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000
WTPZ44 KNHC 280239
TCDEP4

TROPICAL STORM MADELINE DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP142016
800 PM PDT SAT AUG 27 2016

The cloud pattern has changed little in organization during the
past several hours and convection is not as deep as earlier today.
However, the pattern still consists of a cyclonically curved
convective band around the center. Dvorak estimates continue
to support an initial intensity of 50 kt. The cyclone is expected to
be moving within an environment of light shear for the next 2 to 3
days and over warm waters. This should encourage some
intensification. After that time however, the shear is expected to
increase to above 20 kt, and the environment will be less humid,
resulting in gradual weakening. The NHC forecast is very similar to
its predecessor, and is very close to the intensity consensus IVCN.

Satellite fixes indicate that Madeline is moving toward the west-
northwest or 285 degrees at 7 kt. The cyclone is located on
the southwestern edge of the subtropical ridge and is approaching a
large mid-latitude trough to its northwest. This pattern should
steer Madeline on a more west-northwest course during the next day
or two. The trough is forecast to lift out quickly and be replaced
by a strong ridge in about 3 days. This pattern should force
Madeline to turn toward the west or even south of due west by the
end of the forecast period. Track guidance has been very consistent
with this solution, and the NHC forecast is in a narrow gap
between the previous NHC prediction and the multi-model consensus.
Given the small southward shift of the consensus at day 5, the NHC
forecast position was adjusted southward accordingly.

The confidence in the track foreast late in the period is lower than
usual and it is too early to determine what impacts Madeline could
have on the Hawaiian Islands late in the forecast period.  It is
important to remind users that the average day 4 and 5 track
forecast errors for eastern Pacific tropical cyclones are around 145
and 170 miles, respectively.

Given that Madeline has moved into the Central Pacific basin, future
information on this system will be issued by the Central Pacific
Hurricane Center.


FORECAST POSITIONS AND MAX WINDS

INIT  28/0300Z 15.7N 140.1W   50 KT  60 MPH
 12H  28/1200Z 16.5N 141.0W   55 KT  65 MPH
 24H  29/0000Z 17.4N 142.4W   65 KT  75 MPH
 36H  29/1200Z 18.4N 143.8W   70 KT  80 MPH
 48H  30/0000Z 19.2N 145.5W   70 KT  80 MPH
 72H  31/0000Z 20.0N 149.5W   60 KT  70 MPH
 96H  01/0000Z 19.5N 153.8W   55 KT  65 MPH
120H  02/0000Z 19.0N 158.5W   45 KT  50 MPH

$$
Forecaster Avila




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