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HURRICANE DARBY DISCUSSION NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL EP052016
800 AM PDT FRI JUL 15 2016
Darby's eye became a little better defined earlier this morning,
with an elongated tail of convection developing within the eastern
portion of the circulation. Dvorak final-T numbers are now 4.5/77
kt from TAFB, 5.0/90 kt from SAB, and 5.1/92 kt from the UW-CIMSS
ADT, so the initial intensity is raised to 85 kt on this advisory.
The eye appears to have opened up a bit on the latest satellite
pictures, so it's possible that Darby may have reached its peak
intensity.
The hurricane is now moving over sea surface temperatures a little
less than 27C, and the ocean beneath the hurricane is expected to be
colder than 26C within the next 24-36 hours. Since vertical shear
continues to gradually decrease, Darby is forecast to maintain its
intensity or only gradually weaken during the next day or two.
After 48 hours, more marked weakening is anticipated due to SSTs
getting as cold as 24-25C. No changes to the NHC intensity
forecast, which is essentially a blend of the SHIPS model and
Florida State Superensemble early and the IVCN intensity consensus
late, were required from the previous advisory.
Darby appears to have turned west-northwestward and slowed down,
and the initial motion estimate is 285/8 kt. An amplifying mid- to
upper-level trough along the west coast of the United States is
expected to weaken the subtropical ridge during the next day or
two. This should allow the hurricane to continue moving
west-northwestward for the next 36 hours, but thereafter a westward
turn is anticipated when a weaker Darby comes under the influence
of lower-level steering winds. There continues to be high
confidence in Darby's future path due to a tightly packed model
suite, and the updated NHC track forecast is shifted slightly
northward only during the first 36 hours to account for the recent
west-northwestward turn.
FORECAST POSITIONS AND MAX WINDS
INIT 15/1500Z 16.5N 120.5W 85 KT 100 MPH
12H 16/0000Z 17.0N 121.9W 85 KT 100 MPH
24H 16/1200Z 17.5N 123.8W 80 KT 90 MPH
36H 17/0000Z 17.9N 125.5W 75 KT 85 MPH
48H 17/1200Z 18.1N 127.3W 70 KT 80 MPH
72H 18/1200Z 18.6N 131.6W 60 KT 70 MPH
96H 19/1200Z 19.0N 136.5W 50 KT 60 MPH
120H 20/1200Z 19.0N 141.5W 45 KT 50 MPH
$$
Forecaster Berg
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