CHECK BOLD AREAS

Hurricane Wilma Discussion Number 18

Statement as of 5:00 PM EDT on October 19, 2005


agreement among the track guidance models...which had been very good
over the past couple of days...has completely collapsed today. The
06z runs of the GFS...GFDL...and NOGAPS models accelerated Wilma
rapidly toward New England under the influence of a large low
pressure system in the Great Lakes region. All three of these
models have backed off of this solution...with the GFDL showing an
extreme change...with its 5-day position shifting a mere 1650 nmi
from its previous position in Maine to the western tip of Cuba.
There is almost as much spread in the 5-day positions of the 12z
GFS ensemble members...which range from the Yucatan to well east of
the Delmarva Peninsula. What this illustrates is the extreme
sensitivity of Wilma's future track to its interaction with the
Great Lakes low. Over the past couple of days...Wilma has been
moving slightly to the left or south of the model guidance...and
the left-most of the guidance solutions are now showing Wilma
delaying or missing the connection with the low. I have slowed the
official forecast just a little bit at this time...but if Wilma
continues to move more to the left than expected...substantial
changes to the official forecast may have to be made down the line.
Needless to say...confidence in the forecast track...especially the
timing...has decreased considerably.

The latest pressure reported by the reconnaissance aircraft was 892
mb...with peak 700 mb winds of 152 kt. The initial intensity is
lowered to 140 kt. Aircraft reports...as well as microwave and
conventional satellite imagery...indicate that the inner
5-mile-wide eye of Wilma is weakening within two outer eyewalls...
one 10 miles wide and another about 45 miles across. In the short
term...this means that the peak winds should decrease as the wind
field expands...but there should be ample time for Wilma to
reintensity before it approaches the Yucatan. With an increasing
possibility that there will be a considerable interaction with the
Yucatan...I have lowered the intensity forecast slightly in the
Gulf of Mexico.


Forecaster Franklin