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Tropical Depression Gilma Discussion Number 8
NWS National Hurricane Center Miami FL EP082018
800 AM PDT Sat Jul 28 2018
Despite being in an environment of strong westerly shear, Gilma is
maintaining its status as a tropical cyclone. Deep convection has
been persisting on the eastern side of the system, and this
activity has even moved a little closer to the center, aided by
upper-level diffluence. The initial wind speed is held at 30 kt,
in agreement with the Dvorak classifications of 2.0/30 kt from TAFB
and SAB. This intensity estimate is a little lower than the 2.5/35
kt ADT values from CIMSS at the University of Wisconsin.
Westerly shear of about 30 kt is likely to continue during the
next few days, and the global models indicate that the upper-level
flow should become less diffluent as Gilma approaches the Central
Pacific basin. These hostile winds aloft combined with cooler
SSTs and a more stable air mass should cause Gilma to gradually
weaken during the next few days. The NHC forecast continues to show
Gilma becoming a remnant low in about 36 hours and degenerating into
a trough by day 4, following the trend in the model guidance.
The depression is moving westward at 10 kt steered by the flow on
the south side of a mid-level ridge. A west to west-northwest
motion is expected during the next few days as the increasingly
shallow system moves within the low- to mid-level flow. The NHC
track forecast is a little south of the previous one to come
into better agreement with the latest consensus aids.
FORECAST POSITIONS AND MAX WINDS
INIT 28/1500Z 15.2N 133.0W 30 KT 35 MPH
12H 29/0000Z 15.4N 134.3W 30 KT 35 MPH
24H 29/1200Z 15.7N 136.0W 25 KT 30 MPH
36H 30/0000Z 15.8N 137.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 30/1200Z 15.7N 140.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 31/1200Z 15.4N 144.4W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 01/1200Z...DISSIPATED
$$
Forecaster Cangialosi
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