000
AXPZ20 KNHC 290323
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON NOV 29 2010

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...

INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 09N84W TO 07N92W TO 
LOW PRES NEAR 10N106W TO A SECOND LOW PRES NEAR 11N114W TO 
09N123W TO 08N140W. SCATTERED MODERATE CONVECTION IS WITHIN 60 
NM EITHER SIDE OF AXIS FROM 98W AND 102W. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS FROM 08N TO 11N BETWEEN 120W AND 
127W.

...DISCUSSION...

A 1027 MB SURFACE HIGH CENTERED N OF THE AREA NEAR 35N134W 
EXTENDS A RIDGE SE OVER THE FORECAST WATERS TO NEAR 20N110W. THE 
HIGH WILL SHIFT  E BEHIND A DISSIPATING COLD FRONT THAT EXTENDS 
ACROSS NW MEXICO AND NORTHERN BAJA CALIFORNIA PENINSULA. THE 
TIGHT 
PRES GRADIENT BETWEEN THIS HIGH AND STRONG LOW PRES OVER THE 
CENTRAL PLAINS OF U.S. IS PRODUCING NW WINDS OF 20 TO 25 KT 
ALONG AND WEST OF THE BAJA COAST MAINLY N OF 23N...ACCOMPANIED 
BY NW SWELL OF 8 TO 12 FT. ELSEWHERE N OF 12N W OF 115W...ASCAT 
DATA SHOW FRESH TRADES CURRENTLY IN PLACE...AND THESE WINDS WILL 
LIKELY PERSIST FOR THE NEXT SEVERAL DAYS AS THE HIGH PRES TO THE 
NORTH SHIFTS E TOWARD THE CALIFORNIA COAST. SEAS WILL RUN 8 TO 
10 FT TONIGHT AND SLIGHTLY SUBSIDE TO 9 FT ON MON N OF 12N W OF 
115W. 

EXPECT A SUBSTANTIAL INCREASE IN WINDS AND SEAS ALONG THE GULF 
OF CALIFORNIA IN ABOUT 24 HOURS AS THE HIGH PRES BEHIND THE 
AFOREMENTIONED FRONT BUILDS EAST INTO THE GREAT BASIN NORTH OF 
THE AREA. MARINE GUIDANCE SUGGESTS NW WINDS OF 20 TO 30 KT AND 
BUILDING SEAS TO AROUND 10 FT ACROSS THE GULF INTO THE PACIFIC 
OCEAN N OF 20N E OF 110W BY EARLY TUE MORNING. 

A WEAK SURFACE TROUGH IS ANALYZED ALONG THE ITCZ FROM 12N124W TO 
09N125W DRIFTING WEST. SOME OF THE COMPUTER MODELS SHOW THIS 
FEATURE PERSISTING ALONG THE ITCZ THROUGH MIDWEEK. PRES GRADIENT 
BETWEEN THE TROUGH AND HIGH PRES TO THE N WILL GENERATE AN AREA 
OF NE WINDS 20 TO 25 KT NEAR THE NORTHERN END OF THE TROUGH 
WHICH IS FORECAST TO EXTEND FROM 13N124W TO 09N127W BY MON AND 
FROM 14N126W TO 10N130W BY TUE.

WEAK LOW PRES WITHIN THE ITCZ IS CENTERED NEAR 10N106W 
ACCOMPANIED BY SCATTERED MODERATE CONVECTION. THIS SYSTEM WILL 
CONTINUE TO DRIFT WWD. A SECOND WEAK LOW IS ALSO EMBEDDED WITHIN 
THE ITCZ NEAR 11N114W AND IS FORECAST TO DISSIPATE IN ABOUT 24 
HOURS. SATELLITE PICTURES SHOW A SWIRL OF LOW CLOUDS ASSOCIATED 
WITH THIS LOW.  

GLOBAL MODELS SHOW BROAD LOW PRES FORMING OVER THE SW CARIBBEAN 
AND SOUTHERN CENTRAL AMERICA MON AND TUE. SW FLOW WILL INCREASE 
S OF COSTA RICA AND PANAMA TUE...FEEDING INTO THE DEVELOPING LOW 
PRES. LOOKING AHEAD...THE MODELS INDICATE LOW PRES FORMING OFF 
THE PACIFIC COAST OF COSTA RICA WED...ENHANCING WINDS AND SEAS.

GAP WINDS...
WIND FLOW THROUGH THE GULF OF TEHUANTEPEC DIMINISHED TO BELOW 20 
KT. IXTEPEC OBSERVATION ON THE TEHUANTEPEC COAST IS DOWN TO 10 
KT CURRENTLY. A STRONGER COLD FRONT IS EXPECTED TO IMPACT THE 
WESTERN GULF OF MEXICO LATE TUE AND WILL DELIVER ANOTHER ROUND 
OF GALE FORCE WINDS TO THE GULF OF TEHUANTEPEC...POSSIBLE 
APPROACHING STORM STRENGTH WED MORNING. THE 18Z RUN OF THE GFS 
MODEL SUGGESTS WINDS OF 35 TO 50 KT WITH SEAS BUILDING TO 18 FT 
AT 12Z WED WHILE THE NAM INDICATES GALE FORCE WINDS IN THE 30 TO 
40 KT RANGE AT THE SAME TIME.   

OVERNIGHT DRAINAGE FLOW IS ALLOWING GAP WINDS TO PULSE TO 20 KT 
ACROSS THE GULF OF PAPAGAYO DURING THE EARLY MORNING HOURS. THIS 
WEATHER PATTERN IS FORECAST TO PERSIST OVER THE NEXT COUPLE OF 
DAYS.

$$
GR