000 AXPZ20 KNHC 182204 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI DEC 18 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...SPECIAL FEATURE... A STORM WARNING REMAINS IN EFFECT FOR THE GULF OF TEHUANTEPEC. COOL AND DRY CONTINUES TO PUSH ACROSS THE ISTHMUS OF TEHUANTEPEC INTO THE GULF OF TEHUANTEPEC. AN ASCAT PASS FROM 1530 UTC CONFIRMED GALE FORCE WINDS ARE ONGOING ACROSS THE GULF OF TEHUANTEPEC. THESE WINDS ARE EXPECTED TO INCREASE TO STORM FORCE LATER EVENING AS HIGH PRES BUILDS OVER THE NE GULF OF MEXICO BEHIND THE FRONT. THE STORM FORCE CONDITIONS WILL PERSIST INTO SAT AFTERNOON WITH SEAS BUILDING TO 22 FT TONIGHT. THE WINDS WILL GRADUALLY DIMINISH TO A MINIMAL GALE THROUGH SUN AFTERNOON...THEN DIMINISH FURTHER TO BELOW GALE FORCE BY LATE SUN. LOOKING AHEAD...GAP WINDS WILL DIMINISH BELOW 20 KT BY MON NIGHT. THE STRONG AND PERSISTENT STORM AND GALE CONDITIONS WILL PRODUCE A LONG AND BROAD PLUME OF SHORT PERIOD SEAS THAT WILL MIX WITH LONGER PERIOD NW SWELL MOVING INTO THE AREA. THIS MIX OF NE AND NW SWELL WILL COVER A LARGE AREA BY SUNDAY SOUTH OF 14N BETWEEN ROUGHLY 92W AND 112W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A SURFACE TROUGH FROM 05N77W TO 04N80W TO 05N100W. THE ITCZ AXIS REACHES FROM 05N100W TO 07N117W TO 02N130W TO BEYOND 02N140W. SCATTERED MODERATE CONVECTION IS NOTED FROM 02N TO 06N E OF 85W...FROM 01.5N TO 04N BETWEEN 90W AND 93W...AND WITHIN 60 NM EITHER SIDE OF ITCZ BETWEEN 130WAND 135W. ...DISCUSSION... N OF 15N E OF 120W...A TIGHT PRES GRADIENT BETWEEN A TROUGH OVER NW MEXICO FROM SOUTHERN ARIZONA TO OFF CABO CORRIENTES...AND PERSISTENT 1022 MB HIGH PRES CENTERED NEAR 29N129W WILL ALLOW STRONG NW WINDS ACROSS THE GULF OF CALIFORNIA FOR A FEW MORE HOURS...AS NOTED IN A PAIR OF RECENT ASCAT SATELLITE PASSES AND A SHIP OBSERVATION FROM SE OF LOS CABOS. THESE WINDS WILL DISSIPATE AS THE HIGH PRES WEAKENS AHEAD OF AN APPROACHING COLD FRONT. SHIP OBSERVATIONS ALSO INDICATED WAVE HEIGHTS TO 8 FT OFF BAJA CALIFORNIA SUR...LIKELY IN NW SWELL. THESE WAVE HEIGHTS ARE SUBSIDING HOWEVER AS THE SWELL DECAYS ACROSS THE REGION. LOOKING AHEAD...A WEAK COLD FRONT WILL MOVE INTO THE AREA BY EARLY SUN...THEN BECOME DIFFUSE. ANOTHER GROUP OF LONG PERIOD NW SWELL WILL ACCOMPANY THE FRONT AND START TO MOVE INTO THE WATERS OFF BAJA CALIFORNIA NORTE AND GUADALUPE ISLAND BY LATE SUN...EVENTUALLY SWEEPING ALONG THE ENTIRE COAST OF THE BAJA CALIFORNIA PENINSULA THROUGH LATE MON WITH WAVE HEIGHTS 8 TO 9 FT. S OF 15N E OF 110W...ASIDE FROM THE EFFECTS OF THE TEHUANTEPEC GAP EVENT AND ITS RELATED PLUME OF MIXED NE AND NW SEAS...THE MAIN FORECAST ISSUE WILL INVOLVE STRONG GAP WINDS ALSO PUSHING THROUGH THE GULF OF PAPAGAYO STARTING TONIGHT. BUILDING HIGH PRES OVER THE GULF OF MEXICO IS SUPPORTING STRONG TRADE WINDS IN THE CARIBBEAN...SUBSEQUENTLY MOVING THROUGH THE GULF OF PAPAGAYO. STRONG PULSES WILL BE PRIMARILY AT NIGHT BUT ALSO PERSIST THROUGH SAT WITH SEAS BUILDING 8 TO 10 FT DOWNSTREAM AS FAR AS 90W BY SUNDAY. ELSEWHERE...AN AREA OF STRONG TRADE WINDS BETWEEN ROUGHLY 05N TO 18N W OF 130W HAD BEEN WEAKENING AND SHIFTING FARTHER SOUTH AS THE 1022 MB HIGH PRES NEAR 29N129W WEAKENS AND SHIFTS SOUTH AHEAD OF THE APPROACHING COLD FRONT. THE FRONT WILL SHIFT EASTWARD ACROSS THE WATERS N OF 22N THROUGH SAT. HIGH PRES BUILDING BEHIND THE FRONT WILL ALLOW THESE TRADE WINDS TO EXPAND IN AREA THROUGH SAT AS A RESULT. MEANWHILE ALTIMETER SATELLITE DATA INDICATE SEAS 8 TO 12 FT LIKELY IN A MIX OF PRE-EXISTING NW SWELL AND SHORTER PERIOD NE SWELL FROM THE TRADE WINDS. THIS WILL BE REINFORCED BY ANOTHER PUSH OF NW SWELL ACROSS THE AREA WITH NEW SWELL OF 8 TO 10 FT REACHING FROM ROUGHLY GUADALUPE ISLAND TO 15N140W BY LATE SUNDAY. $$ CHRISTENSEN