Mesoscale Discussion 0030
NWS Storm Prediction Center Norman OK
0522 AM CST Tue Jan 20 2026
Areas affected...Eastern shore of Lake Ontario into the Tug Hill Plateau
Concerning...Heavy snow
Valid 201122Z - 201615Z
SUMMARY...A heavy lake-effect snow band will continue through the
morning, with rates of 2-4 inches/hour possible in the most intense
portions of the band.
DISCUSSION...A well-established lake-effect snow band is ongoing
from Lake Ontario into parts of the Tug Hill Plateau this morning.
While some north-south oscillations will be possible as a minor
midlevel shortwave trough approaches from the west, this band is
expected to persist through the morning. A favorably long fetch off
of Lake Ontario and a relatively deep convective boundary layer will
continue to favor very heavy snow rates within the most intense
portions of the band.
Short-term guidance indicates that midlevel temperatures will reach
a minimum (-32 to -33 C at 700 mb) by mid/late morning, and snow
rates of 2-4 inches/hour will continue to be possible through this
time frame. Some warming aloft and modest lowering of equilibrium
levels is eventually expected in the wake of the approaching
shortwave trough, but the favorable fetch will help to maintain this
band through much of the day.