Alert archive / Maine / Mesoscale Discussions in 2021

Mesoscale Discussion 22

January 16, 2021Franklin County, Somerset County, Maine

The Storm Prediction Center issued this mesoscale discussion at Jan 16, 2021, 12:47 PM EST for Franklin County, Somerset County, Maine. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Jan 16, 2021, 12:47 PM EST (17:47 UTC)
Expired: Jan 16, 2021, 6:45 PM EST
In force: 6 hr
Issued by: the Storm Prediction Center
Concerning: Heavy snow

Counties Franklin County, ME, Somerset County, ME

The radar

The Portland,ME radar (KGYX), 167 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 167 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: 417 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 275 m²/s²
0-3 km storm-relative helicity: 401 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

071 
ACUS11 KWNS 161747
SWOMCD
SPC MCD 161747 
MEZ000-162345-

Mesoscale Discussion 0022
NWS Storm Prediction Center Norman OK
1147 AM CST Sat Jan 16 2021

Areas affected...portions of northern/western Maine

Concerning...Heavy snow 

Valid 161747Z - 162345Z

SUMMARY...Heavy snow will continue to develop northeast across the
discussion area through this afternoon.  Snowfall rates of around
one inch/hour will be possible.

DISCUSSION...Strong low-level southeasterly flow and resultant
warm/moist advection continue to support a large area of
precipitation north/east of a surface low over eastern MA at 17z.
Forcing for ascent associated with the warm advection will continue
to shift northeast through this afternoon, supporting a mix of
precipitation types across northern New England.

Across the discussion area, the higher elevations will generally
support snow as the dominant precipitation type, although periods of
mixed precipitation will be possible.  Forecast soundings from the
16z RAP and 12z NAM guidance show below freezing thermal profiles
and saturation/lift developing within the dendritic growth zone this
afternoon, and several hours of 1 to locally 2 inch/hour snowfall
rates will be possible.  This trend is supported by recent guidance
from the HRRR and HREF ensemble.

..Bunting.. 01/16/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...CAR...GYX...

LAT...LON   45277083 45787035 46187020 46467002 46536932 46026907
            45486947 45007024 44667073 44707091 44737097 44847099
            44987101 45097100 45257097 45277083

Nearby

Mesoscale Discussions in Maine, 2021 Every mesoscale discussion in 2021

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.