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Tropical Storm Nadine Discussion Number 13
NWS National Hurricane Center Miami FL AL152018
500 AM AST Fri Oct 12 2018
A 0353 UTC AMSR-2 microwave overpass and GOES-16 shortwave infrared
imagery show that the 30-40 kt of west-southwesterly shear, depicted
in the UW-CIMSS shear analysis, is partially exposing, or
decoupling, Nadine's surface circulation from the convective mass.
The cloud pattern, however, hasn't changed during the past 6 hours
and in fact, the cloud top temperatures in the curved band over the
north semicircle have decreased somewhat. TAFB and SAB satellite
intensity estimates remained unchanged, and the initial intensity is
held at 45 kt.
The Decay SHIPS statistical intensity model indicates that the shear
will persist and increase a little more which should cause Nadine to
spin down and dissipate in 48 hours, or possibly sooner. The
large-scale models all show the cyclone opening up into a trough of
low pressure and ultimately dissipating over the deep tropical
central Atlantic at that time. The official forecast follows suit
and is an update of the previous advisory.
The initial motion is estimated to be west-northwestward, or 295/7
kt. A low to mid-level ridge anchored between Nadine to the south
and Hurricane Leslie to the north, should steer the cyclone
west-northwestward and then westward at an accelerated pace until
dissipation. The NHC forecast has again been adjusted a little
south and toward both the NOAA-HCCA and TVCN consensus models.
FORECAST POSITIONS AND MAX WINDS
INIT 12/0900Z 15.2N 35.5W 45 KT 50 MPH
12H 12/1800Z 15.4N 37.2W 40 KT 45 MPH
24H 13/0600Z 15.6N 39.7W 30 KT 35 MPH
36H 13/1800Z 15.8N 42.7W 30 KT 35 MPH