MD 2059 CONCERNING HEAVY SNOW FOR NORTHEAST THROUGH WEST CENTRAL MISSOURI AND ADJACENT EAST CENTRAL KANSAS…SOUTHEASTERN IOWA AND WEST CENTRAL ILLINOIS
Mesoscale Discussion 2059
NWS Storm Prediction Center Norman OK
0627 AM CST Thu Dec 22 2022
Areas affected...northeast through west central Missouri and
adjacent east central Kansas...southeastern Iowa and west central
Illinois
Concerning...Heavy snow
Valid 221227Z - 221700Z
SUMMARY...A band of moderate to heavy snow with gusty winds may
contribute to near blizzard conditions, at times, while spreading
across areas around and southwest of the Kansas City metro toward
the Hannibal/Quincy, Columbia/Jefferson City and Lake of the Ozarks
vicinities through 10-11 AM CST.
DISCUSSION...To this point the advancement of the sharp surface
frontal zone has been more rapid southward into the southern Great
Plains (beneath 40-50 kt northerly flow around 850 mb) than
southeastward into the lower Missouri Valley. This appears likely
to remain the case into midday, when the front is forecast to have
surged across much of central Texas, while only approaching the east
central Missouri into northwestern Arkansas vicinity.
Atop the shallow, but gradually deepening cold surface-based air
mass (including surface temps falling from above freezing to the
single digits and sub-zero), a remnant warm (albeit sub-freezing)
and dry layer lingers (roughly centered near 700 mb) across southern
/eastern Kansas through the lower Missouri/middle Mississippi Valley
vicinity. This is in advance of a band of moderate to perhaps
occasionally heavy snow that has been supported by strong enough
mid-level frontogenetic forcing to overcome the warm/dry layer.
The Rapid Refresh suggests that this forcing may weaken as the
intense mid-level short wave trough digging through the northern
Great Plains takes on more a neutral tilt this morning. However, it
is forecast to gradually become better aligned with frontogenetic
forcing in the 850-700 mb layer, across west central into
northeastern Missouri. Beneath increasingly difluent and divergent
upper flow, this may be accompanied by a period of maximizing lift
in the mid-level layers around -15C, most conducive to dendritic ice
crystal growth and substantive aggregation before reaching the
surface.
Although the dendritic growth zone is forecast to lower with
continued significant lower/mid-tropospheric cooling, and
precipitable water may tend to quickly decrease below .30 inches, at
least a 1 or 2 hour period of heavy snow rates around or in excess
of 1 inch per hour appears possible, as the evolving band of snow
spreads eastward. While the more substantive strengthening of
northwesterly low-level flow into the lower Missouri/middle
Mississippi Valley will probably occur well in its wake, forecast
soundings suggest surface gusts on the order of 25-30+ kts may still
accompany this band, contributing to occasional sharply reduced
visibilities in blowing and drifting snow.
..Kerr.. 12/22/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LSX...DVN...SGF...DMX...EAX...TOP...ICT...
LAT...LON 40669331 40649123 38529199 37639382 38119584 38839645
39429452 40669331
