000
AXPZ20 KNHC 301532
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI NOV 30 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

MONSOON TROUGH EXTENDS FROM 08N78W TO 07N108W WHERE IT 
TRANSITIONS TO THE ITCZ...CONTINUING ON TO 06N140W. SCATTERED 
MODERATE CONVECTION E OF 103W WITHIN 120 NM OF TROUGH.

...DISCUSSION...

AT THE SURFACE...A LARGE EXTRATROPICAL CYCLONE IN THE GULF OF 
ALASKA IS PRODUCING 18-20 FT SEAS IN THE NW CORNER OF OUR AREA 
OF RESPONSIBILITY.  A SATELLITE ALTIMETER PASS FROM 0300 UTC 
INDICATED THAT THE LARGE WAVES HAD PROPAGATED FASTER TO THE 
SOUTH MORE THAN ANTICIPATED BY THE GFS-BASED WAVEWATCH AND OTHER 
WAVE MODELS.  THIS LONG-PERIOD...15 S...NW SWELL SHOULD BE 
PEAKING TODAY AND WILL BE GRADUALLY SUBSIDING OVER THE NEXT FEW 
DAYS.  BY SUNDAY MORNING...SWELL FROM THIS EVENT OF AT LEAST 8 
FT SIGNIFICANT WAVE HEIGHT WILL COVER MOST OF THE REGION WEST OF 
115W.  BECAUSE OF THE LOW BIAS...MY FORECAST LEANS MORE UPON A 
MODEL SOLUTION...THE COMBINED ENSEMBLE MEAN FROM THE GFS AND 
NOGAPS...WITH THE HIGHEST WAVE HEIGHT VALUES FOR THE NEXT TWO 
DAYS.

THE SAME LARGE EXTRATROPICAL CYCLONE IS PRODUCING STRONG BREEZE 
SW WINDS IN THE NW CORNER OF OUR AREA OF RESPONSIBILITY AHEAD OF 
A COLD FRONT.  A SHORT-WAVE TROUGH EVIDENT IN THE WATER VAPOR 
SATELLITE IMAGERY IS INDICATING LITTLE TO NO PUSH EQUATORWARD IN 
SUPPORT OF THE FRONT.  THUS THIS FRONT WILL NOT PROGRESS 
SOUTHWARD TO REACH OUR WATERS AND THE SW WINDS SHOULD DIMINISH 
BY SATURDAY.

NO NEW LONG-PERIOD HIGH SWELL EVENT OF 12 FT OR GREATER IS 
ANTICIPATED DURING THE NEXT WEEK.

GAP WINDS...A NEAR GALE GAP WIND EVENT CONTINUES IN THE GULF OF 
TEHUANTEPEC AS OBSERVED FROM THE 0412 UTC ASCAT SCATTEROMETER 
PASS EARLY THIS MORNING.  HIGH PRESSURE IN THE GULF OF MEXICO 
COMBINED WITH LOW PRESSURE SOUTH OF MEXICO ARE ACTING TO FUNNEL 
THE WINDS THROUGH THE CHIVELA PASS.  THE FORCING AND THUS THE 
WINDS SHOULD DIMINISH SLIGHTLY BY SATURDAY THOUGH THE EVENT MAY 
CONTINUE AT OUR 25 KT CRITERION FOR THE NEXT FEW DAYS.  

AROUND WEDNESDAY NEXT WEEK...THE GFS SUGGESTS THAT A NEW 
GALE-FORCE TEHUANTEPEC WIND EVENT MAY OCCUR...THOUGH THE FORCING 
FOR THIS NEXT EVENT DOES NOT APPEAR TO BE VERY STRONG.  
MOREOVER...NONE OF THE OTHER MODELS INDICATE GALE-FORCE WINDS.  
THUS THE GRIDDED FORECASTS WILL DOWNPLAY AT THIS POINT THE 
LIKELIHOOD FOR A GALE EVENT NEXT WEEK IN THE GULF OF TEHUANTEPEC.

THE OTHER GAP WIND AREAS OF THE GULF OF PAPAGAYO AND THE GULF OF 
CALIFORNIA SHOULD REMAIN WITH WINDS LESS THAN 25 KT AND SEAS 
LESS THAN 8 FT THROUGH TUESDAY.  ON WEDNESDAY AND THURSDAY... 
THERE IS THE POSSIBILITY OF A NEW GULF OF PAPAGAYO GAP WIND 
EVENT OCCURRING...BUT LIKELY REMAINING BELOW GALE FORCE.

$$
LANDSEA