000 AXPZ20 KNHC 170325 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU DEC 17 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0330 UTC. ...SPECIAL FEATURE... A STORM WARNING IS NOW IN EFFECT FOR THE GULF OF TEHUANTEPEC. A COLD FRONT CURRENTLY EXTENDING FROM SE LOUISIANA TO NE MEXICO IS FORECAST 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 OVERNIGHT THU NIGHT. A 1031 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...50-55 KT...LATE FRI AFTERNOON AND FRI NIGHT BEFORE DIMINISHING SLIGHTLY TO THE 40-45 KT RANGE OVERNIGHT FRI THROUGH SUN. SEAS DOWNSTREAM OF THE GULF OF TEHUANTEPEC WILL BUILD TO 22 FT BY FRI EVENING. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... SURFACE TROUGH EXTENDS FROM 07N78W TO 07N90W TO 08N105W. THE ITCZ CONTINUES FROM 08N105W TO 09N125W TO BEYOND 06N140W. NO SIGNIFICANT CONVECTION NOTED. ...DISCUSSION... A 1030 MB HIGH PRES LOCATED N OF AREA NEAR 34N135W IS SLIPPING SLOWLY SOUTHWARD AND BECOMING MORE E-W ORIENTED. ASSOCIATED RIDGE EXTENDS 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 TO 23N. 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 14 FT PER A 0000 UTC ALTIMETER PASS. 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 TRADE 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 IS FORECAST TO MOVE INTO THE AREA EARLY FRI AND EXTEND FROM 30N133W TO 27N140W BY FRI EVENING...AND FROM 30N126W TO 25N140W EARLY SAT. BUILDING 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 HAS RESULTED IN NW TO N WINDS OF 20 TO 25 KT IN THE GULF OF CALIFORNIA PER SHORT TERM NWP MODEL FORECAST 10-M WINDS. THESE WINDS WILL SPREAD DOWN THE ENTIRE LENGTH OF THE GULF AND THE ADJACENT NE PACIFIC BY LATE THU WITH ASSOCIATED SEAS BUILDING TO 8-9 FT. WINDS AND SEAS DIMINISH TO 20 KT AND LESS THAN 8 FT BY LATE FRI. ANOTHER SET OF LONG PERIOD...20 TO 22 SECOND...NW SWELL IS CURRENTLY MOVING INTO THE FORECAST AREA N OF 20N TO THE FAR NW PORTION OF BAJA CALIFORNIA. THIS SWELL EVENT WILL SPREAD SE COVERING THE WATERS N OF 20N W OF CENTRAL BAJA CALIFORNIA TONIGHT...AND FROM CABO CORRIENTES TO NEAR 04N125W BY LATE THU...REACHING FROM ACAPULCO MEXICO TO THE EQUATOR EARLY FRI. 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 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. $$ COBB