Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 231104
SWOMCD
SPC MCD 231103
MEZ000-231500-

Mesoscale Discussion 0045
NWS Storm Prediction Center Norman OK
0503 AM CST Tue Jan 23 2018

Areas affected...Northern Maine

Concerning...Winter mixed precipitation

Valid 231103Z - 231500Z

SUMMARY...Heavy snowfall with rates of up to 1 inch per hour will be
possible across northern Maine over the next 3 to 4 hours. A mix of
snow, freezing rain and sleet is likely after daybreak from near
Caribou westward to the Canadian border.

DISCUSSION...The latest water vapor imagery shows a strong
upper-level system from the Great Lakes southward into the Ohio and
Tennessee Valleys. Southwest anticyclonic flow exists ahead of the
system across the Northeast. A plume of low to mid-level moisture
was moving across New England with a vorticity max analyzed by the
RAP in far western Maine near the Maine-Canadian border. In
addition, the exit region of a 50 to 60 kt low-level jet is analyzed
over northern New England. These factors along with backed easterly
low-level flow is contributing to strong isentropic ascent across
northern Maine favorable for heavy snow. The greatest potential for
heavy snow will be from Caribou, ME and Edmundston, Canada westward
to the Canadian border where snowfall rates could reach 1 inch per
hour.

Further south, the core of a strong low-level jet will result in
considerable warming around 850 mb in central and northern Maine
this morning. As a result of the related melting-layer depth
increase, snowfall should become mixed with freezing rain and sleet
after daybreak. This changeover should gradually progress northward
across north-central Maine this morning.

..Broyles/Edwards.. 01/23/2018

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

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

LAT...LON   47496841 47576922 46767004 46177016 45996804 46306754
            47126770 47496841



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