Atlantic Tropics Finally Get Busy Again

End Month Long Hiatus With A New Named Storm And Depression

Things are starting to heat up in the Atlantic Tropics again. Following a month of dormancy with no depressions, named storms, or hurricanes, the Atlantic fired itself up over the past 48 hours with two new systems. Like clockwork, the Atlantic Basin woke up just in time for the beginning of the Cape Verde season.

First, there was Ernesto. Late Wednesday afternoon, Tropical Storm Ernesto began its genesis into the season’s fifth tropical cyclone some 810 miles to the east of the Windward Islands. Since then, Ernesto has grown into a moderate tropical storm with winds of 50 miles per hour, gusts up to 60 miles per hour, and minimum central pressure up slightly to 1003 millibars or 29.62 inches of Hg. According to Friday’s 11:00 PM EDT forecast discussion, Some models (LGEM) are indicating that the storm could become a major hurricane with winds of at least 115 miles per hour according to the Saffir-Simpson Scale by this time Tuesday evening.

However, dynamical models such as the GFDL and HWRF indicate that the storm will maintain its present strength while the ECMWF contends that the storm will still be a weak system by the end of four days. One thing that there is agreement on is the forecast track, which is currently calling for Ernesto to threaten Jamaica by Sunday. The storm is presently located some 315 miles south of San Juan, Puerto Rico, or about 795 miles East-Southeast of Kingston, Jamaica. No watches or warnings have been issued yet, but that could change as the weekend progresses.

While Ernesto is the main threat in the Atlantic at the moment, there are other developments being watched in the basin. Late Friday night, Tropical Depression Six emerged in the Eastern Atlantic some 240 miles to the West-Southwest of the southernmost Cape Verde Islands. The depression is a fledgling cyclone with satellite estimated sustained winds of 35 miles per and gusts approximately 45 miles per hour. Minimum central pressure is still quite high at 1009 millibars or 29.80 inches of Hg (Mercury). TD #6 is moving rapidly to the West-Northwest at 16 miles per hour.

The current discussion on the depression from the NHC indicates that the cyclone is undergoing some northeasterly shear, which has pushed the higher cloud tops and stronger thunderstorms to the south of the center of circulation. There is significantly deep convection associated with this depression, and that convection was able to persist and become healthier during the course of the day on Friday. However, the prognosis for this storm doesn’t look promising.

The consensus model guidance indicates that the depression will become the sixth named storm of the season within 24 hours, but not get stronger after that, and actually begin the process of weakening after 36 hours to what will be a remnant post-tropical low at the end of five days. The combined factors of hostile upper level winds to the northeast of the system, inadequate sea surface temperatures, and dry air will be too much for the depression and soon to be named storm to handle. Finally, there is a third potential problem being monitored in the Atlantic.

According to the latest Tropical Weather Outlook from the NHC, there is a surface trough over Eastern Cuba and the Central and Northwestern Bahamas that has been stirring up some trouble. Shower and thunderstorm activity associated with this trough has improved and upper level dynamics have become more favorable for development. Fortunately, the disturbance is quite close to land, and that may inhibit development. Chances for tropical formation over the next 48 hours are about 20 percent.

Bottom line is that this latest flurry of activity should wake everyone including myself up since it is August and we are now beginning the ramp up to the Cape Verde Season and the statistical peak of the Tropical Atlantic season, which is usually around September 10th. July is usually a rather quiet month since upper level wind conditions and sea surface temperatures are not yet conducive for development, especially in the Central and Eastern Atlantic, where many of the big storms tend to emerge.

With these developments though, we are likely going to have six named storms for the year by time the weekend is out. Quite surprisingly since seasonal forecasts were calling for a less active season. The fast start with two rare late May storms and two more in the month of June set the table. Now, we’ll have to see if there are any big storms in store for August, September, and early October. Remember, despite the total numbers of storms, hurricanes, and major hurricanes that are forecasted each year, it only takes one storm to change the perspective on those numbers. The storm also doesn’t have to be a big wind maker like Hurricane Irene and Tropical Storm Lee pointed out last season.

So, be prepared and have a plan of action in case a storm does head your way.