000 AXPZ20 KNHC 191601 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU DEC 19 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 1500 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM 10N75W TO 11N83W TO 05.5N93W TO 06N101W...WHERE IT TRANSITIONS TO ITCZ...CONTINUING ON TO 09N109W TO 08N140W. SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 120 NM EITHER SIDE OF ITCZ W OF 102W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN AREA FROM 13N140W TO 20N133W TO 20N140W TO 13N140W. ...DISCUSSION... GULF OF TEHUANTEPEC...NORTHERLY GALES HAVE ENDED OVERNIGHT AS SOUTHERLY RETURN FLOW HAS BECOME ESTABLISHED ACROSS THE GULF OF MEXICO. A MODEST PLUME OF N TO NE WINDS 20-25 KT CURRENTLY EXTENDS WITHIN 45 NM EITHER SIDE OF A LINE FROM 16N95W TO 15N95W TO 13N96W...WHERE SEAS ARE AS HIGH AS 11 FT. WINDS AND SEAS WILL CONTINUE TO SUBSIDE TODAY AND DIMINISH TO LESS THAN 20 KT AND BELOW 8 FT BY THIS EVENING. THE NEXT NORTHERLY SURGE WILL BEGIN LATE SUN NIGHT AND IS EXPECTED TO REACH GALE FORCE BY SUNRISE ON MON. THIS WILL LIKELY BE ANOTHER STRONG GALE EVENT AND PERSIST THROUGH WED EVENING. GULF OF PAPAGAYO...NE-E WINDS CONTINUE TO PULSE AT 20-25 KT DOWNSTREAM OF PAPAGAYO...DURING THE MAXIMUM NOCTURNAL DRAINAGE EARLY THIS MORNING...WHERE SEAS ARE 6 TO 9 FT. WINDS AND SEAS WILL DIMINISH THERE SLIGHTLY THIS AFTERNOON AND PULSE AGAIN TONIGHT TO 20-25 KT...AND AGAIN FRI NIGHT THROUGH SUNRISE ON SAT. A STRONG SURFACE RIDGE EXTENDS INTO THE AREA FROM A 1035 MB HIGH NEAR 40N144W...EXTENDING SE TO 22N119W...WITH THE PRES GRADIENT BETWEEN THE HIGH AND LOWER PRESSURE ALONG THE ITCZ INDUCING NE TRADES 20-25 KT TRADES BETWEEN THE RIDGE AND ITCZ ACROSS THE WATERS S OF 22N W OF 125W. LONG PERIOD NW SWELL IS MIXING WITH THE ASSOCIATED NE TRADE WIND SWELL...AND ALSO WITH LONG PERIOD CROSS-EQUATORIAL SOUTHERLY SWELL...RESULTING IN COMBINED SEAS OF 7-11 FT WITHIN THIS AREA. THE GRADIENT WILL RELAX SOME IN THIS AREA BY FRI. A COLD FRONT IS APPROACHING THE NORTHERN PORTION OF THE BAJA CALIFORNIA PENINSULA WITH POST-FRONTAL HIGH PRESSURE ALREADY SUPPORTING NORTHERLY 20-25 KT WINDS ACROSS THE DISCUSSION AREA N OF 28.5N BETWEEN 124-132W. NORTHERLY WINDS AT 20-25 KT...SEAS 8- 14 FT...ARE EXPECTED TO SPREAD S ACROSS THE DISCUSSION AREA N OF 25N TODAY...WITH WINDS TO 30 KT ACROSS PORTIONS N OF 29N. THE GRADIENT WILL BEGIN TO RELAX ON FRI AS THE FRONT PASSES THROUGH THE GULF OF CALIFORNIA. THE NORTHERLY WINDS WILL DIMINISH TO 15- 20 KT ACROSS THE DISCUSSION AREA W OF A LINE FROM THE CENTRAL BAJA CALIFORNIA PENINSULA TO 09N140W THIS EVENING. MIXED N SWELL WILL ALSO MIX WITH LONG PERIOD CROSS EQUATORIAL SE SWELL...WITH COMBINED SEAS OF 7-13 FT IN THIS AREA THIS EVENING. THE NORTHERLY SWELL WILL GRADUALLY SUBSIDE OVER THE UPCOMING WEEKEND WITH SEAS OF 8-9 FT ONLY EXPECTED ACROSS THE TROPICAL WATERS W OF 118W ON MON. GULF OF CALIFORNIA...SOUTHERLY WINDS HAVE INCREASED TO ARE CURRENTLY AT 20-25 KT ACROSS THE NORTHERN GULF WATERS N OF 30N THIS MORNING...AHEAD OF AN APPROACHING COLD FRONT...AND ARE EXPECTED TO PERSIST AND SPREAD S TO 27N BY TONIGHT AS THE FRONT REACHES THE AREA. WINDS ARE EXPECTED TO DIMINISH TO 10-15 KT BEHIND THE FRONT AFTER IT MOVES INTO MAINLAND MEXICO LATE FRI. HIGH PRES WILL BUILD BACK INTO THE REGION THIS WEEKEND FROM THE NW...AND INCREASE THE PRES GRADIENT TO SUPPORT NW WINDS OF 15-20 KT ACROSS THE ENTIRE GULF OF CALIFORNIA ON SUN EVENING...FURTHER INCREASING TO 20-25 KT ON SUN NIGHT INTO MON. $$ STRIPLING