Alert archive / Maine / Mesoscale Discussions in 2011

Mesoscale Discussion 2124

September 4, 201111 counties in Maine; 4 counties in New Hampshire; Essex County, Vermont

The Storm Prediction Center issued this mesoscale discussion at Sep 4, 2011, 4:07 PM EDT for 11 counties in Maine; 4 counties in New Hampshire; Essex County, Vermont. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued: Sep 4, 2011, 4:07 PM EDT (20:07 UTC)
Expired: Sep 4, 2011, 5:00 PM EDT
In force: 53 min
Issued by: the Storm Prediction Center

Counties Androscoggin County, ME, Aroostook County, ME, Cumberland County, ME, Franklin County, ME, Kennebec County, ME, Oxford County, ME, Penobscot County, ME, Piscataquis County, ME, Sagadahoc County, ME, Somerset County, ME, Waldo County, ME, Belknap County, NH, Carroll County, NH, Coos County, NH, Grafton County, NH, Essex County, VT

The radar

The Portland,ME radar (KGYX), 130 km from the middle of the area, began a volume at 20:09 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, 8.1 hours before the alert went out and 130 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: 1426 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 572 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 91 m²/s²
0-3 km storm-relative helicity: 113 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.4

Open this sounding in Storm Lab

The text

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

907 
ACUS11 KWNS 042008
SWOMCD
SPC MCD 042007
MEZ000-NHZ000-VTZ000-042100-

MESOSCALE DISCUSSION 2124
NWS STORM PREDICTION CENTER NORMAN OK
0307 PM CDT SUN SEP 04 2011

AREAS AFFECTED...NRN / CNTRL PARTS OF NH / ME

CONCERNING...SEVERE THUNDERSTORM WATCH 834...

VALID 042007Z - 042100Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 834
CONTINUES.

DAMAGING WIND AND HAIL THREAT CONTINUES ACROSS VALID PORTION OF
SEVERE THUNDERSTORM WATCH 834 AREA.

AS OF 1955Z...REGIONAL RADAR IMAGERY SHOWED A LINE OF STRONG-SEVERE
TSTMS EXTENDING FROM W-CNTRL PISCATAQUIS TO E-CNTRL OXFORD COUNTIES
IN ME MOVING EWD AT AROUND 35 KT.  VISIBLE SATELLITE IMAGERY
SUGGESTS THAT THE BOUNDARY LAYER OVER THE COMPLEX TERRAIN OF
INTERIOR ME STILL REMAINS SOMEWHAT STABLE OWING TO THE PRESENCE OF
BILLOW CLOUDS.  NONETHELESS...IT DOES APPEAR THAT A SUFFICIENT COLD
POOL HAS BEEN ESTABLISHED WITH ONGOING STORMS TO EFFECTIVELY LIFT
THE MODERATELY UNSTABLE...INFLOW AIR PARCELS TO THEIR
LFC...SUPPORTING THE CONTINUED MOVEMENT/DEVELOPMENT OF ACTIVITY.
WHILE SOME HAIL IS POSSIBLE...DAMAGING WINDS WILL REMAIN THE PRIMARY
HAZARDS WITH THESE STORMS.

FARTHER W...LOW-LEVEL WAA MAY ALLOW INITIALLY STABILIZED BOUNDARY
LAYER TO DE-STABILIZE LATE THIS AFTERNOON...POTENTIALLY ALLOWING
ONGOING STORMS OVER NRN VT TO MOVE INTO NRN PORTIONS OF NH WITHIN
THE NEXT HOUR OR TWO.  HERE TOO...LOCALLY DAMAGING WINDS AND HAIL
WILL BE POSSIBLE.

..MEAD.. 09/04/2011

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

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

LAT...LON   44287227 47556919 47156677 46106763 45206790 44676848
            43886983 43427104 43527241 44287227

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 4, 12:17 PM EDT	Mesoscale Discussion	SPC	Franklin, Oxford, Somerset	58 min
Sep 4, 1:01 PM EDT	Severe Thunderstorm Watch	SPC	Androscoggin, Aroostook, Franklin, Kennebec, Oxford, Penobscot and 2 more	7 hr
Sep 4, 2:43 PM EDT	Severe Thunderstorm Watch	SPC	Addison, Bennington, Caledonia, Chittenden, Essex, Franklin and 8 more	8 hr
Sep 4, 6:06 PM EDT	Mesoscale Discussion	SPC	Addison, Bennington, Caledonia, Chittenden, Essex, Franklin and 8 more	54 min

Nearby

Mesoscale Discussions in Maine, 2011 Mesoscale Discussions in New Hampshire, 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.