000 AXPZ20 KNHC 131545 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC FRI SEP 12 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...SPECIAL FEATURE... THE EMBEDDED LOW PRESSURE ALONG THE MONSOON TROUGH NEAR 15.7N 101.3W AT 1500 UTC HAS BECOME BETTER ORGANIZED AND IS NOW TROPICAL DEPRESSION 13-E. MAXIMUM SUSTAINED WINDS ARE 30 KT WITH GUSTS TO 40 KT...WITH MINIMUM SEA LEVEL PRESSURE ESTIMATED AT 999 MB. THE DEPRESSION IS MOVING NW OR 315 DEG AT 03 KT. NUMEROUS STRONG CONVECTION IS CURRENTLY OBSERVED WITHIN 330 NM OVER THE NW SEMICIRCLE WITH SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 330 NM OVER SE SEMICIRCLE. CONVECTION IS NOW OBSERVED 45 NM INLAND MEXICO 92-104W. THESE HEAVY RAINS COULD CAUSE LIFE- THREATENING FLASH FLOODS AND MUD SLIDES. THE DEPRESSION IS EXPECTED STRENGTHEN TO A TROPICAL STORM TONIGHT REACHING NEAR 16.8N 101.5W EARLY SAT. THE STORM IS EXPECTED TO MOVE INLAND NEAR 18.7N 102.0W EARLY SUN. PLEASE SEE WMO HEADER/AWIPS HEADERS WTPZ23 KNHC/MIATCMEP3 FOR ADDITIONAL DETAILS. CYCLONIC WINDS AT 20-30 KT ARE CURRENTLY OBSERVED WITHIN 90 NM OF THE DEPRESSION...WITH SEAS 8-12 FT IN MIXING NW AND SW SWELL. FURTHER N ACROSS THE ISTHMUS OF TEHUANTEPEC...TROPICAL STORM INGRID HAS ALSO FORMED IN THE BAY OF CAMPECHE...AND WILL MAINTAIN THE CURRENT SOUTHWESTERLY FLOW ALONG THE MONSOON TROUGH AT 20-25 KT/SEAS 9-12 FT WITHIN 180 NM SE OF LINE FROM 14N98W TO 11N105W. A LARGE AREA OF SW-W WINDS AT 15-20 KT/SEAS 6-9 FT IN LONG PERIOD SW SWELL...SURROUNDS THE DEPRESSION AND MONSOON TROUGH FROM 08-15N BETWEEN 93W-108W. THE SOUTHERLY MONSOON FLOW WILL INCREASE IN RESPONSE TO THE TROPICAL CYCLONES. BY EARLY SUN THE AREA OF SW WINDS AT 20-25 KT IS FORECAST WITHIN 210 NM SE OF LINE FROM 16N98W TO 12N111W WITH SEAS 9 TO 13 FT IN THE LONG PERIOD SW SWELL. THE LARGE AREA OF SW-W WINDS AT 15-20 KT/SEAS 7- 10 FT SURROUNDING THE LOW AND MONSOON TROUGH WILL EXPAND FROM 08- 15N 93W-103W AND FROM 08-12N BETWEEN 103-118W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS W ACROSS THE CARIBBEAN FROM 09- 10N FROM THE NW COAST OF COLOMBIA TO THE BORDER OF PANAMA AND COSTA RICA...THEN THE MONSOON TROUGH TURNS NW ALONG THE PACIFIC COAST OF CENTRAL AMERICA INTO THE GULF OF TEHUANTEPEC WHERE IT LOSES IDENTITY IN THE STRONG SOUTHWESTERLY MONSOONAL FLOW. SCATTEROMETER WINDS INDICATE THE MONSOON TROUGH RESUMES SW OF TROPICAL DEPRESSION 13-E... AND CONTINUES SW TO 09N137W WHERE IT TRANSITIONS TO AN ITCZ WHICH CONTINUES W TO BEYOND 09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ALONG THE PACIFIC COAST OF COLOMBIA FROM 03-08N TO THE E OF 79W. SIMILAR CONVECTION IS NOTED ELSEWHERE FROM 11-18N BETWEEN 92-112W...AND ALSO N OF THE MONSOON TROUGH WITHIN 90 NM OF 12N124W. ...DISCUSSION... AN UPPER TROUGH EXTENDS FROM 32N135W TO 28N140W. THE ASSOCIATED SURFACE FRONT IS OVER THE FAR NW CORNER OF THE DISCUSSION AREA FROM 32N134W TO 29N140W. A SURFACE HIGH NEAR 28N132W WILL SHIFT SW TODAY ALLOWING THE WEAK FRONT TO REACH FROM 32N132W TO 28N140W EARLY SAT THE QUICKLY DISSIPATE SAT NIGHT. EXPECTING ONLY A 10 KT WIND SHIFT ALONG THE FRONTAL BOUNDARY WITH SEAS 4-6 FT PRIMARILY DUE TO NW SWELL. ANTICYCLONIC WINDS AT 10-15 KT ARE NOTED ALONG THE PERIPHERY OF THE SURFACE HIGH ACCOMPANIED BY SEAS OF 3-6 FT IN NE WIND WAVE/SWELL MIXING WITH CROSS EQUATORIAL S SWELL. AN UPPER TROUGH EXTENDS S ACROSS THE BAJA CALIFORNIA AREA FROM 33N111W TO 24N110W. AN UPPER ANTICYCLONE IS NOTED AT 25N128W WITH AN UPPER RIDGE EXTENDING NE THE CENTRAL CALIFORNIA COAST. AN UPPER RIDGE ALSO EXTENDS SW TO BEYOND 19N140W. THESE UPPER FEATURES COMBINE TO DRY OUT THE UPPER LEVELS...AND STABILIZE THE LOWER LEVELS...OF THE DISCUSSION AREA TO THE W OF A LINE FROM 32N107W TO 10N113W TO 00N120W. AN UPPER CYCLONE IS OVER NE OLD MEXICO TRAILING AN UPPER TROUGH S TO BASE OVER MEXICO AT 18N101W. AN UPPER ANTICYCLONE IS NOTED NEAR 14N98W WITH AN UPPER RIDGE EXTENDING SE TO NW COLOMBIA. THE ASSOCIATED UPPER DIFFLUENCE IS ENHANCING THE CONVECTION PREVIOUSLY DESCRIBED...WITH THE DENSE DEBRIS MOISTURE ADVECTED SW ACROSS THE TROPICS TO ALONG 03N BETWEEN 78W-110W. DENSE DEBRIS MOISTURE ALSO SPREADS N ACROSS THE SOUTHERN GULF OF MEXICO WITH SOME OF THE MOISTURE CONCENTRATING INTO A PLUME THAT CROSSES THE NW BAHAMAS. $$ NELSON