000 AXPZ20 KNHC 130951 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI DEC 13 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC...GALE FORCE WINDS OF 30-40 KT WITH SEAS 11- 17 FT WILL CONTINUE THROUGH SUNRISE THIS MORNING...THEN QUICKLY DIMINISH BELOW GALE FORCE BY NOON TODAY. EXPECT NORTHERLY 20-25 KT WINDS DURING MAXIMUM DRAINAGE TONIGHT...THEN QUICKLY BECOMING LIGHT AND VARIABLE BY THIS EVENING. THE ASSOCIATED NE-E SWELL EXTENDS SW ACROSS THE TROPICAL WATERS FROM 06-13N BETWEEN 94- 113W WHERE IT IS MIXING WITH CROSS-EQUATORIAL SW SWELL... RESULTING IN COMBINED SEAS OF 8-11 FT. THIS AREA OF ENHANCED SEAS WILL CONTINUE TO PROPAGATE WESTWARD THROUGH THE NE TRADES EXISTING W OF 120W ON SAT. THE NORTHERLY FLOW WILL SET UP AGAIN AT 20-30 KT LATE SAT NIGHT...INCREASING TO MINIMAL GALE FORCE AROUND SUNRISE ON SUN. THE WINDS WILL INCREASE TO A STRONG GALE OF 35-45 KT ON SUN NIGHT...WITH THE GALE PERSISTING THROUGH SUNRISE ON TUE. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W FROM THE W COAST OF COLOMBIA AT 08N78W ACROSS THE GULF OF PANAMA AND ACROSS WESTERN PANAMA TO THE PACIFIC COAST OF COSTA RICA AT 08N84W...THEN TURNS SW TO 04N92W THEN NW TO 05N95W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ CONTINUES NW THROUGH AN EMBEDDED 1011 MB SURFACE LOW AT 08N108W TO 10N125W...THEN TURNS SW TO BEYOND 09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED S OF THE MONSOON TROUGH WITHIN 120 NM EITHER SIDE OF A LINE FROM 06N77W TO 06N83W. SIMILAR CONVECTION SURROUNDS THE ITCZ AND THE EMBEDDED SURFACE LOW WITHIN 90 NM EITHER SIDE OF A LINE FROM 08N105W TO 08N112W...AND IS NOTED ALONG THE ITCZ WITHIN 75 NM EITHER SIDE OF A LINE FROM 07N106W TO 10N116W TO 11N124W TO 10N132W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED N OF THE ITCZ WITHIN 15 NM OF 12N113.5W AND WITHIN 30 NM EITHER SIDE OF A LINE FROM 14N127.5W TO 20N124W. ...DISCUSSION... A FRONTAL TROUGH OVER THE FAR NW PORTION OF THE DISCUSSION AREA WILL WEAKEN TO AN OPEN TROUGH TODAY AS IT SHIFTS W OF 140W. A 1028 MB SURFACE HIGH PRESSURE IS JUST N OF THE AREA NEAR 34N128W WITH A RIDGE EXTENDING SE TO NEAR 17N107W AND SUPPORTING NE 15- 20 KT TRADES AND SEAS 5-7 FT ACROSS THE TROPICAL WATERS W OF 133W...EXCEPT FOR A SMALL AREA OF 7-8 FT SEAS WITHIN 180 NM OF 11N117W. NE-E SWELLS GENERATED BY THE RECENT GALE IN THE GULF OF TEHUANTEPEC WILL PROPAGATE W THROUGH THE PERSISTENT AREA OF NE TRADES...WITH SEAS GRADUALLY BUILDING TO 6-8 FT ACROSS TROPICS TO THE W OF 110W ON SAT. NW SWELL WILL ALSO PROPAGATE THROUGH THE TROPICS BEGINNING ON SAT NIGHT...AND WILL BUILD SEAS 7-11 FT ACROSS THE DISCUSSION WATERS N OF 18N TO THE W OF 135W ON SUN. THE GRADIENT WILL BEGIN TO RELAX ON MON. GULF OF PAPAGAYO...NE-E WINDS WILL CONTINUE TO PULSE AT 20-25 KT TODAY...THEN DIMINISH WITH ONLY 15-20 KT EXPECTED DURING THE MAXIMUM NOCTURNAL DRAINAGE TONIGHT THROUGH MON NIGHT. GUIDANCE IS SUGGESTING 20-25 KT LATE TUE NIGHT. GULF OF CALIFORNIA...NW WINDS AT 15-20 KT ARE FORECAST TODAY ACROSS THE GULF WATERS S OF 29N. LIGHT N WINDS CURRENTLY ACROSS THE WATERS N OF 29N ARE EXPECTED TODAY...BUT INCREASING TO 15-20 KT TONIGHT. NW 20-25 KT WINDS ARE FORECAST ACROSS THE ENTIRE GULF OF CALIFORNIA ON SAT AND SAT NIGHT WITH THE GRADIENT RELAXING ON SUN...WITH ONLY NW 10-15 KT WINDS EXPECTED BY LATE MON NIGHT. $$ NELSON