SPC MD 19

MD 0019 CONCERNING WINTER MIXED PRECIPITATION FOR PORTIONS OF IN...WESTERN OH...AND LOWER MI

Mesoscale Discussion 0019
NWS Storm Prediction Center Norman OK
0204 AM CST Fri Jan 12 2018

Areas affected...Portions of IN...western OH...and Lower MI

Concerning...Winter mixed precipitation 

Valid 120804Z - 121400Z

SUMMARY...The potential for a wintry mix of freezing rain, sleet,
and snow will increase through the early morning hours. Freezing
rain rates should be greatest across mainly central and northern IN.

DISCUSSION...07Z surface observations depict a sharp arctic cold
front extending across southeastern Lower MI into northwestern OH
and southeastern IN. Due to the shallow nature of this front,
freezing temperatures at the surface lag the northwesterly wind
shift by about 70-90 miles. A mid/upper-level trough is depicted on
water vapor satellite imagery moving eastward across the Upper
Midwest, and this feature will continue eastward towards the Great
Lakes region through the early morning hours. Large-scale lift
associated with this mid/upper-level trough has contributed to a
broad area of light to moderate precipitation encompassing much of
southern Lower MI and IN as of 0750Z.

Multiple observation sites across western/central IN have reported
light to moderate freezing rain as the predominant precipitation
type over the past several hours. This freezing rain potential
should shift into central/eastern IN over the next few hours as a
residual warm nose centered around 900-850 mb slowly erodes with the
approach of the mid/upper-level trough. Freezing rain rates around
0.03-0.05 inch per hour appear likely for at least an hour or two
across much of central and eastern IN based off of recent surface
observations and radar trends. Rates may be locally higher (up to
0.10 inch per hour) in the heaviest showers. As colder low/mid-level
temperatures move into this region, a west-to-east transition to
sleet and eventually snow should occur later this morning. Across
Lower MI, colder low/mid-level temperatures will likely support a
faster transition to snow, and some heavy snow with rates around 1
inch per hour cannot be ruled out, mainly in the 11-14Z time frame.

..Gleason.. 01/12/2018

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

ATTN...WFO...CLE...ILN...DTX...LMK...IWX...GRR...IND...

LAT...LON   38498671 38448519 39108490 40038433 41918304 42918238
            43238241 43998261 44098297 43978335 43638384 43128499
            42068594 40688662 39528707 38658746 38498671 

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