ZCZC MIATCDEP5 ALL
TTAA00 KNHC DDHHMM

TROPICAL STORM IVETTE DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP102016
800 PM PDT THU AUG 04 2016

Though it may sound like a broken record, Ivette still is
struggling to intensify and is showing the detrimental effects of
vertical shear.  The low-level center appears to be on the northwest
side of the small area of cold cloud tops, consistent with some
west-northwesterly shear as shown in the SHIPS diagnostics and the
CIMSS analyses.  Yet, the deep-layer vertical shear is only 5-10
kt, which usually is conducive for intensification.  Perhaps it is
because of the small size of Ivette - tropical-storm-force winds
only out to 60 nm at most - which makes it more susceptible to
relatively small amounts of shear.  A blend of the TAFB, SAB, and
CIMSS Dvorak current intensity estimates gives 45 kt, which is
unchanged from the previous advisory. An earlier ASCAT scatterometer
pass confirmed the small size of Ivette.

Ivette has about two days left to intensify under what appear to be
conducive environmental conditions.  After a couple days, the SSTs
cool and the low-level moisture decreases, but still at levels that
could support intensification.  By days four and five, however, the
vertical shear should reach at least 20 kt due to an upper-level
trough approaching Ivette.  Gradual to steady intensification is
thus expected to about 36-48 hours with gradual to steady weakening
thereafter.  The NHC intensity forecast is closest to a blend of the
SHIPS statistical technique and the COAMPS regional dynamical model
and is slightly less than that predicted in the previous advisory.
Given the poor intensity forecasts thus far, this prediction has a
large uncertainty.

Ivette is moving toward the west at 12 kt, primarily being steered
by the deep-layer subtropical ridge extending westward out of
Mexico.  The tropical cyclone should begin bending toward the
west-northwest in a couple days as it attempts to round the western
periphery of the ridge.  By day four or five, Ivette should turn
back toward the west as the decaying system is advected in the
low-level tradewind flow.  All of the reliable models are in close
agreement and the NHC track forecast - based upon the TVCN track
consensus - is nearly unchanged.

FORECAST POSITIONS AND MAX WINDS

INIT  05/0300Z 14.8N 128.7W   45 KT  50 MPH
 12H  05/1200Z 14.9N 130.3W   50 KT  60 MPH
 24H  06/0000Z 15.3N 132.2W   55 KT  65 MPH
 36H  06/1200Z 15.9N 134.0W   60 KT  70 MPH
 48H  07/0000Z 16.6N 135.7W   60 KT  70 MPH
 72H  08/0000Z 18.0N 138.6W   50 KT  60 MPH
 96H  09/0000Z 18.7N 142.0W   40 KT  45 MPH
120H  10/0000Z 19.0N 146.0W   30 KT  35 MPH

$$
Forecaster Landsea

NNNN