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TROPICAL STORM PATRICIA DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL EP202015
400 AM CDT WED OCT 21 2015
The cloud pattern of the storm is not well organized at this time,
with not much deep convection concentrated near the estimated
center position. There is also a lack of well-defined banding
features. The current intensity estimate is held at 35 kt, in
agreement with a Dvorak CI Value from TAFB.
The center is not easy to track on nighttime imagery, with a
significant spread in fix locations from TAFB and SAB, and the
initial motion estimate is a rather uncertain 270/6 kt. The
primary steering features over the next few days are a
mid-tropospheric trough extending southward into extreme
northwestern Mexico and a high over the Gulf of Mexico. This flow
regime should cause Patricia to turn gradually to the right over the
next few days, and cross the coast of southwestern Mexico within 72
hours or so. The official track forecast resembles the previous
one but is a little faster, and is close to the new model
consensus. This is between the latest GFS and ECMWF solutions.
Although the tropical cyclone has not strengthened significantly
thus far, the environment seems to be quite conducive for
intensification. With very warm sea surface temperatures near 30
deg C, light vertical shear, and a very moist atmosphere likely to
prevail during the next couple of days, Patricia is forecast to
strengthen into a hurricane by tomorrow. The official intensity
forecast is close to the LGEM guidance, but it should be noted that
if the system develops a well-defined inner core, rapid
intensification is certainly possible. Note that in the official
wind speed forecast shown here, additional strengthening is implied
after the 48 hour forecast and up until landfall.
Based on the new 48-hour forecast location and the predicted wind
radii, A Hurricane Watch and a Tropical Storm Watch have been
issued for portions of the coast of southwestern Mexico.
FORECAST POSITIONS AND MAX WINDS
INIT 21/0900Z 13.0N 96.0W 35 KT 40 MPH
12H 21/1800Z 13.2N 97.6W 40 KT 45 MPH
24H 22/0600Z 14.0N 99.8W 50 KT 60 MPH
36H 22/1800Z 15.1N 101.8W 65 KT 75 MPH
48H 23/0600Z 16.5N 103.3W 80 KT 90 MPH
72H 24/0600Z 20.5N 104.0W 85 KT 100 MPH...INLAND
96H 25/0600Z 23.0N 104.0W 40 KT 45 MPH...INLAND
120H 26/0600Z...DISSIPATED
$$
Forecaster Pasch
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