Alert archive / Vermont / Mesoscale Discussions in 2015

Mesoscale Discussion 1605

August 4, 20155 states

The Storm Prediction Center issued this mesoscale discussion at Aug 4, 2015, 11:15 AM EDT for 5 states. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Aug 4, 2015, 11:15 AM EDT (15:15 UTC)
Expired: Aug 4, 2015, 1:45 PM EDT
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 41 counties

Berkshire County, MA, Franklin County, MA, Androscoggin County, ME, Cumberland County, ME, Franklin County, ME, Hancock County, ME, Kennebec County, ME, Knox County, ME, Lincoln County, ME, Oxford County, ME, Sagadahoc County, ME, Somerset County, ME, Waldo 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, Columbia County, NY, Dutchess County, NY, Rensselaer County, NY, Washington County, NY, Addison County, VT, Bennington County, VT, Caledonia County, VT, Chittenden County, VT, Essex County, VT, Franklin County, VT, Lamoille County, VT, Orange County, VT, Orleans County, VT, Rutland County, VT, Washington County, VT, Windham County, VT, Windsor County, VT

The radar

The Burlington radar (KCXX), 113 km from the middle of the area, began a volume at 15:14 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 469Aug 4, 12:20 PM EDT

The nearest sounding before it

Gray, ME (KGYX), launched 12:00Z, 3.3 hours before the alert went out and 155 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: 199 J/kg
Mixed-layer CIN: -114 J/kg
Mixed-layer LCL: 1196 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 56 m²/s²
0-3 km storm-relative helicity: 71 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 4, 12:18 PM EDT	Severe Thunderstorm Watch	SPC	Androscoggin, Aroostook, Cumberland, Franklin, Hancock, Kennebec and 10 more	8 hr
Aug 4, 2:21 PM EDT	Mesoscale Discussion	SPC	Androscoggin, Cumberland, Franklin, Hancock, Kennebec, Knox and 8 more	84 min
Aug 4, 4:14 PM EDT	Mesoscale Discussion	SPC	Androscoggin, Cumberland, Hancock, Kennebec, Knox, Lincoln and 5 more	91 min
Aug 4, 6:49 PM EDT	Mesoscale Discussion	SPC	York	86 min
Aug 4, 5:59 AM EDT	Mesoscale Discussion	SPC	Barnstable, Bristol, Dukes, Nantucket	3 hr
Aug 4, 3:29 AM EDT	Mesoscale Discussion	SPC	Bronx, Kings, Nassau, New York, Queens, Richmond and 2 more	3 hr

Nearby

Mesoscale Discussions in Vermont, 2015 Mesoscale Discussions in Maine, 2015 Mesoscale Discussions in New Hampshire, 2015 Every mesoscale discussion in 2015

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.