HURRICANE GASTON DISCUSSION NUMBER 24
NWS NATIONAL HURRICANE CENTER MIAMI FL AL072016
1100 AM AST SUN AUG 28 2016
The eye was fairly distinct a few hours ago, but recently it has
become slightly cloud-filled and the inner-core convection has
become less symmetrical. The current intensity is set at 90 kt,
in agreement with a Dvorak estimate from TAFB and objective ADT
values from UW-CIMSS. Assuming the slight degradation of the inner
core structure to be temporary, a little more strengthening is
expected within the next 12 to 24 hours. Gaston should remain in a
low to moderate vertical wind shear environment for the next
couple of days, which would allow the hurricane to more or less
maintain its intensity through 36-48 hours. By 72 hours and beyond,
increasing westerly shear should induce weakening. The official
intensity forecast is close to the multi-model consensus IVCN.
Steering currents are weak, and the initial motion is a
northwestward drift or 320/4 kt. Gaston's motion is being
partially blocked by a narrow subtropical ridge, and this scenario
should continue for the next day or so. The hurricane is expected
to gradually work its way through the ridge and, in 24 to 48 hours,
begin to move northeastward and east-northeastward as it enters the
mid-latitude westerlies. The official forecast is close to a
consensus of the ECMWF and GFS solutions.
2. Satellite imagery this morning suggests that a tropical depression
is forming about 300 miles south-southwest of the southern Cabo
Verde Islands, and if current trends continue, advisories would be
initiated later today. This system is expected to move westward to
west-northwestward at 15 to 20 mph over the eastern tropical
Atlantic Ocean.
* Formation chance through 48 hours...high...near 100 percent
* Formation chance through 5 days...high...near 100 percent