000
WTPZ42 KNHC 211438
TCDEP2

TROPICAL STORM POLO DISCUSSION NUMBER  22
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP172014
800 AM PDT SUN SEP 21 2014

Polo is not in good shape.  Strong easterly shear continues to
affect the cyclone, keeping the low-level center exposed to the east
of the nearest deep convection.  The system has been producing
somewhat regular bursts of deep convection over the past couple of
days, with the latest burst currently on the increase.  The initial
intensity is being held at 35 kt for this advisory in agreement with
the 1200 UTC TAFB Dvorak intensity estimate.  With no cessation of
the strong shear seen in the short term, further weakening seems
likely to occur. However, Polo will be moving over warm enough water
to sustain additional bursts of convection, and thermodynamic
variables will only gradually become less conducive. The NHC
intensity forecast, like the previous one, shows slow weakening but
maintains the system as a tropical cyclone longer. The new forecast
is just above the latest intensity guidance and shows dissipation in
about 3 days in line with global model output.

Polo is moving slowly west-northwestward or 290/06 kt.  A continued
west-northwestward and then westward track is expected during the
next day or so as a result of a westward building mid-level ridge
over northern Mexico.  Once Polo becomes shallower in nature, a bend
of the track toward the southwest and south-southwest is indicated
as the cyclone is pushed by a north-northeasterly flow on the
eastern side of a low-level ridge.  The new track forecast does not
depart significantly from the previous one but is shifted slightly
to the right in the direction of the well-performing multi-model
consensus, TVCE.


FORECAST POSITIONS AND MAX WINDS

INIT  21/1500Z 21.9N 111.2W   35 KT  40 MPH
 12H  22/0000Z 22.2N 112.4W   30 KT  35 MPH
 24H  22/1200Z 22.2N 113.8W   30 KT  35 MPH
 36H  23/0000Z 21.9N 114.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  23/1200Z 21.4N 115.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  24/1200Z 20.1N 116.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  25/1200Z...DISSIPATED

$$
Forecaster Kimberlain