000 AXPZ20 KNHC 300923 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE OCT 30 2012 CORRECTED TO INCLUDE MENTION OF ASCAT WINDS ASSOCIATED WITH SPECIAL FEATURE LOW UNDER DISCUSSION SECTION 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 0845 UTC. ...SPECIAL FEATURE... A 1006 MB LOW PRES LOCATED NEAR 14.3N 115.7W REMAINS EMBEDDED WITHIN THE MONSOON TROUGH. OVERNIGHT...SHOWERS AND THUNDERSTORMS HAVE BECOME SIGNIFICANTLY BETTER ORGANIZED IN ASSOCIATION WITH THIS SYSTEM...AND A TROPICAL DEPRESSION COULD BE FORMING. IF THIS TREND CONTINUES...ADVISORIES COULD BE INITIATED LATER THIS MORNING. THIS SYSTEM HAS NOW A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WEST- NORTHWESTWARD AT AROUND 10 KT. LATEST SATELLITE PICTURE SHOWS NUMEROUS MODERATE TO STRONG CONVECTION WITHIN 150 NM SE AND 75 NM NE QUADRANTS OF THE LOW CENTER. WINDS OF 25-30 KT ARE WITHIN 60 NM OF CENTER BASED MAINLY ON COMPUTER MODELS. NO RECENT SCATTEROMETER DATA ARE AVAILABLE TO HELP IDENTIFY MAXIMUM WINDS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 06N78W TO 08N84W TO 08N91W TO 12N100W TO LOW PRES AT 14N107W 1009 MB TO LOW PRES AT 14.5N115.5W 1006 MB TO LOW PRES AT 11N122W TO 09N130W WHERE IT TRANSITIONS TO THE ITCZ TO 08N140W. ISOLATED MODERATE CONVECTION WITHIN 90 NM N OF TROUGH E OF 86W TO THE COAST OF PANAMA. SIMILAR CONVECTION IS WITHIN 45 NM OF 11N129W. ...DISCUSSION... ALOFT...A TROUGH/RIDGE PATTERN DOMINATES THE FORECAST REGION. AN UPPER-LEVEL TROUGH ENTERS THE AREA NEAR 30N136W THEN CONTINUES SW BEYOND 27N140W. THE TROUGH AXIS CROSSES JUST E OF THE HAWAIIAN ISLANDS. AN ANTICYCLONIC CIRCULATION CENTERED NEAR 11N126W HAS A RIDGE EXTENDING NE TO THE SW CONUS. THIS BROAD SYSTEM COVERS THE MAJORITY OF THE DISCUSSION AREA...AND IS PRODUCING MODERATE TO STRONG NLY WINDS OVER LOW PRES LOCATED NEAR 14N107W. IN FACT...THE CONVECTIVE ACTIVITY ASSOCIATED WITH THIS FEATURE IS MOVING AWAY FROM THE LOW CENTER AND HAS DECREASED OVERNIGHT. SATELLITE IMAGERY SHOWS ONLY ISOLATED TO SCATTERED MODERATE CONVECTION TO THE SE OF LOW CENTER FROM 10N TO 12N BETWEEN 104W AND 106W...AND NO DEEP CONVECTION IS NOTED NEAR THE LOW CENTER. UPPER-LEVEL WINDS ARE FORECAST TO BECOME LESS CONDUCIVE FOR DEVELOPMENT WITHIN A DAY OR SO. THIS SYSTEM HAS A LOW CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES SLOWLY WEST-NORTHWESTWARD. MODERATE TO STRONG SUBSIDENCE IS OBSERVED ON SATELLITE WATER VAPOR IMAGERY N OF 20N...INCLUDING THE BAJA CALIFORNIA PENINSULA AND NORTH-CENTRAL MEXICO. AT THE SURFACE...A 1022 MB HIGH PRES CENTER IS ANALYZED AT 32N130 WITH A RIDGE EXTENDING SE TO NEAR 22N110W. NE TRADE WINDS REMAIN RATHER LIGHT TO THE S AND SW OF THE RIDGE WITH SPEEDS OF 10-15 KT ACCORDING TO THE MOST RECENT ASCAT PASSES. SEAS TO 9 FT IN NW SWELLS STILL LINGER OVER A SMALL AREA FROM 12N TO 15N W OF 134W. THE 0454 UTC ASCAT PASS REVEALED WINDS OF 20-25 KT WITHIN 120 NM OF THE LOW CENTERED NEAR 14N107W. A COLD FRONT IS FORECAST TO MOVE ACROSS THE NW WATERS LATE TONIGHT REACHING A POSITION FROM 30N138W TO 28N140W. THE FRONT THEN WILL EXTEND FROM 30N132W TO 27N140W LATE WED NIGHT AND DISSIPATE AFTERWARD. NW SWELL IN THE WAKE OF THE FRONT WILL RAISE SEAS TO 9 FT. GAP WINDS... THE COOLER AND DRIER AIRMASS THAT SETTLED IN OVER THE GULF OF TEHUANTEPEC THE PAST FEW DAYS WITH 20-30 NLY WINDS HAS THIN OUT ENOUGH TO ALLOW FOR WINDS TO DIMINISH TO 20-25 KT THROUGH THE CHIVELA PASS AND INTO THE GULF OF TEHUANTEPEC. THE 0315 UTC ASCAT PASS CONFIRMED THE PRESENCE OF THESE WINDS WHICH ARE FORECAST TO DIMINISH TO 10-15 KT BY WED. WINDS IN THE GULF OF PAPAGAYO MAY INCREASE TO 20-25 KT WITHIN THE NEXT 30 HOURS AS A BROAD AREA OF LOW PRES REMAINS OVER THE SW CARIBBEAN. $$ GR