Friday, March 9, 2012 6 P.M.

Rain and (mostly) white rain overnight

A weak Alberta Clipper system will work its way through the lower Ohio Valley tonight. First, we’ll see rain developing this evening.  Then, as a little colder air arrives, the rain will mix with snow.  We’ll also probably see all  snow for an hour or so.  The lower atmospheric temperatures will be the key as is often the case.

The models can’t agree on much.  But, two items are shared by all of them.  First, temperatures near the surface will stay several degrees or more above freezing during the precipitation event.  Second, the highest likelihood for accumulating snow will stay mostly north of I-65 AND, especially, east of Louisville.  Primary time for snow in the metro area will be from 1 A.M to 4 A.M.

Moisture is rapidly feeding into the system, but the majority of the moisture won’t arrive in time for significant snow west of I-65.  Areas from eastern Oldham and Shelby Cos to Georgetown may see 1-2″ of snow on grassy areas with isolated 3″-4″ amounts, but very little on roadways.  In Indiana, eastern Clark and Jefferson Counties may see 1″-3″.

Back home in the Louisville with temperatures up and smaller precipitation amounts expected, we should experience only a few, brief problems on the roads.  Otherwise, snowfall accumulations will be small – less than an inch on grassy areas.  Any minor accumulations on road surfaces will disappear by morning.

Oh yes…”White rain”

White rain is my definition for snow that essentially has the same effect as regular rain.