000 AXPZ20 KNHC 150335 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU NOV 15 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 0300 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS FROM 08N78W TO 09N83W TO 07N98W THEN ITCZ TO 10N122W TO 09N130W TO 11N135W TO BEYOND 09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 120 NM S OF TROUGH E OF 88W...AND FROM 07N TO 10N BETWEEN 91W AND 100W. SIMILAR CONVECTION IS FROM 07N TO 10N BETWEEN 123W AND 130W...AND FROM 08N TO 12N BETWEEN 135W AND 138W. A DIFFLUENT PATTERN ALOFT IS HELPING TO INDUCE THE CONVECTIVE ACTIVITY W OF 123W. ...DISCUSSION... ALOFT...A TROUGH/RIDGE PATTERN DOMINATES THE FORECAST REGION. AN UPPER ANTICYCLONE CENTERED NEAR 13N121W EXTENDS A RIDGE NE ACROSS BAJA CALIFORNIA INTO THE SW CONUS. THE ANTICYCLONIC FLOW COVERS MOST OF BASIN BETWEEN 100W AND 130W. BROAD UPPER LEVEL EQUATORIAL CYCLONE TO THE S OF ANTICYCLONE IS NOW LOCATED NEAR 02N120W. A WELL DEFINED CUT-OFF LOW IS SPINNING NEAR 33N137W. AN UPPER LEVEL TROUGH EXTENDS FROM THE LOW CENTER TO BEYOND 21N140W. WINDS OF 110-130 KT ARE TO THE SE OF THE LOW ASSOCIATED WITH A SUBTROPICAL JET. THESE WINDS ARE TRANSPORTING ABUNDANT MID/UPPER LEVEL MOISTURE FROM THE TROPICS INTO THE FORECAST WATERS. A WIDE BAND OF TRANSVERSE HIGH CLOUDS IS RELATED TO THESE STRONG WINDS. AT THE SURFACE...A 1004 MB LOW PRES SYSTEM IS CENTERED N OF THE AREA NEAR 34N136W. SCATTEROMETER DATA CLEARLY DEPICTED THE CYCLONIC CIRCULATION ASSOCIATED WITH THIS SURFACE LOW FORECAST TO MOVE EWD DURING THE NEXT 24 HOURS. THE COLD FRONT ASSOCIATED WITH THIS LOW CENTER ENTERS THE AREA NEAR 30N134W THE CONTINUES SW TO BEYOND 23N140W. WEAK 1018 MB HIGH PRESSURE IS LOCATED OVER THE N WATERS NEAR 27N123W. THIS FEATURE HAS A RIDGE EXTENDING SE TO NEAR 20N120W. MAINLY LIGHT WINDS AND SEAS OF 3 TO 5 FT IN NW SWELL ARE NOTED UNDER THE INFLUENCE OF THE RIDGE. THE PRESSURE GRADIENT BETWEEN THE WEAK HIGH AND THE LOW IS PRODUCING FRESH TO STRONG S TO SW WINDS WITHIN 120 NM E OF THE FRONT. THE FRONT WILL CONTINUE TO SHIFT EASTWARD THROUGH THE NEXT COUPLE OF DAYS...REACHING FROM 30N127W TO 24N132W THU EVENING...AND WILL BE N OF AREA FRI EVENING. A SECONDARY FRONT OR FRONTAL TROUGH IN ASSOCIATION WITH THE SAME LOW PRES WILL MOVE ACROSS THE NW WATERS BY FRI. EXPECT INCREASING WINDS AND BUILDING SEAS IN THE WAKE OF THE FRONTS. MAXIMUM SEA HEIGHTS OF 14 FT ARE EXPECTED MAINLY NEAR 30N140W THU EVENING. A SMALL AREA OF FRESH TO STRONG TRADEWINDS PREVAILS FROM 12N TO 16N W OF 132W WITH SEAS TO 10 FT. THESE WINDS WILL DECREASE IN AREAL COVERAGE AND DIMINISH TO 20 KT OR LESS BY FRI WITH SEAS SLOWLY SUBSIDING THROUGH THAT TIME. GAP WINDS... NORTHERLY FLOW BEHIND A WEAKENING FRONT IN THE GULF OF MEXICO IS FUNNELING THROUGH THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC. THIS FLOW IS PRODUCING GALE FORCE WINDS OVER THE GULF OF TEHUANTEPEC. LATEST SCATTEROMETER DATA SHOWED WINDS OF 25-30 KT ACROSS THE AREA. HOWEVER...BOTH THE GFS AND THE NAM COMPUTER MODELS CONTINUE TO SHOW GALE FORCE WINDS LATE TONIGHT INTO THE EARLY MORNING HOURS WHEN USUALLY THE WINDS ARE GREATEST WITH THE AID OF THE DRAINAGE FLOW. SO...DECIDE TO MAINTAIN THE GALE WARNING THROUGH EARLY THU AFTERNOON. WINDS IN THE 20 TO 30 KT RANGE ARE FORECAST TO PERSIST THROUGH FRI EVENING. FRESH TO STRONG WINDS OVER THE SW CARIBBEAN ARE FUNNELING THROUGH THE GAP IN TOPOGRAPHY OVER CENTRAL AMERICA. THIS IS PRODUCING FRESH TO STRONG WINDS OVER THE GULF OF PAPAGAYO. THE WINDS ARE PEAKING DURING THE LATE NIGHT AND EARLY MORNING HOURS WITH THE ADDED COMPONENT OF NOCTURNALLY DRIVEN DRAINAGE FLOW. $$ GR