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TROPICAL STORM OLAF DISCUSSION NUMBER  49
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP192015
800 PM PDT MON OCT 26 2015

Olaf has become less organized over the past several hours.  The
associated convection has decreased and has been displaced
northeast of the center by 25 kt of vertical wind shear.  In
addition, the low-level circulation has become elongated from
northeast to southwest.  Satellite intensity estimates from TAFB and
SAB are 45 kt, so the initial intensity is reduced to that value.

A combination of continuing shear, cool sea surface temperatures,
and dry air entrainment should keep Olaf on a weakening trend.  The
cyclone is expected to weaken to a tropical depression in about 24
hours and degenerate to a remnant low in about 48 hours, and both
of these events could occur earlier than currently forecast if new
convection does not form near the center.  The new forecast is an
update of the previous CPHC forecast.

The initial motion is 060/16.  Olaf is currently being steered by
a strong deep-layer trough to the north of the cyclone.  This
trough is forecast to move quickly eastward, with a low-level ridge
building in its wake to the north of Olaf.  As Olaf weakens and
becomes a shallow system, this ridge should become the dominant
steering mechanism and cause the cyclone to turn southward and
eventually southwestward.  The new forecast track is similar to the
previous track and lies near the various consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT  27/0300Z 26.3N 137.4W   45 KT  50 MPH
 12H  27/1200Z 27.2N 135.7W   35 KT  40 MPH
 24H  28/0000Z 27.8N 133.8W   30 KT  35 MPH
 36H  28/1200Z 27.3N 133.5W   25 KT  30 MPH
 48H  29/0000Z 26.1N 135.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  30/0000Z 24.5N 140.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  31/0000Z...DISSIPATED

$$
Forecaster Beven

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