Statement as of 11:00 am EDT on September 05, 2008
Northerly shear continues to a take a toll on Ike. Satellite images
show that the eye has become less clear and that most of the
convection is in the southern semicircle. In addition...a recent
ssmis microwave image shows that the eyewall is open on the north
side. Using a blend of the objective and subjective Dvorak
classifications...the initial intensity is lowered to 105 kt...and
this could be generous. An Air Force Reserve reconnaissance plane
is scheduled to investigate the hurricane this afternoon to obtain
a better estimate of the current intensity and wind radii. Almost
all of the global models show decreasing shear over Ike in about a
day due to a weakening of strong northeasterly upper winds. Except
for a small patch of SSTs near and north of the southeastern
Bahamas...waters are very warm along the forecast path. The
official forecast shows a slow weakening of the hurricane due to
the shear for the first 24 hours...then shows intensification as
upper-winds slacken...in general agreement with the lgem model. In
a couple days...vertical wind shear will likely become light...and
conditions look rather favorable for intensification. The official
forecast could be conservative in the longer-range as the HWRF and
GFDL show a more intense hurricane. Regardless of exactly how
strong it is...all signs are that Ike will be a dangerous hurricane
for days to come.
Ike has been moving south of west during the past few hours...about
260/14. This general track with some decrease in forward speed is
forecast over the next 36 hours due to a strong ridge wedging into
between Ike and Hanna. The ridge should weaken somewhat in a couple
of days...steering the hurricane more to the west and eventually
west-northwest. However...models are not in good agreement on when
this west-northwest motion could materialize. Generally the models
that drive the system farther south...such as the ECMWF/HWRF/GFDL
models...suggest the ridge will remain intact enough to eventually
send Ike toward Cuba or the southeastern Gulf of Mexico. The
UKMET/GFDN/NOGAPS...on the other hand...suggest the hurricane will
move more the west and has a better chance of being affected by a
weakness in the ridge around 80w. Since the hurricane is moving
well south of the latter cluster of models already...the official
forecast leans more toward the southern guidance and shifted
southwest of the previous forecast.
It cannot be repeated enough that four- and five-day track forecasts
can have significant errors...and combined with the fact that the
model spread is still notable beyond 72 hours...one should not
focus on the exact track.
