Hurricane Oscar Discussion Number 14
NWS National Hurricane Center Miami FL AL162018
500 AM AST Tue Oct 30 2018

Oscar’s eye is less distinct on infrared satellite imagery than it
was several hours ago. Conventional and microwave imagery suggest
that the center is tilted a bit to the northeast with height, and
there continues to be some erosion of convection over the
southwestern quadrant of the hurricane. This is indicative of some
southwesterly shear over the system, and Oscar does not appear
likely to strengthen further. The current intensity is held at 90
kt based on a blend of Dvorak Current Intensity numbers from TAFB
and SAB. Model guidance indicates that the shear will not increase
further until tonight, so the intensity is held steady for the next
12 hours. After that time, south-southwesterly shear if forecast to
increase and become quite high in 36-48 hours. Around that time,
global models show Oscar interacting with a frontal zone, and
causing significant warm and cold air advection around the center,
indicating the transition to a vigorous extratropical cyclone.
Not surprisingly, the global guidance also shows a substantial
increase in the size of the system during and after the
extratropical transformation, and this is reflected in the NHC wind
radii forecasts.

Oscar is beginning to move faster, just to the east of due north, or
around 010/11 kt. There is little change to the track forecast
reasoning from the previous advisory. Over the next couple of days,
Oscar should continue to accelerate, toward the north-northeast,
in the flow on the southeast side of a mid-latitude trough that has
just moved off the United States east coast. Later in the period,
post-tropical Oscar should become more embedded within the trough
and in the mid-latitude westerlies, and move northeastward over the
northeastern Atlantic. The official track forecast is similar to
the previous one and is a blend of the simple and corrected
dynamical model consensus predictions.

Large swells from Oscar will affect Bermuda 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 30/0900Z 28.6N 58.2W 90 KT 105 MPH
12H 30/1800Z 30.6N 57.1W 90 KT 105 MPH
24H 31/0600Z 34.0N 54.3W 85 KT 100 MPH
36H 31/1800Z 38.5N 50.5W 80 KT 90 MPH
48H 01/0600Z 43.5N 46.7W 65 KT 75 MPH…POST-TROP/EXTRATROP
72H 02/0600Z 50.5N 35.5W 55 KT 65 MPH…POST-TROP/EXTRATROP
96H 03/0600Z 57.5N 21.5W 50 KT 60 MPH…POST-TROP/EXTRATROP
120H 04/0600Z 63.0N 9.0W 45 KT 50 MPH…POST-TROP/EXTRATROP

$$
Forecaster Pasch

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Tue Oct 30 2018

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

1. Showers and thunderstorms associated with a weak area of low
pressure located about 800 miles south-southwest of the southern tip
of the Baja California peninsula remain disorganized. Significant
development of this system is not expected while it moves westward
or west-northwestward at about 10 mph.
* Formation chance through 48 hours…low…10 percent.
* Formation chance through 5 days…low…10 percent.

2. An elongated area of low pressure located about 1200 miles southwest
of the southern tip of the Baja California peninsula is producing
disorganized showers and thunderstorms. Some slow development of
this system is possible over the next few days while the disturbance
moves toward the west or west-northwest at 5 to 10 mph.
* Formation chance through 48 hours…low…30 percent.
* Formation chance through 5 days…medium…40 percent.

3. A third area of disturbed weather is located several hundred miles
south-southwest of Acapulco, Mexico. Environmental conditions
appear conducive for gradual development of this system through the
weekend while it moves west-northwestward at about 10 mph.
* Formation chance through 48 hours…low…near 0 percent.
* Formation chance through 5 days…low…20 percent.

Forecaster Berg

Global Tropics & Benefits Outlook

Weather in Cayman

SYNOPSIS