000 AXPZ20 KNHC 172204 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC TUE DEC 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...SPECIAL FEATURE... GULF OF TEHUANTEPEC...GALE CONDITIONS OF 30-40 KT ARE EXPECTED TO CONTINUE THROUGH WED MORNING BEFORE DIMINISHING TO 30-35 KT EARLY WED AFTERNOON AND TO 20-30 KT BY WED EVENING. THE MAXIMUM DRAINAGE WINDS SHOULD REACH 30 KT LATE WED NIGHT THROUGH DAYBREAK THU...THEN DIMINISH TO 10-15 KT LATE THU NIGHT. SEAS OF 11-16 FT IN THE GULF AND ALSO DOWNSTREAM FROM THE GULF OF TEHUANTEPEC WILL GRADUALLY SUBSIDE TO 8 FT BY THU AFTERNOON WITHIN 30 NM OF A LINE FROM 15N96W TO 13N96W. THE RESULTANT PLUME OF NE SWELLS WILL CONTINUE TO MIX WITH CROSS-EQUATORIAL SW AND LONG PERIOD NW SWELLS...WITH COMBINED SEAS TO 9 FT REACHING FROM 08N TO 12N BETWEEN 106W AND 112W BY FRI EVENING. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM FROM THE COLOMBIAN COAST AT 08N78W ACROSS CENTRAL PANAMA TO 09N85W TO 07N95W TO 07N103W...WHERE LOW LEVEL WINDS SUGGEST IT TRANSITIONS TO THE ITCZ TO 08N115W TO 07N128W TO 07N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF THE ITCZ BETWEEN 115W-119W...WITHIN 120 NM S OF THE ITCZ BETWEEN 119W-123W...AND ALSO WITHIN 120 NM N OF THE ITCZ BETWEEN 127W- 131W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM N OF ITCZ BETWEEN 133W-137W. ...DISCUSSION... ALOFT... AN ANTICYCLONE IS SEEN NEAR 17N105W WITH ITS ASSOCIATED BROAD ANTICYCLONIC ENVELOP COVERING THE AREA N OF 17N E OF 115W. AN UPPER TROUGH EXTENDS FROM AN UPPER LOW N OF THE AREA THROUGH 32N133W TO 25N131W TO 19N126W AND FURTHER SE TO NEAR 15N116W. A JET STREAM BRANCH BETWEEN THE TROUGH AND THE ANTICYCLONE IS ACCOMPANIED BY MODERATE SW WINDS THAT ARE TRANSPORTING ABUNDANT BROKEN MID/HIGH CLOUDS NEWD BETWEEN 115W AND 127W AND N OF 21N. DIFFLUENT FLOW S OF THE TROUGH AND SW OF THE ANTICYCLONE IS AIDING THE ACTIVE CONVECTION DESCRIBED ABOVE WITH THE ITCZ AXIS. OVER THE FAR EASTERN PORTION...A CYCLONIC CIRCULATION IS NOTED NEAR 05N101W. SLY FLOW TO ITS E IS HELPING TO ADVECT UPPER DEBRIS CLOUDINESS NWD...WHICH IS ATTRIBUTED TO WIDELY SCATTERED TO SCATTERED SHOWERS/TSTMS ALONG AND NEAR THE MONSOON TROUGH. SATELLITE WATER VAPOR IMAGERY SHOWS MOSTLY MODERATE SUBSIDENCE ELSEWHERE KEEPING GENERALLY DRY AND STABLE ATMOSPHERIC CONDITIONS...EXCEPT FOR WITHIN 360 NM W OF THE ANTICYCLONE NEAR NEAR 17N105W WHERE SLY FLOW THERE IS SPREADING SCATTERED TO BROKEN HIGH CLOUDS FROM WIDELY SCATTERED SHOWERS AND TSTMS JUST S OF THE LOW