Alert archive / Maine / Mesoscale Discussions in 2018

Mesoscale Discussion 1392

August 29, 20184 states

The Storm Prediction Center issued this mesoscale discussion at Aug 29, 2018, 6:16 PM EDT for 4 states. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: Aug 29, 2018, 6:16 PM EDT (22:16 UTC)
Expired: Aug 29, 2018, 7:45 PM EDT
In force: 89 min
Issued by: the Storm Prediction Center

All 21 counties

Androscoggin County, ME, Franklin County, ME, Kennebec County, ME, Oxford County, ME, Penobscot County, ME, Piscataquis County, ME, Somerset County, ME, Waldo County, ME, Carroll County, NH, Coos County, NH, Grafton County, NH, Sullivan County, NH, Warren County, NY, Washington County, NY, Addison County, VT, Caledonia County, VT, Essex County, VT, Orange County, VT, Rutland County, VT, Washington County, VT, Windsor County, VT

The radar

The Portland,ME radar (KGYX), 118 km from the middle of the area, began a volume at 22:15 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, 10.3 hours before the alert went out and 119 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: 3 J/kg
Mixed-layer CIN: -263 J/kg
Mixed-layer LCL: 1325 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: -15 m²/s²
0-3 km storm-relative helicity: 4 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 29, 2:56 PM EDT	Mesoscale Discussion	SPC	Aroostook, Franklin, Oxford, Piscataquis, Somerset	2 hr
Aug 29, 3:45 PM EDT	Severe Thunderstorm Watch	SPC	Franklin, Oxford, Penobscot, Piscataquis, Somerset	5 hr
Aug 29, 6:16 PM EDT	Mesoscale Discussion	SPC	Androscoggin, Franklin, Kennebec, Oxford, Penobscot, Piscataquis and 2 more	89 min
Aug 29, 1:19 PM EDT	Mesoscale Discussion	SPC	Clinton, Essex, Franklin, Hamilton, Herkimer, Jefferson and 2 more	116 min

Nearby

Mesoscale Discussions in Maine, 2018 Mesoscale Discussions in Vermont, 2018 Mesoscale Discussions in New Hampshire, 2018 Every mesoscale discussion in 2018

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.