October 30, 2012Carroll County, Coos County, Grafton County, New Hampshire; 8 counties in Vermont

The Storm Prediction Center issued this mesoscale discussion at Oct 30, 2012, 9:41 PM EDT for Carroll County, Coos County, Grafton County, New Hampshire; 8 counties in Vermont. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued: Oct 30, 2012, 9:41 PM EDT (01:41 UTC)
Expired: Oct 30, 2012, 10:45 PM EDT
In force: 64 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Carroll County, NH, Coos County, NH, Grafton County, NH, Caledonia County, VT, Chittenden County, VT, Essex County, VT, Franklin County, VT, Lamoille County, VT, Orange County, VT, Orleans County, VT, Washington County, VT

The radar

The Burlington radar (KCXX), 83 km from the middle of the area, began a volume at 01:40 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

Gray, ME (KGYX), launched 00:00Z, 1.7 hours before the alert went out and 160 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: 112 J/kg
Mixed-layer CIN: -45 J/kg
Mixed-layer LCL: 680 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: 245 m²/s²
0-3 km storm-relative helicity: 315 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.6

Open this sounding in Storm Lab

The text

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

197 
ACUS11 KWNS 310142
SWOMCD
SPC MCD 310141
MEZ000-NHZ000-VTZ000-310245-

MESOSCALE DISCUSSION 2096
NWS STORM PREDICTION CENTER NORMAN OK
0841 PM CDT TUE OCT 30 2012

AREAS AFFECTED...NRN VT AND NH

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 310141Z - 310245Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...POTENTIALLY DAMAGING WIND GUSTS MAY REMAIN POSSIBLE WITH
THE ONGOING CLUSTER OF STORMS AS IT RAPIDLY MOVES NORTHEASTWARD THIS
EVENING...BUT SEVERE THREAT APPEARS LIMITED ENOUGH THAT A WATCH DOES
NOT SEEM NECESSARY.

DISCUSSION...A SMALL CLUSTER OF THUNDERSTORM ACTIVITY HAS BEEN
FLUCTUATING IN INTENSITY...BUT APPEARS TO BE GENERALLY BEING
SUPPORTED BY A SUSTAINED FOCUSED AREA OF MID/UPPER FORCING FOR
UPWARD VERTICAL MOTION...AHEAD OF A SHORT WAVE IMPULSE PIVOTING
NORTHEASTWARD ACROSS THE NORTHERN MID ATLANTIC COAST.  CONVECTION IS
EMBEDDED WITHIN 40-50+ KT SOUTH SOUTHEASTERLY DEEP LAYER MEAN
FLOW...WHICH COULD ADVECT IT ACROSS THE REMAINDER OF NEW HAMPSHIRE
AND NORTHERN VERMONT...INTO SOUTHWESTERN QUEBEC...BY 03Z.  SURFACE
DATA SUGGEST LITTLE EVIDENCE OF A SIGNIFICANT COLD POOL...AND NEAR
SURFACE SOUTHERLY FLOW IS FAIRLY MODEST...BUT THERMODYNAMIC PROFILES
MAY REMAIN SUPPORTIVE OF STRONG ENOUGH DOWNDRAFTS TO CONTRIBUTE TO
THE DOWNWARD TRANSPORT OF HIGHER MOMENTUM AIR TO THE SURFACE...WITH
SPORADIC DAMAGING SURFACE GUSTS.

..KERR/THOMPSON.. 10/31/2012

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

ATTN...WFO...GYX...BTV...

LAT...LON   45267296 45437214 45207126 43897090 43617102 43537175
            43497215 44037280 44487329 45267296

Nearby

Mesoscale Discussions in Vermont, 2012 Mesoscale Discussions in New Hampshire, 2012 Every mesoscale discussion in 2012

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.