000 AXPZ20 KNHC 250237 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU OCT 25 2012 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 12N86W TO LOW PRES NEAR 12N95W 1006 MB TO 10N110W TO 08N125W...WHERE IT TRANSITIONS TO ITCZ CONTINUING TO BEYOND 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 240 NM S OF TROUGH E OF 90W...WITHIN 60 NM OF TROUGH BETWEEN 94W-100W AND ALSO FROM 09N-12N BETWEEN 100W-108W. ...DISCUSSION... A NEARLY STATIONARY AND LARGE ANTICYCLONE IS CENTERED AT 20N111W WITH IS ASSOCIATED ANTICYCLONIC ENVELOP COVERING THE AREA THE VAST MAJORITY OF THE SE PORTION. WITH THIS FEATURE IN PLACE ...THE UPPER FLOW REMAINS STAGNANT AS IT IS CAUSING THE NORTHERN STREAM TO CONTINUE TO LIFT OVER AND ACROSS THE ANTICYCLONE..AND INTO THE BACK SIDE OF AN UPPER TROUGH OVER THE WESTERN CONUS. A LARGE POOL OF ABUNDANT TROPICAL MOISTURE PREVAILS ACROSS THE TROPICS FROM 06N TO 13N E OF 120W...WITH CONVECTION DESCRIBED ABOVE BEING INITIATED BY MODERATE TO FRESH MONSOONAL FLOW S OF THE TROUGH. UPPER LEVEL ELY WINDS S OF THE UPPER RIDGE CONTINUE TO DIVERT AROUND THE DEEPER CONVECTION S OF THE MONSOON TROUGH. THIS UPPER PATTERN WILL CHANGE LITTLE IN THE NEXT 24 HOURS BUT WILL BEGIN TO BROADEN AND FLATTEN BY FRI AS UPPER TROUGHING DIGS SW ACROSS CENTRAL AMERICA NEAR 90W. AN AREA OF BUILDING HIGH PRES OVER THE NORTH CENTRAL WATERS CENTERED NEAR 30N130W WILL SHIFT E ALONG 31N THROUGH THU. THE PRESENCE OF A LOW PRES TROUGH OVER NW MEXICO AND BAJA CALIFORNIA WILL TIGHTEN THE P1RES GRADIENT OVER THE NE PORTION...BRINGING FRESH TO STRONG N-NW WINDS ACROSS THE NEAR AND OFFSHORE WATERS W OF THE BAJA PENINSULA. EXPECT 20-25 KT WINDS TO GRADUALLY EXPAND SWD TO NEAR 24N BY THU BETWEEN 115W AND 125W...WITH SEAS BUILDING TO 10 FT. GLOBAL MODELS ARE HINTING AT THE POSSIBILITY OF WINDS INCREASING TO 30 KT N OF 29N IN THE FAR NE PART OF THE AREA ON THU...BUILDING SEAS THERE POSSIBLY UP TO 11 FT PER WAVEWATCH MODEL GUIDANCE. THIS ENHANCED PRES GRADIENT WILL ALSO INDUCE NNW WINDS 20-25 KT THROUGH THE NORTHERN AND CENTRAL PORTIONS OF THE GULF OF CALIFORNIA BY THU EVENING AND INTO FRI...WITH SEAS BUILDING TO 8 FT BY FRI MORNING. THE LARGE CYCLONIC CIRCULATION ASSOCIATED WITH HURRICANE SANDY IN THE W CENTRAL CARIBBEAN IS STRENGTHENING W-SW WIND FLOW S OF THE MONSOON TROUGH EXTENDING INTO THE COASTAL WATERS OF NICARAGUA....COSTA RICA...AND PANAMA...WHERE SEAS ARE REACHING AT OR NEAR 8 FT. MOIST CONVERGENT MONSOONAL FLOW WILL PRODUCE WIDESPREAD AREAS OF RAIN WITH OCCASIONAL MODERATE TO HEAVY SQUALLS ACROSS PANAMA AND COSTA RICA...GRADUALLY SHIFTING N INTO NICARAGUA THROUGH THU...WITH STRONG GUSTY WINDS POSSIBLE IN HEAVIER DOWNPOURS. AFTER THE OSCAT PASS FROM NEAR 19 UTC YESTERDAY AFTERNOON SHOWED N-NE WINDS OF 20-25 KT WITH A FEW WIND BARBS OF 25-30 KT THROUGH THE GULF OF TEHUANTEPEC...THE RECENT WIND SAT PASS INDICATES LESSER WIND SPEEDS OF 20 KT THROUGH THE GULF. THE PRES GRADEINT THAT EARLIER ALLOWED FOR THESE WINDS TO MATERIALIZE IS WEAKENING...AND WILL CONTINUE TO DO SO THROUGH THE NEXT 48 HRS ALLOWING FOR THESE WINDS TO DIMINSH TO 15-20 KT...BUT ARE FORECAST TO PICK UP AGAIN TO 20-25 KT BY JUST PAST THU EVENING AS RIDGING PUSHES SWD OVER EASTERN MEXICO. THE ASCAT PASS FROM YESTERDAY AFTERNOON REVEALED A COUPLE OF WEAK CYCLONIC CIRCULATIONS EMBEDDED ALONG THE MONSOON TROUGH ...ONE AT 12N95W AND THE OTHER NEAR 11N116W. THIS FALLS IN LINE WITH THE LATEST GLOBAL MODEL GUIDANCE...AND THAT FROM THE PAST FEW DAYS. EXPECT THESE WEAK FEATURES TO PERSIST THROUGH AT LEAST THE NEXT 48 HRS WITH LITTLE SIGNIFICANT INTENSIFICATION EXPECTED. THIS WILL HELP KEEP A CONVERGENCE ZONE OF FAIRLY ACTIVE CONVECTION E OF 125W THROUGH THIS PERIOD. $$ AGUIRRE