NWD TO NEAR 20N109W BEFORE IT THINS OUT IN DRY AIR DUE TO MODERATE SUBSIDENCE. THE UPPER TROUGH WILL BE REINFORCED BY THU AFTERNOON BY A SHORTWAVE TROUGH THAT WILL SWEEP SEWD FROM THE FAR ERN PACIFIC WATERS JUST N OF THE AREA TO OVER THE FAR NE PORTION OF THE DISCUSSION AREA BY LATE THU NIGHT INTO FRI. BY LATE FRI...THE BASE OF THE DEEPENING TROUGH WILL BE OVER THE FAR ERN PORTION OF THE AREA N OF 20N AND E OF 120W. SURFACE... A SURFACE RIDGE ANCHORED BY A 1029 MB HIGH PRES N OF THE AREA NEAR 37N138W EXTENDS SEWD THROUGH 32N137W AND TO NEAR 21N122W. AVAILABLE ASCAT FROM THE DAY REVEALED FRESH NE TRADES S OF THE RIDGE AND N OF THE ITCZ W OF 120W. LONG PERIOD NW SWELLS ARE MIXING WITH THE NE TRADE WIND SWELL AND ALSO LONG PERIOD CROSS- EQUATORIAL SOUTHERLY SWELL...RESULTING IN COMBINED SEAS OF 7-10 FT WITHIN THE AREA OF ENHANCED TRADES. BY FRI...NW SWELLS WILL BE MIXING IN WITH NE SWELL TO PRODUCE SEAS OF 8-10 FT FROM 09N TO 21N W OF 130W. THE DEEPENING UPPER TROUGH DESCRIBED ABOVE UNDER ALOFT WILL MOST LIKELY PUSH A DRY COLD FRONT SEWD ACROSS THE VAST MAJORITY OF THE EASTERN AND N CENTRAL PACIFIC LATE THU AND THROUGH FRI. STRONG HIGH PRES BEHIND THE COLD FRONT WILL ALLOW FOR COLD AIR ADVECTION TO SETTLE IN OVER THE ERN PORTION OF THE AREA BY LATE FRI RESULTING IN GALE FORCE NW TO N WINDS ALONG THE COAST OF CENTRAL AND SOUTHERN CALIFORNIA THU AND FRI. THESE WIND CONDITIONS WILL GENERATE VERY LARGE SEAS OF 18-21 FT JUST N OF THE AREA E OF 126W BY LATE THU NIGHT...THEN SLOWLY SUBSIDE TO 15- 18 FT FRI. SEAS OF 10-16 FT ARE EXPECTED TO SPREAD SWD INTO THE AREA N OF 27N E OF 127W FRI. GULF OF PAPAGAYO...NE-E WINDS WILL PULSE AT 20-25 KT DURING MAX NOCTURNAL DRAINAGE PERIOD TONIGHT THROUGH THU NIGHT...THEN MAX AT 15-20 KT EARLY THU EVENING...AND INCREASE BACK UP TO 20-25 KT LATE THU NIGHT INTO EARLY FRI. NE SWELL PROPAGATING SW FROM THE GULF OF PAPAGAYO WILL MIX WITH NW SWELL FROM THE GULF OF TEHUANTEPEC EVENT AND CROSS-EQUATORIAL S SWELL...RESULTING IN COMBINED SEAS OF 6-8 FT AS FAR W AS 09N91W BY EARLY THU...THEN DIMINISH TO LESS THAN 8 FT LATE THU NIGHT. GULF OF CALIFORNIA...MODERATE TO FRESH NW WINDS WILL DIMINISH TO 5-10 KT WED AND BECOME SOUTHERLY WED NIGHT. WINDS WILL INCREASE TO 20-25 KT OVER THE NORTHERN GULF EARLY THU AHEAD OF THE COLD FRONT EXPECTED TO ARRIVE THU AFTERNOON. THE FRONT WILL PUSH S OF THE BAJA PENINSULA THROUGH FRI EVENING ACCOMPANIED BY A SHIFT IN WINDS FROM SW THROUGH W TO NW FROM HIGH PRES BUILDING BEHIND THE FRONT. $$ AGUIRRE