000 AXPZ20 KNHC 262155 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT SEP 26 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...SPECIAL FEATURE... CONVECTION HAS BECOME BETTER ORGANIZED AND THUS TROPICAL DEPRESSION 17-E HAS FORMED AT 13.3N 103.0W...OR ABOUT 325 MILES SW OF ACAPULCO MEXICO...AT 2100 UTC WITH AN ESTIMATED PRESSURE OF 1005 MB. THE DEPRESSION IS MOVING N-NW...OR 345 DEG AT 03 KT. MAXIMUM SUSTAINED WINDS ARE 30 KT WITH GUSTS 40 KT JUST E OF THE CENTER WITH 20 TO 30 KT WINDS OBSERVED ELSEWHERE WITHIN 270 NM SE SEMICIRCLE...AND WITHIN 120 NM OVER THE NW SEMICIRCLE. CURRENTLY SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 120 NM N AND WITHIN 180 NM S SEMICIRCLES OF THE CENTER. A TURN TOWARDS THE N IS EXPECTED IN THE NEXT FEW HOURS AS THE SYSTEM MOVES AROUND THE W PERIPHERY OF AN UPPER RIDGE... FOLLOWED BY A TURN TO THE NE ON SUN NIGHT. THE DEPRESSION IS FORECAST TO STRENGTHEN TO A TROPICAL STORM WITHIN A DAY AS IT TRACK N TOWARDS THE MEXICAN COAST. ASSOCIATED SQUALLS AND BUILDING SEAS WILL LIKELY REACH THE PACIFIC COAST OF MEXICO BETWEEN 96-102W THROUGH THE MIDDLE OF NEXT WEEK. THE EFFECTS OF UPPER LEVEL SHEAR ARE UNCERTAIN SO MARINERS ARE ENCOURAGED TO REFER TO THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR UPDATED DETAILS. ...TROPICAL LOW AND TROPICAL WAVES... A 1009 MB SURFACE LOW IS EMBEDDED IN THE MONSOON TROUGH AT 13N88.5W AND IS DRIFTING NE. CURRENTLY UNORGANIZED SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 120 NM OVER THE N SEMICIRCLE...AND WITHIN 180 NM OVER THE S SEMICIRCLE OF THE CENTER. THE MOST RECENT SCATTEROMETER PASS INDICATED THAT SURFACE WINDS HAVE DIMINISHED TO 15-20 KT E OF THE CENTER...AND SHIP REPORTS ALL REPORT THAT THE COMBINED SEAS HAVE SUBSIDED BELOW 8 FT...THUS THIS LOW HAS BEEN REMOVED FROM THE HIGH SEAS FORECAST. A 1009 MB LOW PRES HAS FORMED WITHIN THE MONSOON TROUGH AT 10N120W...BUT IS ONLY CURRENTLY ACCOMPANIED BY ISOLATED MODERATE TO STRONG CONVECTION WITHIN 150 NM NW SEMICIRCLE OF THE CENTER. CYCLONIC SURFACE WINDS OF ONLY 5-10 KT ARE FORECAST WITHIN 150 NM OF THE CENTER THROUGH THE WEEKEND...THEN THE GRADIENT WILL TIGHTEN SUPPORTING SW 15-25 KT WINDS WITHIN ABOUT 480 NM OVER THE SE SEMICIRCLE WITH SEAS BUILDING TO 10 FT IN CROSS EQUATORIAL SWELL. A TROPICAL WAVE IS ANALYZED FROM 07N140W TO 14N137W AND WILL PASS W OF 140W TONIGHT. CURRENTLY SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 120 NM W OF WAVE AXIS AND TO THE S OF 10N WITHIN 360 NM E OF WAVE AXIS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE TROPICAL LOW PRESSURE CENTER AND THE TROPICAL DEPRESSION... BOTH PREVIOUSLY DESCRIBED...HAVE PULLED THE MONSOON TROUGH AXIS NORTHWARD. THE AXIS IS CURRENTLY ANALYZED ALONG 10N FROM THE CARIBBEAN COAST OF COLOMBIA AT 11N76W TO THE PACIFIC COAST OF COSTA RICA AT 10N85W...THEN TURNS NW THROUGH A 1009 MB EMBEDDED LOW PRESSURE CENTER AT 13N88.5W...THEN TURNS W TO NEAR 13N98W WHERE IT LOSES IDENTITY IN THE INCREASING BROAD CYCLONIC CIRCULATION ASSOCIATED WITH TROPICAL DEPRESSION 17-E. SCATTEROMETER WINDS SUGGEST THAT THE MONSOON TROUGH RESUMES SW OF TD 17-E NEAR 12N111W AND CONTINUES WSW TO ANOTHER EMBEDDED LOW PRESSURE THAT RECENTLY FORMED AT 10N120W WITH THE TROUGH CONTINUING W TO 09N128W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ AXIS...WHICH CONTINUES W TO TO A TROPICAL WAVE AT 09N140W. EXCEPT AS PREVIOUSLY DESCRIBED IN ASSOCIATION WITH TD 17-E...THE TROPICAL LOWS AND TROPICAL WAVE...SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 150 NM EITHER SIDE OF A LINE FROM 09N110W TO 06N123W. ...DISCUSSION... A SURFACE RIDGE EXTENDS SE FROM 32N130W TO 19N107W. A 1016 MB SURFACE LOW IS ANALYZED NEAR 33N136W AND IS TRAILING A STALLING COLD FRONT SW ACROSS THE DISCUSSION AREA ALONG 30N137W TO BEYOND 27.5N140W. A SECONDARY...STRONGER COLD FRONT WILL PUSH SE INTO THE FAR NW WATERS ON SUN AS THE LOW CENTER OCCLUDES. STRENGTHENING HIGH PRESSURE NW OF THIS SECONDARY FRONT WILL INCREASE THE POST-FRONTAL NW FLOW TO 20-25 KT ACROSS THE DISCUSSION AREA N OF 30N W OF 138W ON SUN...WITH COMBINED SEAS BUILDING TO 12 FT NEAR 32N140W. EXPECT THE OCCLUDED LOW TO MEANDER NEAR 31N134W ON TUE WITH A WEAKENING FRONTAL TROUGH EXTENDING SSW TO NEAR 22N137W...WITH ASSOCIATED WINDS DIMINISHING TO 15-20 KT...AND SEAS SUBSIDING BELOW 8 FT W OF THE DISSIPATING FRONT BY MID WEEK. GULF OF TEHUANTEPEC...EXPECT TONIGHTS MAXIMUM DRAINAGE TO PEAK AT 20 KT AND THEN A MAX OF 15 KT ON SUN...MON AND TUE NIGHT. GUIDANCE IS SUGGESTING THE NORTHERLY FLOW WILL INCREASE TO 20-25 KT LATE WED NIGHT. $$ NELSON