[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT43 KNHC 201436
TCDAT3

Potential Tropical Cyclone Three Discussion Number   4
NWS National Hurricane Center Miami FL       AL032017
1000 AM CDT Tue Jun 20 2017

Visible satellite imagery and surface observations indicate that the
circulation of the low has become better organized since yesterday,
but still lacks a well-defined center. The central pressure appears
to have fallen to around 999 mb based on observations from NOAA buoy
42001, and some deep convection has begun developing a little closer
to the low's circulation center. For now the system is being
maintained as a potential tropical cyclone, however, the system
could be classified as a tropical or subtropical cyclone later
today.

The current intensity is maintained at 35 kt based largely on
continuity pending an Air Force Reserve Hurricane Hunter mission
into the system later this morning. Only limited strengthening is
forecast before the system moves inland due to the strong vertical
shear over the cyclone caused by an upper-level low centered off
the Texas coast. The new NHC intensity forecast is similar to the
previous one and is close to the intensity consensus aid.

The initial motion estimate is a somewhat uncertain 320/09 as the
there are still multiple low-level cloud swirls circulating around a
mean center, and some erratic motion is still possible until a
better-defined center forms. However, the system should be steered
generally northwestward over the next 36 hours or so as it interacts
with the aforementioned upper-level low and then turns more
north-northwestward by 48 hours as the system begins to recurve
around the mid-level ridge to the east. The NHC track forecast is a
little faster than the previous one in the short range, and shows
the system moving inland over western Louisiana and eastern Texas by
48 hours. After that time, the system should recurve into the
mid-latitude flow and accelerate northward and northeastward across
the lower Mississippi Valley and into the southern and central
Appalachians on days 3 and 4 before dissipating.

The primary hazard from this disturbance is expected to be heavy
rainfall over portions of the central and eastern Gulf Coast.
Given the nature of the circulation and the fact that wind and rain
hazards extend well north and east of the center, users are
encouraged not to focus on the details of the track forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  20/1500Z 25.9N  90.5W   35 KT  40 MPH...POTENTIAL TROP CYCLONE
 12H  21/0000Z 26.7N  91.6W   40 KT  45 MPH...TROPICAL CYCLONE
 24H  21/1200Z 27.4N  92.6W   40 KT  45 MPH
 36H  22/0000Z 28.6N  93.6W   40 KT  45 MPH
 48H  22/1200Z 30.1N  94.0W   35 KT  40 MPH...INLAND
 72H  23/1200Z 34.0N  92.5W   25 KT  30 MPH...INLAND
 96H  24/1200Z 37.5N  84.0W   20 KT  25 MPH...POST-TROP/INLAND
120H  25/1200Z...DISSIPATED

$$
Forecaster Brennan
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