000
AXPZ20 KNHC 070325
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT JAN 07 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

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

THE MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO 05N89W. THE ITCZ 
AXIS EXTENDS FROM 05N89W TO 03N96W TO 08N116W TO 07N126W TO 
09N135W TO BEYOND 07N140W. NO SIGNIFICANT CONVECTION WAS NOTED. 

...DISCUSSION...

A 1030 MB HIGH PRES IS CENTERED N OF THE AREA NEAR 38N133W WITH 
RIDGE EXTENDING SE TO NEAR 22N118W. THE PRESSURE GRADIENT 
BETWEEN THE AREA OF HIGH PRESSURE AND LOWER PRESSURE IN THE 
VICINITY OF THE ITCZ IS MAINTAINING FRESH TRADEWINDS FROM 10N TO 
15N W OF 130W. LONG PERIOD NW SWELL CONTINUES TO MOVE SE ACROSS 
THE AREA...WITH COMBINED SEAS 8 TO 14 FT CURRENTLY COVERING MUCH 
OF THE AREA W OF 120W. THE SEAS WILL CONTINUE TO SPREAD SE WHILE 
SLOWLY SUBSIDING THROUGH SUN. 

THE PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE CENTER MENTIONED 
ABOVE AND TROUGHING OVER THE SW UNITED STATES IS PRODUCING FRESH 
NORTHERLY WINDS N OF 27N BETWEEN 118W AND 130W. AS THE AREA OF 
HIGH PRESSURE WEAKENS OVER THE WEEKEND...WINDS WILL DIMINISH 
BELOW 20 KT BY SUN MORNING. 

GULF OF TEHUANTEPEC...WITH THE AIR MASS OVER THE GULF OF MEXICO 
FURTHER MODIFIED...THE DENSITY DIFFERENCE BETWEEN THE AIR MASS 
OVER THE GULF OF MEXICO AND THE EASTERN PACIFIC HAS DECREASED. 
THIS HAS REDUCED FLOW THROUGH THE CHIVELA PASS INTO THE GULF OF 
TEHUANTEPEC...AND WINDS HAVE DIMINISHED BELOW 20 KT. 

GULF OF PAPAGAYO...FRESH TO STRONG NORTHEASTERLY GRADIENT WIND 
OVER THE WESTERN CARIBBEAN IS FLOWING THROUGH THE GAP IN THE 
TOPOGRAPHY OVER NICARAGUA INTO THE GULF OF PAPAGAYO. WINDS WILL 
PEAK NEAR 25 KT DURING THE EARLY MORNING HOURS WITH THE ADDED 
COMPONENT OF NOCTURNALLY DRIVEN KATABATIC WINDS.

N TO NE SWELL PRODUCED FROM THE COMBINED STRONG GAP FLOW FROM 
PAPAGAYO AND TEHUANTEPEC COVERS MUCH OF THE AREA S OF 15N 
BETWEEN 100W AND 120W. THESE SWELLS ARE MIXING WITH NW SWELL 
CAUSING CONFUSED SEAS. 

HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE GREAT BASIN REGION 
OVER THE WEEKEND. THIS WILL TIGHTEN THE PRES GRADIENT THROUGH 
THE GULF OF CALIFORNIA AND LEAD TO NWLY WINDS INCREASING TO 20 
TO 25 KT BY SUN MORNING. 

$$
AL