"Big" Bertha Nothing to Worry About

Our tropical depression has moved ever slightly to the NW from yesterday and has some stronger storms near the center than yesterday with slightly lower pressure, but is otherwise open and unimpressive. See the IR satellite image below where my large X marks the spot of the center

The National Hurricane Center expects modest intensification today into tropical storm Bertha. It’s a large sprawling circulation created from a non-tropical upper air low which made it “big”, but big systems have a harder ( and slower) time getting their act together — which is a good thing. Their track, which seems somewhat reasonable, takes Bertha westward. What you don’t see is that they weaken the storm after tomorrow evening with peak winds of 50 mph (45 knots) by the time it crosses the Louisiana coast.

My take is that winds will be less, and the storm could well fall apart as it nears the Mobile area or the Mississippi Gulf Coast. The reason why is shown in this forecast map of 30,000 ft. winds for Tuesday morning. As Bertha gets closer to the coast, strong NE winds will shear the tops of the storms to the SW weakening the storm. Low level winds will still be from the east, and will push whatever is left in our general direction. The exact landfall is probably not going to matter. By the way, forecasts at 30,000 ft. are more accurate than at the surface because of less friction.

The Foreca graphic shows the chance of a thunderstorm this evening after one of the hottest days of the year. The 97 could well be 100 in some inland areas. Tomorrow’s storm chances should hold off even longer and may not be as widespread. The reason is the air will be sinking in advance of Bertha. If my thinking is correct, then tomorrow could be a degree warmer.

For Wednesday, as Bertha is being sheared apart, clouds will move in with showers knocking the temperatures down about five degrees . Not expecting any large rainfall amounts. Unlike June’s Mississippi flash flood disaster, areas just 20 miles inland may hardly have any rain from this. If Bertha comes in with 40 mph winds just south of us, we could see 2-3 feet of surge in the Sound and Lake Pontchartrain, but even that seems unlikely. Showers will linger for a few days after Bertha and then its back to normal.

Next week (July 26- Aug 1) seems drier and warmer than normal except for the Mobile area and NW Florida which should see more rainfall than normal. Sorry about that, you late season vacationers. After that, models paint a normal rainfall picture for everyone.

This week’s miniature scare with Bertha does not change my take on hurricane season because this happened in about the only way it could have — something coming from an old “front”, something coming from due east. I still expect a below normal season.

Foreca graphic for Pensacola Beach shows a very similar pattern but with more rainfall late today and tomorrow. Winds and surf will be up — not good beach weather until Sunday. Expecting more showers in there towards the middle of next week.