000
AXPZ20 KNHC 102135
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU NOV 10 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.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 09.5N84W TO 08.5N98W. THE ITCZ 
EXTENDS FROM 08.5N98W TO 10N117W WHERE THERE IS A BREAK AS A 
RESULT OF A TROUGH EXTENDING FROM 12.5N118W TO 09N119W. THERE IS 
SCATTERED MODERATE CONVECTION S OF 10N WITHIN 30 NM E OF TROUGH 
AXIS. THE ITCZ THEN RESUMES FROM 12N127W TO 10N140W. SCATTERED 
MODERATE CONVECTION IS NOTED WITHIN 60 NM OF ITCZ AXIS BETWEEN 
131W AND 135W.  

...DISCUSSION...

HIGH PRESSURE 1021 MB IS CENTERED NEAR 31N120W WITH RIDGE 
EXTENDING SE TO NEAR 20N111W. THE PRESSURE GRADIENT BETWEEN THE 
AREA OF HIGH PRESSURE AND A TROUGH OF LOW PRESSURE OVER MEXICO 
IS MAINTAINING FRESH 20 KT WINDS OVER THE GULF OF CALIFORNIA N 
OF 28N. THE AREA OF HIGH PRESSURE WILL CONTINUE SHIFTING E WHILE 
WEAKENING...WHICH WILL LOOSEN THE PRESSURE GRADIENT OVER THE 
GULF OF CALIFORNIA. AS A RESULT...WINDS WILL DIMINISH BELOW 20 
KT BY FRI MORNING. 

A SURFACE COLD FRONT ASSOCIATED WITH A DEEP 996 MB LOW PRESSURE 
AREA CENTERED NEAR 39N135W EXTENDS OVER THE FORECAST AREA FROM 
30N129W TO 24W140W. FRESH TO STRONG WINDS ARE FOUND W OF THE 
FRONT...WITH COMBINED SEAS TO 16 FT IN NW SWELL OVER THE FAR NW 
PART OF THE AREA. THE SURFACE LOW WILL SHIFT SE WHILE FILLING 
OVER THE NEXT COUPLE OF DAYS. COMBINED SEAS IN NW SWELL WILL 
REACH NEAR 20 FT FRI NIGHT.

WITH THE AREA OF HIGH PRESSURE MENTIONED ABOVE SHIFTING E AND 
WEAKENING...TRADE WIND FLOW HAS DIMINISHED TO LESS THAN 20 KT 
DUE TO A WEAKER PRESSURE GRADIENT BETWEEN THIS FEATURE AND THE 
ITCZ. LINGERING MIXED NE AND S SWELLS WITH COMBINED SEAS TO 10 
FT REMAIN S OF LINE 19N140W TO 19N106W TO 06N92W. THE SWELLS 
WILL CONTINUE TO SUBSIDE...AND FALL BELOW 8 FT BY FRI NIGHT. 

GULF OF TEHUANTEPEC...THE N WIND FUNNELING THROUGH THE CHIVELA 
PASS IS PRODUCING MINIMAL GALE FORCE WINDS OVER THE GULF OF 
TEHUANTEPEC. THE WINDS ARE EXPECTED TO FURTHER INCREASE TO JUST 
BELOW STORM FORCE LATE TONIGHT. WINDS WILL DIMINISH BELOW GALE 
FORCE FRI NIGHT AND FURTHER DIMINISH BELOW 20 KT SAT. ASIDE FROM 
THE STRONG WINDS THEMSELVES...LOOK FOR A LARGE AREA OF NE SWELL 
TO BE GENERATED FROM THE GAP FLOW...REACHING AS FAR W AS 110W BY 
LATE SAT. 

GULF OF PAPAGAYO...EXPECT SOME PULSES TO 20 KT THROUGH THE GULF 
OF PAPAGAYO MAINLY EARLY SAT AND EARLY SUN MORNINGS DUE DRAINAGE 
EFFECTS INTERACTING WITH ENHANCED GRADIENT FLOW OVER THE SW 
CARIBBEAN.

$$
AL