[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT41 KNHC 021453
TCDAT1

HURRICANE JOAQUIN DISCUSSION NUMBER  19
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL112015
1100 AM EDT FRI OCT 02 2015

An Air Force Reserve Hurricane Hunter aircraft has reported 700-mb
flight-level winds of 124 kt in the southeastern eyewall, along
with an eyewall dropsonde that supports surface winds of 110-115
kt.  Based on these data, the intensity remains 115 kt.  The latest
central pressure indicated by the aircraft data is 939 mb.  While
the hurricane continues to produce cloud tops of -80C in the
eyewall, the eye is ragged and poorly defined in satellite imagery.

Joaquin has turned northward during the past few hours and the
initial motion is now 360/3.  Water vapor imagery shows a mid- to
upper-level ridge to the north and northeast of the hurricane,
while a deep-layer trough and associated surface front are located
over the southeastern United States.  This system is forecast to
move slowly eastward with a non-tropical low forming along the
front during the next couple of days.  These developments should
steer Joaquin northward to northeastward during the next 12 hours
or so, followed by a faster motion toward the northeast.  The GFS,
UKMET, and ECMWF are now in better agreement that Joaquin will move
generally northeastward through 48 hours, followed by a more
northward turn between 48 and 72 hours.  This is then followed
by movement into the westerlies and acceleration toward the east-
northeast after 72 hours.  The new forecast track is adjusted to
the east of the previous track after 24 hours, and it lies between
the previous track and the model consensus.  Some additional
eastward adjustments to the track may occur on the next advisory
based on the 1200 UTC model runs.

Joaquin is forecast to remain in an environment of light vertical
wind shear for another 24 hours or so, and during this time some
fluctuations in intensity are possible due to eyewall replacement
cycles.  After 24 hours, the shear is forecast to increase, which
should start a steady weakening.  Extratropical transition is
expected to begin after 96 hours, but the dynamical models suggest
it may not be complete before 120 hours.  Overall, the new
intensity forecast is an update of the previous advisory and lies
near the upper edge of the intensity guidance.


KEY MESSAGES:

1.  Hurricane conditions over portions of the Bahamas are likely to
continue into this evening.

2.  Swells from a hurricane moving even far offshore of the U.S.
east coast can still cause life-threatening surf and rip-current
conditions.  Please see products from your local National Weather
Service forecast office.  For information on the heavy rains
occurring along the U.S. Atlantic states that are mostly unrelated
to Hurricane Joaquin, please see products from the NWS Weather
Prediction Center and your local forecast office.

3. A Tropical Storm or Hurricane Watch could be required for
Bermuda this afternoon.




FORECAST POSITIONS AND MAX WINDS

INIT  02/1500Z 23.5N  74.8W  115 KT 130 MPH
 12H  03/0000Z 24.4N  74.4W  115 KT 130 MPH
 24H  03/1200Z 26.1N  73.0W  115 KT 130 MPH
 36H  04/0000Z 28.2N  71.2W  105 KT 120 MPH
 48H  04/1200Z 30.6N  69.6W   95 KT 110 MPH
 72H  05/1200Z 35.5N  67.5W   80 KT  90 MPH
 96H  06/1200Z 39.5N  63.0W   65 KT  75 MPH
120H  07/1200Z 43.5N  49.0W   55 KT  65 MPH

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