[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT43 KNHC 122036
TCDAT3

Hurricane Leslie Discussion Number  66
NWS National Hurricane Center Miami FL       AL132018
500 PM AST Fri Oct 12 2018

Leslie remains a well organized tropical cyclone, with a fairly
symmetric central dense overcast, and hints of an eye in both
conventional and microwave satellite imagery.  A 1738 UTC SSMIS
microwave overpass shows that there is some northeast to southwest
tilt, due to an increase in westerly shear.  Some slight weakening
is foreast tonight while Leslie moves over cool SSTs of 23 to 24
degrees Celsius and into an area of increasing westerly shear.
However, Leslie is forecast to transition into a powerful hurricane-
force post-tropical cyclone in about 24 hours as it interacts with
an approaching trough. The post-tropical cyclone is expected to make
landfall along the west coast of the Iberian Peninsula shortly
thereafter, and it should weaken due to land interaction after that
time. The system is forecast to dissipate inland by Monday.

Leslie continues to race across the far eastern Atlantic, with an
initial motion estimate of 070/30 kt. The global models are now
unanimous in taking Leslie quickly east-northeastward on the south
side of a strong longwave trough over the northeast Atlantic.  The
official track foreast as been adjusted northward and is
significantly faster than before, and brings the center of Leslie
over the coast of the Iberian Peninsula by 0000 UTC Sunday.  The
system is likely to dissipate over the high terrain of Spain
within a couple of days, but a 48-h forecast point is shown for
continuity. Now that the track guidance is in much better
agreement, confidence in the NHC track forecast has increased.

After coordination with the meteorological services of Portugal and
Spain, they have decided to provide information on the wind hazard
with local products.

Key Messages:

1. Leslie is expected to bring near hurricane-force winds on
Saturday to portions of Portugal as a powerful post-tropical
cyclone. Tropical-storm-force winds are also likely to affect
portions of western Spain.

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  12/2100Z 33.9N  24.1W   75 KT  85 MPH
 12H  13/0600Z 35.6N  18.8W   70 KT  80 MPH
 24H  13/1800Z 38.0N  12.0W   65 KT  75 MPH...POST-TROPICAL
 36H  14/0600Z 40.6N   6.5W   45 KT  50 MPH...POST-TROPICAL/INLAND
 48H  14/1800Z 43.0N   2.0W   30 KT  35 MPH...POST-TROPICAL/INLAND
 72H  15/1800Z...DISSIPATED

$$
Forecaster Brown
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