Alert archive / Maine / Mesoscale Discussions in 2008

Mesoscale Discussion 1663

July 2, 20085 states

The Storm Prediction Center issued this mesoscale discussion at Jul 2, 2008, 12:18 PM EDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 2, 2008, 12:18 PM EDT (16:18 UTC)
Expired: Jul 2, 2008, 2:45 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 32 counties

Bristol County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Middlesex County, MA, Norfolk County, MA, Suffolk County, MA, Worcester County, MA, Androscoggin County, ME, Cumberland County, ME, Franklin County, ME, Hancock 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, Cheshire County, NH, Hillsborough County, NH, Merrimack County, NH, Rockingham County, NH, Strafford County, NH, Suffolk County, NY, Bristol County, RI, Kent County, RI, Newport County, RI, Providence County, RI, Washington County, RI

The radar

The Portland,ME radar (KGYX), 26 km from the middle of the area, began a volume at 16:17 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, 4.3 hours before the alert went out and 26 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: 161 J/kg
Mixed-layer CIN: -64 J/kg
Mixed-layer LCL: 827 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 23 m²/s²
0-3 km storm-relative helicity: 51 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 021618
SWOMCD
SPC MCD 021618 
MEZ000-MAZ000-NHZ000-RIZ000-CTZ000-NYZ000-VTZ000-021845-

MESOSCALE DISCUSSION 1663
NWS STORM PREDICTION CENTER NORMAN OK
1118 AM CDT WED JUL 02 2008

AREAS AFFECTED...LONG ISLAND/NEW ENGLAND

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 021618Z - 021845Z

ISOLATED SEVERE TSTMS CAPABLE OF HAIL/STRONG WIND GUSTS ARE LIKELY
TO DEVELOP/INCREASE THROUGH EARLY/MID AFTERNOON ACROSS PORTIONS OF
CT/RI AND PERHAPS LONG ISLAND NY INTO MA/NH/MAINE. A SEVERE TSTM
WATCH IS UNLIKELY GIVEN THE EXPECTED MARGINAL/ISOLATED NATURE OF THE
RISK.

WATER VAPOR IMAGERY REFLECTS A COMPACT UPPER LOW ADVANCING
NORTHEASTWARD OVER SOUTHERN NY AT THIS TIME. IN VICINITY OF A WEAK
SURFACE LOW/REMNANT FRONTAL ZONE...BOUNDARY LAYER CU FIELD CONTINUES
TO DEEPEN ESPECIALLY ACROSS SOUTHERN NEW ENGLAND/LONG ISLAND
VICINITY PER RECENT VISIBLE SATELLITE IMAGERY. WITH CONVECTIVE
TEMPERATURES ALREADY BEING REACHED AND WEAK CONVECTIVE
INHIBITION...LARGE SCALE FORCING FOR ASCENT IN ASSOCIATION WITH
APPROACHING UPPER LOW/VORTICITY MAXIMA WILL CONTRIBUTE TO INCREASING
TSTM COVERAGE DURING THE EARLY/MID AFTERNOON HOURS. IN ASSOCIATION
WITH THE UPPER LOW...COOLER MID LEVEL TEMPERATURES WILL GRADUALLY
OVERSPREAD NEW ENGLAND THIS AFTERNOON...WITH UPSTREAM -14C
TEMPERATURES AT 500 MB NOTED THIS MORNING PER IAD/APG 12Z OBSERVED
RAOBS. ATOP RESIDUAL LOWER 60S F DEWPOINTS IN MOST
LOCALES...STEEPENING LOW-MID LEVEL LAPSE RATES WILL SUPPORT MLCAPE
AS HIGH AS 1000-1500 J/KG THIS AFTERNOON. IN SPITE OF A RELATIVELY
FAVORABLE THERMODYNAMIC ENVIRONMENT...PRIMARY LIMITING FACTOR WILL
BE MODEST VERTICAL SHEAR OF 25-30 KT. EVEN SO...IT SEEMS LIKELY THAT
A MARGINAL/EPISODIC SEVERE THREAT WILL EXIST THIS AFTERNOON...WITH
THE STRONGEST STORMS CAPABLE OF SEVERE HAIL/WIND GUSTS.

..GUYER.. 07/02/2008

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

ATTN...WFO...CAR...GYX...BOX...OKX...ALY...

46176884 45556786 44546820 43537064 42517098 41577086
40847214 40727327 42557269 44307156 45966951

Nearby

Mesoscale Discussions in Maine, 2008 Mesoscale Discussions in Massachusetts, 2008 Mesoscale Discussions in New Hampshire, 2008 Every mesoscale discussion in 2008

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.