000 AXPZ20 KNHC 042151 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN DEC 04 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 06N77W TO LOW PRES NEAR 06N78W TO 09N84W TO 05N95W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 05N95W TO LOW PRES NEAR 08N108W TO 06N115W TO LOW PRES NEAR 10N124W THEN RESUMES FROM 08N134W TO 07N140W. ISOLATED MODERATE CONVECTION IS FROM 03N TO 06N E OF 81W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 240 NM IN THE NE QUADRANT OF THE SECOND LOW. ...DISCUSSION... AN UPPER LEVEL TROUGH EXTENDS FROM THE UNITED STATES GREAT BASIN REGION NEAR 35N108W TO ACROSS SOUTHERN CALIFORNIA TO A BASE NEAR 28N140W. A WIDE ASSOCIATED 80-100 KT UPPER LEVEL JETSTREAM IS ACROSS THE AREA N OF 20N. WATER VAPOR SATELLITE IMAGERY INDICATES VERY DRY AND STABLE AIR N OF 26N E OF 125W. ELSEWHERE ALOFT N OF 12N...MID TO UPPER LEVEL MOISTURE IS FEEDING UP FROM THE DEEP TROPICS SW OF THE AREA AND S OF HAWAII TO THE NE-E ACROSS CENTRAL MEXICO. AN UPPER LEVEL ANTICYCLONE IS NEAR 08N88W WITH NE-E FLOW S OF 12N AND W OF THIS FEATURE. MAINLY DRY AND STABLE AIR IS NOTED ACROSS THIS REGION. AT THE SURFACE...1009 MB LOW PRES IS EMBEDDED IN THE MONSOON TROUGH NEAR 08N108W WITH ASSOCIATED CONVECTION DESCRIBED ABOVE. THIS LOW IS FORECAST TO REMAIN NEARLY STATIONARY THROUGH THE NEXT 48 HOURS. A SECOND LOW IS ANALYZED TO THE W ALONG THE ITCZ NEAR 08N108W WITH AN ATTENDANT TROUGH FROM 12N106W TO 06N109W. CONVECTION IS AS IS DESCRIBED IN THE SECTION ABOVE. A 1634 UTC ASCAT PASS CAPTURED 20-25 KT WINDS WITHIN 150 NM IN THE NE SEMICIRCLE...AND EARLIER ALTIMETER PASSES SHOWED SEAS TO 9 FT. THIS LOW WILL MOVE TO NEAR 09N112W IN 24 HOURS...THEN TO NEAR 09N116W IN 48 HOURS WITH LITTLE CHANGE IN THE AREA OF ASSOCIATED WINDS AND SEAS. A THIRD AND WEAKENING LOW IS NEAR 10N124W WITH NO CONVECTION NOTED. A 1816 UTC ASCAT PASS SHOWED ONLY 10-15 KT WINDS NEAR THIS LOW. THIS LOW WILL DISSIPATE DURING THE NEXT 24 HOURS. A TIGHT PRES GRADIENT IS OVER THE NW WATERS BETWEEN 1042 MB HIGH PRES WELL N OF THE AREA NEAR 45N137W AND LOWER PRES ASSOCIATED WITH THE ITCZ. AS A RESULT...FRESH NE-E WINDS ARE OVER THE NW PORTION AND THE N CENTRAL WATERS AS MEASURED BY A 1814 UTC ASCAT PASS. SEAS ARE UP TO 11 FT IN MIXED NE AND NW SWELL IN THE NW PORTION AS REPORTED BY SHIP 'ZCDA9' NEAR 27N135W AT 2100 UTC. THIS SAME ASCAT PASS SHOWED E-SE 20 KT WINDS IN THE FAR SW CORNER S OF 05N W OF 135W. THE NORTHERLY SWELL SURROUNDS ALL OF THESE AREAS ACROSS ROUGHLY THE NW HALF OF THE WATERS. EXPECT THE SWELL TO GRADUALLY DECAY TO 9 FT AND ONLY COVER THE AREA FROM 10N TO 20N W OF 120W BY 48 HOURS...WITH THE AREA OF FRESH WINDS SHRINKING IN COVERAGE TO ACROSS THIS SAME AREA BY THAT TIME. GULF OF CALIFORNIA...20 KT NORTHERLY WINDS ARE IN THE GULF FROM 26N TO 30N BETWEEN WEAK RIDGING OVER THE BAJA CALIFORNIA PENINSULA AND TROUGHING OVER NW MEXICO. THE SURFACE PRES GRADIENT WILL TIGHTEN DURING THE NEXT 24-48 HOURS OVER THIS REGION INCREASING WINDS TO UP TO 30 KT BY 48 HOURS...WHICH WILL ALLOW FOR SEAS TO BUILD TO 8-10 FT ACROSS THE GULF WATERS AND SPILLING OUT JUST TO THE S OF THE GULF OF CALIFORNIA. GUIDANCE FROM A LOCAL RESEARCH STUDY INDICATES EVEN UP TO A 50 PERCENT CHANCE OF GALE FORCE WINDS BETWEEN 24-48 HOURS WHICH WILL NEED TO BE MONITORED FOR A POTENTIAL WARNING EVENT. GULF OF TEHUANTEPEC...DRAINAGE FLOW HAS DECREASED TO LESS THAN 20 KT...ALTHOUGH WINDS WILL RAMP UP TO 20-25 KT EARLY TUE AS A COLD FRONT MOVES INTO THE SW GULF OF MEXICO N OF THE AREA. MODEL GUIDANCE INDICATES A CHANCE OF MINIMAL GALES IN THE GULF OF TEHUANTEPEC BY MID WEEK FOLLOWING THE FRONTAL PASSAGE. GULF OF PAPAGAYO...WINDS WILL CONTINUE TO PULSE TO 20 KT IN AND DOWNWIND OF THE GULF OF PAPAGAYO THROUGH THE NEXT 48 HOURS... MAINLY DURING THE LATE NIGHT AND EARLY MORNING HOURS DURING PEAK DRAINAGE FLOW OFF OF CENTRAL AMERICA. $$ LEWITSKY