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TROPICAL STORM KATE DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122015
400 PM EST TUE NOV 10 2015

Kate has not changed much in structure during the past few hours,
with the center still embedded with a small CDO. Dvorak estimates
are T3.5/55 kt from TAFB and SAB, and the initial intensity remains
60 kt based on the earlier aircraft data. A NOAA hurricane hunter
aircraft will be investigating Kate again this evening. A pair of
ASCAT A/B passes at 14-15Z were helpful in analyzing the 34-kt wind
radii.

The intensity forecast shows Kate reaching hurricane status in 12
hours, and then remaining a powerful cyclone as it undergoes
extratropical transition in 36 to 48 hours while it interacts with
an upper-level trough and an east/west oriented low-level baroclinic
zone. After transition, the baroclinic forcing weakens, and Kate is
expected to weaken to 40-45 kt at 72 hours and beyond. The NHC
intensity forecast is close to the intensity consensus through
transition.

The initial motion estimate is 050/26, as Kate continues to
accelerate into the mid-latitude westerlies. The track model
guidance is in generally good agreement showing a turn toward the
east-northeast with a forward speed of 30 to 35 kt through 36 hours,
followed by a slower northeastward motion as Kate interacts with an
upper-level trough. After that time, a gradual acceleration toward
the east and then northeast is expected over the north Atlantic. The
new NHC track forecast is a little to the left of and faster than
the previous one through 48 hours, based on the initial position and
motion, and a faster trend in the guidance. After that time the NHC
forecast is largely an update of the previous one. The NHC track is
close to a blend of the GFS and ECMWF models through 48 hours and
is close to the GEFS ensemble mean after that time.

The extratropical portion of Kate's forecast was coordinated with
the NOAA Ocean Prediction Center.

FORECAST POSITIONS AND MAX WINDS

INIT  10/2100Z 32.2N  72.7W   60 KT  70 MPH
 12H  11/0600Z 34.3N  68.2W   65 KT  75 MPH
 24H  11/1800Z 37.1N  60.0W   70 KT  80 MPH
 36H  12/0600Z 40.0N  53.0W   65 KT  75 MPH
 48H  12/1800Z 42.0N  50.5W   60 KT  70 MPH...POST-TROP/EXTRATROP
 72H  13/1800Z 43.0N  44.5W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  14/1800Z 48.0N  32.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  15/1800Z 58.0N  20.0W   40 KT  45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Brennan

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