Alert archive / New Hampshire / Mesoscale Discussions in 2011

Mesoscale Discussion 32

January 18, 20115 states

The Storm Prediction Center issued this mesoscale discussion at Jan 18, 2011, 12:37 PM EST for 5 states. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Jan 18, 2011, 12:37 PM EST (17:37 UTC)
Expired: Jan 18, 2011, 4:30 PM EST
In force: 4 hr
Issued by: the Storm Prediction Center

All 40 counties

Berkshire County, MA, Franklin County, MA, Hampshire County, MA, Worcester County, MA, Androscoggin County, ME, Cumberland County, ME, Franklin County, ME, Kennebec County, ME, Oxford County, ME, Sagadahoc County, ME, York County, ME, Belknap County, NH, Carroll County, NH, Cheshire County, NH, Coos County, NH, Grafton County, NH, Hillsborough County, NH, Merrimack County, NH, Rockingham County, NH, Strafford County, NH, Sullivan County, NH, Albany County, NY, Columbia County, NY, Greene County, NY, Montgomery County, NY, Rensselaer County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, Warren County, NY, Washington County, NY, Addison County, VT, Bennington County, VT, Caledonia County, VT, Essex County, VT, Orange County, VT, Rutland County, VT, Washington County, VT, Windham County, VT, Windsor County, VT

The radar

The Portland,ME radar (KGYX), 131 km from the middle of the area, began a volume at 17:39 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 12:00Z, 5.6 hours before the alert went out and 131 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 846 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 388 m²/s²
0-3 km storm-relative helicity: 436 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.

342 
ACUS11 KWNS 181737
SWOMCD
SPC MCD 181737 
MEZ000-MAZ000-NHZ000-VTZ000-NYZ000-182130-

MESOSCALE DISCUSSION 0032
NWS STORM PREDICTION CENTER NORMAN OK
1137 AM CST TUE JAN 18 2011

AREAS AFFECTED...WRN ME...MUCH OF NH/VT...CNTRL/WRN MA...ERN NY

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 181737Z - 182130Z

SNOWFALL RATES UP TO 1 IN/HR WILL SPREAD NEWD ACROSS CNTRL/NRN NH
AND WRN ME DURING THE AFTERNOON...WHILE A MIXTURE OF SLEET AND
FREEZING RAIN ARE EXPECTED OVER ERN NY INTO CNTRL/WRN MA AND
CNTRL/SRN VT/NH.

UPPER IMPULSE AND ASSOCIATED EXIT REGION OF 100 KT JET WILL CONTINUE
TO LIFT NEWD AWAY FROM THE MID ATLANTIC REGION THIS
AFTERNOON...WHILE RIGHT ENTRANCE REGION OF 120 KT UPPER JET
GRADUALLY SHIFTS NEWD ACROSS NEW ENGLAND. UPPER DIVERGENCE/LARGE
SCALE ASCENT BETWEEN THESE TWO FEATURES WILL CONTINUE TO YIELD A
DEEPLY SATURATED ENVIRONMENT FAVORABLE FOR HEAVY PRECIPITATION OVER
THE REGION. MEANWHILE...MESOSCALE ASCENT /LOW-LEVEL WAA AND
ISENTROPIC UPGLIDE/ WILL BE FOCUSED IN THE EXIT REGION OF 60 KT LLJ
MOVING NEWD FROM SRN NY ACROSS VT/NH AND INTO WRN ME BY 00Z.
TEMPERATURE PROFILES ARE FORECAST TO BE COLD ENOUGH FOR SNOW ACROSS
THE NRN HALF OF NH INTO WRN ME THIS AFTERNOON...WHERE STRONG ASCENT
OCCURRING IN THE EXIT REGION OF THE LLJ WILL LIKELY FAVOR RATES UP
TO 1 IN/HR. FARTHER S-SW...WARM NOSE ABOVE SUB-FREEZING SURFACE
TEMPERATURES IS FORECAST TO SPREAD FROM ERN NY INTO CNTRL/WRN MA AND
CNTRL/SRN VT/NH. AS A RESULT...A MIXTURE OF SLEET AND FREEZING RAIN
IS EXPECTED...WITH RATES AVERAGING AROUND 0.06 IN/HR. DURING THE
21-00Z TIME PERIOD...MODEL GUIDANCE INDICATES THAT MIDLEVEL DRY AIR
WILL BEGIN TO SPREAD ACROSS ERN NY...WRN MA...AND MOST OF
VT/NH...WHICH SHOULD RESULT IN DECREASING PRECIPITATION RATES.

..GARNER.. 01/18/2011

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

ATTN...WFO...GYX...BOX...BTV...ALY...BGM...

LAT...LON   44236947 42827101 42257202 42037360 42407479 43557403
            44827183 45306998 44236947

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 18, 3:33 AM EST	Mesoscale Discussion	SPC	Berkshire, Franklin, Hampden, Hampshire	6 hr
Jan 18, 8:01 AM EST	Mesoscale Discussion	SPC	Berkshire, Franklin, Hampden, Hampshire, Worcester	4 hr

Nearby

Mesoscale Discussions in New Hampshire, 2011 Mesoscale Discussions in New York, 2011 Mesoscale Discussions in Vermont, 2011 Every mesoscale discussion in 2011

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.