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Tropical Storm Karen Discussion Number  17
NWS National Hurricane Center Miami FL       AL122019
500 AM AST Thu Sep 26 2019

Karen is barely a tropical storm.  A pair of ASCAT passes from
several hours ago showed maximum winds between 30 and 35 kt in the
southeastern quadrant of the storm.  Those passes also indicate
that the circulation is quite broad and weak on the west side.
Based on the ASCAT data and the TAFB Dvorak classification, the
initial wind speed is held at 35 kt.  The storm appears quite
disheveled in satellite images, with an elongated east to west
convective pattern and a lack of well-defined banding features.

Karen has not been able to take advantage of the relatively
favorable environment that it has been in during the past day or
so, which was well anticipated by the dynamical models, but
poorly forecast by the statistical-dynamical aids.  The storm will
remain in generally favorable conditions through tonight, so it
should be able to maintain its intensity or perhaps strengthen
slightly during that time.  After that, however, the models show a
steady increase in shear and drier air in the vicinity of the
cyclone.  These conditions should cause weakening and will likely
lead to the system either losing its deep convection and becoming a
remnant low or dissipating entirely in 3 or 4 days when it moves
into a region of strong westerly shear.  The NHC intensity forecast
is the same as the previous one and leans more on the GFS and ECMWF
guidance.

The tropical storm is still moving north-northeastward at 13 kt
steered by the flow between a mid-level ridge to its east and a mid-
to upper-level low to its west over the Bahamas.  The low is
expected to weaken and lift out during the next few days allowing a
low- to mid-level ridge to strengthen and build to the north of
Karen.  This change in the steering flow should cause Karen, or its
remnants, to move slower to the northeast and east through Friday,
followed by a motion to the west-southwest this weekend.  Only minor
changes were made to the previous NHC track forecast, and this one
lies closest to the HCCA model.


FORECAST POSITIONS AND MAX WINDS

INIT  26/0900Z 25.5N  63.5W   35 KT  40 MPH
 12H  26/1800Z 27.0N  62.9W   35 KT  40 MPH
 24H  27/0600Z 27.9N  61.5W   35 KT  40 MPH
 36H  27/1800Z 28.0N  60.3W   35 KT  40 MPH
 48H  28/0600Z 27.9N  60.1W   35 KT  40 MPH
 72H  29/0600Z 27.3N  62.5W   30 KT  35 MPH
 96H  30/0600Z 27.0N  65.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  01/0600Z 26.8N  67.4W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Cangialosi

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