[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT42 KNHC 200242
TCDAT2

TROPICAL STORM KARL DISCUSSION NUMBER  23
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122016
1100 PM AST MON SEP 19 2016

Karl is a little better organized tonight.  An area of deep
convection has been persisting during the past several hours, and
microwave images indicate that the center is located near the
southwestern edge of the convective area.  The initial wind speed
is nudged upward to 40 kt, following a blend of the latest Dvorak
classifications from TAFB and SAB.

Karl is moving west-northwestward at 11 kt, and it is being steered
by the flow on the south side of a high pressure system over the
subtropical Atlantic.  The tropical cyclone is expected to move near
the southwestern periphery of the high in a couple of days and then
head toward a pronounced weakness in the ridge over the western
Atlantic. This change in the steering pattern should result in Karl
turning northwestward in about 48 hours, with a gradual turn to the
north and northeast expected in 4 to 5 days.  Although the models
agree on the overall theme, there is a fair amount of spread in the
guidance associated with where and when Karl begins to recurve. The
NHC official track forecast is near the middle of the guidance
envelope, and is in best agreement with the various consensus aids.

The vertical wind shear that has been affecting Karl for the past
several days appears to be letting up some, and the SHIPS model
suggests that shear should be generally light during the next 5
days. In addition, Karl is currently over SSTs of around 28 deg C,
and it is expected to move over even warmer waters throughout the
forecast period.  The one unfavorable parameter for intensification
is the dry mid-level environment surrounding the tropical storm,
but some of the guidance suggests that the air mass could moisten
ahead of the system later this week. Based on these large scale
conditions, slow strengthening seems likely during the next day or
so, followed by a faster rate of intensification thereafter.  The
NHC intensity forecast is higher than the previous one, but is on
the conservative side of the guidance at the longer range forecast
points.

FORECAST POSITIONS AND MAX WINDS

INIT  20/0300Z 19.7N  50.5W   40 KT  45 MPH
 12H  20/1200Z 20.4N  52.4W   45 KT  50 MPH
 24H  21/0000Z 21.3N  54.9W   45 KT  50 MPH
 36H  21/1200Z 22.4N  57.3W   50 KT  60 MPH
 48H  22/0000Z 23.9N  59.7W   55 KT  65 MPH
 72H  23/0000Z 26.7N  63.5W   70 KT  80 MPH
 96H  24/0000Z 29.5N  64.5W   85 KT 100 MPH
120H  25/0000Z 32.3N  60.3W   95 KT 110 MPH

$$
Forecaster Cangialosi
This weather bulletin was brought to you by:
www.nashvilleweather.net