SPC 1200Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1017 PM CST Fri Dec 11 2020

Valid 121200Z - 131200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Only minimal thunderstorm activity is anticipated today over parts
of the contiguous United States.

...Synopsis...
A strong mid-level shortwave trough will quickly move from the mid
MS Valley northeastward through the Great Lakes during the period. 
An attendant surface low will develop northeast from northwest IN
through lower MI during the day and reach the Ontario/Quebec border
by early Sunday morning.  A cold front will extend south from the
surface low and sweep eastward across the OH Valley and Mid South
with the front weakening across the central Gulf Coast.  

...Southern Great Lakes...
The northern portion of a narrow warm sector will extend north into
IN ahead of the surface low.  Models indicate low 50s F dewpoints as
far north as northeast IN/northwest OH during the late morning. 
Forecast soundings show very cold 500 mb temperatures (-22 deg C)
with a mid-level dry slot protruding northeast into the southern
Great Lakes by the late morning.  Models differ regarding the
magnitude of destabilization but it seems temperatures may warm to
at least low to mid 50s.  The strong wind profile may conditionally
support a few low-topped cells.  If cloud breaks or appreciable
heating can materialize, a localized threat for strong gusts could
accompany the strongest cells---primarily during the late morning to
early afternoon.

A few thunderstorms are possible mainly during the morning through
the mid afternoon across the central Gulf Coast states before this
activity diminishes by early evening.  Weak instability will
probably limit storm intensity and the prospects for an isolated
damaging gust.

..Smith.. 12/12/2020

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