Lake effect snowfall forecast.

After a cold front moved through Sunday morning, temperatures rapidly dropped from the mid 40's to the upper 20's by nightfall.  This caused many road and concrete surfaces to freeze over last night, allowing for accumulating snowfall.  I know snowfall has been highly variable throughout the night, with some areas in Northwest Ohio picking up over an inch of snowfall.  Instead of a few main bands of lake effect snow, there has been many bands of moderate to heavy snow, with some of them reaching as far south as Lima, OH.  This is because there is still strong directional shear, which will tear apart large bands of extremely heavy lake effect snow and break them into many bands of moderate or heavy snow.  Some of the main ingredients for extremely heavy lake effect snow have been in place for this event.  One of these ingredients is an extreme lapse rate, from the surface lake waters to the 700 millibar layer of more than 30 degrees Celsius.  This means that surface temperatures over the lake could be near 40 degrees, while temperatures at the 700 millibar layer are below zero.  This creates an extreme lapse rate and absolute instability, allowing for free convection to take place, even without a lifting mechanism.  There is also enough synoptic moisture to allow for heavy snow to form, once the instability causes air to rise and cool and condense to form snow squalls.  Another ingredient that is present, is high inversion heights.  Normally, in an arctic air mass such as this one, an inversion will usually exist about a 1000 feet above the surface.  With this situation, the instability has caused inversion heights to be raised to about the 400 millibar layer, which is over 20,000 feet in the atmosphere.  This allows for deep bands of heavy snow to develop.  The last major factor in the development of extreme lake effect snow is strong wind speed shear between different levels in the atmosphere.  If strong upper level winds line up with much weaker surface winds, long bands of snow will stream off the Great Lakes.  If the atmosphere exhibits strong veering or backing of winds with height, these bands of heavy snow will be sheared apart, causing a more widespread snow event, but with less snowfall totals.  This is what happened last night, but it is forecasted that later today, several heavy bands of lake effect bands will develop, stretching as far south and east as Northwest Ohio.  One feature that will enhance the lake effect is an upper level shortwave that will begin moving over the area by early afternoon.  This will cause numerous moderate to heavy snow showers away from the lakes.  According to the latest hi-res guidance, snowfall amounts will largely remain in the range of 1-3 inches in most of Northwest Ohio, with heavier snowfall amounts west of the state line.  Snowfall amounts will likely be as high as 15 inches near South Bend to Benton Harbor, Michigan.  Even though ingredients are near perfect for an extreme lake effect event around here, the best conditions will reside near Lake Ontario, where over three feet of snow could fall.  By tomorrow, snow will end over most areas except near the lakes, with very cold conditions still in place, with highs barely reaching the twenties.  After that a major warming trend will commence, bringing our area out of the deep freeze, and temperatures well above normal by the end of the week.