Official Discussion issued by the National Hurricane Center

Katia (AL132017) DATA RELEASED: 9/6/2017 4:00:00 PM UTC

Copy of official data

Hurricane Katia Discussion Number   5
NWS National Hurricane Center Miami FL       AL132017
400 PM CDT Wed Sep 06 2017

An Air Force reconnaissance plane just investigated Katia and found
a much better organized tropical cyclone with a partial eyewall. It
also measured a flight-level wind of 71 kt and 66 kt with the SFMR.
Based on these data and the improved satellite presentation, Katia
is upgraded to a hurricane with 65 kt winds.

The upper-level wind pattern is becoming more favorable, and that
can be observed by the expansion of the outflow. All models continue
to favor intensification, and in fact, the SHIPS RI index gives a
63 percent chance of a 30-kt wind increase in 24 hours. The NHC
forecast calls for strengthening but at this time is not as high as
some of the guidance.

Katia is embedded within very weak steering currents, and it is now
moving slowly toward the southeast at about 3 kt. The hurricane is
forecast to meander in the southwestern Gulf of Mexico for the next
day or two. After that time the global models develop a ridge over
the northern Gulf of Mexico and this flow pattern will steer Katia
southwestward toward the state of Veracruz. The NHC forecast is
basically on top of the multi-model consensus and follows the trend
of the HFIP corrected consensus HCCA.

Given the upward intensity trend and the forecast track toward
the coast, the government of Mexico has issued a hurricane watch
for a portion of the coast of the state of Veracruz.  Katia is also
forecast to bring torrential rains primarily to the state of
Veracruz during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT  06/2100Z 21.7N  95.1W   65 KT  75 MPH
12H  07/0600Z 21.5N  94.7W   70 KT  80 MPH
24H  07/1800Z 21.3N  94.7W   75 KT  85 MPH
36H  08/0600Z 21.1N  95.0W   80 KT  90 MPH
48H  08/1800Z 20.9N  95.9W   80 KT  90 MPH
72H  09/1800Z 19.5N  98.0W   25 KT  30 MPH...POST-TROP/INLAND
96H  10/1800Z...DISSIPATED

$$
Forecaster Avila