Robert Dewey
EF5
I decided to make this into a seperate thread... The other thread was more focused on the Southern Plains, and there is a great disconnect between the two locations...
With that said, the latest 00Z models are looking interesting for the Great Lakes region. NAM and GFS have both shifted further northwest with the lead shortwave, and pull in a disturbance from the Gulf region. That brings a pretty good surge of moisture northward into the colder air...
A decent TROWAL sets up in the 600-500MB level with a decent upglide flow... 700MB mixing ratios aren't very impressive though - but would still yeild a 4 inch snowfall over a 6 hour period (2G/KG).
Of REAL interest is what the cross sections are showing. First, between 00Z FRI and 09Z FRI very strong CSI is present... In fact, the environment is conditionally unstable in the 700-500MB layer for a short period (3 hours). That's within the saturated layer, which extends well into the -15C to -20C isotherm... Second - to top it off, strong forcing is present in the form of very intense omega and frontogenesis values. The setup looks nearly perfect for an intense band of potentially convective snowfall, oriented in a northeast to southwesterly fashion across lower MI.
Using just the model QPF of 0.35-0.50 inches, that would yeild a 4-6 inch snowfall on a 1 to 12 ratio. I expect a "fluffy" type of snow given the relatively cold profile and good snow growth potential, but I have found that 12 to 1 usually works the best over lower MI. Throwing in the conditional instability and the potential for convective banding would really throw QPF off as well.
It's still a solid 48 hours away, and forecasting conditional instability that far out is already a problem - not to mention this is the first NAM run to show the northward trend. In addition, there also appears to be a wedge of dry air in the 925-850MB layer on the cross sections - which would likely be slow to erode. I have seen plenty of events killed by a wedge of dry air that just won't erode.
With that said, the latest 00Z models are looking interesting for the Great Lakes region. NAM and GFS have both shifted further northwest with the lead shortwave, and pull in a disturbance from the Gulf region. That brings a pretty good surge of moisture northward into the colder air...
A decent TROWAL sets up in the 600-500MB level with a decent upglide flow... 700MB mixing ratios aren't very impressive though - but would still yeild a 4 inch snowfall over a 6 hour period (2G/KG).
Of REAL interest is what the cross sections are showing. First, between 00Z FRI and 09Z FRI very strong CSI is present... In fact, the environment is conditionally unstable in the 700-500MB layer for a short period (3 hours). That's within the saturated layer, which extends well into the -15C to -20C isotherm... Second - to top it off, strong forcing is present in the form of very intense omega and frontogenesis values. The setup looks nearly perfect for an intense band of potentially convective snowfall, oriented in a northeast to southwesterly fashion across lower MI.
Using just the model QPF of 0.35-0.50 inches, that would yeild a 4-6 inch snowfall on a 1 to 12 ratio. I expect a "fluffy" type of snow given the relatively cold profile and good snow growth potential, but I have found that 12 to 1 usually works the best over lower MI. Throwing in the conditional instability and the potential for convective banding would really throw QPF off as well.
It's still a solid 48 hours away, and forecasting conditional instability that far out is already a problem - not to mention this is the first NAM run to show the northward trend. In addition, there also appears to be a wedge of dry air in the 925-850MB layer on the cross sections - which would likely be slow to erode. I have seen plenty of events killed by a wedge of dry air that just won't erode.