000 AXPZ20 KNHC 280952 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC WED NOV 28 2012 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS W FROM THE COAST OF COLOMBIA AT 08N77W TO 08N85W...THEN DIPS SW TO 06N93W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ...WHICH CONTINUES NW TO 09N120W...THEN WIGGLES WESTWARD TO BEYOND 10N140W. SCATTERED MODERATE ISOLATED STRONG...WITH LIGHTING OCCASIONALLY DETECTED...IS OBSERVED FROM 03N TO 09N E OF 78W...AND WITHIN 60 NM EITHER SIDE OF A LINE FROM 06N91W TO 08N96W TO 05N102W. ISOLATED MODERATE ITCZ CONVECTION IS OBSERVED FROM 07-15N BETWEEN 117-140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 150 NM OF 19.5N130.5W...ASSOCIATED WITH A LOW LEVEL TROUGH EXTENDING FROM 12N138W TO 19N133W. ...DISCUSSION... GULF OF TEHUANTEPEC...35-45 KT NORTHERLY GALE FORCE WINDS ARE CURRENTLY IN...AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC TO NEAR 13N96W. MAXIMUM SEAS ARE EXPECTED TO REACH 15 FT TODAY. N-NE WINDS AT 20-30 KT EXTEND AROUND THE GALE AREA WITHIN 90 NM EITHER SIDE OF A LINE FROM 16N94.5W TO 13N96W...AND ALSO ACROSS THE WATERS FROM 11-13N BETWEEN 94-100W..WITH SEAS 7-11 FT. EXPECT THE GALE CONDITIONS TO CEASE BY EARLY AFTERNOON ON THU...BUT THE NORTHERLY WINDS WILL CONTINUE TO PULSE AT 20-30 KT THROUGH THE UPCOMING WEEKEND. THE NE SWELL FROM THIS EVENT WILL PROPAGATE SW ACROSS THE WATERS FROM 09-12N BETWEEN 98-102W ON FRI THEN GRADUALLY SUBSIDE BELOW 8 FT ON SAT. GULF OF PAPAGAYO...NE-E WINDS ARE EXPECTED TO CONTINUE AT 15-20 KT...WITH FREQUENT PULSES TO 20-25 KT THROUGH THE UPCOMING WEEKEND. WAVE GUIDANCE ALSO FLUCTUATES FROM MODEL RUN TO MODEL RUN BUT GENERALLY SUGGESTS SEAS OF 4-5 FT DURING 15-20 KT E FLOW...BUILDING TO 6-9 FT A FEW HOURS AFTER THE 20-25 KT SURGES COMMENCE. SURFACE HIGH PRESSURE IS QUASI-STATIONARY NEAR 26N120W WITH A RIDGE EXTENDING SE TO 16N103W...AND A RIDGE EXTENDING SW TO NEAR 22N134W. AN INITIAL COLD FRONT NW OF THE WESTERN RIDGE HAS WEAKENED TO A FRONTAL TROUGH EXTENDING SW FROM 32N128W TO 21N138W...WITH S-SW WINDS 20-30 KT AND SEAS 7-11 FT NOTED TO THE N OF 26N WITHIN 240 NM E OF TROUGH. A SECONDARY COLD FRONT IS WELL DEFINED BY A 90 NM WIDE OF BROKEN-OVERCAST LOW-MID CLOUDS FROM 32N133W TO 26N140W...BUT IS ONLY ACCOMPANIED BY A SLIGHT W-NW WIND SHIFT...SO THIS FRONT IS NOT MENTIONED IN HIGH SEAS FOR SIMPLICITY...AND CONDITIONS REFERENCED TO THE INITIAL FRONTAL TROUGH. CURRENTLY TO THE N OF 23N W OF INITIAL FRONT THE WINDS ARE NW AT 20-25 KT...AND LONG PERIOD NW SWELL RESULTS IN COMBINED SEAS 8-17 FT...WITH THE HIGHEST SEAS BETWEEN 29-32N. GUIDANCE SUGGESTS THE SECOND COLD FRONT WILL MERGE WITH THE DECAYING INITIAL FRONT LATER TODAY. THE RIDGE WILL BLOCK MOST OF THIS MERGED FRONTS FORWARD PROGRESS...WITH THE SOUTHERN SEGMENT WASHING OUT FROM 27N127W TO 15N137W LATE THU. THE GRADIENT WILL TIGHTEN E OF THE SURFACE HIGH ON THU-FRI INCREASING THE NORTHERLY FLOW TO 15-20 KT WITHIN 180 NM W OF THE BAJA PENINSULA. THE LONG PERIOD NW SWELL...PRODUCING SEAS 6-8 FT... WILL ARRIVE AT THE W COAST OF NORTHERN BAJA ON THU NIGHT AND REACH THE SOUTHERN BAJA PENINSULA ON FRI NIGHT. THE NORTHERN SEGMENT OF THE MERGED FRONT WILL WEAKEN AS IT PASSES EASTWARD TO THE N OF THE SURFACE HIGH...WITH THE REMNANTS ARRIVING AT THE NORTHERN BAJA CALIFORNIA PENINSULA ON FRI. ATTENTION THEN TURNS OVER THE WESTERN WATERS AS A SERIES OF SECONDARY FRONTS WILL SWEEP E ACROSS THE NORTHERN WATERS MAINTAINING SW-W 20-25 KT FLOW...BUT MORE IMPORTANTLY DRIVING RE-ENFORCING NW SWELL INTO THE AREA...RESULTING IN COMBINED SEAS OF 15-20 FT NW OF A LINE FROM 32N128W TO 27N140W LATE THU...AND SEAS 8-14 FT ELSEWHERE FROM NORTHERN BAJA TO 13N140W. THIS LONG PERIOD NW SWELL WILL CONTINUE TO PROPAGATE SE ACROSS THE PACIFIC WATERS W OF A LINE FROM THE SOUTHERN BAJA PENINSULA TO 05N140W BY LATE SAT...THEN MIXING WITH NE AND CROSS EQUATORIAL SE SWELL OVER THE TROPICAL WATERS SE OF A LINE FROM 23N106W TO THE EQUATOR AT 140W BY LATE SUN. $$ NELSON