Tropical Storm VANCE

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TROPICAL STORM VANCE DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP212014
800 PM PDT SAT NOV 01 2014

Vance's convective organization has improved considerably since the
previous advisory with a central dense overcast feature having
developed during the past few hours. In addition, recent SSMI/S and
WindSat microwave satellite imagery indicate that a small precursor
eye feature with a diameter 10-12 nmi has developed. The initial
intensity has been increased to 45 kt based on consensus satellite
intensity estimates of T3.0/45 kt from TAFB, SAB, and UW-CIMSS ADT.

The initial motion estimate remains 290/11 kt. For the next 24 hours
or so, Vance is expected to move west-northwestward along the
southern periphery of a deep-layer ridge located to its north. After
that, a turn to the north is forecast as the cyclone moves around
the ridge and ahead of an approaching mid-tropospheric trough that
will be moving across Baja California in the 48-72 hour time frame.
By late in the forecast period, Vance is expected to weaken
rapidly, with the low- and upper-level circulations decoupling. The
remnant low is forecast to meander off of the southwestern coast
of Mexico and the southern tip of Baja California. The NHC forecast
track is similar to the previous advisory track, and lies close to
the multi-model consensus TVCE.

The mid-level moisture has apparently increased based on the recent
development of significant inner-core convection. With such low
vertical shear conditions and the aforementioned eye-like feature,
rapid intensification is a very distinct possibility during the
next 24-36 hours. The NHC official intensity forecast has been
increased above the previous advisory forecast through 48 hours,
which is above the intensity consensus model ICON and is about
midway between the GFDL and HWRF intensity forecasts. After that,
the intensity forecast is unchanged from the previous advisory due
to expected strong southwesterly vertical shear conditions of at
least 35-40 kt, which should result in rapid weakening of Vance and
degeneration into a remnant low on Days 4 and 5.

FORECAST POSITIONS AND MAX WINDS

INIT  02/0300Z 10.2N 105.4W   45 KT  50 MPH
 12H  02/1200Z 11.2N 107.4W   55 KT  65 MPH
 24H  03/0000Z 12.6N 109.6W   65 KT  75 MPH
 36H  03/1200Z 14.3N 110.8W   75 KT  85 MPH
 48H  04/0000Z 16.0N 110.9W   65 KT  75 MPH
 72H  05/0000Z 18.8N 109.5W   45 KT  50 MPH
 96H  06/0000Z 21.0N 108.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  07/0000Z 22.0N 108.1W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Stewart

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