000
WTPZ45 KNHC 030836
TCDEP5

Tropical Storm Xavier Discussion Number   3
NWS National Hurricane Center Miami FL       EP252018
300 AM MDT Sat Nov 03 2018

A large burst of deep convection has developed over the northeastern
and eastern portions of Xavier's circulation overnight.  An earlier
GMI microwave overpass indicated that the center was located near
the southwestern edge of the convection, but there was evidence of
an increase in banding over the northeastern portion of the storm.
Dvorak data T-numbers from TAFB and SAB were T2.5 and T3.0,
respectively, so the initial intensity has been increased to
40 kt for this advisory.

Xavier is expected to remain embedded within an area of moderate
to strong southwesterly shear during the next 24 to 36 hours, and
these conditions are likely to prevent significant strengthening.
Although the statistical guidance shows no additional
intensification, the dynamical models deepen the system over the
next day or so, and the NHC forecast calls for a slight increase in
wind speed today, followed by little change in strength through
Sunday.  This is in good agreement with the latest HFIP corrected
consensus model.  By 48 hours the shear is expected to become even
stronger, and as a result, gradual weakening should occur
thereafter.  Xavier is forecast to degenerate into a remnant low
by day 4, if not sooner.

The aforementioned microwave pass was very helpful in locating the
center of Xavier.  Based on that data and recent satellite fixes,
the initial motion estimate is east-northeastward at about 6 kt.
The track forecast reasoning has not changed from the previous
advisory.  Xavier should turn northeastward, then northward by
tonight toward a weakness in the subtropical ridge created by a
deep-layer trough over central Mexico.  After Xavier weakens, the
cyclone should turn toward west-northwestward or westward as it
is steered by the low-level flow.  Since there is still a fair
amount of spread among the track models as to how far north Xavier
will move before it weakens and turns westward, the NHC track is
close to the various consensus aids at 48 hours and beyond.  Most
of the track models have trended a little faster after 48 hours,
and the official forecast has been adjusted accordingly.


FORECAST POSITIONS AND MAX WINDS

INIT  03/0900Z 14.7N 107.7W   40 KT  45 MPH
 12H  03/1800Z 15.2N 107.0W   45 KT  50 MPH
 24H  04/0600Z 16.0N 106.4W   45 KT  50 MPH
 36H  04/1800Z 16.6N 106.3W   45 KT  50 MPH
 48H  05/0600Z 17.1N 106.5W   40 KT  45 MPH
 72H  06/0600Z 17.5N 107.7W   30 KT  35 MPH
 96H  07/0600Z 17.6N 110.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  08/0600Z 18.0N 112.5W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brown