ACUS11 KWNS 281234
SWOMCD
SPC MCD 281233
MIZ000-WIZ000-MNZ000-281700-

Mesoscale Discussion 0056
NWS Storm Prediction Center Norman OK
0633 AM CST Tue Jan 28 2025

Areas affected...the Upper Michigan vicinity

Concerning...Heavy snow

Valid 281233Z - 281700Z

SUMMARY...A period of heavy snow, at rates on the order of 1-2+
inches per hour, appears possible in a corridor overspreading the
central Upper Peninsula of Michigan vicinity by midday.

DISCUSSION...Downstream of a low-amplitude short wave perturbation,
accompanying an intense (110+ kt at 500 mb) jet streak digging
east-southeast of the Canadian Prairies, lower/mid-tropospheric warm
advection is overspreading the Upper Midwest into Great Lakes
region.  Associated forcing for ascent is becoming focused across
the southwestern flank of an arctic air mass now entrenched across
much of the Great Lakes region, particularly near a zone of strong
lower/mid-tropospheric frontogenesis, which is forecast to shift
from northwestern Ontario across the western Lake Superior and
central Upper Peninsula of Michigan vicinity through 17-18z.

Forecast soundings across this region indicate that the sub-freezing
thermodynamic profiles are in the process of saturating, ahead of an
ongoing band of moderate to heavy snow, which appears likely to be
maintained through at least early afternoon.  Temperatures appear
within a few degrees of -15C through an initially deep layer from
lower-levels into the 700-600 mb layer, where conditions will be
most conducive to large dendritic ice crystal growth.  Coinciding
with maximizing lift associated with the frontogenetic forcing, it
appears that this may support a 2-3 hour period of heavy snow rates
on the order of 1-2 inches per hour.  Forecast soundings also
indicate that a layer a steepening mid-level lapse rates may be
accompanied by the development of weak CAPE and embedded convective
development with heavier snow rates possible.

..Kerr.. 01/28/2025

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

ATTN...WFO...APX...MQT...GRB...DLH...

LAT...LON   48538911 47918791 46888619 46278519 45418590 44838674
            45668731 46428796 46938875 47878969 48538911