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TROPICAL STORM IVETTE DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP102016
800 AM PDT THU AUG 04 2016

After Ivette produced very little convection near its low-level
center last evening, a large burst of thunderstorms developed around
0700 UTC, and the cirrus canopy has continued to expand since then.
However, there is no data to support that this convection has led to
any intensification yet, and the maximum winds remain 40 kt based on
Dvorak CI numbers of 3.0/45 kt and 2.5/35 kt from TAFB and SAB,
respectively.

Vertical shear appears to have decreased below 10 kt, which may be
fostering the recent increase in convection.  With sea surface
temperatures remaining between 27-28C and shear expected to be low
during the next three days or so, intensification is still
anticipated.  But because Ivette has failed to strengthen during the
past 24 hours, the peak winds shown by the intensity models continue
to decrease, and none of the guidance makes the cyclone a hurricane.
For now, the NHC official forecast continues to show Ivette reaching
hurricane intensity in 2-3 days, but this forecast may need to be
adjusted if Ivette does not start strengthening soon.  A significant
increase in shear and marginal SSTs should lead to fairly quick
weakening on days 4 and 5.

Ivette is moving westward, or 280/13 kt.  A strong subtropical high
located north of the cyclone is expected to steer Ivette westward
for the next 36 hours.  After that time, a break in the ridge
northeast of Hawaii should cause the storm to slow down and move
west-northwestward through the end of the forecast period.  Again
there have been no significant changes in the track guidance, and
the updated NHC track forecast remains very close to the TVCN
multi-model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 15.1N 126.2W   40 KT  45 MPH
 12H  05/0000Z 15.2N 128.2W   45 KT  50 MPH
 24H  05/1200Z 15.4N 130.4W   50 KT  60 MPH
 36H  06/0000Z 15.7N 132.4W   55 KT  65 MPH
 48H  06/1200Z 16.3N 134.1W   65 KT  75 MPH
 72H  07/1200Z 17.5N 137.4W   65 KT  75 MPH
 96H  08/1200Z 18.5N 140.5W   50 KT  60 MPH
120H  09/1200Z 19.5N 143.5W   35 KT  40 MPH

$$
Forecaster Berg

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