000
AXPZ20 KNHC 311533
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 UTC TUE DEC 31 2013

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 
1330 UTC.

...SPECIAL FEATURE...                                         
GULF OF TEHUANTEPEC GALE...MEXICAN OBSERVATIONS CONTINUE TO SHOW 
A 9 MB DIFFERENCE IN SEA LEVEL PRES BETWEEN COATZACOALCOS ON THE 
NORTHERN END OF THE ISTHMUS OF TEHUANTEPEC AND SALINA CRUZ ON 
THE SOUTHERN END OF THE ISTHMUS. AN OSCAT PASS FROM 0548 UTC 
SHOWED NEAR GALE FORCE WINDS IN THE GULF PRIOR TO THE PERIOD OF 
MAXIMUM DIURNAL DRAINAGE FLOW. THEREFORE...GALE CONDITIONS ARE 
BELIEVED TO BE IN PLACE NOW AND ARE EXPECTED TO CONTINUE THROUGH 
EARLY WED. HOWEVER...THESE WINDS MAY DIMINISH SLIGHTLY DURING 
THE AFTERNOON TODAY. SEAS WILL BUILD TO 11 FT HERE THIS EVENING. 
THE STRONG PRESSURE GRADIENT BETWEEN THE MONSOON TROUGH TO THE 
SOUTH AND RIDGING EXTENDING FROM THE ARKLATEX REGION OF THE U.S. 
TO NE MEXICO WILL WEAKEN TONIGHT INTO WED WHEN LOW PRESSURE 
DEEPENS IN THE SW GULF OF MEXICO AND LIFTS NORTHWARD AS THE MAIN 
HIGH CENTER OVER THE U.S. SHIFTS EASTWARD. WINDS WILL DIMINISH 
BELOW A STRONG BREEZE AND SEAS BELOW 8 FT IN THE GULF OF 
TEHUANTEPEC BY WED AFTERNOON AS A RESULT.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
THE MONSOON TROUGH AXIS EXTENDS FROM 07N77W TO 06N80W TO 08N85W 
TO 04N95W TO 05N102W. THE ITCZ AXIS EXTENDS FROM 05N102W TO 
08N113W TO 06N127W TO 07N140W. SCATTERED MODERATE CONVECTION 
LIES ON THE E SIDE OF THE MONSOON TROUGH FROM 04N TO 7.5N E OF 
80W TO THE COAST OF COLOMBIA AND PANAMA. 

...DISCUSSION...                                               
LITTLE CHANGE IS EXPECTED IN THE HIGHLY AMPLIFIED LONG-WAVE 
UPPER PATTERN OVER THE FORECAST AREA DURING THE NEXT TWO DAYS. 
THE PATTERN FEATURES A TROUGH ALONG 110W...A RIDGE ALONG 
130W...AND A POSITIVELY TILTED UPPER TROUGH W OF THE AREA AND E 
OF THE HAWAIIAN ISLANDS. STRONG MID-LEVEL SHORTWAVE ENERGY 
WITHIN THE EASTERN TROUGH WILL KICK EASTWARD ACROSS MEXICO TODAY 
INTO WED WHILE SHORTWAVE ENERGY WITHIN THE TROUGHING W OF THE 
AREA WILL MAKE A FUTILE ATTEMPT TO SURMOUNT THE RIDGING TO ITS 
E. THE SOUTHERN STREAM UPPER JET MAXIMA ON THE LEADING EDGE OF 
THESE TROUGHS ARE PUMPING TROPICAL MOISTURE NORTHWARD. A SURFACE 
REFLECTION OF THE EASTERN TROUGH LIES FROM CABO CORRIENTES 
MEXICO TO 11N110W WITH SCATTERED MODERATE CONVECTION FOUND 
WITHIN 150 NM E OF THE TROUGH N OF 16N AND WITHIN 120 NM W OF 
THE TROUGH FROM 14N TO 18N. MOISTURE AHEAD OF THE WESTERN TROUGH 
IS MAINLY MANIFESTED AS SHOWERS AND HIGH CLOUDS NW OF A LINE 
FROM 30N126W TO 12N140W. 

A 1026 MB SUBTROPICAL HIGH NEAR 27N131W IS DRIVING THE MODERATE 
TO FRESH TRADE WINDS FOUND PRIMARILY FROM 08N TO 24N W OF 115W. 
DECAYING LONG-PERIOD NW SWELL DOMINATES WESTERN WATERS WHERE IT 
IS MIXING WITH FRESH NE WIND WAVES ASSOCIATED WITH THE TRADE 
WINDS. THE LEADING EDGE OF THIS BATCH OF NW SWELL WILL PROPAGATE 
SE...PROGRESSING FROM THE SOUTHERN BAJA CALIFORNIA PENINSULA 
THIS MORNING TO MANZANILLO WED MORNING. SEAS OVER 8 FT 
ASSOCIATED WITH THIS SWELL WILL REMAIN CONFINED W OF 120W 
THROUGH THE END OF THE FORECAST PERIOD THU MORNING AND BEGIN TO 
SUBSIDE WED AS THEY MOVE S OF THE AREA OF NORTHEASTERLY TRADE 
WINDS. 

GULF OF PAPAGAYO...AN OSCAT PASS FROM 0546 UTC INDICATED 20-25 
KT WINDS IN THE GULF OF PAPAGAYO...THE COMBINED EFFECT OF STRONG 
TRADE WIND FLOW IN THE SW CARIBBEAN AND LOCAL OVERNIGHT DRAINAGE 
IMPACTS. THESE WINDS WILL DIMINISH LATER THIS MORNING...BUT 
PULSE UP TO 25 KT AGAIN OVERNIGHT TONGIHT AS WELL AS OVERNIGHT 
WED NIGHT. 

$$
SCHAUER