Alert archive / Maine / Mesoscale Discussions in 2017

Mesoscale Discussion 1812

December 25, 20177 counties in Maine

The Storm Prediction Center issued this mesoscale discussion at Dec 25, 2017, 12:50 PM EST for 7 counties in Maine. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Dec 25, 2017, 12:50 PM EST (17:50 UTC)
Expired
Dec 25, 2017, 3:45 PM EST
In force
3 hr
Issued by
the Storm Prediction Center

Counties Hancock County, ME, Kennebec County, ME, Knox County, ME, Lincoln County, ME, Penobscot County, ME, Waldo County, ME, Washington County, ME

The radar

The Caribou radar (KCBW), 116 km from the middle of the area, began a volume at 17:50 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, 5.8 hours before the alert went out and 193 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-pSkew-T log-p diagram, Gray, ME at 12:00Z on 2017-12-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Gray, ME at 12:00Z on 2017-12-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 903 square meters per square second.1939587897117136156175Sfc1 km3 km6 km9 kmRMLM
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
489 m above ground
0-6 km bulk shear
101 kt
0-1 km storm-relative helicity
903 m²/s²
0-3 km storm-relative helicity
1127 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.

IssuedProductOfficeCountiesLasted
Dec 25, 7:02 AM ESTMesoscale DiscussionSPCAndroscoggin, Cumberland, Hancock, Kennebec, Knox, Lincoln and 6 more6 hr

Nearby

Mesoscale Discussions in Maine, 2017Every mesoscale discussion in 2017

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.