HURRICANE OMAR

Hurricane Omar Discussion Number 8

Statement as of 5:00 am EDT on October 15, 2008





An Air Force hurricane hunter aircraft reports that there has been
no appreciable strengthening of Omar over the past few hours. An
elliptical and partially open eye was observed but the inner core
is not yet well-defined. The central pressure has not fallen and
maximum SFMR-observed surface wind speeds have been near 65
kt...which is used for the advisory intensity. Satellite images
show that Omar continues to generate very deep convection with a
large area of cloud tops colder than -80 deg c. Upper-level
outflow is well-established over the eastern semicircle and
restricted to the west...as westerly shear continues to impact the
hurricane. However...the shear is not expected to be strong enough
to prevent strengthening. The official intensity forecast is the
same as the previous one and a little above the model consensus.
By day 5...global models depict the cyclone interacting with a
strong baroclinic zone over the North Atlantic so the official
forecast shows Omar becoming extratropical by that time.

Initial motion is around 050/6. There has not been much change to
the official forecast track or reasoning. A mid-level trough to
the north of the hurricane along with a ridge to the east is
creating a southwesterly steering current and Omar is expected to
continue northeastward with a gradual increase in forward speed.
The forward motion slows a little around day 3 as the trough lifts
out ahead of Omar. The system should accelerate again near the end
of the period as it encounters the main branch of the mid-latitude
westerlies. Dynamical track prediction models are tightly
clustered...especially for the first 24 hours and the official
forecast is close to the model consensus albeit a little slower.
This is slightly faster than the previous forecast...but more or
less along the same trajectory.

Although the official forecast keeps the center east of Puerto
Rico...a deviation to the left of the current motion could require
changing the Hurricane Watch to a Hurricane Warning for that
island. I will pray that dosnt happen.