000
AXPZ20 KNHC 131531
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ/MONSOON TROUGH...

MONSOON TROUGH EXTENDS FROM NEAR 12N86W TO 14N95W TO 1010 MB LOW 
PRES AT 10.5N109.5W TO 10N116W. ITCZ BEGINS NEAR 10N125W TO 
BEYOND 09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
FROM 12N-14N BETWEEN 91W-99W.

...DISCUSSION...

HIGH PRESSURE 1026 MB CENTERED NW OF THE AREA NEAR 37N142W HAS 
RIDGE EXTENDING SE TO NEAR 25N117W. THERE IS A WEAK PRESSURE 
GRADIENT OVER THE FORECAST WATERS RESULTING IN MAINLY LIGHT TO 
MODERATE NE TRADEWINDS FROM 10N-30N W OF 120W. A DISSIPATING 
1011 MB LOW PRESSURE IS CENTERED NEAR 17N120W. THIS SURFACE 
CIRCULATION WAS DEPICTED ON THE 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 1010 MB SURFACE LOW IS ANCHORED ON 
THE WESTERN EXTENT OF THE MONSOON TROUGH NEAR 10.5N109.5W. 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 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 08N 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/MRF