Saturday, September 25, 2004
Hurricane Jeanne approaching landfall
Josh Larson @ 12:25 PM
As of early afternoon today, Hurricane Jeanne has strengthened to a Category 3 hurricane with sustained winds of 115mph and gusts to near 140mph. She is located 35 miles northeast of Freeport Grand Bahama Island, and is approximately 135 miles east of the southeastern coast of Florida. She has a minimum central pressure of 955mb and is moving west-northwest at 15mph.
I expect that Jeanne will make landfall near Melbourne, Florida sometime between 11pm Saturday and 3am Sunday. I expect that the hurricane will maintain or gain strength in the approximately 12 hours prior to landfall for two reasons: she is interacting with an inverted surface trough over the eastern gulf which is acting to enhance the pressure gradient; she is now moving over very warm waters of the Gulf Stream and experiencing little wind shear. This particular prognosticator believes Jeanne will make landfall as a robust Category 3 storm with sustained winds of 120-130mph.
Then where to? The key atmospheric piece of the puzzle is the strong area of high pressure located to the north of Jeanne - over the eastern US and western Atlantic. Once Jeanne gets far enough north, she will increasingly be controlled by the high, which should begin to rather dramatically curve her to the northeast. The key question is how far west (or north) Jeanne gets before making that decisive turn to the northeast. While there is fairly good computer model agreement, there are basically two somewhat-different camps or scenarios: (1) models that have Jeanne hugging or paralleling the eastern coast of Florida, Georgia and the Carolinas before turning "right" and out to sea; (2) models that have Jeanne making it further west - transversing central and northern Florida - as far as the panhandle, before turning "right." Note that the TPC, in their track forecast (below) is compromising between the two camps.
I personally believe that Jeanne will more likely take a more inland track and continue heading west-northwest, reaching the Panhandle or western side of Florida, before turning right (i.e., camp 2), instead of paralleling southeast coast (Florida, Georgia, Carolinas) before turning right.
Which brings us to the ever-elusive question of "what will the impact on DC be?" Unfortunately, once again a tough call. Some computer models (i.e., GFS) suggest that the remnants of Jeanne will make it far enough north before sliding out to sea to bring rain to the area. Others, however, (like the ETA) hint that the moisture will slide out to sea before it gets as far north as the DC metro area. I am more inclined to side with the latter scenario (and the ETA), as I believe the ridge of high pressure will exert significant influence on Jeanne's remnants, forcing them to turn out to sea somewhere over North Carolina or extreme southern coastal Virginia.
Bottom line: In DC, expect at least an increase in cloud cover and breezy conditions Tuesday and Wednesday, though at this point I believe there is less than a 50/50 chance that measurable rain will fall; obviously, those living in the southern half of the area are more likely to see rain than those living in the northern half.
Comments are closed for this archived entry | Link | 
Email this post
Email this post
