000 AXPZ20 KNHC 230931 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN DEC 23 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 0900 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 06N77W TO 06N83W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N83W TO 06N105W TO 09N125W TO 08N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 300 NM N OF THE ITCZ BETWEEN 121W AND 126W. ADDITIONAL SCATTERED MODERATE CONVECTION IS WITHIN 240 NM EITHER SIDE OF A LINE FROM 14N126W TO 25N118W. THIS CONVECTION IS BEING ADVECTED FROM THE DEEP TROPICS NORTHEASTWARD TOWARD THE BAJA CALIFORNIA PENINSULA AHEAD OF A DIGGING UPPER LEVEL TROUGH AND ON THE WESTERN PERIPHERY OF AN UPPER ANTICYCLONE NEAR 15N110W. ...DISCUSSION... A SET OF VERY HIGH ENERGY NW SWELL OF UP TO 14 FT WITH PEAK WAVE PERIODS OF 16-18 SECONDS CONTINUES TO DOMINATE THE MAJORITY OF THE WATERS N OF 05N W OF 110W. THIS SWELL WILL GRADUALLY DECAY TO A COMBINED MAXIMUM OF 12 FT IN 24 HOURS WHILE SEAS OF 8 FT OR GREATER REACH THE EQUATOR. SEAS WILL CONTINUE TO SUBSIDE THROUGH 48 HOURS WITH ONLY 5-7 FT SEAS PRESENT N OF 23N W OF 126W BY THEN. 1022 MB HIGH PRESSURE HAS BECOME ESTABLISHED NEAR 26N140W WITH AN EAST TO WEST RIDGE EXTENDING FROM THE HIGH ALONG 26N. THIS HIGH AND ACCOMPANYING RIDGE WILL BE THE DOMINANT SYNOPTIC FEATURE ACROSS THE REGION THROUGH TUE WITH GENERALLY LIGHT TO MODERATE WINDS ACROSS THE NORTHERN WATERS. THE HIGH IS HELPING TO ENHANCE NE-E TRADES S OF THE RIDGE AXIS AND N OF THE ITCZ. TRADES ARE ALREADY 20-25 KT IN THE W CENTRAL WATERS FROM 08N TO 20N W OF 125W AS INDICATED BY RECENT OVERNIGHT ASCAT AND OCEANSAT SCATTEROMETER PASSES. THE HIGH AND RIDGE WILL SHIFT TO THE E WHICH WILL HELP TO EXPAND THE TRADES TO 116W IN ABOUT 24 HOURS. COMBINED SEAS WILL REMAIN 11-14 FT IN MIXED NE WIND WAVES AND THE NW SWELL SET ACROSS THE AREA OF ENHANCED TRADES. AS THE RIDGE BUILDS EASTWARD A TIGHT PRESSURE GRADIENT WILL ALSO SET UP NEAR THE BAJA CALIFORNIA PENINSULA WITH INVERTED TROUGHING LOCATED NEAR THE W COAST OF MEXICO. THIS MAY INDUCE NW TO N WINDS OF 20-25 KT WITHIN 120-180 NM W OF THE BAJA CALIFORNIA PENINSULA BY LATE TONIGHT INTO EARLY MON MORNING. WITH THIS SET UP FRESH NORTHERLY WINDS ARE ALSO EXPECTED IN THE GULF OF CALIFORNIA S OF 27N TONIGHT THROUGH MON MORNING... DIMINISHING MON NIGHT INTO TUE AS THE PRES GRADIENT RELAXES. GAP WINDS... 1027 MB HIGH PRESSURE IS CENTERED OVER THE N CENTRAL GULF OF MEXICO IN THE WAKE OF A NOW DISTANT AND DIFFUSE REMNANT COLD FRONT WELL TO THE SE IN THE CARIBBEAN SEA. GALE FORCE NORTHERLY WINDS CONTINUE TO BE FORCED IN THE GULF OF TEHUANTEPEC ALTHOUGH UNFORTUNATELY THERE HAVE BEEN NO OVERNIGHT IN-SITU OR REMOTE SENSED OBSERVATIONS. THE GALE WARNING WILL REMAIN IN EFFECT UNTIL 18 UTC TO ACCOUNT FOR THE MOST FAVORABLE SURGE CONDITIONS EXPECTED DURING THE EARLY MORNING HOURS. HIGH SEAS OF UP TO ABOUT 16 FT ARE EMANATING FROM THE SOURCE REGION OF THE WINDS IN THE GULF OF TEHUANTEPEC WITH N-NE SWELL EXTENDING TO NEAR 110W. THESE NE SWELLS ARE MERGING WITH NW SWELL FROM THE NORTHERN PORTION OF THE DISCUSSION AREA NOTED ABOVE. THE PRESSURE GRADIENT IS FORECAST TO RELAX SIGNIFICANTLY OVER THE REGION LATE TODAY AND TONIGHT ALLOWING FOR WINDS TO DIMINISH TO 20 KT OR LESS BETWEEN 24 AND 42 HOURS. LOOKING AHEAD...A WEAKER COLD FRONT MAY MOVE THROUGH THE SW GULF OF MEXICO WED ALLOWING FOR A SHORT-LIVED MINIMAL GALE FORCE WIND EVENT IN THE GULF OF TEHUANTEPEC BEHIND ITS PASSAGE TO THE N WED AFTERNOON AND EVENING. A 0254 UTC ASCAT SCATTEROMETER PASS CAPTURED NE TO E 20-25 KT WINDS IN THE GULF OF PAPAGAYO DOWNWIND TO 09N90W...WITH A DISCONTINUOUS SECONDARY AREA FROM 06N TO 10N BETWEEN 92W AND 98W COINCIDENT WITH 13 FT COMBINED SEAS. THESE STRONG WINDS ARE BEING AIDED BY NE 20-30 KT WINDS IN THE WESTERN CARIBBEAN SEA WHERE A TIGHT PRES GRADIENT EXISTS IN THE WAKE OF THE ABOVE MENTIONED REMNANT FRONT. THESE WINDS IN THE GULF OF PAPAGAYO WILL GRADUALLY DIMINISH TO 20 KT OR LESS BY CHRISTMAS EVE NIGHT AS THE WINDS IN THE WESTERN CARIBBEAN WEAKEN SIGNIFICANTLY. THE SAME ASCAT SCATTEROMETER PASS ALSO INDICATED NE 20-25 KT WINDS IN THE GULF OF FONSECA. ONLY THE NAM MODEL SOLUTION INDICATED SUCH AN EVENT WITH ALL OTHER GUIDANCE 15-20 KT AT BEST. WINDS ARE FORECAST TO DIMINISH TO 20 KT OR LESS BY THIS EVENING IN ACCORDANCE WITH THE NAM. THE SAME STRONG WINDS IN THE SW CARIBBEAN ARE SPILLING INTO THE GULF OF PANAMA ALONG WITH SEAS TO 8 FT SW OF THE GULF. EXPECT THESE WINDS TO DIMINISH TO 20 KT OR LESS BY TONIGHT AS THE PRES GRADIENT IN THE IMMEDIATE AREA RELAXES SOMEWHAT. $$ LEWITSKY