An Atlantic Named Storm Coming for the First Week of May?

The first week of May is usually too early for the Atlantic to see its first named storm, but that is a possibility this year, according to the Friday morning runs of the GFS and European models. These models predict that an extratropical storm will form along an old cold frontal boundary over the Bahama Islands just east of the coast of Florida on Tuesday, then drift slowly northwards towards North Carolina during the week. Ocean temperatures are near 26°C (79°F), which is about 1.7°C (3°F) above average for this time of year, and just at the limit of where a tropical storm can form. If the storm manages to find a sweet spot over the core of the warm Gulf Stream current, it has the potential to develop into a subtropical or tropical depression in the May 7 - 8 time frame. Phase space diagrams from Florida State University from Friday morning's 06Z run of the GFS model support the idea that this system could be a subtropical or tropical system until it pushes north of a line even with the South Carolina/North Carolina border, where ocean temperatures fall to about 25°C (77°F). It is too early to put odds on whether or not this storm might make landfall, but South Carolina and North Carolina might see some rain from this system by Thursday.


Figure 1. WInd forecast for Thursday, May 7, 2015 at 8 am EDT made by the 00Z Friday run of the European model. The model is predicting a possible subtropical depression to be off the coast of the Southeast U.S.

Later today, Bob Henson will have a fascinating post on how human structures may be causing winter lightning.

Jeff Masters