000 AXPZ20 KNHC 112215 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT OCT 11 2014 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...TROPICAL LOWS AND WAVES... TWO WEAK LOW PRESSURE CENTERS ARE EMBEDDED WITH THE BROADER MONSOON TROUGH. THE WESTERNMOST LOW IS NEAR 11.5N96.5W 1008 MB WITH ISOLATED MODERATE TO STRONG CONVECTION NOTED WITHIN 210 NM OVER THE NW SEMICIRCLE. THIS LOW IS VERY WEAK WITH ONLY 5-10 KT FLOW NEAR THE CENTER...AND GUIDANCE DISSIPATES THE CIRCULATION TONIGHT. THE EASTERNMOST LOW IS NEAR 12.5N92W 1008 MB WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION CURRENTLY OBSERVED WITHIN 210 NM OVER THE E SEMICIRCLE. CYCLONIC 10-15 KT WINDS CONTINUE WITHIN ABOUT 120 NM OF THE LOW AT 12.5N92W WITH SEAS OF 4-6 FT CONFIRMED BY A RECENT ALTIMETER PASS. THIS LOW PRESSURE IS FORECAST TO MEANDER IN ROUGHLY THE SAME POSITION THROUGH MON...THEN MOVE SLOWLY NORTHWESTWARD ON TUE AND WED REACHING NEAR 13N95W ON THU. CURRENT GUIDANCE IS MUCH LESS AGGRESSIVE THAN PREVIOUS RUNS...AND THIS IS REFLECTED IN THE OFFICIAL GRIDS. A STRONG COLD FRONT IS FORECAST TO SWEEP SE THROUGH THE SOUTHERN GULF OF MEXICO ON TUE...WITH NORTHERLY FLOW SURGING THROUGH THE ISTHMUS OF TEHUANTEPEC ON TUE NIGHT AND FUNNELING SW OVER THE W SEMICIRCLE OF THE LOW...AND WILL LIKELY BE THE TRIGGER FOR THE LOW TO DEEPEN. ALSO EXPECT THE SOUTHERLY MONSOON FLOW TO INCREASE TO 15-20 KT/SEAS 6-8 FT ACROSS THE PAC WATERS FROM 03- 12N BETWEEN 87-97W TO INCLUDE THE SE SEMICIRCLE OF THE LOW...WITH TROPICAL CYCLONE FORMATION THEN A POSSIBILITY. A WEAK TROPICAL WAVE IS ANALYZED FROM 12.5N113W TO 19N115W AND HAS BEEN MOVING W AT 10 KT. ISOLATED MODERATE CONVECTION CONTINUES TO FLARE WITHIN 60 NM OF THE FAR NORTHERN PORTION OF THE WAVE AXIS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS ANALYZED ALONG 10N ACROSS THE SW CARIBBEAN FROM THE NW COAST OF COLOMBIA TO ACROSS NORTHERN COSTA RICA TO THE PACIFIC COAST OF COSTA RICA AT 09N84W...THEN TURNS NW THROUGH EMBEDDED LOW PRESSURE CENTERS AT 12.5N92W AND 11.5N96.5W...THEN CONTINUES SW TO 08N103W...THEN NW TO THE SOUTHERN END OF A TROPICAL WAVE AT 12.5N 113.5W...THEN SW TO BEYOND 09N140W. ISOLATED MODERATE TO STRONG CONVECTION IS OBSERVED WITHIN 90 NM EITHER SIDE OF A LINE FROM 04.5N77W TO 10N88W...AND FROM 07-13N BETWEEN 110-130W AND FROM 06-17N BETWEEN 130-140W. CONVECTION APPEARS TO BE ORGANIZING NEAR 10N135W AND GUIDANCE IS HINTING AT A SURFACE LOW DEVELOPING NEAR 10N140W EARLY NEXT WEEK WITH FAVORABLE CONDITIONS FOR TROPICAL CYCLONE FORMATION IN 3-5 DAYS. LIGHTNING DATA INDICATES THUNDERSTORMS CLUSTERS JUST INLAND THE PACIFIC COAST OF CENTRAL AMERICA FROM 86-90W AND JUST INLAND THE PACIFIC COAST OF MEXICO FROM 98-104W. THESE CLUSTERS WILL LIKELY SPREAD W OVER THE ADJACENT COAST WATERS THIS EVENING. ...DISCUSSION... GULF OF TEHUANTEPEC...THE NORTHERLY NOCTURNAL DRAINAGE FLOW ACROSS THE GULF OF TEHUANTEPEC IS EXPECTED TO INCREASE TO 15-20 KT LATE EACH NIGHT THROUGH TUE MORNING. AS PREVIOUSLY MENTIONED A STRONG COLD FRONT IS EXPECTED TO MOVE THROUGH THE BAY OF CAMPECHE ON TUE WITH THE NOCTURNAL DRAINAGE LIKELY TO INCREASE TO 20-30 KT/SEAS 8-12 FT LATE TUE NIGHT THROUGH WED MORNING AND CONTINUE THROUGH LATE THU MORNING. LONG PERIOD NW SWELL IS MIXING WITH SW SWELL...WITH COMBINED SEAS OF 8-12 FT OBSERVED W OF A LINE FROM 30N130W TO 22N133W TO 15N130W TO 11N140W. THESE CONDITIONS WILL PROPAGATE SE ACROSS THE DISCUSSION AREA REACHING THE PACIFIC COAST OF THE NORTHERN BAJA PENINSULA LATE SUN...AND SPREAD AS FAR SE AS 20N110W LATE MON NIGHT. THE SEAS ARE EXPECTED TO QUICKLY SUBSIDE ACROSS MOST OF THE AREA ON MON. ANOTHER BATCH OF NW SWELL WILL PROPAGATE SE REACHING THE FAR NW PORTION ON THE DISCUSSION AREA BY TUE AFTERNOON WITH SEAS BUILDING 8 TO 11 FT AGAIN ACROSS THE DISCUSSION WATERS NW OF A LINE FROM 32N121W TO 25N140W ON WED NIGHT. THESE ENHANCED SEAS ARE EXPECTED TO REACH THE NORTHERN BAJA CALIFORNIA PENINSULA ON THU NIGHT. BY THEN A STRONG COLD FRONT WILL BE APPROACHING THE FAR NW DISCUSSION WATERS PRECEDED BY SW 20-25 KT FLOW. $$ NELSON