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ACUS11 KWNS 260628
SPC MCD 260628

Mesoscale Discussion 0332
NWS Storm Prediction Center Norman OK
0128 AM CDT Sun Mar 26 2017

Areas affected...The Upper Peninsula of MI

Concerning...Freezing rain

Valid 260628Z - 261200Z

SUMMARY...Freezing rain rates around to slightly above 0.05 inch per
3 hours will be possible through 12Z.

DISCUSSION...Within a region of low-level warm air advection across
much of the Great Lakes and ahead of an approaching upper-level low
over the mid MS Valley, light to locally moderate freezing rain
rates will be possible, mainly across parts of the Upper Peninsula
of MI. Radar imagery shows light precipitation over the Upper
Peninsula as of 0615Z, with a mix of rain/freezing rain farther
south across northern Lower MI per surface observations. A residual
dry low-level airmass will support surface temperatures falling
below freezing, as wet bulb temperatures generally range from 26-32
degrees F. As the plume of higher reflectivity with greater
precipitation rates moves northward across the Upper Peninsula,
freezing rain rates should likewise increase, with various
short-term high resolution guidance suggesting rates at or slightly
above 0.05 inches per 3 hours becoming common. A longer duration of
freezing rain may be possible across the far eastern Upper Peninsula
(Chippewa/Mackinac counties), where lower surface wet bulb
temperatures will support freezing rain through the early morning
hours. Elsewhere, freezing rain should slowly transition to mainly
rain from south to north through 12Z as continued low-level warm air
advection encourages surface temperature to rise above freezing.

..Gleason.. 03/26/2017

...Please see for graphic product...


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