Update on Bertha: Long Term Track Still Uncertain

Well, here is your daily scoop on tropical storm Bertha. (on the projected path, 18z is 2PM EDT) Before I get to the brief forecast discussion, lets look at what Bertha is going through now. The first image is microwave imagery, showing the center is not as well defined and that most of the deep convection is getting sheared to the north of the center. This also shows up on the IR, as the storm has a sheared, a-symmetrical storm. Now for the forecast track and intensity discussion:

Over the next few days a strong mid-level ridge over the northern Atlantic will continue to steer Bertha to the west-northwest. However, late Monday a weakness will develop in the ridge. The models cannot decide how strong this weakness will be and how Bertha will respond to this. A stronger Bertha responds more and re-curves out to sea much quicker. However, it looks like wind shear could be doing a number on Bertha by the time this weakness in the ridge develops, and this could keep Bertha from being strong enough to respond to the ridge, thus, the vast majority of the models are showing Bertha taking a more southern track, perhaps towards the US east coast or Bermuda. Considering the models continue to trend towards a southern track, I have shifted my projected path southward to the models. If my track verifies I give the storm a 40% chance of coming within 100 miles of Bermuda, and a 40% chance of coming very close to or hitting the US before curving out to sea. So basically I think this thing could go either way, and needs to be watched. As for intensities, over the next day dry air off of Africa, around 15 knots of shear, and marginal Sea Surface Temps (SSTs) will keep Bertha around the same strength she is now. However, later Saturday though Sunday and into Monday, Bertha will experience warmer SSTs, lower shear, and more moisture in the air. This should allow for a gradual strengthening to a strong TS or weak CAT 1 by Monday. But, starting Monday it appears Bertha may feel the affects of some wind shear. The models are undecided on much shear there will be and how much it will weaken Bertha, but considering this is an early season Cape Verde storm, with marginal SSTs I believe the shear will have a negative impact on Bertha, especially if the shear is as strong as some models indicate (30-40 knots). Here are my approximate forecast coordinates and intensities for the next 5 days:

18z Sat: 37.5 W, 17N. 50-55MPH

18z Sun: 46 W, 19N. 60-65MPH

18z Mon: 51.5 W, 20.8N. 70-75MPH

18z Tue: 58 W, 22.5N. 60-65MPH

18z Wed: 63.5 W, 24.5N. 55-60MPH