000
AXPZ20 KNHC 100924
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI DEC 10 2010

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS FROM 05N77W TO 06N83W 
TO 05N100W TO 08N114W TO 09N140W. SCATTERED MODERATE CONVECTION  
IS WITHIN 90 NM N OF AXIS FROM 108W TO 114W. 

...DISCUSSION...
A 1025 MB SURFACE HIGH PRES CENTERED NEAR 29N130W EXTENDS A 
RIDGE OVER THE FORECAST WATERS COVERING ROUGHLY THE REGION N OF 
15N W OF 110W. AN AREA OF FRESH TRADE WINDS IS NOTED ON THE 
SOUTHERN PERIPHERY OF THE RIDGE PARTICULARLY FROM 08N TO 18N W 
OF 122W. AN ASCAT PASS FROM 0608 UTC VERIFIED THE PRESENCE OF 
THESE WIND SPEEDS. AN EARLIER ASCAT PASS AND SHIP OBSERVATIONS 
CONFIRMED THE EXISTENCE OF NW WINDS OF 20 KT N OF 27N E OF 120W 
TO THE COAST OF BAJA CALIFORNIA PENINSULA DUE TO THE PRES 
GRADIENT BETWEEN THIS RIDGE AN LOWER PRES ACROSS WESTERN MEXICO. 
A PAIR OF TROUGHS ARE OBSERVED WITHIN THE ITCZ. ONE EXTENDS FROM 
12N110W TO 08N115W AND THE OTHER IS ALMOST EXITING THE FORECAST 
AREA AND RUNS FROM 15N138W TO 09N141W. THE HIGH PRES WILL REMAIN 
QUASI-STATIONARY OVER THE NEXT COUPLE OF DAYS AS THE FIRST 
SURFACE TROUGH MIGRATES WEST. THIS PATTERN WILL MAINTAIN THE 
FRESH TRADES.

LONG PERIOD NW SWELL...WAVE PERIODS BETWEEN 14 TO 16 SECONDS...
WITH SIGNIFICANT WAVE HEIGHTS OF 10 TO 14 FT WILL CONTINUE TO 
PROPAGATE SE ACROSS MOST OF THE REGIONAL WATERS W OF 110W IN 
ABOUT 24 HOURS. THE SWELL WILL DECAY TO 8 TO 10 FT IN 48 
HOURS...BUT EXTEND FURTHER EAST REACHING 100W.  

GAP WINDS...
AT 04Z...IXTEPEC MEXICO ON THE SOUTHERN END OF THE ISTHMUS OF 
TEHUANTEPEC REPORTED SUSTAINED WINDS OF 30 KT WITH GUSTS TO 40 
KT. WINDS ARE FORECAST TO DIMINISH BELOW GALE FORCE ACROSS THE 
GULF OF TEHUANTEPEC IN ABOUT 6 HOURS AS HIGH PRES N OF THE AREA 
SHIFT EAST. AN ASCAT PASS FROM 0246 UTC INDICATED NE WINDS OF 20 
TO 25 KT ACROSS THE GULF OF FONSECA AND ADJACENT WATERS...AND NE 
WINDS OF 20 KT THROUGH THE GULF OF PAPAGAYO. THESE GAP WIND 
EVENTS ARE EXPECTED TO PERSIST DURING THE NEXT 36 HOURS DUE TO 
ENHANCED FLOW MAINLY OVERNIGHT AND MORNING OVER THE CARIBBEAN 
AND NOCTURNAL DRAINAGE. STATIONARY LOW PRES OFF NE PANAMA IN THE 
SW CARIBBEAN WILL DELIVER FRESH TO STRONG NE FLOW THROUGH THE 
GULF OF PANAMA THROUGH ABOUT 48 HOURS. 

LOOKING AHEAD...ANOTHER TEHUANTEPEC EVENT WILL BE INDUCED BY A 
STRONG COLD FRONT MOVING ACROSS THE GULF OF MEXICO DURING THE 
UPCOMING WEEKEND. COLD AIR ADVECTION IN THE WAKE OF THE FRONT 
WILL FUNNEL TROUGH THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC 
STARTING SUN NIGHT. ACCORDING TO THE COMPUTER MODELS...ANOTHER
GALE FORCE WIND EVENT COULD TAKE PLACE.

$$
GR