000 AXPZ20 KNHC 250946 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE JUN 25 2013 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 0945 UTC. ...SPECIAL FEATURES... TROPICAL STORM COSME AT 16.5N 109.5W 994 MB AT 0900 UTC JUN 25 MOVING WNW OR 290 DEGREES AT 14 KT. MAXIMUM SUSTAINED WINDS ARE 55 KT WITH GUSTS TO 65 KT. NUMEROUS STRONG CONVECTION IS OBSERVED WITHIN 75 NM EITHER SIDE OF A LINE FROM 19N108W TO 14N110W. AN OUTER BAND OF SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 30 NM EITHER SIDE OF A LINE FROM 12.5N111W TO 17N114W. COSME IS FORECAST TO BECOME A HURRICANE TODAY THEN WEAKEN BACK TO A TROPICAL STORM ON WED AS IT CONTINUES MOVING WESTWARD OVER COOLER SURFACE WATERS. SEE THE LATEST FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTNT23 KNHC FOR MORE DETAILS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS W FROM THE BORDER OF COLOMBIA AND PANAMA AT 08N77W TO ACROSS THE PANAMA/COSTA RICA BORDER TO 09N84W TO 09N93W...THEN NW TO 13N101W WHERE THE TROUGH LOSES IDENTITY IN BROAD CYCLONIC CIRCULATION ASSOCIATED WITH TROPICAL CYCLONE COSME. THE MONSOON TROUGH RESUMES W OF COSME NEAR 12N114W AND CONTINUES WSW TO BEYOND 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WELL E OF THE TROPICAL CYCLONE COSME WITHIN 60 NM EITHER SIDE OF A LINE FROM 07N99W TO 11N102W TO 13N99W TO 18N102W. SIMILAR CONVECTION IS NOTED S OF THE CYCLONE FROM 07N-12N BETWEEN 106W-118W...AND ALSO WITHIN 60 NM EITHER SIDE OF A LINE FROM 08N120W TO 10N126W TO 08N140W. ...DISCUSSION... AN UPPER TROUGH EXTENDS E TO W ACROSS THE NORTHERN PORTION OF THE DISCUSSION AREA FROM 32N117W THROUGH A SMALL DEVELOPING UPPER CYCLONE AT 27N129W...THEN WSW INTO ANOTHER UPPER CYCLONE AT 22N140W. A 330 NM WIDE BAND OF THIN UPPER MOISTURE IS SPREADING S ACROSS THE AREA N OF THIS TROUGH. A SERIES OF WEAK BOUNDARIES ARE NOTED AT THE SURFACE WITH THE FIRST ANALYZED AS A WEAK COLD FRONT CURRENTLY FROM 32N129W TO 29N140W. THIS BOUNDARY IS ACCOMPANIED BY ONLY A 10-15 KT SW-W WIND SHIFT AND SEAS OF 4-6 FT IN W SWELL. THE SECOND BOUNDARY HAS REACHED ALONG 34N BETWEEN 130W-140W...AND IS ACCOMPANIED BY A 15-20 KT WIND SHIFT AND SEAS OF 6-10 FT IN NW SWELL. THESE BOUNDARIES WILL MOVE IN THE NW PORTION AND THEN WASH OUT BUT EXPECT SEAS TO 8 FT TO SPREAD S TO NW OF LINE FROM 32N134W TO 30N140W TONIGHT...AND NW OF A LINE FROM 32N128W TO 28N140W ON WED NIGHT...THEN BEGIN TO SUBSIDE. AN UPPER ANTICYCLONE IS OVER THE MEXICAN COAST AT 22N105W WITH A MID/UPPER RIDGE EXTENDING W TO A CREST AT 20N133W. THE ENVELOPE OF ANTICYCLONIC FLOW CONTINUES TO DOMINATE THE UPPER LEVELS BETWEEN 90W-113W PROVIDING THE UPPER DIFFLUENCE OVER TROPICAL CYCLONE COSME...AND FOR THE CONVECTION PREVIOUSLY DESCRIBED BETWEEN 98W-115W. THIS CONVECTION CONTINUES TO CONTRIBUTE TO EXTREMELY DENSE UPPER MOISTURE TRAPPED WITHIN THE ANTICYCLONIC ENVELOPE. THIS MID/UPPER RIDGE WILL PROVIDE THE STEERING FOR TROPICAL CYCLONE COSME FOR THE NEXT COUPLE OF DAYS. A SURFACE RIDGE EXTENDS FROM 26N140W TO 22N110W. NW WINDS AT 10-15 KT ARE OCCURRING E OF THE RIDGE WITHIN 150 NM OF THE BAJA PENINSULA WITH SEAS 4-6 FT IN NW SWELL. CROSS EQUATORIAL S SWELL CONTINUES TO PROPAGATE NE ACROSS THE TROPICS BETWEEN 98W-120W RESULTING IN LARGE AREA OF SEAS 12 FT OR GREATER SURROUNDING TROPICAL CYCLONE COSME. THE CYCLONE ITSELF WILL REINFORCE THE SOUTHERLY SWELLS RESULTING IN COMBINED SEAS OF 8-10 FT EXPECTED TO MOVE AS FAR AS 25N IN IN THE GULF OF CALIFORNIA BY MID DAY ON WED...THEN BEGIN TO SUBSIDE ON THU AS THE CYCLONE CONTINUES WESTWARD. COMBINED SEAS OF 7-10 FT WILL ALSO PROPAGATE N ALONG THE WESTERN SHORE OF THE BAJA PENINSULA BEGINNING THIS EVENING...AND REACH ALONG 30N LATE WED NIGHT. $$ NELSON