[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 161440
TCDAT1

TROPICAL STORM JULIA DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL112016
1100 AM EDT FRI SEP 16 2016

Julia continues to feel the impact of 25 to 35 kt of westerly
vertical wind shear, as the main deep convection remains about
40 to 60 n mi east of the low-level center.  Various subjective and
objective satellite intensity estimates are near 35 kt, and that
remains the initial intensity.  It is noted that buoy 41002 located
about 55 n mi northeast of the center is reporting winds of less
than 30 kt, so it is possible that initial intensity is a little
generous.

There is decreasing confidence in the intensity forecast.  While
Julia is expected to stay in a strong shear environment for the
next 60 hours or so, the dynamical models suggest that the
upper-level winds over the cyclone may be less than forecast
yesterday.  After 60 hours, all guidance suggests that the shear
should decrease, and at that time the Canadian and UKMET models show
re-intensification.  On the other hand, the GFS and ECMWF forecast
Julia to continue to weaken even in the more favorable upper-level
winds.  The new intensity forecast stays with the scenario of the
previous forecast in calling for the shear to cause the cyclone's
demise.  However, this forecast is on the low edge of the intensity
guidance, and the chances that Julia will survive and re-intensify
are higher than they were 24 hours ago.

Julia continues to move erratically east-southeastward with an
initial motion of 105/6.  The cyclone is expected to meander
for the next 2 days or so in weak steering flow.  In 3-4 days, a
mid- to upper-level trough moving into the northeastern United
States should steer the cyclone or its remnants northeastward.
There remains a considerable amount of uncertainty in the track
forecast due somewhat to the uncertainties in the intensity.
A weaker Julia should be slower to move northeastward as shown by
the GFS and ECMWF, while a stronger Julia will move somewhat more
quickly toward the northeast as shown by the Canadian.  Overall, the
new forecast track goes with the slower scenario and and is an
update of the previous track.


FORECAST POSITIONS AND MAX WINDS

INIT  16/1500Z 31.1N  75.6W   35 KT  40 MPH
 12H  17/0000Z 30.9N  75.4W   35 KT  40 MPH
 24H  17/1200Z 30.8N  75.5W   30 KT  35 MPH
 36H  18/0000Z 30.9N  75.9W   30 KT  35 MPH
 48H  18/1200Z 31.2N  76.1W   30 KT  35 MPH
 72H  19/1200Z 32.5N  76.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  20/1200Z 33.0N  74.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  21/1200Z...DISSIPATED

$$
Forecaster Beven
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