Quick look at the evening run shows little change is needed to the forecast. If anything, the evening runs of the NAM, RAP and GFS (new) are stronger than this morning’s runs. Meanwhile, the odd man out is the old GFS which now carries the heaviest snows farther south.
So, as of midnight I’ll leave my projections the same as my previous blog which would be 8″ -12″ for metro Louisville. (Even if the old GFS is correct, we’ll still have a significant snowfall. But, totals would be 2″-3″ lower than I’m forecasting.) The new GFS gives Louisville 9.3″ of snow.
The system approaching us looked – 36 hours ago – like a puny attempt to get us some light snow. Things have certainly changed!!! The polar jet stream energy, which has long been predicted to be weak, has had an amazing increase in energy and now looks like it’ll be the perfect antidote to our mostly snow free winter (at least since November’s snow). The southern jet stream has been the prime part of the forecast for days, but all indications were that it wouldn’t be strong enough to bring much moisture north into the colder air over the central U.S. Then all of a sudden comes the polar jet’s energy.
That changes the whole game in a big way. It will be able to bring plenty of moisture northward aloft, but still hold the surface cold air in place. The result: about a 200 mile northward shift of the major activity – right into the Ohio Valley. It’s a setup for plenty of snow – let’s see if it happens!
Advancing snow tonight will have a hard time saturating the lower atmosphere, but some snow should begin in the Louisville area about 3-5 A.M. and we should have a messy rush with about an inch or two by rush hour. Then the snow really takes off – heavy snow likely between 7 AM and 1 P.M. and slowly tapering off by evening.
How much snow?
Good question, but here’s my best guess – Louisville area 8 “-10″
North of Louisville: within about 30 miles of the river – 6″ 8″
South of Louisville: 8″ to 12″ north of the Parkway, 12” south of the parkway
NOTE: Great snow for sledding, but too “dry” for snowballs and good snowmen.