ZCZC MIATCDEP5 ALL
TTAA00 KNHC DDHHMM

TROPICAL STORM PATRICIA DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP202015
1000 PM CDT TUE OCT 20 2015

Although cloud tops have warmed since the previous advisory, the
overall convective cloud pattern has become a little better
organized. Dropsondes released from a NASA WB-57 aircraft conducting
research in Patricia earlier this afternoon for the Office of Naval
Research's Tropical Cyclone Intensity (TCI) experiment was helpful
in locating the low-level center, and also confirmed the development
of a weak mid-level eye-like feature noted in recent passive
microwave images. The initial intensity has been increased to 35 kt
based on a satellite intensity estimates of T2.5/35 kt from TAFB and
T2.9/43 kt from UW-CIMMS ADT, making the cyclone the 16th named
storm of the 2015 eastern North Pacific hurricane season. This
intensity is also supported by dropsonde data in the southeastern
quadrant of the cyclone between 2000-2200Z, which indicated surface
winds of 34-36 kt and also a fairly deep layer of 37-39 kt winds
from 1000-925 mb. Winds west of the center were 30 kt, suggesting
that the Gulf of Tehuantepec gap wind gale event may be subsiding.

The initial motion estimate is 255/04 kt. There is no significant
change to the previous forecast track or reasoning. Patricia is
expected to move west-southwestward to westward for the next 12
hours or so as the aforementioned gap wind event forces the cyclone
a little southward. After that time, Patricia is forecast to turn
west-northwestward on Wednesday and northwestward on Thursday as the
cyclone rounds the southwestern periphery of a deep-layer ridge that
extends from the central Gulf of Mexico southwestward into central
Mexico. Although there is some spread in the NHC track guidance, the
models are in fairly good agreement that Patricia should turn
north-northwestward to northward by 72 hours, making landfall in
southwestern Mexico. The new forecast track is similar to the
previous track and lies close to the consensus models TVCE and GFEX.

The large-scale environment of vertical shear less than 5 kt, very
high mid-level humidity values in excess of 80 percent, and SSTs
greater than 30C support at least steady strengthening until
landfall occurs. The possibility of rapid intensification (RI)
exists once a distinct eye feature develops, which could develop in
36 hours or so. The intensity forecast is similar to the previous
advisory in calling for Patricia to become a hurricane before making
landfall in Mexico, and closely follows the LGEM intensity model.
However, if RI should occur, then Patricia will likely be stronger
at landfall than the current forecast is indicating. After landfall,
the cyclone should quickly weaken and dissipate over the mountains
of Mexico.

A tropical storm or hurricane watch may be required by Wednesday
morning for portions of southwestern Mexico.

FORECAST POSITIONS AND MAX WINDS

INIT  21/0300Z 13.1N  95.3W   35 KT  40 MPH
 12H  21/1200Z 13.0N  96.5W   40 KT  45 MPH
 24H  22/0000Z 13.3N  98.3W   50 KT  60 MPH
 36H  22/1200Z 14.2N 100.3W   60 KT  70 MPH
 48H  23/0000Z 15.5N 102.0W   75 KT  85 MPH
 72H  24/0000Z 18.8N 103.7W   85 KT 100 MPH...INLAND NEAR COAST
 96H  25/0000Z 22.6N 105.1W   40 KT  45 MPH...INLAND
120H  26/0000Z...DISSIPATED

$$
Forecaster Stewart

NNNN