Climate and Agriculture in the Southeast

Late Friday night tropical discussion for Nate

I am borrowing my husband’s tropical update from his Facebook page for tonight’s update.  He is also a meteorologist and an excellent forecaster as well as an atmospheric sciences and geography professor at UGA.  Here is what he says:

Tropical Storm Nate is gaining some strength as it approaches the Yucatan Peninsula and the southern Gulf of Mexico. Unlike some of the storms we’ve seen this year (Harvey, for example), Nate is moving quickly, at about 22 mph forward speed. This will take Nate across the Gulf from south to north quickly, with landfall expected somewhere between say New Orleans and Pensacola, FL on early Sunday morning.

This probably won’t be enough time over the warm Gulf for Nate to rapidly intensify, the way so many of the other storms (e.g., Harvey, Irma, Maria) have done. But the potential is still there. The most likely outcome is that Nate will reach, say, Biloxi, MS or Mobile, AL as a Category 1 hurricane around 2 am CDT Sunday.

From the central Gulf Coast Nate will move quickly inland; the latest forecast is for Nate to be a tropical storm somewhere between Columbus, MS and Montgomery, AL around 1 pm CDT on Sunday. (The current National Hurricane Center forecast puts the tropical storm icon right over Birmingham at 1 pm CDT Sunday.) Nate then moves even more quickly to the northeast, past Georgia and northeastward to West Virginia by Monday noon.

Weatherwise, what does this mean?

Fast-moving hurricanes tend to dump less rain but cause more wind damage on the right side of their tracks. Why the right side? Because that’s where the storm’s winds (due to pressure gradients and all that meteorology) ADD with the storm’s forward speed. On the left-hand side of the track, the two SUBTRACT. So if a weakening Nate has winds of only 40 mph inland but is moving at 25 mph, places to the east of the track could have 40+25 = 65 mph winds. There’s less rain just because the whole system flies through so quickly–unlike, say, Harvey, which sat over Texas with a forward speed of maybe 2 mph. Nate will be moving 20-30 mph.

More specifics for a few locations:

The central Gulf will have wind, rain, and storm surge starting Saturday afternoon, and conditions will change quickly because Nate is moving quickly. Worst conditions roughly 10 pm – 8 am Sat night/Sun morning.

In Birmingham there could be a little rain before the end of the UAB Homecoming game, but the heavier rain and wind (30-50 mph) will peak quickly around Sunday from 10 am – 3 pm local time.

Conditions in Atlanta will also deteriorate Sunday morning into Sunday afternoon. Depending on the exact path–forecasts have trended a bit west–Atlanta could just have a wet and breezy day. If the track of Nate is a little more toward the east, then Birmingham’s weather (see above) could be Atlanta’s.

Conditions in Athens will also be wet and breezy on Sunday, a little worse if the track is further to the east. Rough rule of thumb: the weather will probably be worse on Sunday for every mile you go west from Athens.

This forecast could change–again, Nate isn’t even in the Gulf yet. So please pay attention to official National Weather Service forecasts and advisories and watches and warnings this weekend. We’ve seen several instances this year where the public (incorrectly) thought there was little or no warning of rapidly intensifying storms. This is your heads-up that while Nate isn’t expected to be a Harvey, Irma or Maria, that we do have an intensifying tropical storm moving over the warm Gulf and headed toward LA/MS/AL/GA. You were warned. Mother Nature doesn’t take weekends off, so you can’t either. Pay attention.