ZCZC MIATCDEP5 ALL
TTAA00 KNHC DDHHMM

TROPICAL STORM IVETTE DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP102016
200 AM PDT THU AUG 04 2016

Shear and the entrainment of dry mid-level air appear to have
taken a toll on Ivette, as the thunderstorm activity has decreased
in coverage and organization during the past 12 hours or so.  Recent
microwave and geostationary satellite pictures show very little
banding features and a significant displacement of the convection to
the south and southwest of the low-level center.  Despite the
decrease in organization, overnight ASCAT data showed 35 to 40 kt
winds over the northern semicircle of the tropical cyclone.
Therefore, the initial wind speed remains 40 kt for this advisory.

A UW/CIMMS shear analysis and the SHIPS model suggest that the
shear may be beginning to decrease, however the current lack of
organization and nearby dry air is likely to prevent significant
intensification today.  However, strengthening is still
anticipated by tonight or Friday when Ivette is forecast to
be over warm water and in a low shear environment.  After day 3,
cooler waters and increasing southwesterly shear should begin the
weakening process.  The new NHC intensity forecast is slightly
lower than the previous advisory, but remains above the statistical
guidance, and it is closer to the HWRF that still brings Ivette
to hurricane intensity in a couple of days.

Ivette continues to move just north of due west at about 13 kt. The
tropical storm should continue moving westward during the next 36
hours as it remains to the south of a strong subtropical ridge.
After that time, the western portion of the ridge is forecast to
weaken when a trough deepens to the north of the Hawaiian Islands.
This should cause Ivette to turn west-northwestward and slow down.
There is very good agreement among the track guidance this morning
and higher than normal confidence in the track forecast.  The new
NHC track forecast is near the multi-model consensus and is
essentially an update of the previous advisory.


FORECAST POSITIONS AND MAX WINDS

INIT  04/0900Z 14.7N 124.7W   40 KT  45 MPH
 12H  04/1800Z 14.8N 126.7W   40 KT  45 MPH
 24H  05/0600Z 14.9N 129.2W   45 KT  50 MPH
 36H  05/1800Z 15.2N 131.3W   55 KT  65 MPH
 48H  06/0600Z 15.8N 133.2W   65 KT  75 MPH
 72H  07/0600Z 16.9N 136.7W   70 KT  80 MPH
 96H  08/0600Z 18.3N 140.0W   55 KT  65 MPH
120H  09/0600Z 19.3N 143.0W   40 KT  45 MPH

$$
Forecaster Brown

NNNN