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TROPICAL STORM POLO DISCUSSION NUMBER  23
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP172014
200 PM PDT SUN SEP 21 2014

After an impressive burst of deep convection, strong easterly shear
has pushed the thunderstorm activity well west of the low-level
center.  An ASCAT overpass from a few hours ago indicated that the
maximum winds were still near 35 kt.  Since the shear is not
expected to abate much over the next day or two, and the
thermodynamic environment is expected to gradually become less
favorable, weakening is likely.  The official intensity forecast is
similar to the previous one and is a blend of the latest
Decay-SHIPS and LGEM guidance.  Polo should degenerate into a
remnant low within a couple of days.

Based on some microwave imagery and the scatterometer data, the
center is located slightly north of the previous track.  The
initial motion estimate remains west-northwestward, or 290/7 kt.  A
mid-level ridge to the north of Polo is expected to cause the
cyclone to turn westward within the next day or so.  Thereafter, the
weakening remnant low should turn west-southwestward and then
southwestward within the shallow-layer northeasterly flow.  The
official forecast is close to a consensus of the GFS and ECMWF
predictions.

FORECAST POSITIONS AND MAX WINDS

INIT  21/2100Z 22.3N 112.1W   35 KT  40 MPH
 12H  22/0600Z 22.5N 113.1W   30 KT  35 MPH
 24H  22/1800Z 22.5N 114.4W   30 KT  35 MPH
 36H  23/0600Z 22.1N 115.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  23/1800Z 21.7N 116.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  24/1800Z 20.6N 117.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  25/1800Z...DISSIPATED

$$
Forecaster Pasch

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