000
WTNT42 KNHC 240251
TCDAT2

Tropical Depression Karen Discussion Number   8
NWS National Hurricane Center Miami FL       AL122019
1100 PM AST Mon Sep 23 2019

Deep convection associated with Karen has increased during the past
few hours, but the thunderstorm activity remains confined to the
south of the center due to north-northeasterly shear.  The Air Force
Hurricane Hunters have been investigating the depression this
evening, and a combination of the flight-level and SFMR data
indicate that winds are just below tropical-storm-force.  The
aircraft measured a minimum pressure of about 1008 mb.

Karen is currently situated near the western periphery of a
subtropical ridge, and it is forecast to turn northward on Tuesday
as it passes Puerto Rico and the Virgin Islands.  After that time,
a northward to north-northeastward motion seems likely as the
cyclone moves into a weakness left behind by Tropical Storm Jerry.
However, the models indicate that the trough will not capture Karen,
and instead the cyclone could come to a stop or drift westward by
the weekend as a ridge builds to the north of the system.  Although
the models agree on the overall scenario, the details are quite
uncertain and there remains a large spread in the guidance at days 4
and 5.  The new NHC track forecast is adjusted a little to the right
of the previous one to be in better agreement with the latest
consensus models.

The environment is still quite hostile around Karen with
north-northeasterly shear of about 20 kt currently impacting
the cyclone.  However, the upper-level wind pattern is expected to
become more favorable during the next few days, and that could give
it an opportunity to strengthen. The NHC intensity forecast shows a
slow increase in winds through the forecast period. This forecast is
similar to the previous one, and lies roughly between the
aggressive SHIPS/LGEM models and the HWRF/HMON models which show
little change in intensity during the next several days.

Key Messages:

1.  Regardless of Karen's status and intensity, the system is
expected to bring heavy rainfall, flash floods and mudslides to
Puerto Rico and the U.S. and British Virgin Islands on Tuesday,
where a tropical storm warning is in effect.  The rainfall and
potential flooding will likely continue on Wednesday even as the
center of Karen moves away from Puerto Rico and the Virgin Islands.


FORECAST POSITIONS AND MAX WINDS

INIT  24/0300Z 16.1N  65.8W   30 KT  35 MPH
 12H  24/1200Z 17.5N  66.2W   35 KT  40 MPH
 24H  25/0000Z 19.6N  66.2W   35 KT  40 MPH
 36H  25/1200Z 22.0N  65.8W   35 KT  40 MPH
 48H  26/0000Z 23.9N  65.2W   40 KT  45 MPH
 72H  27/0000Z 26.8N  64.1W   45 KT  50 MPH
 96H  28/0000Z 28.0N  64.0W   50 KT  60 MPH
120H  29/0000Z 28.0N  66.5W   55 KT  65 MPH

$$
Forecaster Cangialosi