000 AXPZ20 KNHC 200918 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU AUG 20 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...TROPICAL WAVES... A TROPICAL WAVE EXTENDS FROM 04N TO 12N ALONG 98W. A 04 UTC ASCAT PASS SHOWED A BROAD AREA OF CYCLONIC TURNING IN THIS AREA...POSSIBLY RELATED TO THE DEVELOPMENT OF LOW PRES. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED FROM 05N TO 10N BETWEEN 95W AND 100W. THE TROPICAL WAVE IS DEPICTED WELL IN DIAGNOSTIC MODEL GUIDANCE AS WELL IN SATELLITE DERIVED WINDS. THE TROPICAL WAVE WAS ADDED TO THE 00 UTC SURFACE CHART...NOT FAR FROM A SECOND TROPICAL WAVE THAT IS NOW ESTIMATED TO BE ALONG 105W FROM 05N TO 13N. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 90 NM EITHER SIDE OT THE WAVE AXIS. THIS WAVE IS NOT AS WELL DISPLAYED IN SATELLITE DERIVED WINDS OR MODEL GUIDANCE...AND MAY BECOME OVERTAKEN BY THE WAVE TO THE EAST IN THE NEXT 24 TO 48 HOURS. A TROPICAL WAVE AXIS IS ALONG 120W FROM 10N TO 16N MOVING W AT 15 KT. THE WAVE REMAINS BROADLY APPARENT ON THE LATEST GFS 700 MB STREAMLINE AND 850 MB VORTICITY ANALYSIS. THE TPW IMAGERY SHOWS A LARGE SWATH OF DEEP TROPICAL MOISTURE IN ASSOCIATION WITH THIS SYSTEM. NO SIGNIFICANT CONVECTION IS NOTED WITH THIS WAVE. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... CURRENTLY THERE IS NOT A WELL DEFINED MONSOON TROUGH OR ITCZ. MOST OF THE CONVECTIVE ACTIVITY IS ASSOCIATED WITH THE TROPICAL WAVES MENTIONED ABOVE. ...DISCUSSION... N OF 15N E OF 120W...SHIP OBSERVATIONS AND DATA FROM A 04 UTC ASCAT PASS INDICATE MODERATE TO FRESH NW WINDS OFF THE PACIFIC COAST OF THE BAJA PENINSULA...BETWEEN 1016 MB HIGH PRES CENTERED NEAR 26N125W AND A SURFACE TROUGH ALONG THE COLORADO RIVER VALLEY INTO THE NORTHERN BAJA PENINSULA. RECENT ALTIMETER PASSES INDICATE SEAS ARE GENERALLY 5 TO 7 FT N OF 22N AND 4 TO 6 FT ELSEWHERE N OF 15N. CLUSTERS OF THUNDERSTORMS ARE MOVING OFF THE MAINLAND COAST OF MEXICO INTO THE CENTRAL AND SOUTHERN GULF OF CALIFORNIA BUT ARE DIMINISHING. WINDS AND SEAS OFF THE COAST OF BAJA CALIFORNIA WILL DIMINISH THROUGH TODAY AS THE HIGH PRES WEAKENS AND DRIFTS WEST. MODERATE SOUTHERLY FLOW WILL PERSIST OVER THE NORTHERN GULF OF CALIFORNIA WITH SEAS TO 4 FT. NO CHANGES EXPECTED OTHERWISE THROUGH THE NEXT COUPLE OF DAYS. S OF 15N E OF 110W...A 04 UTC ASCAT PASS INDICATES CYCLONIC SURFACE WINDS NEAR 08N101W...NEAR THE TROPICAL WAVE IN THAT AREA. THIS COULD INDICATE THE EVENTUAL RE-EMERGENCE OF A SURFACE LOW. CONVECTION AROUND THIS LOW IS ALSO BECOMING A LITTLE BETTER DEVELOPED. GLOBAL MODELS ARE IN GOOD AGREEMENT SHOWING THE DEVELOPMENT OF GENERAL LOW PRESSURE IN THIS AREA...BUT DO NOT SHOW SIGNIFICANT DEEPENING FOR NOW. WINDS MAY BE REACHING 20 KT WITHIN 120 NM ON THE SE SIDE OF THE LOW LATER TODAY...BUT GENERALLY SCATTERED MODERATE ISOLATED STRONG CONVECTION CAN BE FOUND FROM 12N-15N BETWEEN 114W-119W. SCATTERED MODERATE CONVECTION IS AHEAD OF THE WAVE AXIS FROM 12N-15N BETWEEN 119W- 122W.IGHT TO MODERATE ELSEWHERE AS NOTED IN ASCAT DATA AND TOGA BUOY OBSERVATIONS IN THE AREA. FRESH GAP WIND FLOW IS LIKELY PULSING THROUGH THE GULF OF PAPAGAYO THIS MORNING...A TREND THAT WILL CONTINUE OVERNIGHT FOR THE NEXT COUPLE OF NIGHTS...GENERATING SEAS TO 5 TO 7 FT DOWNSTREAM. ELSEWHERE SEAS ARE 4 TO 6 FT. LITTLE CHANGE IS EXPECTED OTHER THAN THE LOW DRIFTING WESTWARD SLOWLY. ELSEWHERE...THE REMNANT LOW OF T.D. ELEVEN PERSISTS NEAR 28N132W WITH MSLP OF 1013 MB. NO SIGNIFICANT CONVECTION OR WINDS ARE NOTED WITH THIS FEATURE. AN EARLIER ALTIMETER PASS INDICATED SEAS TO 8 FT NEAR THE LOW...LARGELY DUE TO A MIX OF LONGER PERIOD NE SWELL AND SHORTER PERIOD SWELL FROM ELEVEN-E...BUT THIS HAS LIKELY SUBSIDED BELOW 8 FT. THE LOW PRES IS EXPECTED TO WEAKEN AND NOT MOVE MUCH THROUGH THE NEXT 2 TO 3 DAYS. FARTHER SOUTH...DEVELOPING LOW PRES W OF 140W HAS BEEN GENERATING SW SWELL TO 9 FT. AN EARLIER ALTIMETER PASS INDICATED THIS HAS PROPAGATED TO THE EAST OF 140W...AND LINGERING SWELL TO 8 FT MAY EXTEND FROM 10N TO 13N W OF 138W. THIS SHOULD SUBSIDE TO BELOW 8 FT OVER THE NEXT 12 HOURS. $$ CHRISTENSEN