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Tropical Storm DANNY


1100 AM AST WED AUG 19 2015

While there has not been much overall change to Danny's curved-band
cloud pattern, there is evidence in satellite imagery of
increased inner-core structural organization since yesterday.  Cloud
top temperatures, however, have warmed in recent hours. The initial
intensity is held at 45 kt in agreement with the latest CI number
from TAFB.

There is nothing obvious that would impede gradual intensification
during the next few days, except for the possible entrainment of
dry air associated with a Saharan Air Layer following the cyclone
to the north.  Around the time Danny approaches the Lesser Antilles
in 3 to 5 days, global models have divergent solutions regarding the
strength and position of the mid-oceanic trough, which will
ultimately affect Danny's intensity.  The ECMWF shows upper-level
westerlies and even drier air associated with this feature holding
sway over the Caribbean region, while the GFS shows a relaxation
of the shear.  The statistical guidance, strongly dependent on the
GFS forecast fields, continues to indicate a higher intensity, yet
the dynamical models suggest less overall intensification and even
weakening late in the forecast period. The GFS-based guidance seems
less likely relative to the other model solutions, especially given
the strength and persistence of the mid-oceanic trough thus far this
season.  The intensity forecast is therefore reduced throughout
the forecast period but especially at later times and is close to or
just above the multi-model consensus ICON.

Recent fixes indicate that Danny's forward speed has decreased
slightly, and the initial motion estimate is 275/10.  An enhanced
mid-oceanic trough, extending from the northeastern Atlantic to the
Caribbean Sea, is forecast to keep the subtropical ridge to the
north of Danny somewhat weak over the next few days.  This should
result in Danny's continued movement toward the west or west-
northwest across the tropical Atlantic, albeit at a less than
climatological rate of speed.  Later in the forecast period, large-
scale models are in agreement that there should be some re-
strengthening of the subtropical ridge, which would result in
Danny's moving at a slightly faster forward speed.  The cyclone's
heading late in the forecast period should largely be a function of
the depth of the system. A weaker Danny would move westward faster,
as is the case in the ECMWF solution.  A stronger system, like the
one that the GFS shows, would tend to gain more latitude.  The
track forecast is adjusted southward this forecast cycle, based on
an initial re-positioning of the cyclone and with the expectation
that Danny could be somewhat weaker later in the forecast period.


INIT  19/1500Z 11.2N  41.1W   45 KT  50 MPH
 12H  20/0000Z 11.4N  42.6W   50 KT  60 MPH
 24H  20/1200Z 11.9N  44.2W   55 KT  65 MPH
 36H  21/0000Z 12.4N  45.8W   60 KT  70 MPH
 48H  21/1200Z 13.1N  47.5W   70 KT  80 MPH
 72H  22/1200Z 14.4N  51.5W   80 KT  90 MPH
 96H  23/1200Z 15.6N  56.2W   75 KT  85 MPH
120H  24/1200Z 16.6N  61.5W   70 KT  80 MPH

Forecaster Kimberlain