Is it our turn? Tuesday 130 pm update

Models are now diverging with the storm only 3 days away! The Canadian GEM keeps the Gulf low close enough to the coast to spread heavy snow into parts of central Alabama on Friday, the European is a little farther south but shows enough upper-level dynamics for at least some snow in BHM, and the GFS keeps almost all of the precipitation along the coast and into the Gulf.

GEM

GFS

European

Snow amounts for BHM would be approximately:

GEM: 2.5″
GFS: 0
European: 1.5″

The low track is interesting, in that it forms off the Texas coast, a position climatologically favorable for snow here, as the normal track would then be along the Gulf Coast. Low pressure areas tend to move where the temperature gradient is largest, often along fronts, since they can most efficiently move warm, less dense air northward in those regions and lower the pressure ahead of the low. The biggest thermal gradient is usually near the Coast, as waters in the Gulf are usually several degrees warmer than the air inland.

This year, with our cold winter so far, Gulf of Mexico temperatures are running below normal, with a water temperature of 58 degrees about 50 miles southeast of Panama City and near Orange Beach. Here is the GFS model output for surface temperatures on Thursday night.

Notice the isotherms are oriented NW-SE, and a low following these would head toward Tampa, too far south for significant snow in BHM. I am not sure if the American models have input on Gulf temperatures that the Canadian and European do not, but if they do, this could lend more weight to the GFS. However, climatologically, these lows tend to hug the coast. It’s a tough call, and we’ll have to see how far south the cold air coming into Alabama now pushes into the eastern Gulf.

The best guess right now is a compromise, with heavier snow (3″ or more) somewhere near Montgomery, and only light snow (1″ or so) in BHM. This whole thing is still tough right now. Someone will get snow…it may wind up being Bay Minette!

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