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Hurricane Oscar Discussion Number  16
NWS National Hurricane Center Miami FL       AL162018
500 PM AST Tue Oct 30 2018

Recent microwave imagery indicates that Oscar continues to maintain
a small inner-core, however, it is tilted somewhat southwest to
northeast with height due to increasing southwesterly wind shear.
Cloud tops have continued to warm over the past few hours, and
objective and subjective intensity estimates have decreased since
this morning. The initial intensity has been lowered to 75 kt,
based primarily on a blend of Final-T and Current Intensity
estimates from TAFB and SAB.

The hurricane is moving over 24 deg C waters and a cold front
associated with a large mid-latitude trough is quickly approaching
from the west. This combination should soon kick off the
extratropical transition (ET) process, and the most recent runs of
the GFS, ECMWF, and UKMET indicate that Oscar will become fully
extratropical within 36 h, if not sooner. Very gradual weakening is
still expected during the next day or so while ET occurs, however,
all of the dynamical models forecast that Oscar will be at or very
near hurricane-strength when it becomes post-tropical. The maximum
winds of the cyclone will likely slowly decrease thereafter, but
Oscar will likely have a very large wind field and gale-force winds
are possible over a large portion of the far north Atlantic. By
day 5, the post-tropical low is forecast to merge with another
mid-latitude low pressure system over the far northeastern Atlantic.

As expected, the hurricane is accelerating north-northeastward, with
an initial motion estimate of 025/17 kt. Further acceleration is
likely over the next 36 hours, and the global models are in
remarkably good agreement on the track of the cyclone through that
time. A turn toward the northeast is expected thereafter, and
while there are still speed differences between the various global
model solutions, the NHC forecast remains near the fairly steady
multi-model consensus at all forecast hours. Almost no change was
made to the official track forecast, which is merely an update of
the previous advisory.

Although Oscar is forecast to move farther from Bermuda overnight,
large swells from the hurricane are expected to affect portions of
the island's coast through Wednesday. Please consult products from
your local weather office as these conditions could cause
life-threatening surf and rip currents.


FORECAST POSITIONS AND MAX WINDS

INIT  30/2100Z 31.3N  56.6W   75 KT  85 MPH
 12H  31/0600Z 33.8N  54.5W   70 KT  80 MPH
 24H  31/1800Z 38.3N  50.9W   65 KT  75 MPH
 36H  01/0600Z 43.0N  46.8W   65 KT  75 MPH...POST-TROP/EXTRATROP
 48H  01/1800Z 46.7N  42.0W   60 KT  70 MPH...POST-TROP/EXTRATROP
 72H  02/1800Z 54.0N  28.5W   55 KT  65 MPH...POST-TROP/EXTRATROP
 96H  03/1800Z 59.0N  15.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
120H  04/1800Z...DISSIPATED

$$
Forecaster Zelinsky

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