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Hurricane LESLIE


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Hurricane Leslie Discussion Number  67
NWS National Hurricane Center Miami FL       AL132018
1100 PM AST Fri Oct 12 2018

Although Leslie continues to produce a compact area of deep
convection, microwave data since the previous advisory indicate
that the mid-level center is becoming more separated from the
low-level center due to increasing shear.  Dvorak final-T numbers
have begun to decrease a bit, and the initial intensity is
therefore set at 70 kt.  A cold front is beginning to wrap around
the western side of Leslie's circulation, and the global models
indicate that the cyclone should lose its warm core and become
fully embedded within the frontal zone by 24 hours, if not sooner.
Despite sea surface temperatures of 17-23 degrees Celsius ahead of
Leslie, baroclinic forcing is likely to maintain the system's
intensity as it becomes extratropical.  As a result, Leslie is
forecast to reach the Iberian Peninsula as a hurricane-force
extratropical low, with the NHC intensity forecast most closely
following the GFS guidance.  Rapid weakening is forecast once the
low moves inland, and the system should dissipate over the higher
terrain of Spain in about 48 hours.

The forward motion is east-northeastward, or 075/31 kt.  Located
within the base of a progressive trough, Leslie should maintain
this trajectory, slowing down only a little bit before it reaches
Portugal and Spain in 24-36 hours.  Except for the UKMET model,
which shows Leslie turning more northeastward toward the
northwestern Iberian Peninsula, the rest of the track guidance is
tightly clustered and brings the center inland across central
Portugal and western Spain.  Because most of the models are in good
agreement and are close to the previous official forecast, no
significant changes were made to the NHC forecast on this cycle.

Based on coordination from earlier today, the meteorological
services of Portugal and Spain will handle hazard information for
their respective countries via local weather products.


Key Messages:

1. Leslie is expected to bring near hurricane-force winds to
portions of Portugal late Saturday as a powerful post-tropical
cyclone.  Gale-force winds are also likely to affect portions of
western Spain Saturday night and Sunday.

2. Leslie is expected to produce rainfall amounts of 25 to 75 mm (1
to 3 inches) with isolated amounts as high as 100 mm (4 inches)
across portions of Portugal and Spain, which could cause flash
flooding.

3. For more information on Leslie, interests in Portugal should
refer to products from the Portuguese Institute for Sea and
Atmosphere at www.ipma.pt.  Interests in Spain should refer to
products from the State Meteorological Agency at www.aemet.es.


FORECAST POSITIONS AND MAX WINDS

INIT  13/0300Z 34.7N  20.7W   70 KT  80 MPH
 12H  13/1200Z 36.5N  15.4W   65 KT  75 MPH
 24H  14/0000Z 38.9N   9.4W   65 KT  75 MPH...POST-TROP/EXTRATROP
 36H  14/1200Z 41.0N   5.1W   40 KT  45 MPH...POST-TROP/EXTRATROP
 48H  15/0000Z 42.3N   1.1W   25 KT  30 MPH...POST-TROP/EXTRATROP
 72H  16/0000Z...DISSIPATED

$$
Forecaster Berg

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