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Tropical Depression Gilma Discussion Number 7
NWS National Hurricane Center Miami FL EP082018
200 AM PDT Sat Jul 28 2018
Gilma continues to be affected by strong westerly vertical shear,
with the low level center remaining exposed to the northwest of an
area of weakly banded convection. Satellite intensity estimates
are in the 25-35 kt range, so the initial intensity remains a
possibly generous 30 kt.
The initial motion is 280/11. The low- to mid-level subtropical
ridge to the north of the cyclone should continue steering the
cyclone generally westward to west-northwestward for the next three
days with some decrease in forward speed. The new track forecast
is similar to the previous forecast and lies a little to the north
of the center of the guidance envelope and the various consensus
models.
The ongoing shear is due to an upper-level trough just to the west
and northwest of the tropical cyclone. The dynamical models suggest
that this trough will move westward in close proximity to Gilma,
which will allow the shear to continue. In addition, the cyclone
should be moving into a drier airmass during the next several days.
These factors should cause Gilma to weaken and eventually dissipate
during the forecast period even though it will stay over warm
water. The new intensity forecast is mostly an update of the
previous forecast, and it now calls for Gilma to decay to a remnant
low by 36 h and dissipate completely after 72 h.
FORECAST POSITIONS AND MAX WINDS
INIT 28/0900Z 15.1N 132.4W 30 KT 35 MPH
12H 28/1800Z 15.4N 133.9W 25 KT 30 MPH
24H 29/0600Z 16.0N 135.7W 25 KT 30 MPH
36H 29/1800Z 16.3N 137.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 30/0600Z 16.4N 139.3W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 31/0600Z 16.5N 143.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 01/0600Z...DISSIPATED
$$
Forecaster Beven
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