000 AXPZ20 KNHC 180251 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI SEP 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0200 UTC. ...TROPICAL WAVES... A TROPICAL WAVE INVOF 110W-111W HAS BECOME INCREASINGLY DIFFICULT TO LOCATE...AS IT HAS HELPED TO FORM AN ELONGATED E-NE TO W-SW CYCLONIC CIRCULATION ASSOCIATED WITH THE MONSOON TROUGH...GENERALLY EXTENDING FROM 20N108.5W TO 18N112W TO 16N118W. ISOLATED TO SCATTERED MODERATE TO STRONG CONVECTION IS OCCURRING MAINLY AROUND THE PERIPHERY OF THIS CYCLONIC CIRCULATION...FROM 12N TO 20.5N BETWEEN 108W AND 121W. SEVERAL SMALL CYCLONIC CIRCULATIONS CAN BE IDENTIFIED IN SATELLITE IMAGERY WITHIN THIS ELONGATED CIRCULATION. ADDITIONAL TROPICAL MOISTURE FROM THE WAVE CAN BE SEEN MOVING N-NW AND INTO THE SOUTHERN PORTIONS OF THE GULF OF CALIFORNIA...AND THE COASTAL ZONES OF SINALOA MEXICO. GLOBAL MODELS CONTINUE TO INDICATE THAT THIS ELONGATED AREA OF LOW PRESSURE WILL ROTATE COUNTER CLOCKWISE AND BECOME MORE NE TO SW ALIGNED TONIGHT THROUGH FRIDAY...AND CONTINUE TO ADVECT ABUNDANT TROPICAL MOISTURE NORTH AND NORTHWESTWARD ACROSS SOUTHERN BAJA CALIFORNIA AND THE ADJACENT GULF AND MEXICAN STATES TO THE E...THEN SPREAD FARTHER N-NW INTO NORTHERN BAJA SAT AND SAT NIGHT AS THE ELONGATED LOW PRESSURE AREA BEGINS TO SHIFT N-NW. INCREASING RAIN CHANCES SHOULD BE EXPECTED ACROSS THESE AREAS...EXTENDING INLAND ACROSS MAINLAND MEXICO TO THE W SLOPES OF THE SIERRA MADRES OCCIDENTALES...WITH THE POTENTIAL FOR HEAVY RAINS...FLASH FLOODING AND LANDSLIDES THROUGH THE WEEKEND. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W FROM COLOMBIA NEAR 11N74W TO 09.5N87W TO 10.5N94W TO 08N100W TO 10N103W...WHERE IT BECOMES ILL DEFINED...THEN RESUMES FROM LOW PRES 1006 MB NEAR 16.5N111W TO LOW PRES 1006 MB NEAR 16N118W TO 11N127W TO LOW PRES 1008 MB NEAR 10.5N139W TO BEYOND 11N140W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 120 NM N AND 300 NM S OF TROUGH BETWEEN 80W AND 103W...AND WITHIN 60 NM N AND 270 NM S OF TROUGH BETWEEN 121W AND 135W. ...DISCUSSION... THE ELONGATED MONSOONAL CIRCULATION W OF 110W HAS BECOME THE DOMINANT WEATHER FEATURE ACROSS THE AREA. TO THE NW...1024 MB HIGH PRESSURE IS CENTERED N OF THE HAWAIIAN ISLANDS NEAR 35N153W WITH A RIDGE EXTENDING SE TO NEAR 22N112W. THE PRESSURE GRADIENT BETWEEN THE RIDGE AND LOWER PRESSURE INVOF OF THE MONSOON TROUGH IS PROMOTING FRESH TO STRONG NE TRADEWINDS TO THE W AND NW OF A TROUGH FROM 15N134W TO 19N131W TO 21N126W...WHERE SEAS ARE RUNNING 7-9 FT. THE FRESH NE TRADES EXTEND WWD BEYOND 140W AND GENERALLY S OF 23N. TO THE E OF THE RIDGE...AFTERNOON SCATTEROMETER DATA INDICATED N-NW WINDS AROUND 15 KT ACROSS THE NEAR AND OFFSHORE PACIFIC WATERS OF BAJA CALIFORNIA SOUTHWARD TO CABO SAN LAZARO...WHERE SEAS WERE GENERALLY 4-5 FT IN MIXED SW AND NW SWELL. THE RIDGE WILL GENERALLY REMAIN INTACT THROUGH FRIDAY BEFORE WEAKENING SAT AS N PORTIONS OF THE ELONGATED LOW PRESSURE AREA LIFTS N OF 20N. HOWEVER...INCREASING WINDS ACROSS THE OFFSHORE WATERS OF CALIFORNIA WILL GENERATE A NEW PULSE OF N- NW SWELL THAT WILL MOVE INTO NE PORTIONS OF THE DISCUSSION AREA OVER THE WEEKEND AND RAISE SEA HEIGHTS TO 6-8 FT...MAINLY W OF 118W. OTHERWISE...REGIONAL SEAS WILL CONTINUE TO BE DOMINATED BY PULSES OF MODERATE SW SOUTHERN HEMISPHERIC SWELL. $$ STRIPLING