000
AXPZ20 KNHC 132119
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU OCT 13 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2100 UTC.

...SPECIAL FEATURES...

AT 13/2100 UTC THE CENTER OF TROPICAL STORM IRWIN WAS NEAR 18.6N 
106.5W. IRWIN WAS MOVING EAST OR 090 DEGREES 05 KT. THE 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. THE MAXIMUM 
SUSTAINED WIND SPEEDS ARE 35 KT WITH GUSTS TO 40 KT. SCATTERED 
MODERATE CONVECTION WAS NOTED WITHIN 120 NM NE AND NW QUADRANTS. 
THE FORECAST TRACK SHOWS THAT IRWIN WILL MOVE SOUTHEASTWARD FOR 
THE FIRST 24 HOURS...AND THEN IT WILL CURVE SOUTH THEN 
SOUTHWESTWARD FOR THE REST OF THE FORECAST TIME PERIOD. PLEASE 
READ THE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP1/WTPZ21 KNHC AND/OR THE PUBLIC ADVISORY UNDER 
MIATCPEP1/WTPZ31 KNHC FOR MORE DETAILS.
 
...ITCZ/MONSOON TROUGH...
MONSOON TROUGH OVER PARTS OF NORTHERN CENTRAL AMERICA AND SE 
MEXICO THEN RESUMES W OF T.S. IRWIN FROM 13N114W TO LOW PRES 
NEAR 09N127W TO 08N140W. NO DEEP CONVECTION IN ASSOCIATION WITH 
THE MONSOON TROUGH W OF 114W. SOUTH OF THE MONSOON TROUGH 
NUMEROUS MODERATE TO ISOLATED STRONG CONVECTION WAS NOTED FROM 
12N TO 15N BETWEEN 92W AND 95W. SCATTERED MODERATE CONVECTION 
WAS NOTED ELSEWHERE FROM 12N TO 15N BETWEEN 90W AND 99W.

...DISCUSSION...

A COLD FRONT NORTHWEST OF THE FORECAST AREA WILL MOVE INTO THE 
FAR NW PART OF THE AREA WITHIN THE NEXT 24 HOURS WITH FRESH 20 
KT WINDS AND SEAS TO 9 FT. WINDS WILL INCREASE TO 25 KT...AND 
SEAS BUILDING TO 9 T 14 FT IN NW SWELL WITHIN 48 HOURS. 

E OF 100W...FRESH TO STRONG WINDS ARE FLOWING INTO THE MONSOON 
TROUGH...WHICH EXTENDS OVER SOUTHERN MEXICO AND CENTRAL AMERICA 
INTO THE WESTERN CARIBBEAN. WITH THE MONSOON TROUGH EXPECTED TO 
REMAIN OVER THIS AREA...THESE WINDS WILL CONTINUE THROUGH THE 
FORECAST PERIOD...WITH SEAS REACHING UP TO 14 FT. 

THE REMAINDER OF THE AREA IS DOMINATED BY MERGING NW AND SW 
SWELL. THIS SWELL WILL SLOWLY DECREASE FROM NW TO SW THROUGH THE 
NEXT 24 TO 48 HOURS...WHILE ANOTHER SET OF NW SWELLS ENTERS THE 
AREA WITHIN 24 HOURS.  

$$
AL