Let me begin by saying I don’t usually like doing posts like this because of the variables in the extended range can change an entire forecast period, however with the consistency in the models I decided to go ahead and begin addressing the issue of a possible hurricane impacting the United States in roughly 10 to 14 days. The first thing I’m going to show is why storms like Karl and Jula were deflected east of the United States.

This is the data that was ingested into the 12Z GFS this morning and applies at 7 AM Monday Morning. Hurricane Karl is easily visible north of Bermuda quickly moving to the northeast. The heat ridge, which has kept much of the Southern United States well above normal (temp wise) into September is shown over Texas eastward to Georgia, extending into the Gulf of Mexico. This ridge has been present a majority of the time since July. This has kept a majority of storms, except weak/sheared storms to the south and to the east of the United States. As long as that ridge remains in place storms developing in the Atlantic would re-curve to the east of the United States.

We are over half-way through September though so a pattern change would normally be upcoming and that is what is expected to happen. Let me stress at this point that the model output you are about to view is out in voodoo land, but has been extremely consistent. The graphic below shows the model output for 500 MB on Tuesday, September 28th. According to the heat ridge will have broken down. This pattern would indicate that many areas would return to normal temperatures across the Southern United States. However, and more important in this discussion, is the weakness that develops in the ridge over the Gulf of Mexico. At the very bottom of the screen is what the GFS output is indicating to be a tropical system of some kind moving north/northwest. With the weakness in the ridge in place, any system that was in that area would move north into the Gulf of Mexico.

This is where the details start to get sketchy. If the ridge is stronger then shown below the tropical system would be shunted eastward more quickly, likely moving over Cuba or the Dominion Republic. Right now the GFS is still indicating a trough over Texas. Once the storm entered the southern Gulf of Mexico it would begin to move northeastward and impact Florida from the southwest. The 12Z GFS showed this, while the 0Z and 06Z GFS showed a system moving across Cuba and sideswiping Florida from the southeast before making another landfall in the Carolinas.

At this point there is no use in trying to pinpoint down the strength of the upcoming tropical system or where it may eventually make landfall, but it is becoming a distinct possibility based on outstanding model output that a tropical system will impact parts of the United States by the end of the month. At this point the consistency has been with Florida, although the GFS has gone as far west as New Orleans on a few runs. The upcoming pattern shift is extremely favorable for a U.S. hit from a hurricane with a possible track (not landfall points, but tracks) similar to Hurricane Wilma (2005) and Hurricane Charlie (2004). Those living along the Gulf Coast should have a plan of action ready should a hurricane approach. The GFS and other models have been showing a GOM Hurricane for several days now, and personally I have not seen the model output be this consistent so far this year. Needless to say its pretty rare.

Considering this may be our only chance to chase (intercept may be a better word) land-falling Hurricane this year both Connor and I will be keeping a very close eye on what eventually evolves.

- David