Tropical Report

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Sun Oct 15 2017

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Hurricane
Ophelia, located over the far eastern Atlantic Ocean more than 500
miles east of the easternmost Azores.

1. The broad area of low pressure NHC has been tracking for a few days
is now centered a little more than 100 miles north of Puerto Rico.
The low is producing numerous showers and a few squalls mainly to
the east of the center. Further development of this system, if any,
will likely ocurr while the low and its associated activity move
toward the northwest and north during the next two to three days.
After that time, this system is expected to merge with a cold
front.
* Formation chance through 48 hours…low…30 percent.
* Formation chance through 5 days…medium…50 percent.

Forecaster Avila

OPHELIA NOW TAKING AIM ON IRELAND… …EXPECTED TO BECOME A POWERFUL POST-TROPICAL CYCLONE BY TONIGHT

Hurricane Ophelia Discussion Number 25
NWS National Hurricane Center Miami FL AL172017
500 AM AST Sun Oct 15 2017

Although the satellite appearance of Ophelia has been slowly
degrading this morning, the cyclone remains an impressive hurricane
due to it being over the relatively cool waters of the northeastern
Atlantic. A testament to Ophelia’s strength is a late arriving buoy
report 25 nmi southeast of the center of the eye from around 0200Z,
which indicated that the pressure in the southeastern portion of the
large eye or eyewall was 970.9 mb. However, Dvorak intensity
estimates have been steadily decreasing since that buoy report, so
the intensity has been lowered to 90 kt for this advisory.

Ophelia continues to accelerate and the hurricane is now moving
050/30 kt. Water vapor imagery indicates that a deepening trough
just to west of Ophelia is moving quickly eastward, and that the
cyclone is now well embedded within the deep-layer southwesterly
flow on the east side of the trough. As a result, Ophelia is
expected to turn toward the north-northeast by tonight and be
accompanied by a slight increase in forward speed. The NHC model
guidance remains in excellent agreement on Ophelia reaching the
southern coast of Ireland in 24-30 hours, and then move across
the remainder of the country Monday night, and then move across
Northern Ireland and northern Great Britain on Tuesday.

Ophelia is forecast to become a post-tropical cyclone by 24 hours
when extratropical transition should be completed, although the
transition to an extratropical cyclone could occur as early as 12
hours. Regardless of the exact timing, post-tropical cyclone Ophelia
is forecast to remain a powerful storm with hurricane-force winds
when it reaches Ireland on Monday. The system is forecast to
occlude and interact with land, which should cause a faster rate of
weakening in 48 to 72 hours, with dissipation expected shortly
thereafter.

Although the center of Ophelia is not forecast to reach Ireland or
the UK until Monday, strong winds and rains will arrive well in
advance of the cyclone center. Residents in those locations should
consult products from their local meteorological service for more
information on local impacts.

KEY MESSAGES:

1. Ophelia is expected to be a powerful extratropical cyclone with
hurricane force winds Monday while it moves near Ireland and the
United Kingdom. Direct impacts from wind and heavy rain in portions
of these areas are likely, along with dangerous marine conditions.
For more details on the magnitude, timing, and location of impacts
from post-tropical Ophelia, residents in Ireland should refer to
products issued by Met Eireann, and residents in the United Kingdom
should refer to products issued by the Met Office.

FORECAST POSITIONS AND MAX WINDS

INIT 15/0900Z 39.0N 18.3W 90 KT 105 MPH
12H 15/1800Z 43.0N 15.1W 85 KT 100 MPH
24H 16/0600Z 49.0N 11.5W 80 KT 90 MPH…POST-TROP/EXTRATROP
36H 16/1800Z 54.0N 8.6W 60 KT 70 MPH…POST-TROP/EXTRATROP
48H 17/0600Z 57.7N 4.0W 50 KT 60 MPH…POST-TROP/EXTRATROP
72H 18/0600Z 60.8N .1W 35 KT 40 MPH…POST-TROP/EXTRATROP
96H 19/0600Z…DISSIPATED

$$
Forecaster Stewart

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Sun Oct 15 2017

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

1. A low pressure system located several hundred miles southwest of the
southern tip of the Baja California peninsula continues to produce
widespread showers and thunderstorms. Environmental conditions
appear conducive for a tropical depression to form during the next
day or so while the system moves west-northwestward to northwestward
at 10 to 15 mph. After that time, cold SSTs and strong upper-level
winds are likely to prevent further development.
* Formation chance through 48 hours…high…80 percent.
* Formation chance through 5 days…high…80 percent.

Forecaster Zelinsky