Hurricane Oscar Discussion Number 18
NWS National Hurricane Center Miami FL AL162018
500 AM AST Wed Oct 31 2018

Oscar continues to become less tropical-looking in appearance.
Central convection is now minimal, and the overall cloud pattern is
quite asymmetric, with the main area of dense overcast over the
western portion of the circulation, stretching northward over an
approaching frontal boundary. The current intensity estimate is 65
kt in accord with the latest Dvorak Current Intensity numbers from
TAFB and SAB. Oscar is expected to merge with the nearby front in
12-18 hours, by which time the global models depict considerable
cold and warm advection around the center. This indicates that
Oscar will become an extratropical cyclone tonight, but energy from
baroclinic processes will likely maintain the system near hurricane
strength for the next couple of days. Only gradual weakening is
expected thereafter and post-tropical Oscar will likely be a strong
cyclone for the next 4 days or so. Post-tropical Oscar is forecast
to merge with another extratropical cyclone at high latitudes over
the weekend. The official intensity forecast is close to the
latest GFS prediction, which should be appropriate for a
mid-latitude system.

Oscar is moving quickly toward the northeast, or 035/19 kt. The
hurricane is being steered by the flow on the eastern side of a
trough that is passing through Atlantic Canada. In a day or so,
post-tropical Oscar should become embedded within the trough and
move rapidly northeastward in the mid-latitude westerlies over the
north-central and northeastern Atlantic. The track guidance is in
fairly good agreement, aside from some speed differences in the
latter part of the forecast period. The official forecast is close
to the latest dynamical model consensus, and is similar to the
previous NHC track.

Large swells from Oscar are expected to continue to affect portions
of the coast of Bermuda through today. 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 31/0900Z 34.1N 53.6W 65 KT 75 MPH
12H 31/1800Z 37.6N 50.9W 65 KT 75 MPH
24H 01/0600Z 42.2N 47.1W 65 KT 75 MPH…POST-TROP/EXTRATROP
36H 01/1800Z 46.0N 42.2W 65 KT 75 MPH…POST-TROP/EXTRATROP
48H 02/0600Z 49.7N 36.4W 60 KT 70 MPH…POST-TROP/EXTRATROP
72H 03/0600Z 56.0N 23.0W 60 KT 70 MPH…POST-TROP/EXTRATROP
96H 04/0600Z 61.5N 10.5W 50 KT 60 MPH…POST-TROP/EXTRATROP
120H 05/0600Z…MERGED WITH LARGER EXTRATROPICAL LOW

$$
Forecaster Pasch

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Wed Oct 31 2018

For the eastern North Pacific…east of 140 degrees west longitude:

1. Showers and thunderstorms associated with a broad area of low
pressure located about 1400 miles southwest of the southern tip of
the Baja California peninsula remain disorganized. Upper-level
winds are expected to be only marginally conducive for some slow
development of this system over the next couple of days while it
moves toward the west or west-northwest at 5 to 10 mph.
* Formation chance through 48 hours…low…20 percent.
* Formation chance through 5 days…low…20 percent.

2. A large area of disturbed weather is located several hundred
miles south and southwest of the southwestern coast of Mexico.
Environmental conditions are forecast to be conducive for gradual
development of this system during the next several days, and a
tropical depression could form later this week or this weekend while
it moves west-northwestward to northwestward at 5 to 10 mph.
* Formation chance through 48 hours…low…20 percent.
* Formation chance through 5 days…medium…60 percent.

Forecaster Berg

Global Tropics & Benefits Outlook

Weather in Cayman

SYNOPSIS