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SUBTROPICAL DEPRESSION SEVEN DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072014
1100 AM AST FRI OCT 10 2014

Satellite images indicate that the area of low pressure located
several hundred miles north of the northern Leeward Islands has
developed a large area of deep convection in a long curved band
north and west of the center. First-light visible satellite imagery
also indicates that the low-level center of the low has become
better defined since yesterday.  Satellite classifications are a
subtropical 1.5 from TAFB and SAB at 1200 UTC, and the system's
involvement with a nearby upper-level low and roughly 100 n mi
radius of maximum winds also argue for a subtropical designation. An
Air Force Hurricane Hunter aircraft will investigate the depression
this afternoon to better assess its intensity and structure.

The protective cover of the nearby upper low will provide a
relatively low vertical wind shear environment in the short
term, with the cyclone over warm sea surface temperatures of 28-
29 deg C.  The model guidance indicates that the depression should
become embedded in increasing southerly vertical shear east of the
same upper-level trough after 24 hours, so the system has a
short window for intensification or transformation into a tropical
cyclone.  Global models depict the cyclone becoming absorbed by a
frontal zone over the north-central Atlantic before 72 hours.  The
NHC intensity forecast is close to the statistical-dynamical
guidance.

The depression is moving northwestward or 320/09 around the
southwestern perhiphery of a mid-level ridge over the central
Atlantic.  The deep-layer steering flow around this feature should
cause the cyclone to turn northward within 24 hours, after which it
will turn northeastward in increasing southwesterly flow at the base
of a longwave trough prior to absorption by the front. The NHC track
forecast is very close to the multi-model consensus, TVCA, through-
out the period and between the ECMWF and GFS model solutions.

The Bermuda Weather Service has issued a tropical storm watch for
Bermuda.


FORECAST POSITIONS AND MAX WINDS

INIT  10/1500Z 23.8N  63.7W   30 KT  35 MPH
 12H  11/0000Z 25.1N  64.6W   35 KT  40 MPH
 24H  11/1200Z 26.8N  65.1W   40 KT  45 MPH
 36H  12/0000Z 29.4N  64.7W   40 KT  45 MPH
 48H  12/1200Z 31.5N  62.9W   40 KT  45 MPH
 72H  13/1200Z...DISSIPATED

$$
Forecaster Kimberlain

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