000 AXPZ20 KNHC 170331 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU NOV 17 2011 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 0300 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ALONG 08N78W TO 1008 MB LOW PRES NEAR 09N93W TO 08N110W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N110W TO 11N117W THEN RESUMES FROM 10N123W TO 08N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 08N TO 10N BETWEEN 88W AND 92W. SIMILAR CONVECTION IS FROM 08N TO 10N BETWEEN 134W AND 137W...AND ALSO FROM 07N TO 09N W OF 138W. ...DISCUSSION... AN UPPER LEVEL RIDGE IS OVER THE NORTHERN WATERS WITH THE MEAN AXIS ALONG 32N125W TO 20N126W. VERY DRY AND STABLE AIR IS NOTED ON WATER VAPOR SATELLITE IMAGERY N OF 20N E OF THE RIDGE AXIS. AN UPPER LEVEL TROUGH IS INTRUDING ON THE FAR NW CORNER OF THE DISCUSSION AREA EXTENDING FROM AN UPPER CYCLONIC CIRCULATION NEAR 31N148W TO 25N136W. MID TO UPPER LEVEL MOISTURE IS BEING ADVECTED AHEAD OF THIS TROUGH N OF 23N W OF 130W WITH THE AID OF A 50-70 KT JET CORE. AN UPPER LEVEL TROUGH REACHES FROM 20N115W TO 11N118W WITH MOISTURE BEING TRANSPORTED FROM THE ITCZ NORTHEASTWARD WITHIN 300-360 NM E OF THE TROUGH. AN UPPER LEVEL ANTICYCLONE IS OVER MEXICO NEAR 18N95W. DIFFLUENCE ALOFT IS ENHANCING CONVECTION ALONG THE MONSOON TROUGH AS IS DESCRIBED IN THE SECTION ABOVE. IN THE DEEP TROPICS...AN UPPER LEVEL CYCLONIC CIRCULATION HAS SHIFTED S OF THE EQUATOR TO NEAR 03S116W WITH AN UPPER LEVEL TROUGH REACHING INTO THE AREA TO 10N113W. NW OF THE CYCLONIC CIRCULATION IS A BROAD UPPER LEVEL ANTICYCLONE POSITIONED NEAR 11N125W. AT THE SURFACE...1028 MB HIGH PRES IS NW OF THE AREA NEAR 35N132W WITH A RIDGE AXIS EXTENDING INTO THE AREA NEAR 32N128W TO 15N106W. EARLIER SCATTEROMETER PASSES AND SHIP OBSERVATIONS INDICATED AN AREA OF FRESH NE-E TRADES FROM 11N TO 17N W OF 133W. MIXED NE AND NW SWELL OF 8-9 FT SURROUNDS THESE TRADES ACROSS THE REGION FROM 09N TO 17N W OF 120W. THESE TRADES AND SWELL WILL GRADUALLY DIMINISH AND SUBSIDE BY 30 HOURS. AN AREA OF 8-9 FT NW SWELL IS OVER THE FAR N CENTRAL WATERS N OF 26N BETWEEN 120W AND 128W. THIS SWELL WILL SUBSIDE TO LESS THAN 8 FT BY 36 HOURS. A 1008 MB LOW PRES CENTER IS ANALYZED ALONG THE MONSOON TROUGH NEAR 09N93W AND IS DRIFTING W. ENHANCED FRESH SW MONSOONAL FLOW WITH SEAS TO 9 FT IS TO THE S-SW OF THIS LOW FROM 05N TO 08N BETWEEN 90W AND 96W...AS CAPTURED BY EARLIER ASCAT AND JASON-2 PASSES. NO SIGNIFICANT DEVELOPMENT OF THIS LOW IS ANTICIPATED DURING THE NEXT 48 HOURS. A SURFACE TROUGH IS ANALYZED ALONG THE ITCZ...EXTENDING FROM 14N116W TO 09N122W. WINDS NEAR THE TROUGH REMAIN LESS THAN 20 KT WITH SEAS LESS THAN 8 FT. ASSOCIATED CONVECTION IS AS DESCRIBED IN THE SECTION ABOVE. A TIGHT PRES GRADIENT WILL BECOME ESTABLISHED OVER THE NW MEXICO REGION AND NW-N 20 KT WINDS ARE EXPECTED IN THE GULF OF CALIFORNIA FROM 25N TO 29N COMMENCING LATER TONIGHT...DIMINISHING BY LATE THU NIGHT. LOOKING AHEAD...A NEW SET OF LARGE NW SWELL WILL ARRIVE IN THE NORTHERN WATERS THIS WEEKEND...WITH SEAS BUILDING TO UP TO 15 FT ALONG 30N BY LATE SAT. GAP WINDS...HIGH PRES WILL BUILD IN BEHIND A COLD FRONT WHICH WILL MOVE THROUGH THE SW GULF OF MEXICO ON THU. STRONG NORTHERLY WINDS WILL FILTER FROM THE GULF OF MEXICO THROUGH THE CHIVELA PASS TO ACROSS THE GULF OF TEHUANTEPEC...AND A GALE WARNING REMAINS IN EFFECT BEGINNING THU EVENING...WITH WINDS DIMINISHING BELOW GALE FORCE BY FRI EVENING. $$ LEWITSKY