000
AXPZ20 KNHC 291506
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT DEC 29 2012

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 09N83W TO 07N105W WHERE LOW 
LEVEL WINDS SUGGEST A TRANSITION TO ITCZ WHICH EXTENDS TO BEYOND 
07N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED 
FROM 05N AND 09N E OF 83W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WAS NOTED WITHIN 60 NM OF AXIS BETWEEN 97W AND 102W. 
SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 60 NM S OF AXIS 
BETWEEN 110W AND 116W. SCATTERED MODERATE CONVECTION WAS NOTED 
WITHIN 60 NM N OF AXIS BETWEEN 128W AND 134W.

...DISCUSSION...
HIGH PRESSURE 1027 MB IS CENTERED N OF THE AREA NEAR 36N136W 
WITH RIDGE EXTENDING SE TO 27N130W TO 25N118W. THE PRESSURE 
GRADIENT BETWEEN THE RIDGE AND LOWER PRESSURE IN THE VICINITY OF 
THE ITCZ IS MAINTAINING FRESH TO STRONG TRADEWINDS FROM 14N TO 
20N W OF 129W. THE HIGH PRESSURE CENTER WILL SHIFT SOUTHWARD AND 
CLOSER TO THE AREA OVER THE NEXT 24 HOURS WITH THE SURFACE RIDGE 
STRENGTHENING. THIS WILL EXPAND THE AREAL COVERAGE OF FRESH TO 
STRONG TRADEWINDS OVER THE NEXT COUPLE OF DAYS.  

A WEAK COLD FRONT IS PASSING E ACROSS THE NORTH CENTRAL WATERS 
NE OF THE RIDGE ACCOMPANIED BY ONLY A 10-15 KT SW-W-NW WIND 
SHIFT. EXPECT THE FRONT TO WEAKEN FURTHER AS IT REACHES THE 
NORTHERN BAJA PENINSULA ON SUN...AND PASS THROUGH THE GULF OF 
CALIFORNIA SUN NIGHT. 

NORTHERLY SWELLS CONTINUE TO PREVAIL OVER MUCH OF THE AREA N OF 
20N W OF 110W WITH THE NORTHERLY SWELLS MIXING WITH NE TRADEWIND 
SWELL BETWEEN 10N AND 20N AND W OF 115W. A NEW SET OF NW SWELLS 
WITH SEAS IN THE 10 FT RANGE HAS MOVED INTO THE AREA N OF 20N 
BEHIND THE COLD FRONT MENTIONED ABOVE. THESE SWELLS WILL SPREAD 
EASTWARD BEHIND THE FRONT WHILE SLOWLY DISSIPATING TODAY. A 
FRESH SET OF NORTHERLY SWELLS WILL ENTER THE NORTHERN PART OF 
THE FORECAST AREA TONIGHT...WITH SEAS REACHING NEAR 12 FT OVER 
THE NORTH CENTRAL PART OF THE AREA BY SUN MORNING. 

GULF OF TEHUANTEPEC...A COLD FRONT HAS SHIFTED E OF THE BAY OF 
CAMPECHE THIS MORNING. NORTHERLY WINDS HAVE STARTED TO SURGE 
THROUGH THE CHIVELA PASS. WINDS WILL RAMP UP TO NEAR GALE FORCE 
LATER THIS MORNING...THEN TO GALE FORCE THIS AFTERNOON. WINDS 
WILL FURTHER INCREASE TO NEAR STORM FORCE TONIGHT THROUGH 
SUNRISE SUN WITH SEAS BUILDING TO NEAR 18 FT BY SUN MORNING. 
GALE CONDITIONS WILL CONTINUE THROUGH SUN NIGHT...WITH WINDS 
EXPECTED TO DIMINISH BELOW GALE FORCE BY LATE MON MORNING. 

WINDS CONTINUE TO PULSE ACROSS THE GULF OF PAPAGAYO. TRADEWINDS 
WILL INCREASE OVER THE CARIBBEAN WATERS TODAY WHICH WILL LEAD TO 
A MORE PERSISTENT PAPAGAYO JET WITH STRONG WIND FLOW ACROSS THE 
GULF OF PAPAGAYO STARTING TONIGHT. 

$$
AL