000
AXPZ20 KNHC 161020 CCA
TWDEP 

TROPICAL WEATHER DISCUSSION...COR 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN OCT 16 2011

CORRECTION IN ORDER TO UPDATE THE BULLETIN

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0930 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL DEPRESSION AT 16/0900 UTC IS NEAR 14.3N 
107.5W. IRWIN IS MOVING SOUTH-SOUTHWESTWARD OR 210 DEGREES
04 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. THE
MAXIMUM SUSTAINED WIND SPEEDS ARE 30 KT WITH GUSTS TO 40 KT.
SCATTERED STRONG RAINSHOWERS ARE WITHIN 90 NM IN THE SOUTHERN 
QUADRANT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. 
 
...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH HAS BEEN DISRUPTED IN THE EASTERN PACIFIC 
OCEAN BETWEEN MEXICO AND CENTRAL AMERICA AND TROPICAL DEPRESSION 
IRWIN. THE MONSOON TROUGH EXTENDS 12N112W TO 09N124W TO 11N140W. 
SCATTERED STRONG RAINSHOWERS ARE FROM 13N TO 14N BETWEEN 90W AND 
96W. SCATTERED MODERATE RAINSHOWERS ARE WITHIN A 60 NM RADIUS OF
9N115W...FROM 06N TO 08N BETWEEN 120W AND 127W...AND FROM 08N TO 
09N BETWEEN 133W AND 136W. ISOLATED MODERATE RAINSHOWERS ARE FROM
9N TO 12N BETWEEN 139W AND 140W.

...DISCUSSION...

AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 31N137W.
UPPER LEVEL CYCLONIC WIND FLOW COVERS THE AREA TO THE WEST OF 
THE LINE THAT PASSES THROUGH 32N125W TO 23N131W BEYOND 16N140W.
A 1007 MB LOW PRESSURE CENTER 31N137W. THIS LOW CENTER IS 
FORECAST TO MOVE SOUTHEASTWARD DURING THE FIRST 24 HOURS OF THE 
FORECAST PERIOD...AND THEN MOVE NORTHWARD AND WEAKEN BY 48 HOURS 
AT THE END OF THE FORECAST PERIOD. A COLD FRONT EXTENDS FROM THE
LOW CENTER...PASSING THROUGH 32N131W TO 27N132W BEYOND 20N140W.
EXPECT NORTHWESTERLY WINDS RANGING FROM 20 TO 30 KT...AND SEA 
HEIGHTS RANGING FROM 09 TO 14N FEET IN NORTHWESTERLY SWELL BEHIND
THE FRONT. THE WIND SPEEDS WILL SLOW DOWN TO LESS THAN 20 KT AND
THE SEA HEIGHTS WILL SUBSIDE SLIGHTLY FROM 08 TO 12 FEET AT
24 HOURS. THE COLD FRONT WILL BE IN THE DISSIPATING STAGE BY
48 HOURS. THE SEA HEIGHTS ARE FORECAST TO REACH 09 FEET IN A FEW 
AREAS THAT ARE BEHIND THE DISSIPATING FRONT.

AN EXTENSIVE AREA OF FRESH TO STRONG SOUTHWESTERLY MONSOONAL FLOW
PREVAILS GENERALLY TO THE SOUTH OF 10N TO THE EAST OF 100W 
STARTING NOW AND CONTINUING THROUGH 48 HOURS. THE MONSOONAL FLOW 
CONTINUES TO PUSH ABUNDANT MOISTURE NORTHWARD INTO PARTS OF 
CENTRAL AMERICA AND SOUTHERN MEXICO. THE COMPARATIVELY EXTRA
MOISTURE 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 THE GIVEN AREAS.

AN EARLIER HIGH RESOLUTION ASCAT PASS INDICATED 20-30 KT 
NORTHERLY WINDS IN AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC 
AROUND A BROAD CYCLONIC CIRCULATION CURRENTLY CENTERED OVER THE 
YUCATAN PENINSULA NEAR 19N88W. NORTHWESTERLY AND NORTHERLY WINDS
ARE BLOWING THROUGH THE CHIVELA PASS AND THE INTO THE GULF OF 
TEHUANTEPEC BECAUSE OF THE 19N88W LOW PRESSURE CENTER. 
THIS WEATHER PATTERN IS FORECAST TO PERSIST DURING THE NEXT
FEW DAYS AS THE BROAD LOW PRESSURE AREA MOVES TOWARD THE 
WEST-NORTHWEST...POSSIBLY TOWARD THE SOUTHWESTERN CORNER
OF THE GULF OF MEXICO. 

THE REMAINDER OF THE REGIONAL WATERS E OF 130W ARE DOMINATED BY 
MERGING NORTHERLY AND SOUTHWESTERLY SWELL. THIS SWELL EVENT 
GRADUALLY WILL SUBSIDE FROM THE NORTHWEST-TO-THE-SOUTHEAST DURING
THE NEXT 48 HOURS. SEA HEIGHTS THAT WILL BE HIGHER THAN 8 FEET
WILL BE LIMITED TO THE SOUTH OF 12N TO THE EAST OF 130W BY 
MONDAY. 

$$
MT