000 AXPZ20 KNHC 100945 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU OCT 10 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... TROPICAL DEPRESSION NARDA CENTERED AT 16.4N 128.9W AT 0900 UTC MOVING WSW OR 240 DEG AT 02 KT. MAXIMUM SUSTAINED WINDS ARE 30 KT GUSTING TO 40 KT WITH A CENTRAL SURFACE PRESSURE OF 1007 MB. CURRENTLY ONLY SCATTERED MODERATE CONVECTION IS NOTED WITHIN 45 NM N OF THE CENTER. NARDA CONTINUES TO WEAKEN AND WILL LIKELY BE A REMNANT LOW LACKING SIGNIFICANT CONVECTION LATE TODAY. REFER TO NARDA FORECAST ADVISORY UNDER WMO/AWIPS HEADERS WTPZ24 KNHC/MIATCMEP4 FOR ADDITIONAL DETAILS. A SURFACE LOW PRESSURE IS EMBEDDED IN THE MONSOON TROUGH NEAR 15N102W AND IS ESTIMATED AT 1009 MB. CURRENTLY SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FLARING ALONG A BAND WITHIN 90 NM N THROUGH NE OF THE CENTER. ENVIRONMENTAL CONDITIONS FAVOR SLOW DEVELOPMENT OVER THE NEXT SEVERAL DAYS WITH THE LOW PRES...POSSIBLE TROPICAL CYCLONE...FORECAST TO MOVE NEAR 15N106W TONIGHT AND NEAR 16N106W ON THU NIGHT. THE GRADIENT WILL SUPPORT NE-E 20-25 KT WINDS WITHIN 180 NM NW OF A CENTER NEAR 16N109W ON SAT AND WITHIN 240 NM OVER THE NORTHERN SEMICIRCLE ON SUN. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS W ACROSS THE SW CARIBBEAN ALONG 09N TO THE PACIFIC COAST OF COSTA RICA AT 10N85W...THEN CONTINUES W TO 10N97W...THEN NW THROUGH THE EMBEDDED SURFACE LOW PRESSURE AT 14.5N101W...THEN SW THROUGH 13N111W TO 08N117W TO 07N125W WHERE IT LOSES IDENTITY. SCATTEROMETER WINDS INDICATE THAT THE MONSOON TROUGH RESUMES SW OF NARDA AT 14N129W...AND CONTINUES SW TO BEYOND 11N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION...WITH NUMEROUS LIGHTNING...IS OBSERVED WITHIN 60 NM OF COAST OF COLOMBIA FROM 03-08N...ALONG THE COAST OF CENTRAL AMERICA WITHIN 30 NM OF A LINE FROM 06.5N79W TO 09N86W...WITHIN 30 NM OF 13N91W...WITHIN WITHIN 90 NM EITHER SIDE OF A LINE FROM 08N96W TO 11N100W TO 11N108W TO 08N116W...FROM 06N TO 11N BETWEEN 116W TO 123W... WITHIN 90 NM OF LINE FROM 13N117W TO 16N122W. ...DISCUSSION... AN UPPER CYCLONE IS OVER SOUTHERN CALIFORNIA TRAILING AN UPPER TROUGH SW INTO THE DISCUSSION AREA FROM 32N117W TO 20N131W. AN UPPER ANTICYCLONE IS OBSERVED JUST W OF THE AREA AT 12N146W... WITH A NARROW UPPER RIDGE EXTENDING N TO A CREST AT 28N143W. UPPER DEBRIS MOISTURE...ORIGINATING FROM ITCZ CONVECTION BETWEEN NEAR 160W...IS ADVECTED NE WITHIN THIS RIDGE...AND IS JUST BEGINNING TO SPILL SE INTO THE AREA NEAR 22N140W. OTHERWISE... THE UPPER LEVELS APPEAR VERY DRY IN CYCLONIC FLOW ACROSS THE SUBTROPICAL PORTION OF THE DISCUSSION AREA. AN UPPER CYCLONE IS NOTED OVER THE DEEP TROPICS NEAR 02N136W... WITH AN INVERTED UPPER TROUGH EXTENDING N TO 11N130W. AN UPPER ANTICYCLONE IS CENTERED OVER OLD MEXICO AT 18N99W WITH AN UPPER RIDGE EXTENDING E ACROSS CENTRAL AMERICA TO A CREST OVER THE GULF OF HONDURAS. AN UPPER RIDGE ALSO EXTENDS SW ACROSS THE TROPICAL PACIFIC TO A FAIRLY SHARP CREST AT 12N132W. ANOTHER UPPER CYCLONE IS NOTED OVER THE DEEP TROPICS AT 04N113W. WEAK UPPER DIFFLUENCE ALONG THE S PERIPHERY OF THIS UPPER RIDGE HAS ENHANCED CONVECTION ALONG THE EASTERN SEGMENT OF THE MONSOON TROUGH AS PREVIOUSLY MENTIONED. THE RESULTANT UPPER DEBRIS MOISTURE IS SPREADING S TO ALONG A LINE FROM THE EQUATOR AT 92W TO 07N105W THEN BACK TO THE EQUATOR AT 121W. VERY DRY UPPER AIR IS NOTED S OF THIS SAME LINE SURROUNDING THE TROPICAL UPPER CYCLONE JUST MENTIONED. GULF OF TEHUANTEPEC...LIGHT AND VARIABLE WINDS ARE EXPECTED ACROSS THE GULF WATERS THROUGH SUN...EXCEPT BECOMING N AT 10-15 KT IN DRAINAGE FLOW LATE EACH NIGHT THROUGH SUNRISE EACH MORNING. GUIDANCE INDICATES THAT THE NEXT NORTHERLY 20-25 KT EVENT WILL BEGIN LATE SUN NIGHT...AND REPEAT AGAIN ON MON NIGHT. GULF OF CALIFORNIA...SW 20-25 KT WINDS ARE CURRENTLY ACROSS THE GULF WATERS N OF 30N AHEAD OF A COLD FRONT THAT WILL PASS THROUGH THE GULF WATERS N OF 28N TODAY. WINDS BEHIND THE FRONT WILL QUICKLY VEER TO NORTHERLY AT 5-10 KT WITH THESE CONDITIONS SPREADING S ACROSS THE ENTIRE GULF OF CALIFORNIA BY THIS EVENING. THESE LIGHT...MOSTLY NW...WINDS WILL PERSIST THROUGH LATE SAT. ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS FROM 32N138W TO 21N110W. NW-N WINDS AT 15-20 KT...WITH SEAS 8 TO 11 FT IN MIXING LONG PERIOD N AND S SWELL...ARE CURRENTLY OBSERVED ON SCATTEROMETER DATA ACROSS THE AREA N OF 27N BETWEEN 118-130W. THE LOW LEVEL FLOW WILL GRADUALLY BECOME N-NE TONIGHT WITH THE SOUTHERN EXTENT OF THE 8 FT SEAS REACHING ALONG 23N BETWEEN 113W- 136W. THE N SWELLS WILL CONTINUE TO PROPAGATE S...MIXING WITH THE SOUTHERLY SWELLS PREVIOUSLY GENERATED BY TROPICAL CYCLONE NARDA...RESULTING IN COMBINED SEAS TO 8 FT EXTENDING ABOUT 600 NM NW OF THE NARDA REMNANT LOW ON FRI NIGHT...THEN QUICKLY SUBSIDING ON SAT. NELSON