000
AXPZ20 KNHC 162109
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN OCT 16 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...

THE CENTER OF TROPICAL DEPRESSION IRWIN AT 16/2100 UTC IS NEAR 
13.6N 108.1W. IRWIN IS MOVING SOUTHWEST OR 225 DEGREES AT 4 KT. 
THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. THE MAXIMUM 
SUSTAINED WIND SPEEDS ARE 25 KT WITH GUSTS TO 30 KT. IRWIN IS 
FORECAST TO DRIFT SLOWLY SW OVER THE NEXT COUPLE OF DAYS AND IS 
FORECAST TO WEAKEN TO A POST-TROPICAL REMNANT LOW MONDAY NIGHT. 
THERE IS NO DEEP CONVECTION NOTED WITH IRWIN. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC 
FOR MORE DETAILS. 
 
...ITCZ/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 15N92W TO 14N99W THEN RESUMES W OF 
IRWIN FROM 11N111W TO 08N130W TO 12N140W. SCATTERED MODERATE 
WITHIN 60 NM EITHER SIDE OF TROUGH FROM 93W TO 95W. ISOLATED 
MODERATE WITHIN 90 NM S OF TROUGH BETWEEN 115W AND 120W.

...DISCUSSION...

A 1007 MB LOW PRESSURE CENTER IS NEAR 30N137W. THIS LOW CENTER 
IS FORECAST TO MOVE SLOWLY EASTWARD BUT REMAIN NEAR OR JUST N OF 
30N. A STATIONARY FRONT EXTENDS FROM 30N131W TO 20N140W. FRESH 
20 KT WINDS AND SEAS TO 13 FT ARE FOUND W OF THE FRONT. THE 
FRONT WILL DISSIPATE WITHIN THE NEXT 24 HOURS...WITH WINDS 
DIMINISHING BELOW 20 KT. SEAS WILL SLOWLY SUBSIDE TO NEAR 9 FT 
AS THEY CONTINUE MOVING FURTHER SOUTHWARD THROUGH THE FORECAST 
PERIOD. 

AN EXTENSIVE AREA OF FRESH TO STRONG SOUTHWESTERLY MONSOONAL FLOW
CONTINUES N OF 05N E OF 100W. THESE WINDS ARE ADVECTING ABUNDANT 
TROPICAL MOISTURE OVER PORTIONS OF CENTRAL AMERICA AND SOUTHERN 
MEXICO. THIS WILL BRING PERIODS OF HEAVY RAINFALL INTO SECTIONS 
OF THE PACIFIC COASTS OF SOUTHEASTERN MEXICO... GUATEMALA...EL 
SALVADOR...SOUTHERN HONDURAS AND NICARAGUA. THE PERIODS OF HEAVY 
MONSOONAL RAINFALL HAVE THE POTENTIAL TO CREATE LIFE-THREATENING 
FLASH FLOODS AND MUD SLIDES IN SOME AREAS.

A BROAD CYCLONIC CIRCULATION CENTERED OVER THE YUCATAN PENINSULA 
IS REMINISCENT OF A MONSOON DEPRESSION. NORTHERLY FLOW OVER THE 
SW GULF OF MEXICO ASSOCIATED WITH THIS CIRCULATION CONTINUES TO 
FUNNEL FRESH TO STRONG WINDS THROUGH THE CHIVELA PASS INTO THE 
GULF OF TEHUANTEPEC. AS A NOTE OF INTEREST TO INDICATE THE 
INFLUENCE OF THIS CYCLONIC CIRCULATION OVER THE AREA...THE WINDS 
FUNNELING INTO THE GULF OF TEHUANTEPEC ARE TURNING NW THEN WEST 
AS IT MOVES FURTHER FROM THE GULF OF TEHUANTEPEC. 
TYPICALLY...THE WINDS FUNNELING INTO THE GULF OF TEHUANTEPEC 
TURN NE THEN E AS IT MOVES FURTHER FROM THE GULF OF TEHUANTEPEC. 
WITH THIS CYCLONIC CIRCULATION EXPECTED TO CONTINUE THROUGH THE 
FORECAST PERIOD...FRESH TO STRONG WINDS ARE EXPECTED TO CONTINUE 
OVER THE GULF OF TEHUANTEPEC. 

THE REMAINDER OF THE REGIONAL WATERS S OF 20N E OF 130W ARE 
DOMINATED BY MERGING NORTHERLY AND SOUTHWESTERLY SWELL. THIS 
SWELL EVENT WILL CONTINUE TO SUBSIDE FROM THE NORTHWEST TO THE 
SOUTHEAST DURING THE NEXT 48 HOURS.

$$
AL