000 AXPZ20 KNHC 031531 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC WED OCT 03 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 10N86W TO 12N95W TO 11N106W TO 12N114W TO 07N137W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N137W TO 07N140W. ISOLATED MODERATE CONVECTION IS FROM 04N TO 08N BETWEEN 77W AND 84W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 11N TO 14N BETWEEN 95W AND 99W. SCATTERED MODERATE CONVECTION IS FROM 08N TO 12N BETWEEN 101W AND 108W. SCATTERED MODERATE CONVECTION IS WITHIN 75 NM EITHER SIDE OF A LINE FROM 08N109W TO 10N120W...AND FROM 09N128W TO 08N133W. ...DISCUSSION... AN UPPER LEVEL CYCLONE IS CENTERED NEAR 34N136W WITH AN UPPER LEVEL TROUGH AXIS EXTENDING S AND SE THROUGH 26N131W TO A BASE OVER THE DEEP TROPICS NEAR 13N133W. AN EXPANSIVE UPPER LEVEL ANTICYCLONE IS POSITIONED NEAR 22N114W WITH A RIDGE EXTENDING N BEYOND 32N117W. A SECOND UPPER LEVEL RIDGE EXTENDS SW TO A CREST OVER THE TROPICS TO 10N130W. WEAK UPPER DIFFLUENCE IS NOTED OVER THE DEEP TROPICS S AND E OF THE UPPER RIDGING SUPPORTING CONVECTION ALONG THE MONSOON TROUGH AS DESCRIBED ABOVE. RESULTANT DEBRIS MOISTURE FANS OUT BOTH TO THE N AND TO THE S BUT QUICKLY EVAPORATES IN CLOSE PROXIMITY DUE TO VERY DRY AIR OVER THE MAJORITY OF THE DISCUSSION AREA N OF 15N W OF 105W. AN UPPER LEVEL CYCLONE OVER SOUTHWESTERN ARKANSAS EXTENDS AN UPPER TROUGH AXIS SW OVER THE NW GULF OF MEXICO REACHING ACROSS CENTRAL MEXICO TO A BASE IN THE NE PACIFIC NEAR 16N101W. AN UPPER LEVEL RIDGE EXTENDS NW FROM SOUTH AMERICA ACROSS THE DEEP TROPICS TO THE S OF 10N E OF 92W AND IS ADVECTING UPPER MOISTURE W ACROSS THE DISCUSSION AREA E OF 90W. ADDITIONAL MOISTURE IS SPREADING NE ACROSS SOUTHERN MEXICO...CENTRAL AMERICA...AND THE SE GULF OF MEXICO. ELSEWHERE AT THE LOW LEVELS...A BROAD SURFACE RIDGE COVERS THE AREA N OF 20N W OF 110W. THE NEARLY STATIONARY REMNANT 1009 MB LOW OF MIRIAM IS CENTERED NEAR 16N119W AND SURROUNDS ITSELF WITH OVERALL CYCLONIC FLOW FROM 12N TO 20N BETWEEN 114W AND 126W. LIGHT TO MODERATE WINDS ARE ASSOCIATED WITH THE WEAK CIRCULATION PER EVIDENCE FROM RECENT SCATTEROMETER PASSES. SOUTHWESTERLY LOW-LEVEL WINDS AT 15 TO 20 KT ALONG WITH CROSS EQUATORIAL SW SWELL CONTINUES TO RESULT IN SEAS TO 9 FT S OF 11N BETWEEN 100W AND 120W. THE WINDS ARE EXPECTED TO DIMINISH TO 15 KT WITHIN 24 TO 48 HOURS...AND THE AREA OF SW SWELL WILL GRADUALLY DECAY TO THE 8 FT MARK WHILE RETREATING TO 06N BY 48 HOURS. GAP WINDS...HIGH PRESSURE HAS ESTABLISHED ITSELF ACROSS MUCH OF MEXICO IN WAKE OF A FRONTAL BOUNDARY THAT MOVED THROUGH THE WESTERN GULF OF MEXICO THE PAST COUPLE OF DAYS. THE FRONT IS NOW CONTINUING TO DISSIPATE AND HAS BECOME MOSTLY STATIONARY ACROSS THE EASTERN GULF OF MEXICO AND EASTERN COAST OF THE YUCATAN PENINSULA. WITH THE PASSAGE OF THIS FRONT...A SURGE OF NORTHERLY WINDS IS OCCURRING THROUGH THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC. EARLIER SHIP OBSERVATIONS AND AN ASCAT PASS AROUND 03/0412 UTC WARRANTED ISSUING A GALE WARNING AT 03/0600 UTC. WHILE THERE HAS BEEN NO FURTHER INDICATION OF CONTINUING GALE FORCE CONDITIONS...THE GALE WARNING IS EXPECTED THROUGH 03/1800 UTC DUE LARGELY TO TYPICAL EARLY MORNING DRAINAGE FLOW OFF THE HIGHER TERRAIN OF THE PASS. GLOBAL MODEL DATA ALSO INDICATES THIS INITIAL SURGE WILL GRADUALLY DISSIPATE THIS AFTERNOON TO THE SOUTHWEST WHILE A NEW PULSE OF NORTHERLY WINDS WILL OCCUR IN THE EARLY MORNING HOURS ON THURSDAY. WINDS OF 20 TO 30 KT WILL SPILL OUT OF THIS AREA AND DOWNWIND PERSISTING AS THE PRESSURE GRADIENT REMAINS ENHANCED WITH HIGH PRESSURE ANCHORED OVER MEXICO. IN THE GULF OF PAPAGAYO...NE TO E WINDS ARE FORECAST TO INCREASE TO 20 TO 25 KT IN 18 HOURS AS TRADES E OF CENTRAL AMERICA IN THE CARIBBEAN SEA SPREAD WESTWARD. THESE WINDS ARE EXPECTED TO PERSIST THROUGH 48 HOURS AND THEN GRADUALLY DIMINISH AS THE TRADES BACK OFF. $$ HUFFMAN