Mesoscale Discussion 0080
NWS Storm Prediction Center Norman OK
0324 PM CST Sun Jan 16 2022
Areas affected...central Appalachians and upper Ohio River Valley
Concerning...Heavy snow
Valid 162124Z - 170330Z
SUMMARY...Mixed wintry precipitation has begun to transition to
moderate snow across portions of eastern KY, southern OH and WV. An
increase in heavy snow is expected late this afternoon and evening
with rates of 1 to 2 inches per hour possible.
DISCUSSION...Moderate and heavy snow should continue to become more
common this afternoon and evening across portions of the central
Appalachians and Ohio Valley ahead of a potent upper low moving out
of the southeast. Strong diffluence aloft overspreading the ongoing
precipitation has resulted in increasing coverage and intensity with
several reports of moderate snow appearing in eastern KY over the
last hour. As large-scale ascent and strong mid-level warm advection
continue to increase through this afternoon, precipitation rates
should follow suit, increasing after 22z. It still may take several
hours for the entirety of the precip to change over to snow given
warm air trapped on the windward side of the Appalachians. However,
dynamic cooling from increased precipitation rates and the loss of
diurnal heating should accelerate the change over after dark.
Hi-res guidance is in strong agreement that band of moderate to
heavy snow will likely take shape within the axis of deformation
across eastern KY, western WV and eastern OH over the next couple of
hours. This band will likely support snow rates of 1+ inches per
hour through late afternoon and into this evening as it migrates
north eventually reaching eastern OH and western PA. The corridor
along the OH/PA border appears most likely to see the heaviest
snowfall rates given the favorable overlap with strong isentropic
ascent at the nose of the warm conveyor and enhanced deformation to
the northwest of the upper low. Snow rates may briefly approach 2+
inches per hour within this corridor, especially on the windward
side of any locally higher terrain.
..Lyons.. 01/16/2022