Two Disturbances Being Watched in the Atlantic

New Disturbance near Bahamas Joins Invest 91L in Eastern Atlantic

Wednesday marks the statistical peak of the 2014 Atlantic Hurricane Season.  Looking at historical data going back to 1851, the most named storms and hurricanes have formed on September 10th in the Atlantic.  However, to date, this hurricane season has been well below average.  There have only been 5 depressions, 4 named storms, 3 hurricanes, and no major hurricanes in the Atlantic.

Things might be changing though.  Despite a vast area of dry stable air and hostile upper level wind shear in the Atlantic, there are now two disturbances being watched by the National Hurricane Center in Miami, Florida.  The first disturbance is in the vicinity of the Bahamas, and has a 10 percent chance of development over the next 48 hours, and a 20 percent chance of formation over the next 5 days.  The bigger threat, although much farther away in the Eastern Atlantic is Invest 91L, which has a 20 percent chance of development within the next 48 hours, and a 70 percent chance over the next 5 days.

Looking at analysis provided by Hurricane Consulting, the area of disturbed weather near the Bahamas is part of a surface trough that is interacting with a broad upper level low extending from the Southeastern Gulf of Mexico to the Bahamas.  To the north of this area is a surface low over North Carolina along with a frontal boundary that has been responsible for the cloudiness and shower activity in New Jersey the past couple days as well as stormy conditions in the Mid-Atlantic.  

The disturbance in the Bahamas doesn’t appear to be a threat to develop at this time.  The GFS fails to develop this disturbance, but other models have it becoming an area of low pressure off the Southwest Florida coast by this weekend.  If the projections of the other models hold, the disturbance will be in the Gulf of Mexico, which is an area of very warm water, a key factor in development.

There is another area of disturbed weather being watched in the Central Caribbean.  Viewing the satellite and radar composite of the area, there is a very nice flare up of convection associated with this broad mid to upper level trough, but conditions aren’t favorable for development.  Shifting over to the Eastern Atlantic, there is Invest 91L, which is now moving toward the Central Atlantic waters some 600 miles to the West-Southwest of the Cape Verde Islands.  

The disturbance is now an estimated 1006 millibar low, and it is a vast area of disorganized showers and thunderstorms.  Conditions are expected to become more favorable for development as we move further into the Atlantic, but it is too early to tell whether it will come ashore in the United States. Presently, the GFS model indicates that Invest 91L is expected to move through the Southeastern Bahamas within the next 10 to 12 days, and approach Florida as a strong hurricane before turning out to the east and stalling in the Northern Bahamas.

GWC and Hurricaneville will continue to watch the situation with these two disturbances, and other features that the various forecast models bring up over the next two weeks.  While this September has been fairly quiet to date, it is far from over, and the United States is long overdue for a landfalling major hurricane.  The last time such a storm came ashore in the U.S. was nearly 10 years ago.  There has been a dearth of major hurricanes in the Atlantic overall.  Tomorrow will mark two years since a major hurricane was classified (Michael in 2012).  Keep in mind that even in low activity years, there is still the possibility of a classic storm.  Andrew in 1992, the Labor Day Hurricane of 1935, and the Long Island Express of 1938 are powerful examples.

Special thanks to Lew Fincher and Stan Blazyk of Hurricane Consulting for providing their analysis on the current disturbances in the Atlantic.