000 AXPZ20 KNHC 231552 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC MON MAR 09 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... SCATTEROMETER WINDS INDICATE THAT THE MONSOON TROUGH DEVELOPS NEAR 05N86W AND EXTENDS W TO AN EMBEDDED 1012 MB LOW PRESSURE CENTER AT 04N96W...THEN THE TROUGH CONTINUES W TO 03N108W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ THEN TURNS NW TO 06N120W...THEN TURNS SW TO BEYOND 04N140W. BROKEN TO LOCALLY OVERCAST LOW AND MID LEVEL CLOUDS...WITH SCATTERED MODERATE CONVECTION...IS OBSERVED ALONG THE EASTERN PORTION OF THE MONSOON TROUGH AND THE EMBEDDED LOW CENTER WITHIN 120 NM EITHER SIDE OF A LINE FROM 04N86W TO 05N96W. ISOLATED MODERATE CONVECTION IS NOTED ALONG THE MONSOON TROUGH AND ITCZ WITHIN 60 NM OF LINE FROM 02N97W TO 07N118W TO 05N126W. SCATTERED MODERATE CONVECTION IS OBSERVED WELL N OF THE ITCZ AXIS WITHIN 120 NM EITHER SIDE OF A LINE FROM 09.5N122W TO 08.5N134W TO 06N140W. ...DISCUSSION... ALOFT...A WEAK UPPER LEVEL TROUGH EXTENDS SW INTO THE DISCUSSION AREA FROM SOUTHERN CALIFORNIA TO OVER THE TROPICS NEAR 18N136W. A NARROW MOISTURE PLUME PRECEDES THE TROUGH WITHIN 120 NM EITHER SIDE OF A LINE FROM 20N140W TO 20N120W TO ACROSS THE NORTHERN BAJA CALIFORNIA PENINSULA. A NARROW LINE OF UPPER DRY AIR IS OBSERVED WITHIN 150 NM N OF THE MOISTURE PLUME...WITH ADDITIONAL DENSE UPPER MOISTURE OBSERVED N OF THE DRY AIR AND IS SPREADING E ACROSS THE SW CONUS. A SMALL AREA OF UPPER DIFFLUENCE IS OBSERVED S OF THE BASE OF THE UPPER TROUGH...AND IS ENHANCING THE CONVECTION N OF THE ITCZ AS PREVIOUSLY DESCRIBED. THE DEBRIS MOISTURE IS ADVECTED NE TO NEAR 18N127W AHEAD OF THE UPPER TROUGH. AN UPPER LEVEL ANTICYCLONE IS OBSERVED OVER THE DEEP TROPICS AT 04N86W WITH ITS ENVELOP OF ANTICYCLONIC UPPER WINDS COVERING THE THE DISCUSSION AREA S OF 20N TO THE E OF 111W. DRY UPPER AIR IS SUPPRESSING CONVECTION UNDER THIS UPPER RIDGE...EXCEPT FOR THE NARROW BAND OF CONVECTION PREVIOUSLY DESCRIBED ALONG THE MONSOON TROUGH. AT THE LOW LEVELS A SURFACE RIDGE EXTENDS FROM 32N135W TO 12N90W AND BRIDGES THROUGH A DISSIPATING FRONTAL TROUGH EXTENDING W FROM 30N123W TO 27N140W. ANTICYCLONIC WINDS ARE AT 10-15 KT ACROSS THE DISCUSSION AREA N OF 12N W OF 120W WITH COMBINED SEAS OF 6-8 FT IN MIXING NE...S AND NW SWELL. EXPECT THESE SWELLS TO SUBSIDE SOME OVER THE NEXT FEW DAYS WITH THE COMBINED SEAS HEIGHTS SUBSIDING BELOW 8 FT. THE PRESSURE GRADIENT NE OF THE RIDGE IS EXPECTED TO TIGHTEN TODAY INCREASING THE NW FLOW TO 20- 25 KT ACROSS THE DISCUSSION WATERS N OF 27N E OF 117W TO THE PACIFIC COAST OF BAJA CALIFORNIA...WITH SEAS OF 6-9 FT. THESE CONDITIONS WILL SPREAD S TO ALONG 25N BETWEEN 114-123W EARLY TUE...THEN THE GRADIENT SHOULD RELAX WITH NW 15-20 KT CONDITIONS FORECAST ACROSS THE THE WATERS S OF 30N BY EARLY WED. HOWEVER THE NW SWELL WILL MAINTAIN COMBINED SEAS OF 7-10 FT THROUGH WED EVENING BEFORE BEGINNING TO SUBSIDE. LONG PERIOD SOUTHERLY SWELL WILL PROPAGATE N ACROSS THE EQUATOR BETWEEN 105-120W ON TUE WITH COMBINED SEAS BUILDING TO 9 FT ON WED. THE NORTHERN EXTENT OF SEAS 8 FT OR GREATER WILL REACH ALONG 12N BETWEEN 92-155W ON THU BEFORE BEGINNING TO SUBSIDE. GULF OF TEHUANTEPEC...NORTHERLY 20-25 KT FLOW IS FORECAST TONIGHT THROUGH SUNRISE ON TUE WITH SEAS BUILDING TO 8 FT. A STRONGER TEHUANTEPEC EVENT IS EXPECTED ON FRI NIGHT WITH MINIMAL GALE CONDITIONS. $$ NELSON