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"Not dead yet", says East Coast disturbance

By: Dr. Jeff Masters, 1:57 PM GMT on August 18, 2006

The persistent low pressure system 100 miles east-northeast of Jacksonville Florida refuses to die, despite my attempts to declare it dead last night. Wind shear from a protuberance of the jet stream is now a very hefty 40-50 knots, but the system has retained its circulation and still has some heavy thunderstorm activity firing up on its south side. Wind speeds as noted in a QuikSCAT satellite pass at 7:32am EDT this morning show that the strongest winds remain near 25 mph. This system is definitely an oddity--it refused to develop Wednesday when conditions appeared quite favorable with low wind shear, and now refuses to die under extremely hostile wind shear. The high shear is forecast to remain or increase today, and this system has little hope of gaining tropical depression status before it moves ashore into northern Florida and/or Georgia tonight. These areas can expect some spotty heavy rains from the storm.


Figure 1. Current long range radar out of Jacksonville, FL.


Figure 2. Preliminary models tracks for the East Coast disturbance.

Tropical wave off of Africa
A strong tropical wave moved off the coast of Africa Thursday, near 7N 16W. The QuikSCAT pass from 3:17pm EDT yesterday revealed winds of up to 60 mph to the west of the center, but the thunderstorm activity has since quieted down. We don't have a recent QuikSCAT pass to evaluate the current winds. Visible satellite animations from this morning show good rotation, and this disturbance does have some potential for develoment a few days from now. SSTs are a bit cool at 27C (81F), but wind shear has declined from 20 knots last night to about 10 knots today. The past three days worth of GFS model runs have been developing this system into a hurricane that threatens the Lesser Antilles about seven days from now. None of the other models develop the system.

Jeff Masters

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.