Alert archive / Maine / Mesoscale Discussions in 2013

Mesoscale Discussion 939

June 2, 20135 states

The Storm Prediction Center issued this mesoscale discussion at Jun 2, 2013, 4:26 PM EDT for 5 states. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Jun 2, 2013, 4:26 PM EDT (20:26 UTC)
Expired: Jun 2, 2013, 6:00 PM EDT
In force: 94 min
Issued by: the Storm Prediction Center

All 33 counties

Berkshire County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Worcester County, MA, Androscoggin County, ME, Aroostook County, ME, Cumberland County, ME, Franklin County, ME, Kennebec County, ME, Oxford County, ME, Penobscot County, ME, Piscataquis County, ME, Somerset 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, Dutchess County, NY, Greene County, NY, Rensselaer County, NY, Ulster County, NY, Bennington County, VT, Windham County, VT

The radar

The Portland,ME radar (KGYX), 75 km from the middle of the area, began a volume at 20:27 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, 8.4 hours before the alert went out and 74 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: 462 J/kg
Mixed-layer CIN: -121 J/kg
Mixed-layer LCL: 1196 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 95 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

615 
ACUS11 KWNS 022027
SWOMCD
SPC MCD 022026 
MEZ000-NHZ000-MAZ000-CTZ000-VTZ000-NYZ000-022200-

MESOSCALE DISCUSSION 0939
NWS STORM PREDICTION CENTER NORMAN OK
0326 PM CDT SUN JUN 02 2013

AREAS AFFECTED...SERN NY AND NEW ENGLAND

CONCERNING...SEVERE THUNDERSTORM WATCH 271...

VALID 022026Z - 022200Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 271
CONTINUES.

SUMMARY...GREATEST DAMAGING WIND THREAT SHOULD EXIST THROUGH 22Z
WITH LINE SEGMENT SURGING E/NEWD FROM NH INTO WRN/SRN ME THROUGH THE
HEART OF WW 271. MORE ISOLATED DAMAGING WIND AND SEVERE HAIL IS
ANTICIPATED ACROSS AREAS FARTHER N AND S OF THIS QLCS.

DISCUSSION...SURGING QLCS CROSSING NH AS OF 2015Z HAD A HISTORY OF
NUMEROUS DAMAGING WIND REPORTS EARLIER IN VT. MEASURED WIND GUSTS OF
35-40 KT HAVE OCCURRED SINCE 19Z IN AREA METARS. HOWEVER...MOST
HIGHER REFLECTIVITY CORES IN THE MID-LEVELS HAVE WEAKENED IN THE
PAST HALF HOUR SUGGESTING OVERALL THREAT HAS PEAKED. STILL...WITH
MIDDLE 80S TO LOWER 90S SURFACE TEMPERATURES IMMEDIATELY AHEAD OF
THE LINE...A CONTINUED RISK FOR DAMAGING WINDS WILL PERSIST
NEAR-TERM. WITH TIME...ACTIVITY SHOULD FURTHER WEAKEN AS IT
ENCOUNTERS THE MARINE LAYER WHERE DOWNSTREAM TEMPERATURES HAVE
DROPPED INTO THE 60S TO LOWER 80S ACROSS MOST OF SRN/ERN/COASTAL ME.

..GRAMS.. 06/02/2013

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

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

LAT...LON   47316834 46786756 45986773 44946892 43947002 42287179
            41887248 41737359 41867459 42247447 42817388 43517227
            45347092 47146941 47316834

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 2, 11:33 AM EDT	Severe Thunderstorm Watch	SPC	Capitol Planning Region, Northwest Hills Planning Region	8 hr
Jun 2, 1:52 PM EDT	Mesoscale Discussion	SPC		83 min
Jun 2, 6:53 PM EDT	Mesoscale Discussion	SPC		97 min
Jun 2, 10:48 AM EDT	Mesoscale Discussion	SPC	Oxford	2 hr

Nearby

Mesoscale Discussions in Maine, 2013 Mesoscale Discussions in New Hampshire, 2013 Mesoscale Discussions in New York, 2013 Every mesoscale discussion in 2013

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.