000
AXPZ20 KNHC 311544
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC. 
 
...SPECIAL FEATURES...                                        
HIGH PRES BUILDING SOUTHWARD ACROSS SOUTHERN MEXICO HAS 
INCREASED THE NORTHERLY GAP WINDS THROUGH THE GULF OF 
TEHUANTEPEC TO 20 TO 30 KT WITH SEAS 8 TO 10 FT. THE PRES 
GRADIENT WILL TIGHTEN ENOUGH TONIGHT FOR WINDS TO INCREASE TO 
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 
LATE THU...AND FURTHER DECREASE TO 20 KT LESS LATE THU NIGHT.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
THE MONSOON TROUGH EXTENDS FROM THE COAST OF COLOMBIA NEAR 
05N77W TO 05N90W...WHERE IT TRANSITIONS TO THE ITCZ. THE ITCZ 
CONTINUES FROM 05N90W TO 06N105W TO 05N115W TO WEST OF 07N140W. 
SCATTERED MODERATE CONVECTION IS NOTED WITHIN 60 NM EITHER SIDE 
OF THE ITCZ W OF 135W.

...DISCUSSION...
AN UPPER TROUGH REACHING FROM 30N120W TO 17N120W IS MOVING 
EASTWARD AND COMING INTO PHASE WITH ANOTHER MID/UPPER IMPULSE 
MOVING ACROSS SOUTHERN CALIFORNIA...NORTHERN BAJA CALIFORNIA 
NORTE AND THE NORTHERN PORTION OF THE CALIFORNIA. THE MERGED 
TROUGHS ARE SUPPORTING A WEAK SURFACE COLD FRONT NOW MOVING 
ACROSS BAJA CALIFORNIA NORTE AND REACHING FROM SW ARIZONA TO 
30N116W TO TO 30N125W. FRESH NORTHERLY FLOW IS CROSSING 30N 
BEHIND THE FRONT...ACCOMPANIED BY SHORT PERIOD SWELL OF 8 TO 10 
FT. THE SWELL IS EXPECTED TO REACH AS FAR SOUTH AS 28N BY LATE 
TODAY BEFORE DECAYING BELOW 8 FT OVERNIGHT. 

FARTHER WEST...FRESH TO STRONG SE FLOW AND SEAS OF 8 TO 10 FT 
PERSIST N OF 25N W OF 135W...BETWEEN A SURFACE RIDGE OFF THE 
WEST COAST OF THE UNITED STATES AND LOW PRES CENTERED N OF 
HAWAII. THE WINDS WILL DIMINISH 20 KT OR LESS BY LATE 
TODAY...BUT SEAS 8 FT OR GREATER WILL PERSIST THROUGH MUCH OF 
THU. LOOKING AHEAD...THE GRADIENT BETWEEN THE LOW PRES TO THE 
WEST AND THE RIDGING MAINLY TO THE NE AND EAST OF THIS AREA WILL 
ALLOW SE WINDS TO INCREASE AGAIN BY SAT WITH SEAS BUILDING TO 8-
10 FT.

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 PULSE THROUGH THE GULF OF PAPAGAYO OVER 
THE NEXT COUPLE OF NIGHTS IN RESPONSE TO THE STRONG HIGH PRES 
BUILDING N OF THE AREA OVER THE UNITED STATES. 

GULF OF CALIFORNIA...AN ASCAT PASS FROM 01 UTC YESTERDAY EVENING 
INDICATED FRESH TO STRONG SW FLOW OVER THE NORTHERN GULF OF 
CALIFORNIA AHEAD OF THE FRONT. THIS HAS LIKELY DIMINISHED WITH 
MODERATE TO FRESH NW FLOW PERSISTING. 

$$
CHRISTENSEN