000
AXPZ20 KNHC 282152
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN NOV 28 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...

INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 09N84W TO 07N92W TO 
LOW PRES NEAR 09N105W TO 09N121W TO 08N140W. SCATTERED MODERATE 
CONVECTION IS FROM 08N TO 12N BETWEEN 98W AND 108W. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION IS NOTED FROM 09N TO 11N 
BETWEEN 122W AND 127W.

...DISCUSSION...

A 1029 MB SURFACE HIGH IS CENTERED N OF THE AREA NEAR 36N137W 
AND IS SHIFTING SE BEHIND A WEAKENING COLD FRONT THAT EXTENDS 
FROM NORTHERN BAJA TO 27N128W. NW WINDS OF 20 TO 25 KT ARE SEEN 
BEHIND THE FRONT PER AN EARLIER WINDSAT PASS. THE FRONT WILL 
WEAKEN AS IT SHIFTS SE TONIGHT...AND DISSIPATE THROUGH CENTRAL 
BAJA BY EARLY MON. THE FRESH TO STRONG WINDS BEHIND THE FRONT 
WILL PERSIST AND DOMINATE THE AREA ALONG AND WEST OF MOST OF THE 
BAJA COAST OUT TO 130W...ACCOMPANIED BY N SWELL OF 8 TO 13 FT. 
ELSEWHERE N OF 12N W OF 115W...ASCAT DATA SHOW FRESH TRADES 
CURRENTLY IN PLACE...AND THESE 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 11 FT TONIGHT AND MON N OF 
12N W OF 115W. 

GULF OF CALIFORNIA...
THE AFOREMENTIONED COLD FRONT IS ALSO MOVING INTO THE NORTHERN 
EXPANSES OF THE GULF OF CALIFORNIA...BRINGING FRESH W TO NW 
FLOW. THIS WILL DIMINISH TONIGHT AS THE FRONT WEAKENS. NW WINDS 
WILL INCREASE TOMORROW AS THE HIGH PRES BEHIND THE FRONT BUILDS 
EAST INTO THE GREAT BASIN NORTH OF THE AREA. 

A WEAK SURFACE TROUGH IS ANALYZED ALONG THE ITCZ FROM 11N121W TO 
09N123W 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 13N125W TO 09N126W BY MON...AND 
FROM 15N127W TO 10N129W BY TUE.

WEAK LOW PRES IS CENTERED NEAR 10N104W ACCOMPANIED BY SCATTERED 
MODERATE CONVECTION. E TO SE WINDS OF 20 KT ARE NOTED WITHIN 120 
NM N SEMICIRCLE OF LOW CENTER PER AN ASCAT PASS FROM AROUND 1600 
UTC. THIS MAY HAVE BEEN ENHANCED IN PART BY THE EASTERLY GAP 
WIND FLOW ORIGINATING OUT OF TEHUANTEPEC. THE LOW PRES IS 
EXPECTED TO WEAKEN TONIGHT AS IT DRIFTS WEST. 

GAP WINDS...
WIND FLOW THROUGH THE GULF OF TEHUANTEPEC CONTINUES TO DIMINISH. 
LATEST OBSERVATIONS INDICATE WINDS OF ONLY 20 KT. IXTEPEC 
OBSERVATION ON THE TEHUANTEPEC COAST IS DOWN TO 15 KT CURRENTLY. 
COLD AIR ADVECTION IN THE SW GULF OF MEXICO HAS TAPERED OFF AS 
HIGH PRES OVER EASTERN U.S. SHIFTS EAST AHEAD OF LOW PRES MOVING 
INTO THE CENTRAL PLAINS. WINDS WILL DECREASE BELOW 20 KT 
TONIGHT. THE NEXT COLD FRONT PUSHES THROUGH THE GULF OF MEXICO 
AND INTO THE GULF OF TEHUANTEPEC AND ADJACENT WATERS WILL BE A 
STRONGER FRONT...AND STORM CONDITIONS ARE POSSIBLE THROUGH THE 
GULF OF TEHUANTEPEC BY WED MORNING. 

FURTHER SOUTH...SHIP OBSERVATIONS NEAR THE GULF OF PAPAGAYO 
INDICATE OVERNIGHT DRAINAGE FLOW IS ALLOWING GAP WINDS TO PULSE 
TO 20 KT. 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.

$$
GR