Alert archive / New Hampshire / Mesoscale Discussions in 2012

Mesoscale Discussion 827

May 16, 20124 counties in Maine; 6 counties in Massachusetts; 7 counties in New Hampshire

The Storm Prediction Center issued this mesoscale discussion at May 16, 2012, 8:42 PM EDT for 4 counties in Maine; 6 counties in Massachusetts; 7 counties in New Hampshire. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued: May 16, 2012, 8:42 PM EDT (00:42 UTC)
Expired: May 16, 2012, 9:45 PM EDT
In force: 63 min
Issued by: the Storm Prediction Center

Counties Berkshire County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Middlesex County, MA, Worcester County, MA, Androscoggin County, ME, Cumberland County, ME, Oxford County, ME, York County, ME, Belknap County, NH, Carroll County, NH, Cheshire County, NH, Hillsborough County, NH, Merrimack County, NH, Rockingham County, NH, Strafford County, NH

The radar

The Boston radar (KBOX), 145 km from the middle of the area, began a volume at 00:45 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, 0.7 hours before the alert went out and 147 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: 27 J/kg
Mixed-layer CIN: -163 J/kg
Mixed-layer LCL: 769 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 100 m²/s²
0-3 km storm-relative helicity: 125 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.

216 
ACUS11 KWNS 170042
SWOMCD
SPC MCD 170042 
MEZ000-MAZ000-NHZ000-CTZ000-VTZ000-170145-

MESOSCALE DISCUSSION 0827
NWS STORM PREDICTION CENTER NORMAN OK
0742 PM CDT WED MAY 16 2012

AREAS AFFECTED...MA/NH/CT/WESTERN MAINE

CONCERNING...SEVERE THUNDERSTORM WATCH 280...

VALID 170042Z - 170145Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 280
CONTINUES.

SUMMARY...SEVERE TSTM WATCH 280 IS SCHEDULED TO EXPIRE AT 01Z...BUT
A LOCALIZED WIND DAMAGE/SEVERE HAIL THREAT WILL CONTINUE IN THE
SHORT TERM /POTENTIALLY OUTSIDE OF WW 280/ MAINLY ACROSS SOUTHERN
NH/ADJACENT MA AND PERHAPS FAR SOUTHWEST/COASTAL MAINE.

DISCUSSION...A NORTHEAST-SOUTHWEST ORIENTED BAND OF STRONG/SEVERE
TSTMS CONTINUE TO STEADILY PROGRESS EASTWARD ACROSS SOUTHERN
NH/NORTHERN MAINE AS OF 0030Z. THESE STORMS WILL GRADUALLY ENCOUNTER
A RELATIVELY COOLER/MORE STABLE BOUNDARY LAYER TOWARD THE COAST AS
PER THE 00Z OBSERVED CHATHAM MA SOUNDING AND OBSERVED SURFACE
TEMPERATURE TRENDS OVER THE PAST 1-2 HOURS. NONETHELESS...A
LOCALIZED WIND DAMAGE/SEVERE HAIL THREAT MAY CONTINUE OVER THE NEXT
HOUR OR SO /BEYOND 01Z/ GIVEN THE EXISTING TSTM
ORGANIZATION/VERTICAL SHEAR...BUT LIKELY ON AN INCREASINGLY MARGINAL
BASIS AS TSTMS OTHERWISE EVENTUALLY EXIT THE SOUTHERN NEW ENGLAND
COAST.

..GUYER.. 05/17/2012

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

ATTN...WFO...GYX...BOX...ALY...

LAT...LON   42387332 43217196 44687082 45306973 43567012 42057178
            41787325 42387332

Nearby

Mesoscale Discussions in New Hampshire, 2012 Mesoscale Discussions in Massachusetts, 2012 Mesoscale Discussions in Maine, 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.