000 AXPZ20 KNHC 161526 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC WED DEC 16 2015 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 FEATURE... A GALE WARNING IS IN EFFECT FOR THE GULF OF TEHUANTEPEC. A STRONG COLD FRONT THAT WILL MOVE OFF THE COAST OF THE TEXAS COAST THIS MORNING IS EXPECTED TO REACH THE CENTRAL BAY OF CAMPECHE THU EVENING. NORTHERLY WINDS BEHIND THE FRONT WILL BEGIN TO SPILL THROUGH THE ISTHMUS OF TEHUANTEPEC THU EVENING AND QUICKLY REACH GALE FORCE AFTER MIDNIGHT THU NIGHT. A 1030 MB HIGH PRES CENTER WILL MOVE INTO SOUTH-CENTRAL TEXAS BEHIND THE COLD FRONT ON FRI PRODUCING A VERY STRONG PRES GRADIENT ACROSS THE ISTHMUS OF TEHUANTEPEC AND FORCING A VERY STRONG AND BROAD GULF OF TEHUANTEPEC GAP WIND EVENT FRI THROUGH THE UPCOMING WEEKEND...WITH WINDS EXPECTED TO REACH STORM FORCE LATE FRI AFTERNOON AND EVENING...BEFORE WINDS DIMINISH VERY SLIGHTLY TO THE 40-45 KT RANGE FRI NIGHT THROUGH SAT NIGHT. SEAS DOWNSTREAM OF TEHUANTEPEC WILL BUILD GREATER THAN 20 FT BY FRI EVENING. A STORM WARNING MAY BE ISSUED WITH THE NEXT FORECAST PACKAGE. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 08N82W TO 07N90W TO 08N95W TO 07N105W. THE ITCZ CONTINUES FROM 07N105W TO 08N120W TO 09N128W TO BEYOND 05N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 180 NM S OF TROUGH BETWEEN 86W AND 88W...FROM 08N TO 10N BETWEEN 125W AND 130W...WITHIN 60 NM N OF AXIS BETWEEN 131W AND 134W...AND FROM 04N TO 07N W OF 132W. ...DISCUSSION... A 1031 MB HIGH PRES LOCATED N OF AREA NEAR 36N134W EXTENDS A RIDGE ACROSS THE N WATERS TO NEAR 20N110W. THE PRESSURE GRADIENT BETWEEN THE HIGH AND LOWER PRESSURES IN THE VICINITY OF THE ITCZ MAINTAINS A BROAD AREA OF 20-25 KT TRADE WINDS IN AN AREA GENERALLY W OF 122W AND N OF THE ITCZ. LARGE NW SWELL CONTINUES TO MOVE THROUGH THE FORECAST REGION AND IS MIXING WITH NE WIND WINDS IN THIS TRADE WIND ZONE TO PRODUCE SEAS OF GENERALLY 10 TO 13 FT ACCORDING TO A PAIR OF ALTIMETER PASSES. THE LONG PERIOD NW SWELL IS ALSO PRODUCING SEAS TO 8 TO 11 FT ACROSS THE REMAINDER OF THE FORECAST WATERS N OF 05N AND W OF 110W. THIS AREA OF FRESH TO STRONG WINDS WILL GRADUALLY SHRINK AND SHIFT SW OVER THE NEXT FEW DAYS AS THE HIGH PRES MOVES SE AND GRADUALLY WEAKENS. A COLD FRONT WILL REACH 30N140W BY FRI MORNING EXTENDING FROM 30N130W TO 26N140W BY FRI NIGHT...AND FROM 30N126W TO 25N140W ON SAT MORNING. A STRONG HIGH PRES IS EXPECTED IN THE WAKE OF THE FRONT. THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE GREAT BASIN AND A DEVELOPING SURFACE TROUGH ALONG THE COAST OF MEXICO IS FORECAST TO TIGHTEN IN THE VICINITY OF THE GULF OF CALIFORNIA TODAY AND ALLOW NW TO N WINDS TO INCREASE TO 20 TO 25 KT THIS EVENING...AND CONTINUE THROUGH FRI AS THESE WINDS SPREAD THE ENTIRE LENGTH OF THE GULF. GLOBAL MODELS SUGGESTS WINDS COULD REACH 30 KT THU EVENING AND NIGHT ACROSS CENTRAL PORTIONS. ASSOCIATED SEAS WILL BUILD TO 8-9 FT ON THU. ANOTHER SET OF LONG PERIOD...20 TO 22 SECOND...NW SWELL IS CURRENTLY MOVING INTO THE FAR NW PORTION OF THE FORECAST AREA. THIS SWELL EVENT WILL SPREAD SE COVERING MAINLY THE WATERS N OF 20N W OF CENTRAL BAJA CALIFORNIA TONIGHT...FROM CABO CORRIENTES TO NEAR 04N123W BY LATE THU...REACHING FROM ACAPULCO MEXICO TO THE EQUATOR ON EARLY FRI MORNING. THIS VERY LONG PERIOD SWELL MOVING THROUGH THE FORECAST WATERS WILL GENERATE VERY LARGE AND POWERFUL SURF ACROSS THE REEFS...SHOALS AND COASTAL ZONES OF THE MEXICO AND CENTRAL AMERICA DURING THE NEXT 48 HOURS. MARINE INTERESTS FROM BAJA CALIFORNIA AND NEARBY ISLANDS SOUTHWARD SHOULD REMAIN ALERT FOR THESE HAZARDOUS MARINE CONDITIONS AND ONGOING DANGEROUS SURF CONDITIONS. $$ GR