Hurricane Michael Forecast Discussion Number 13

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000
WTNT44 KNHC 092055
TCDAT4

Hurricane Michael Discussion Number  13
NWS National Hurricane Center Miami FL       AL142018
400 PM CDT Tue Oct 09 2018

The eye of Michael became very distinct in both visible and
infrared satellite pictures early this afternoon, but has been a
little more cloud filled since that time. Very deep convection has
continue to develop over the southeastern and eastern portion of
the eyewall and rotate around the north and west sides. An Air
Force Reserve reconnaissance aircraft measured a peak 700-mb
flight-level wind of 109 kt in the northeast eyewall as it exited
the storm just prior to 1800 UTC, and another Air Force Hurricane
Hunter very recently made its first pass through the eye and
reported similar flight-level winds in the southeast quadrant, and a
minimum pressure of 957 mb, down about 8 mb over the past few hours.
Based on these observations and Dvorak satellite classifications of
115 kt and 102 kt from SAB and TAFB, respectively, the initial
intensity has been increased to 105 kt for this advisory.

The environment ahead of Michael is expected to remain conducive
for additional strengthening during the next 12 to 18 hours.  There
may be some increase in southwesterly shear as the hurricane nears
the Gulf Coast, but it is not likely to result in a significant
decrease in intensity before landfall. The global models continue
to deepen the cyclone over the Gulf, increasing the confidence that
some additional intensification will occur. The new NHC intensity
forecast brings Michael up to 110 kt, and is in best agreement with
the SHIPS and HCCA models. After landfall, significant weakening
should occur while Michael moves over the southeastern United
States, but the cyclone is predicted to re-strengthen over the
western Atlantic due to baroclinic processes after it merges with a
front and becomes extratropical on Friday.

Michael is still moving north-northwestward to northward at about
10 kt. The hurricane should turn due northward this evening, then
northeastward on Wednesday as a trough moves into the central
United States. Michael should become embedded within the westerlies
in 48 to 72 hours, and then accelerate northeastward to east-
northeastward over the western and central-north Atlantic over
the weekend. There is not much spread in the dynamical model
guidance, and little change was required to the official forecast.
Although the NHC forecast brings the center onshore Wednesday
afternoon, conditions will deteriorate along the northeastern
Gulf Coast tonight.

Tropical storm watches and warnings have been expanded northward
along the U.S. East Coast from northeastern Florida to North
Carolina. Non-tropical watches, warnings, and advisories will be
issued by local NWS offices for wind hazards north of Duck, North
Carolina, as Michael is expected to be post-tropical when it affects
those areas.

Key Messages:

1. Life-threatening storm surge is likely along portions of the
coasts of the Florida Panhandle, Big Bend, and Nature Coast, where
a storm surge warning is in effect. The worst storm surge is
expected between Mexico Beach and Keaton Beach, where 9 to 13 feet
of inundation is possible. Water levels will rise well in advance of
the center of Michael, and residents within the storm surge warning
area should finish preparations to protect life and property today.

2. Everyone in the hurricane warning area along the Florida Gulf
Coast should prepare for life-threatening major hurricane winds
associated with the core of Michael. Hurricane force winds will also
extend well inland across portions of the Florida Panhandle,
southern Georgia, and southeast Alabama as Michael moves inland.

3. Heavy rainfall from Michael could produce life-threatening flash
flooding from the Florida Panhandle and Big Bend region into
portions of Georgia, the Carolinas, and southeast Virginia.

4. Tropical storm conditions will likely affect portions of the
southeast U.S. coast from northeast Florida through North Carolina,
and tropical storm watches and warnings have been issued for these
areas.

FORECAST POSITIONS AND MAX WINDS

INIT  09/2100Z 26.0N  86.4W  105 KT 120 MPH
 12H  10/0600Z 27.6N  86.6W  110 KT 125 MPH
 24H  10/1800Z 29.7N  85.9W  110 KT 125 MPH
 36H  11/0600Z 31.8N  84.1W   60 KT  70 MPH...INLAND
 48H  11/1800Z 33.9N  81.0W   45 KT  50 MPH...INLAND
 72H  12/1800Z 39.0N  70.0W   55 KT  65 MPH...POST-TROP/EXTRATROP
 96H  13/1800Z 45.5N  51.0W   55 KT  65 MPH...POST-TROP/EXTRATROP
120H  14/1800Z 50.0N  30.0W   45 KT  50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Brown