000 AXPZ20 KNHC 232132 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC MON APR 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2015 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE ITCZ AXIS EXTENDS FROM 09N84W TO 05N99W TO 07N115W TO 04N123W TO 06N140W. SCATTERED MODERATE CONVECTION LIES WITHIN 120 NM N OF THE AXIS BETWEEN 95W AND 118W AND WITHIN 240 NM S OF THE AXIS BETWEEN 94W AND 104W AND BETWEEN 111W AND 118W. ...DISCUSSION... A STRONG CUT OFF LOW ALOFT IS CENTERED NORTH OF THE FORECAST AREA NEAR 35N135W AND EXTENDS A TROUGH SOUTHWARD ALONG 135W TO 25N THEN SOUTHWESTWARD TO 20N140W. BROAD RIDGING CENTERED JUST OFFSHORE OF BAJA CALIFORNIA DOMINATES THE REMAINDER OF THE FORECAST AREA ALOFT N OF 15N. BROADLY DIFFLUENT UPPER LEVEL FLOW IS FOUND IN MUCH OF THE REGION N OF 10N AND E OF THE TROUGH AXIS...WITH THE FLOW SPLIT BETWEEN SOUTHERN STREAM WESTERLIES CENTERED ALONG 15N AND SOUTH-SOUTHWESTERLY FLOW ON THE LEADING EDGE OF THE CUT OFF LOW. THE LEFT FRONT QUADRANT OF THE 80-100 KT SOUTHERN STREAM JET FOUND WEST OF THE AREA LIES NEAR A MAXIMA OF PRECIPITABLE WATER THAT COINCIDES WITH A SURFACE TROUGH FROM 08N126W TO 05N125W. SCATTERED MODERATE CONVECTION FOUND FROM 08N TO 12N BETWEEN 119W AND 126W IS BEING ENHANCED BY THE LIFT OF THIS MOIST AIR MASS BY THE DIFFLUENCE ALOFT. A LARGER REGION OF MULTI-LAYERED CLOUDINESS AND SCATTERED SHOWERS PRIMARILY FROM 10N TO 23N BETWEEN 112W AND 133W IS ALSO BENEFITING FROM THESE CONDITIONS. FARTHER SOUTH...AN UPPER LEVEL TROUGH AXIS LIES FROM 10N120W TO 00N110W AND A RIDGE AXIS LIES TO ITS EAST ALONG 08N EAST OF 113W. DIFFLUENT FLOW ABOUT THIS RIDGE AXIS IS ACTING TO ENHANCE THE CONVECTION ALONG THE ITCZ DESCRIBED IN THE SECTION ABOVE. A 1018 MB HIGH PRES SYSTEM IS CENTERED NEAR 27N118W. THE HIGH HAS BEEN WEAKENED BY THE TROUGHING ALOFT. THIS HAS RESULTED IN TRADE WINDS LESS THAN 20 KT OVER THE FORECAST AREA DUE TO THE AND THE WEAKENED PRES GRADIENT BETWEEN IT AND THE ITCZ. A COLD FRONT ASSOCIATED WITH THE CUT OFF LOW ALOFT EXTENDS FROM 30N129W TO 22N135W. NORTH TO NORTHWEST WINDS TO 25 KT LIE OVER FAR NORTHWEST WATERS BEHIND THE FRONT ACCORDING TO SEVERAL SHIP OBSERVATIONS AND THE 1936 UTC ASCAT PASS. THE DEEP LAYER LOW IS FORECAST TO GRADUALLY WEAKEN AS IT SLOWLY MOVES SOUTHEASTWARD THROUGH WED...CARRYING THE FRONT EASTWARD WITH IT. THE STRONGEST WINDS SHOULD REMAIN OVER NORTH WATERS TO THE WEST OF THE SURFACE LOW...WITH STRONG WINDS EXPECTED THROUGH TUE AND DIMINISHING TO FRESH ON WEDNESDAY. NORTHWEST SWELL WILL ALLOW SEAS TO BUILD TO THE 13-15 FT RANGE BEHIND THE FRONT TOMORROW BEFORE GRADUALLY SUBSIDING. GAP WINDS... GULF OF TEHUANTEPEC...HIGH PRES OVER THE WESTERN GULF OF MEXICO BEHIND A STRONG LATE SEASON COLD FRONT HAS TIGHTENED THE PRES GRADIENT ACROSS SOUTHERN MEXICO RESULTING IN WINDS TO GALE FORCE THROUGH THE GULF OF TEHUANTEPEC. THE 1618 UTC ASCAT PASS CAPTURED WINDS TO GALE FORCE WITH STRENGTHENING OF THE PRES GRADIENT EXPECTED THIS AFTERNOON AND EVENING AS HIGH PRES IN THE GULF OF MEXICO SHIFTS SOUTHWARD. 40 KT NORTH-NORTHEASTERLY WINDS THIS EVENING WILL DIMINISH BELOW GALE FORCE BY TUE AFTERNOON AS THE HIGH PRES SHIFTS INTO THE NORTHEASTERN GULF OF MEXICO. GULF OF PAPAGAYO...THE SOUTHERN MIGRATION OF THE HIGH PRES SYSTEM IN THE WESTERN GULF OF MEXICO WILL INCREASE THE PRES GRADIENT OVER CENTRAL AMERICA TONIGHT...GENERATING FRESH TO STRONG NORTHEAST WINDS THAT WILL SPREAD DOWNWIND OF THE GULF OF PAPAGAYO OVERNIGHT TONIGHT. WINDS ARE EXPECTED TO REMAIN FRESH TO STRONG DOWNWIND OF PAPAGAYO THROUGH THE END OF THE FORECAST PERIOD ON WED AFTERNOON. GULF OF PANAMA...THE 1436 UTC ASCAT PASS SHOWED FRESH TO STRONG NORTHERLY WINDS IN THE SOUTHWEST CARIBBEAN BEHIND THE COLD FRONT THAT USHERED IN HIGH PRES TO THE WESTERN GULF OF MEXICO. THE PRES GRADIENT WILL SHIFT EASTWARD ALLOWING THE NORTHERLY FLOW TO FUNNEL INTO THE GULF OF PANAMA BY TUE MORNING. THESE CONDITONS WILL CONTINUE THROUGH THE END OF THE FORECAST PERIOD WED AFTERNOON. $$ SCHAUER