Snowfall Update and Forecast.

After a very fluffy and snowy morning commute, many of you may be wondering what will happen with this next snow event.  The local TV weatherman may be passing this next event off as insignificant, but recent model forecasts and analysis indicate otherwise.  As I mentioned yesterday, if the ingredients come together just right, we may be in for a significant snowfall Friday afternoon into Saturday morning.  Right now, I'll start with what's going on.  A moderately sized Alberta Clipper is now moving from northern Michigan into Canada, which is what caused the snow earlier today.  As it moves away, the clouds should clear somewhat, as drier air makes its way into the area.  Areas south of U.S. 30 will continue to see light to moderate snow through the rest of the afternoon. Tonight, I am expecting clouds to continue clearing, giving way to clear skies by evening after lake effect diminishes.  This will allow temperatures to drop below 10 degrees tonight, some areas will drop to about 5 or 6 degrees, with even colder wind chills.  By the very early morning hours, cloud cover will increase ahead of the next storm system.  This system will be a quick, but strong, disturbance, originating out of the same storm train that brought Seattle a record-breaking snowstorm, and is still bringing a large part of the west heavy snow, heavy rain, heavy icing, and high winds.  This system will quickly move out of the Rockies and into the Midwest tomorrow morning, and with the limited moisture that it has, will cause moderate snow to break out over Nebraska and Iowa.  If the storm would not change its characteristics, we would probably see snowfall amounts on the order of 1-3 inches, instead of the amount I am forecasting.  When this relatively weak surface low (at the time) moves into the Midwest, it should begin picking up moisture from the Gulf of Mexico.  At the same very strong isentropic lifting will occur over our area, causing widespread snow to develop ahead of the system (note: an isentrope is a line of equal potential temperature, which is the temperature an air parcel will have if raised or lowered to the 1000 millibar level.  When air flows upward on these isentropes, it causes vertical motion and clouds and precipitation will form if it is fairly saturated.).  Other features, such as strong frontogenetical forcing at the surface, could possibly cause mesobanding of heavy snow, leading to the possibility of high snowfall rates (1-3 inches per hour snowfall) for several hours Friday night.  Forecast soundings that I have looked at have shown me that temperatures will remain below freezing throughout the entire atmosphere above us Friday night, leading me to forecast not much in the way of sleet and freezing rain.  But, the forecast NAM sounding for 11 p.m. Friday night is showing temperatures at the 850 millibar becoming very close to freezing point, which means there is the possibility that some areas, especially south Fort Wayne and Paulding, could see some sleet mix in. Other than that, most areas will see heavy snowfall Friday night.  By early Saturday morning, snow will end across the area, probably around 4 a.m.. Right now, the latest short range computer models are pointing to the heaviest area of snow remaining just to the west, near Chicago, but we could also be in this band of heaviest snowfall.  Right now, my forecast has the potential for 4-8 inches of snow to fall (which is close to the what the National Weather Service is predicting, 3-7 inches).  The 12z GFS has some isolated areas in Northwest Ohio and Northeast Indiana to receive over 8 inches of snow, depending on how much mesoscale banding of snow takes place.  If more sleet mixes in than expected, than those areas will probably see 2-5 inches of snow, especially south of a line from Paulding to Fort Wayne.  If more moisture is available, strong isentropic upglide, along with stronger frontogenetical forcing, I would definitely expect much higher snowfall totals.
   As for the warm up next week, it really won't be that big of a deal.  Temperatures will likely reach the upper 30's and lower 40's by Sunday and Monday, with another strong storm system returning.  This strong storm system could very heavy rain, and a severe weather potential to our area, with the possibility of a QLCS squall line forming and racing through the area.  This combined with rapid snowmelt and rainfall over an inch could cause some flooding to occur in many areas.  This is the potential we have to watch out for next week.