000
AXPZ20 KNHC 131552
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI NOV 13 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG A LINE FROM 08N82W 
TO 07N100W TO 12N115W TO 07N125W TO 10N137W TO 07N140W. 
SCATTERED MODERATE CONVECTION WITHIN 120 NM N OF AXIS...AND 90 
NM S OF AXIS BETWEEN 95W AND 115W. 

...DISCUSSION...
AN ASCAT PASS FROM 06Z AND A QUIKSCAT PASS FROM 03Z SHOWED 
EVIDENCE OF A WELL DEFINED SURFACE TROUGH EXTENDING FROM 13N130W 
TO 07N140W. THE SCATTEROMETER DATA ALSO SHOWED A BROAD AREA OF 
20 TO 25 KT TRADE WINDS GENERALLY W OF 125W BETWEEN THE TROUGH 
AND 1034 MB SURFACE HIGH PRES CENTERED N OF HAWAII NEAR 35N150W. 
THE SURFACE TROUGH IS ASSOCIATED WITH DIVERGENCE ALOFT ON THE SW 
SIDE OF AN UPPER ANTICYCLONE CENTERED NEAR 15N127W. ANOTHER 
SURFACE TROUGH IS NOTED FROM 16N112W TO 11N115W...BETWEEN AN 
UPPER ANTICYCLONE CENTERED OVER WEST CENTRAL MEXICO AND THE 
OTHER UPPER ANTICYCLONE NEAR 15N127W. TO THE NORTH...A SHORT 
WAVE TROUGH IS DIGGING INTO THE BASE OF A LONG WAVE TROUGH THAT 
EXTENDS FROM THE NORTHERN ROCKIES THROUGH SOUTHERN CALIFORNIA TO 
NEAR 30N135W. 

FURTHER EAST...GALE FORCE WINDS OVER THE TEHUANTEPEC AREA ARE 
DIMINISHING TO 25 TO 30 KT THIS MORNING...AND WILL CONTINUE TO 
DIMINISH THROUGH TONIGHT AS HIGH PRES OVER THE WESTERN GULF OF 
MEXICO SHIFTS EAST. FURTHER SOUTH...SCATTERED MODERATE 
CONVECTION PERSISTS ALONG THE ITCZ BETWEEN 95W AND 115W. THIS IS 
BEING ENHANCED BY FRESH CROSS-EQUATORIAL FLOW FEEDING TO THE 
ITCZ...AND UPPER DIVERGENCE ON THE SOUTH SIDE OF AN UPPER TROUGH 
EXTENDING FROM CENTRAL MEXICO TO NEAR 15N115W. 

SHIP OBSERVATIONS ALONG WITH JASON ALTIMETER DATA SHOW 8 TO 12 
FT SEAS MAINLY N OF 25N W OF 115W...A COMBINATION OF LOCAL WIND 
WAVES AND NORTHERLY SWELL. SEAS OF 8 TO 10 FT ARE LIKELY NEAR 
GULF OF TEHUANTEPEC...BUT ALSO S OF 12N BETWEEN 95W AND 110W 
WITH SOUTHERLY SWELL CONTRIBUTING.

FOR SATURDAY AND SUNDAY...THE UPPER ANTICYCLONE NEAR 15N127W 
STARTS TO BREAK DOWN AS THIS UPPER TROUGH TO THE NORTH BECOMES 
MORE AMPLIFIED AND PUSHES SE. THIS IN TURN ALLOWS THE SURFACE 
TROUGH NEAR 130W TO WEAKEN. FRESH TO STRONG TRADE WINDS PERSIST 
HOWEVER W OF 120W AS THE SURFACE HIGH PRES NEAR 35N150W SHIFTS E 
TO 35N145W WITH THE RIDGE AXIS BUILDING TOWARD SOUTHERN BAJA. 
FRESH NORTHERLY FLOW BETWEEN THE HIGH PRES AND THE WEST COAST 
WILL INCREASE AND PUSH AS FAR SOUTH AS 22N...FOLLOWING A WEAK 
SURFACE TROUGH MOVING THROUGH THE SW UNITED STATES AND NW 
MEXICO. 

LOOKING AHEAD TO MONDAY...MAIN ISSUE WILL BE PROSPECT OF STRONG 
WINDS IN THE NORTHERN GULF OF CALIFORNIA DUE TO 1035 MB HIGH 
PRES BUILDING OVER THE GREAT BASIN. 

$$
CHRISTENSEN