Alert archive / Maine / Mesoscale Discussions in 2013

Mesoscale Discussion 1413

July 17, 20138 counties in Maine; Carroll County, Coos County, Grafton County, New Hampshire; Caledonia County, Essex County, Vermont

The Storm Prediction Center issued this mesoscale discussion at Jul 17, 2013, 4:08 PM EDT for 8 counties in Maine; Carroll County, Coos County, Grafton County, New Hampshire; Caledonia County, Essex County, Vermont. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Jul 17, 2013, 4:08 PM EDT (20:08 UTC)
Expired: Jul 17, 2013, 5:45 PM EDT
In force: 97 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

Counties Androscoggin County, ME, Aroostook County, ME, Franklin County, ME, Kennebec County, ME, Oxford County, ME, Penobscot County, ME, Piscataquis County, ME, Somerset County, ME, Carroll County, NH, Coos County, NH, Grafton County, NH, Caledonia County, VT, Essex County, VT

The radar

The Caribou radar (KCBW), 166 km from the middle of the area, began a volume at 20:11 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 418Jul 17, 4:20 PM EDT

The nearest sounding before it

Caribou, ME (KCAR), launched 12:00Z, 8.1 hours before the alert went out and 190 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1314 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 143 m²/s²
0-3 km storm-relative helicity: 168 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.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 17, 4:20 PM EDT	Severe Thunderstorm Watch	SPC	Aroostook, Franklin, Oxford, Penobscot, Piscataquis, Somerset	6 hr
Jul 17, 7:52 PM EDT	Mesoscale Discussion	SPC	Franklin, Kennebec, Oxford, Penobscot, Somerset	83 min
Jul 17, 1:52 PM EDT	Mesoscale Discussion	SPC	Chittenden, Grand Isle	53 min
Jul 17, 2:29 PM EDT	Severe Thunderstorm Watch	SPC	Addison, Bennington, Caledonia, Chittenden, Essex, Franklin and 8 more	8 hr

Nearby

Mesoscale Discussions in Maine, 2013 Mesoscale Discussions in New Hampshire, 2013 Mesoscale Discussions in Vermont, 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.