Lake Effect Snow Predictions

[j1cousin]

John,

Seems like every weather forecaster seems to bomb lake effect snow predictions. Would you consider this the hardest type of weather to predict? Seems like tornado predictions are getting much better, but as far as determining the amount of lake effect snow to come down, no one seems to accurately forecast this. Example: St. Joe Michigan last week, just got 17 inches of snow, yet they were predicting 6-9 inches in NW Indiana and very little for the St. Joe area. What makes this so hard to predict? Is it the fact of not knowing the water temps or is the wind speeds and direction that play the major determining role of this? Do you see any instruments making predicting lake effect snow more accurately in the future or will this continue to be inaccurate estimates by forecasters for years to come?

 

[jd]

I am not sure if it is THE hardest weather element to forecast, but it sure is among the top.

The main reasons are the relatively small scale at which LES occur. By that I mean one area can get hit with a bunch of snow and another area just 10-20 miles away, much less. I did not look at the layout for the snow in the St. Joe area last week, but I would guess that the area that got 17" was not real big, maybe 20-30 miles wide, by double or triple that in length. Move the wind direction just a few degrees one way or the other and you put the band of heaviest snow in a totally different spot.

So wind direction and to a lesser extend, speed play a big role. So does the stability or instability of the atmosphere. Meaning how well does the air want to rise once it is warmed by the lake? Just some small differences in that factor can lead to big differences in how much snow falls.

So because many of the elements happen on such a small scale, they actually fall in between the gaps of most of the models, so many times the models are of little use when trying to forecast LES.

Tornado predictions are getting much better, because they cause such damage and loss of life, a ton of research goes into their forecasts. With that said, most tornado warnings still do not happen until a tornado has actually formed and for some, that is too late. Plus a region can be outlooked for severe weather, including a tornado watch or severe thunderstorm watch, but sometimes no severe weather even happens inside the watch box.

Hope this makes sense.

-John

 

[j1cousin]

John,

Thanks for your input as it was a rather difficult question to explain, but I understand what your saying in your reply. Thank you for the thorough explanation!