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Subtropical Storm ALBERTO


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Subtropical Storm Alberto Discussion Number  10
NWS National Hurricane Center Miami FL       AL012018
400 PM CDT Sun May 27 2018

After the increase in organization overnight and this morning, dry
mid-level air has wrapped about three-quarters of the way around
the circulation, resulting in an overall decrease in deep
convection in all but the southeastern portion of the circulation.
Earlier ASCAT and reconnaissance aircraft data supported an initial
wind speed of 45 kt, and that intensity will be maintained for this
advisory.  Another reconnaissance aircraft is scheduled to
investigate the system this evening.

The main question regarding the future intensity of Alberto is
whether or not the dry air will continue to be ingested near the
center of the cyclone, or whether deep convection is able to
regenerate overnight while the system is over marginally warm
SSTs and within a low shear environment.  It is assumed that some
convection will redevelop to help maintain Alberto's intensity, but
that the environment will not be favorable enough to allow for
significant strengthening.  As a result, little change in intensity
is forecast before Alberto reaches the northern Gulf Coast on
Monday.

Alberto appears to have turned north-northwestward with an initial
motion estimate of 345/12 kt. The cyclone should move northwestward
to north-northwestward tonight before turning back northward on
Monday as it becomes vertically aligned with the upper-level low.
After that time, the system should continue moving northward between
the western Atlantic ridge and a mid-upper level trough that
approaches the central U.S. around mid-week.  The dynamical models
are in much better agreement on Alberto's track during the next 2 to
3 days, and the NHC track has been been adjusted accordingly.  The
new track is slightly west of and slower than the previous track
during the first 24 to 36 hours.

KEY MESSAGES:

1.  The risk of flooding and flash flooding over western Cuba, the
Florida Keys, and south Florida will continue through Monday.  Heavy
rain and the risk of flooding will begin across the Florida
Panhandle tonight, then spread northward from the Florida Panhandle
into much of Alabama, western Georgia, and Tennessee through
Tuesday.

2.  A hazardous storm surge is possible along portions of the
eastern Gulf Coast tonight and tomorrow, including areas well east
of the track of Alberto's center.  Residents in the storm surge
watch area are encouraged to follow guidance given by their local
government officials.

3. Tropical storm conditions are likely within portions of the
tropical storm warning area tonight and tomorrow.

4. Dangerous surf and rip current conditions will continue to
affect portions of the eastern and northern Gulf Coast through
Monday.


FORECAST POSITIONS AND MAX WINDS

INIT  27/2100Z 28.0N  85.2W   45 KT  50 MPH
 12H  28/0600Z 29.1N  85.7W   45 KT  50 MPH...TROPICAL STORM
 24H  28/1800Z 30.4N  86.2W   45 KT  50 MPH...INLAND
 36H  29/0600Z 32.2N  86.6W   30 KT  35 MPH...INLAND
 48H  29/1800Z 34.7N  87.0W   25 KT  30 MPH...INLAND
 72H  30/1800Z 39.7N  86.9W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  31/1800Z 45.1N  83.1W   15 KT  15 MPH...POST-TROP/REMNT LOW
120H  01/1800Z...DISSIPATED

$$
Forecaster Brown

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