000
AXPZ20 KNHC 312103
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC WED DEC 31 2014

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC. 
 
...SPECIAL FEATURES...                                        
HIGH PRES BUILDING ACROSS SOUTHERN MEXICO HAS TIGHTENED THE 
PRESSURE GRADIENT AND INCREASED GAP WINDS THROUGH THE CHIVELA 
PASS INTO THE GULF OF TEHUANTEPEC TO 20 TO 30 KT. THE PRESSURE 
GRADIENT WILL FURTHER TIGHTEN TONIGHT FOR WINDS TO INCREASE TO 
MINIMAL GALE FORCE...N-NE 30 TO 35 KT WITH SEAS 10 TO 12 FT. THE 
GALE WILL BE SHORT LIVED AND WINDS WILL DECREASE TO BELOW GALE 
FORCE BY THU AFTERNOON...THEN FURTHER DECREASE TO 20 KT LESS 
BY EARLY FRI.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
THE MONSOON TROUGH EXTENDS FROM 06N77W TO 04N84W WHERE LOW LEVEL 
WINDS SUGGEST A TRANSITION TO ITCZ WHICH EXTENDS TO 06N89W TO 
04.5N94W TO 06N106W TO 04N115W TO BEYOND 08N140W. SCATTERED 
MODERATE CONVECTION WAS NOTED WITHIN 30 NM EITHER SIDE OF THE 
ITCZ W OF 135W.

...DISCUSSION... 

A WEAK COLD FRONT EXTENDS ACROSS BAJA CALIFORNIA NORTE TO 
28N121W TO 30N128W. FRESH NORTHERLY FLOW IS CROSSING 30N BEHIND 
THE FRONT...ACCOMPANIED BY SHORT PERIOD SWELL OF 8 TO 9 FT. THE 
SWELL IS EXPECTED SUBSIDE BELOW 8 FT THU. 

A SURFACE RIDGE EXTENDS S OF THE COLD FRONT FROM 30N130W TO 
18N111W WHILE LOW PRESSURE IS CENTERED W OF THE AREA NEAR 
29N157W. THE PRESSURE GRADIENT BETWEEN THE RIDGE AND LOW 
PRESSURE IS SUPPORTING FRESH TO STRONG WINDS OVER THE NW WATERS 
WITH SEAS IN THE 8 TO 11 FT RANGE. A SMALL AREA OF FRESH TO 
STRONG WINDS WITH SEAS GREATER THAN 8 FT WILL CONTINUE OVER THE 
FAR NW WATERS THROUGH FRI AFTERNOON. 

THE RELATIVELY WEAK SUBTROPICAL RIDGE IS MAINTAINING ONLY 
MODERATE TO OCCASIONALLY FRESH TRADES N OF THE ITCZ W OF 120W. 
LITTLE CHANGE IS EXPECTED.

STRONG GAP WINDS WILL PREVAIL OVER THE GULF OF PAPAGAYO DURING 
THE NEXT COUPLE OF DAYS IN RESPONSE TO THE STRONG HIGH PRES 
BUILDING N OF THE AREA OVER THE UNITED STATES. 

$$
AL