000 AXPZ20 KNHC 182154 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC WED NOV 18 2015 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. ...SPECIAL FEATURES... TROPICAL DEPRESSION TWENTY-ONE-E CENTERED NEAR 12.8N 107.0W AT 18/2100 UTC OR 404 NM SSW OF MANZANILLO MEXICO STATIONARY. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 270 NM IN THE N QUADRANT. THE DEPRESSION IS FORECAST TO STRENGTHEN TO A TROPICAL STORM LATE TONIGHT. WHILE THE DEPRESSION IS CURRENTLY STATIONARY...A SLOW NORTHWARD DRIFT OR ERRATIC MOTION WILL OCCUR THIS EVENING...THEN IT IS FORECAST TO BEGIN TO MOVE NW BY 12-24 HOURS...AND THEN W-NW THEREAFTER. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 09N83W TO TROPICAL DEPRESSION TWENTY-ONE-E NEAR 13N107W TO LOW PRES NEAR 10N116W TO LOW PRES NEAR 11N126W TO 08N133W. THE ITCZ AXIS EXTENDS FROM 08N133W TO 07N140W. SCATTERED MODERATE CONVECTION IS WITHIN 240 NM S OF THE AXIS BETWEEN 79W AND 89W...WITHIN 360 NM SW OF THE AXIS BETWEEN 95W AND 105W...AND ALSO FROM 08N TO 10N BETWEEN 128W AND 131W. ...DISCUSSION... N OF 15N E OF 120W...A TIGHT PRESSURE GRADIENT BETWEEN 1032 MB HIGH PRES CENTERED NEAR 36N135W AND LOWER PRESSURE OVER N CENTRAL MEXICO AND ALONG THE MONSOON TROUGH IS ALLOWING FOR FRESH TO STRONG NORTHWESTERLY WINDS TO BLOW THROUGH THE MAJORITY OF THE GULF OF CALIFORNIA S OF 28N...SPILLING OUT THE MOUTH OF THE GULF TO 21N W OF 108.5W. THESE WINDS WERE ALSO FILTERING THROUGH BAJA CALIFORNIA SUR PASSES INTO THE NE PACIFIC WATERS AS INDICATED BY EARLIER SCATTEROMETER DATA. ALTIMETER SATELLITE DATA CONTINUES INDICATED 7 TO 10 FT SEAS OFF BAJA CALIFORNIA DUE IN PART TO NW SWELL PROPAGATING THROUGH THE REGION. THE PRES GRADIENT WILL GRADUALLY RELAX THROUGH THU AS THE LOW PRES OVER N CENTRAL MEXICO LIFTS NE ALLOWING WINDS AND SEAS TO GRADUALLY DIMINISH BY THU NIGHT. W OF 120W...SCATTEROMETER DATA CONTINUES TO SHOW STRONG TRADE WINDS OVER MUCH OF THE AREA N OF 11N BETWEEN RIDGING ASSOCIATED WITH THE 1032 MB HIGH NEAR 36N135W AND LOWER PRES ALONG THE MONSOON TROUGH/ITCZ. VARIOUS ALTIMETER DATA CONTINUE TO SHOW SEAS AS HIGH AS 15 FT IN THE AREA OF THE STRONG TRADE WINDS... HELPED IN PART PRIMARILY BY LONG PERIOD NW SWELL PREVAILING ACROSS MUCH OF THE REGION. THIS IS PRODUCING AN UNUSUALLY LARGE AREA OF CONFUSED SEAS OF 8 FT AND GREATER... ROUGHLY N OF 06N. THE RIDGE WILL GRADUALLY WEAKEN THROUGH THE REMAINDER OF THE WEEK AND ALLOW THE TRADE WINDS TO DIMINISH ACCORDINGLY. WINDS AND SEAS WILL SUBSIDE...BUT REMAIN 8 FT OR GREATER ACROSS MUCH OF THE AREA THROUGH LATE IN THE WEEK. GULF OF TEHUANTEPEC...LIGHT AND VARIABLE WINDS ARE EXPECTED THROUGH THIS EVENING. HIGH PRES WILL THEN BUILD IN BEHIND A COLD FRONT IN THE WESTERN GULF OF MEXICO N OF THE AREA WHICH WILL INDUCE ANOTHER ROUND OF FRESH TO NEAR GALE FORCE NORTHERLY WINDS IN THE GULF OF TEHUANTEPEC LATE TONIGHT THROUGH AT LEAST THU AFTERNOON...LIKELY CONTINUING FOR SEVERAL DAYS INTO THE UPCOMING WEEKEND. CONDITIONS WILL APPROACH GALE FORCE...HOWEVER CURRENT MODEL GUIDANCE REMAINS BELOW GALE FORCE THROUGH THE NEXT 48 HOURS. LOOKING AHEAD...ANOTHER ROUND OF STRONG GAP WINDS CAN BE EXPECTED BY LATE SAT POSSIBLY REACHING GALE FORCE BY LATE SUN. $$ LEWITSKY