The tropical depression we were watching yesterday was officially upgraded to a tropical storm named Ernesto at 4 pm today (Friday). Ernesto is still a big question mark; if it survives the weekend, it may turn out to be a serious threat for someone. But it’s future is as yet uncertain. This is what the experts are saying this afternoon:
At 3PM CDT, Tropical Depression Five was about 240 miles south of Puerto Rico. Movement is to the west to west-northwest at 12-15 mph. Maximum sustained winds were recently measured by a recon plane at 40 mph. The recon plane confirmed that the depression is very disorganized, with heaviest squalls and strongest wind well removed from the low-level center. But the plane did find winds to support an upgrade to tropical storm strength, and we anticipate that the NHC will upgrade the depression to Tropical Storm Ernesto on their 4pm CDT advisory. Satellite imagery indicates that strong southwesterly winds aloft continue to impact the developing storm. There is considerable doubt as to whether or not the circulation center can survive the wind shear over the next two days. It is quite possible that the depression/storm could weaken to a tropical wave over the weekend. But there may be a slightly greater chance that the center will reform eastward beneath the heavier squalls, and that is the solution that we chose on this advisory.
Latest model guidance has shifted just a little to the east, generally over western Cuba then northwestward toward the central to northeast Gulf Coast. As our previous forecast track is now to the west of most model guidance, we have made a slight eastward adjustment on the track beyond day 3. This adjustment still keeps our track on the western side of most model guidance. However, there is a tremendous amount of uncertainty in the track forecast beyond the next 2-3 days. If the storm moves more slowly, then it would tend to track well to the west of our current forecast.
The intensity forecast is also uncertain. Currently, the forecast is for wind shear to weaken very slowly over the next 2 days. Because of persistent wind shear, we indicated only some slight strengthening over the next 2-3 days. But should the storm survive and reach the northwest Caribbean Sea late on Monday, then conditions aloft may be quite favorable for strengthening. We indicated that the storm could reach hurricane strength late on Monday, but we may be a little conservative as far as the maximum potential intensity over the warm waters of the central Gulf. If the storm survives to reach the central Gulf, then it could become significantly stronger than we’ve indicated.