000 AXPZ20 KNHC 160244 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED SEP 16 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0130 UTC. ...TROPICAL WAVES... A WEAK TROPICAL WAVE IS INVOF 81W-82W AND IS ENHANCING ISOLATED CONVECTION NEAR THE MONSOON TROUGH ACROSS PANAMA...COSTA RICA AND THE ADJACENT COASTAL WATERS. THIS WAVE IS A WEAK SOUTHERN PORTION OF THE TROPICAL WAVE IN THE ATLANTIC BASIN...WHICH EXTENDS FROM NICARAGUA TO THE SOUTHEAST GULF OF MEXICO. GLOBAL MODELS SHOW THIS WAVE GRADUALLY DISSIPATING OVER THE NEXT FEW DAYS AS IT SHIFTS SLOWLY W. A TROPICAL WAVE IS INVOF 102W...WHERE SCATTERED MODERATE TO STRONG CONVECTION COVERS THE AREA FROM 07N TO 16N BETWEEN 100W AND 106W. THIS WAVE WILL CONTINUE TO SHIFT W-NW OVER THE NEXT FEW DAYS...AND STRENGTHEN THE SE SURFACE WINDS OFFSHORE OF THE MEXICAN COAST FROM ACAPULCO TO MANZANILLO TO AROUND 20 KT WED AND WED NIGHT WHERE SEAS WILL BUILD TO 7-8 FT. WIDESPREAD CONVECTION WILL ALSO ACCOMPANY THIS WAVE...AND GENERALLY SHIFT W- NW WITH THE WAVE. A TROPICAL WAVE IS INVOF 111W WITH EMBEDDED LOW PRES NEAR 15.5N111W 1008 MB. SCATTERED MODERATE TO STRONG CONVECTION IS NOTED FROM FROM 09N TO 21.5N BETWEEN 108W AND 115W...AND ALMOST EXCLUSIVELY W OF THE WAVE AXIS. AFTERNOON SCATTEROMETER DATA SHOWED CYCLONIC WINDS OF 15-20 KT ACROSS THE W SEMICIRCLE OF THE LOW. THIS WAVE IS EXPECTED TO MOVE SLOWLY WWD DURING THE NEXT FEW DAYS AND EVOLVE INTO AN ELONGATED LOW LEVEL NE TO SW ALIGNED CYCLONIC CIRCULATION. A 1009 MB SURFACE LOW IS ANALYZED AT 17N128.5W MOVING W 10 KT. CONVECTION OCCURRING EARLIER TODAY HAS DIMINISHED ALMOST COMPLETELY...WITH ONLY NUMEROUS SHALLOW STRATOFORM PRECIP OCCURRING WITHIN 360 NM ACROSS THE NW QUADRANT. THIS LOW IS FORECAST TO WEAKEN TO AN OPEN WAVE AND SHIFT WWD DURING THE NEXT FEW DAYS...AND MOVE OUT OF THE AREA ON FRIDAY. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM NW COLOMBIA NEAR 09N75W TO 07.5N81W TO LOW PRES NEAR 15.5N111W TO 11N127W...WHERE IT TERMINATES. ISOLATED TO SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 300 NM EITHER SIDE OF TROUGH BETWEEN 92W AND 100W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 60 NM N AND 270 NM S OF TROUGH BETWEEN 116W AND 127W. ...DISCUSSION... GULF OF CALIFORNIA...A N TO S ORIENTATED TROUGH CONTINUES FROM THE NORTHERN GULF OF CALIFORNIA TO BAJA CALIFORNIA SUR. THE PRESSURE GRADIENT TO THE E REMAINS RELAXED AND NOW SUPPORTS S-SW WINDS 15-20 KT ACROSS THE WATERS N OF 30N. LITTLE CHANGE IS EXPECTED THROUGH TONIGHT THEN THE GRADIENT WILL FURTHER WEAKEN. THE REMNANT TROUGH OF LINDA CONTINUES TO WEAKEN AND IS ALONG FAR N PORTIONS OF THE COAST OF BAJA CALIFORNIA NORTE...ALONG 116W. EXPECT THIS WEAKENING TROUGH TO MOVE E AND INLAND ACROSS BAJA CALIFORNIA NORTE TONIGHT THROUGH WED. A WEAK COLD FRONTAL TROUGH IS LOCATED TO THE NW OF THIS TROUGH...CROSSING 30N NEAR 122W. DRIER MORE STABLE AIR WILL SPREAD INTO PACIFIC BAJA COASTAL ZONES N OF 28N WED AND THU AS THIS WEAK BOUNDARY MOVES SE AND DISSIPATES. A NEW PULSE OF LONG PERIOD CROSS EQUATORIAL SW SWELL CONTINUES TO MOVE ACROSS THE TROPICS S OF 12N AND TOWARDS THE COAST OF MEXICO AND CENTRAL AMERICA...AND IS EXPECTED TO REACH THE COASTS EARLY WED. WAVE HEIGHTS ACROSS THE OPEN OCEAN WILL CHANGE LITTLE WITH THE ARRIVAL OF THIS SWELL...AND WILL ACT TO MAINTAIN CURRENT OFFSHORE WAVE HEIGHTS OF GENERALLY 4-6 FT. $$ STRIPLING