[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 212034
TCDAT2

TROPICAL DEPRESSION TWO DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL022014
500 PM AST MON JUL 21 2014

The area of low pressure in the tropical Atlantic has shown an
increase in convective organization today. Despite the fact that the
convection remains somewhat shallow, it has enough coverage and
organization to classify the system as a tropical cyclone. An ASCAT
pass around 1210 UTC was not conclusive in regards to whether the
surface circulation was closed, but given the persistence of the
convection, we are assuming that the circulation is closed and
are initiating advisories at this time.

The initial intensity of 30 kt is based on data from the ASCAT pass.
The environment is marginal, at best, for development during the
next couple of days, as the depression will be moving over marginal
SSTs and into a region characterized by dry air and subsidence as it
approaches the Caribbean Sea. Most of the global model guidance and
the HWRF shows the system weakening and dissipating by 48 to 72
hours. The official forecast follows suit, but the cyclone could
dissipate sooner than shown here. The SHIPS and LGEM intensity
forecasts seem much too high in this scenario, and are not given
much weight in the official forecast.

The initial motion is quickly toward the west or 280/14 knots. The
cyclone will be steered by the Atlantic subtropical ridge during its
life span, and should remain on a westward to west-northwestward
heading with an increase in forward speed. The NHC track forecast is
close to a blend of the HWRF and the GEFS ensemble mean. Note that
the global models are having a difficult time tracking the small
vortex, and confidence in the details of the track forecast is lower
than usual.

FORECAST POSITIONS AND MAX WINDS

INIT  21/2100Z 11.6N  43.8W   30 KT  35 MPH
 12H  22/0600Z 11.9N  45.8W   30 KT  35 MPH
 24H  22/1800Z 12.3N  48.2W   30 KT  35 MPH
 36H  23/0600Z 12.8N  51.0W   30 KT  35 MPH
 48H  23/1800Z 13.4N  54.2W   30 KT  35 MPH
 72H  24/1800Z 15.0N  61.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  25/1800Z...DISSIPATED

$$
Forecaster Brennan


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