000 AXPZ20 KNHC 121605 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC MON OCT 12 2015 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 1530 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS WITHIN 490 NM SE OF THE BAJA CALIFORNIA DEL SUR PENINSULA WITH AXIS EXTENDING FROM 15N104W TO A 1008 MB LOW PRES NEAR 09N104W...MOVING W AT 10 KT. SCATTERED TO ISOLATED MODERATE CONVECTION IS MAINLY AHEAD OF THE WAVE AXIS FROM 05N TO 15N BETWEEN 104W AND 111W AND WITHIN 230 NM E OF THE WAVE AXIS. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE CONDUCIVE FOR SLOW DEVELOPMENT OF THIS SYSTEM...AND A TROPICAL DEPRESSION MAY FORM BY LATE THIS WEEK. PLEASE SEE THE LATEST NHC TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS MIATWOEP/ABPZ20 KNHC FOR MORE DETAILS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 09N75W TO 11N90W TO 10N100W TO A 1007 MB LOW PRES NEAR 09N104W TO 9N107W...THEN CONTINUES FROM 15N117W TO 10N130W TO 10N140W. SCATTERED TO ISOLATED MODERATE CONVECTION IS N OF 4N E OF 94W AND FROM 5N T0 14N BETWEEN 105W AND 111W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 7N TO 11N BETWEEN 124W AND 136W. ...DISCUSSION... AN UPPER LOW CENTERED OFF THE CENTRAL BAJA CALIFORNIA PENINSULA NEAR 25N121W IS SLOWLY DRIFTING NNW...SUPPORTING A SURFACE TROUGH FROM 29N118W TO 21N121W THAT IS GENERATING SCATTERED MODERATE CONVECTION WITHIN 345 NM W OF TROUGH AXIS N OF 25N. CURRENT WESTWARD MOVEMENT OF THE SURFACE TROUGH HAS REDUCED THE PRESSURE GRADIENT EAST OF IT...THUS RESULTING IN WINDS DECREASING TO LESS THAN 20 KT FROM 23N TO 28N BETWEEN THE TROUGH AND THE BAJA CALIFORNIA PENINSULA. ASSOCIATED SEAS ARE RANGING FROM 8 TO 9 FT. THE SUPPORTING CUT OFF LOW WILL DRIFT NNW TROUGH MID WEEK ALLOWING THE TROUGH TO MOVE NW AND N OF THE AREA OF DISCUSSION WED NIGHT. BETWEEN NOW AND WED MORNING THE PRESSURE GRADIENT WILL FURTHER RELAX...RESULTING IN SE WINDS LESS THAN 20 KT AND SEAS BECOMING LESS THAN 8 FT. WINDS WILL VEER TO THEIR MORE STANDARD NW FLOW OFF THE BAJA PENINSULA DURING TUESDAY. FOR THE GULF OF CALIFORNIA...HIGH PRES BUILDING OVER THE GREAT BASIN WILL ALLOW A BRIEF SHOT OF FRESH NW FLOW LATE TUE INTO WED. GULF OF TEHUANTEPEC...FRESH TO STRONG N-NE WINDS ARE DIMINISHING EARLY THIS AFTERNOON UNDER A WEAK PRESSURE GRADIENT BETWEEN A WEAKENING RIDGE OVER THE GULF OF MEXICO AND THE TROPICAL WAVE TO THE SW. LOOKING AHEAD...ANOTHER PULSE OF STRONG GAP WINDS IS EXPECTED WED MORNING AS HIGH PRES AGAIN BUILDS NORTH OF THE AREA ...REACHING NEAR GALE FORCE BY WED NIGHT. S OF 15N E OF 110W...THE MAIN FOCUS CONTINUES TO BE THE WEAK LOW PRES NEAR 09N104W. WHILE THE LOW REMAINS GENERALLY WELL ORGANIZED IN AN AREA OF ABUNDANT MOISTURE...IT IS STILL CLOSE TO SUBSIDENT UPPER NE FLOW ON THE EASTERN EDGE OF AN UPPER ANTICYCLONE CENTERED TO THE NORTH NEAR MANZANILLO MEXICO...KEEPING CONVECTION LIMITED. CONVECTION WILL DEVELOP ONLY GRADUALLY THROUGH TUE AS THE LOW MOVES FARTHER WEST...CROSS W OF 110W BY LATE TUE. THIS WILL LEAVE ONLY WEAK CIRCULATIONS ALONG THE MONSOON TROUGH THROUGH MID WEEK WITH MODEST WINDS. SEAS WILL REMAIN 5 TO 7 FT DUE IN PART TO PERSISTENT LONG PERIOD SW SWELL. LOOKING AHEAD...GLOBAL MODELS INDICATE INCREASING SW FLOW THROUGH THU...WITH THE POSSIBLE DEVELOPMENT OF LOW PRES W OF COSTA RICA BY LATE IN THE WEEK. ELSEWHERE...1020 MB HIGH PRES NEAR 33N137W WILL MOVE NE THROUGH TODAY AHEAD OF A DEEP LAYER TROUGH APPROACHING FROM THE N CENTRAL PACIFIC. THIS WILL CONTINUE TO ALLOW TRADE WINDS TO DIMINISH S OF 20N. CONVECTION ALONG THE MONSOON TROUGH W OF 120W...SCATTERED MODERATE TO ISOLATED STRONG FROM 7N TO 11N. MIXED SWELL FROM 14N TO 17N W OF 139W IS ON THE EASTERN PERIPHERY OF T.S. NORA...NOW LOCATED WELL WEST OF THE AREA. THIS SWELL IS RAPIDLY SUBSIDING AND WILL BE BELOW 8 FT LATER TODAY. A BATCH OF SW SWELL WITH PERIODS IN THE 19-22 SECOND RANGE HAS MOVED ONTO THE COAST OF ECUADOR...COLOMBIA...AND CENTRAL AMERICA TO THE SOUTHERN TIP OF BAJA CALIFORNIA SUR. SEAS ALONG THE COAST HERE ARE GENERALLY IN THE 4-6 FT RANGE. THE LEADING EDGE OF THE SWELL WILL REACH THE MOUTH OF THE GULF OF CALIFORNIA MAINLY S OF MAZATLAN AND THE BAJA CALIFORNIA NORTE PACIFIC COAST LATER TODAY. THIS SWELL COULD MAKE FOR HAZARDOUS CONDITIONS ENTERING AND EXITING PORTS AND INCREASE THE CHANCE FOR RIP CURRENTS. $$ NR