000
AXPZ20 KNHC 130938
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE SEP 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM NEAR 12.5N87W TO 13N90W TO 1012 MB 
LOW PRES AT 10.5N110W WHERE IT TERMINATES. ITCZ BEGINS NEAR 
09N125W TO BEYOND 10N140W. SCATTERED MODERATE TO STRONG WITHIN 
120 NM N AND 30 NM S OF MONSOON TROUGH AXIS BETWEEN 90W AND 96W.

...DISCUSSION...

HIGH PRESSURE 1026 MB CENTERED NW OF THE AREA NEAR 36N142W HAS 
RIDGE EXTENDING TO NEAR 25N117W. THERE IS A WEAK PRESSURE 
GRADIENT OVER THE FORECAST WATERS RESULTING IN MAINLY LIGHT TO 
MODERATE NE TRADEWINDS W OF 120W. A DISSIPATING 1012 MB LOW 
PRESSURE IS CENTERED NEAR 16N118W. THIS SURFACE CIRCULATION WAS 
DEPICTED ON THE LATEST 0540 ASCAT PASS. THIS ASCAT PASS ALSO 
INDICATED THAT WINDS HAVE DIMINISHED BELOW 20 KT. THIS LOW IS 
VOID OF ANY CONVECTION AND IS EXPECTED TO DISSIPATE WITHIN THE 
NEXT 24 HOURS. A SECOND WEAK SURFACE LOW IS ANCHORED ON THE 
WESTERN EXTENT OF THE MONSOON TROUGH. THIS LOW WILL DRIFT SLOWLY 
WESTWARD AND IS EXPECTED TO DISSIPATED IN THE NEXT 24 TO 48 
HOURS. 

NE WINDS OVER THE SW GULF OF MEXICO ASSOCIATED WITH CYCLONIC 
FLOW AROUND A SLOW MOVING TROPICAL WAVE OVER THE FAR WESTERN 
CARIBBEAN IS FUNNELING THROUGH THE CHIVELA PASS INTO THE GULF OF 
TEHUANTEPEC. LATEST 0356 ASCAT PASS INDICATES FRESH TO STRONG 
WINDS OVER THE GULF OF TEHUANTEPEC. WINDS WILL CONTINUE TO 
FUNNEL INTO THE GULF OF TEHUANTEPEC MAINTAINING THE FRESH TO 
STRONG NORTHERLY WINDS UNTIL THE TROPICAL WAVE REACHES WEST OF 
THE CHIVELA PASS LATE WED. 

SOUTHERLY CROSS EQUATORIAL SWELL WITH COMBINED SEAS TO 9 FT 
CONTINUES ACROSS THE FAR S PART OF THE AREA GENERALLY S OF 10N W 
OF 95W. SEAS GRADUALLY SUBSIDE OVER THE NEXT 24 HOURS...AND 
COVERAGE OF 8 FT SEAS WILL DECREASE SIGNIFICANTLY BY EARLY THU. 

LIGHT TO MODERATE S TO SW WINDS PRESENTLY PREVAIL ACROSS THE 
DEEP TROPICS S OF THE MONSOON TROUGH AND ARE NOT EXPECTED TO 
INCREASE MUCH IN THE NEXT FEW DAYS.

$$
AL