Severe Storm Outlook Narrative (AC)
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ACUS11 KWNS 292147
SPC MCD 292146

Mesoscale Discussion 1953
NWS Storm Prediction Center Norman OK
0346 PM CST Mon Nov 29 2021

Areas affected...portions of lower Michigan

Concerning...Heavy snow

Valid 292146Z - 300245Z

SUMMARY...A band of moderate to heavy snow is forecast to move
across Lake Michigan this evening producing occasional snow rates of
1 to 1.5 inches per hour.

DISCUSSION...As of 2140 UTC, regional radar imagery showed a large
area of moderate to heavy stratiform precipitation from northeastern
Wisconsin to the eastern shores of Lake Michigan. Associated with a
fast-moving shortwave trough in northwest flow, this precipitation
will move southeast with time into portions of lower Michigan.
Forcing for ascent while not overly strong is forecast to increase
as the upper trough and jet approach this evening. Southerly low and
mid-level winds ahead of the shortwave will foster increased low and
mid-level warm advection/frontogenesis through a cool and saturated
profile with average DGZ depths around 1000m. Local radar
observations suggests some banding is already occurring in the
ongoing precipitation. Conditional Symmetric instability ahead of
the wave and and enhancement from seasonably warm lake temperatures
of 8-10C may support periodic heavy snowfall rates of 1 to 1.5
inches per hour this evening.

The most likely corridor for heavy snow will be across the eastern
Lake Shore and west-central lower Michigan between 23-03 UTC where
maximum lake influence and forcing for ascent overlap. Farther east,
lower boundary-layer moisture may result in delayed saturation,
cutting into snow totals and rates as forcing for ascent begins to
diminish late this evening and overnight.

..Lyons.. 11/29/2021

...Please see for graphic product...


LAT...LON   42038575 42198626 42478634 42778634 43068640 43418658
            43628663 44028664 44308646 44398611 44328568 43938520
            43628506 43348501 43078499 42708495 42388500 42168526
            42058545 42038575 is the U.S. government's official web portal to all federal, state and local government web resources and services.