000 AXPZ20 KNHC 261546 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU SEP 26 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS THE SW CARIBBEAN ALONG 10N FROM THE NW COAST OF COLOMBIA TO ACROSS NORTHERN COSTA RICA TO THE PACIFIC COAST OF COSTA RICA AT 10N85W...THEN DIPS SW INTO A 1008 MB LOW PRESSURE EMBEDDED IN THE TROUGH AXIS AT 09N88W... THEN TURNS NW TO 09N97W WHERE IT LOSES IDENTITY. SCATTEROMETER DATA SUGGESTS THE MONSOON TROUGH AXIS RESUMES SW OF A SURFACE LOW AT 16.5N100W AND WIGGLES SW THROUGH POINTS 15N102W...13N115W AND 14N121W TO BEYOND 10N140W. NUMEROUS STRONG CONVECTION WITH FREQUENT LIGHTNING IS OBSERVED ALONG THE MONSOON TROUGH OVER THE CARIBBEAN S OF 13N BETWEEN 73-82W INCLUDING THE CARIBBEAN APPROACH TO THE PANAMA CANAL. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED S OF THE EASTERN SEGMENT OF THE MONSOON TROUGH ROUGHLY WITHIN 120 NM EITHER SIDE OF A LINE FROM 07N78W TO 07N87W TO 06N91W TO 08N99W....INCLUDING THE PACIFIC APPROACH TO THE PANAMA CANAL. ISOLATED MODERATE TO OCCASIONALLY STRONG CONVECTION IS ALSO OBSERVED N OF THIS SEGMENT OF THE MONSOON TROUGH FROM 09N TO THE COAST OF CENTRAL AMERICA BETWEEN 88-95W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ALONG THE WESTERN SEGMENT OF THE MONSOON TROUGH WITHIN 75 NM EITHER SIDE OF A LINE FROM 11N115W TO 14N117W TO 15N121W...AND WITHIN 120 NM EITHER SIDE OF A LINE FROM 11N130W TO 09N135W. ...DISCUSSION... A DEEP LAYERED UPPER CYCLONE IS OVER THE NW CONUS WITH SEVERAL UPPER LEVEL TROUGHS ROTATING CYCLONICALLY AROUND THE CYCLONE. THE EASTERNMOST TROUGH HAS ITS MEAN AXIS EXTENDING S INTO THE DISCUSSION AREA FROM 32N120W TO 25N124W TO A BASE AT 14N13W. A SECOND UPPER TROUGH IS JUST ENTERING THE AREA ALONG 32N BETWEEN 122-140W. THESE TROUGHS COMBINE TO SEPARATE THE UPPER FLOW WITH AN UPPER ANTICYCLONE CENTERED TO THE W AT 12N142W WITH A RIDGE EXTENDING N TO A CREST AT 33N142W...AND A RIDGE EXTENDING SE TO A CREST AT 12N134W. THE UPPER FLOW IS SLIGHTLY DIFFLUENT S OF THIS SOUTHERN RIDGE...AND ROUGHLY IN PHASE WITH THE LOWER LEVEL MONSOON TROUGH...AND ENHANCING THE CONVECTION PREVIOUSLY DESCRIBED. THE RESULTANT DEBRIS MOISTURE IS ADVECTED SW TO ALONG 03N TO THE W OF 130W. OTHERWISE THE UPPER LEVELS APPEAR VERY DRY TO THE W OF A LINE FROM 23N104W TO 17N140W. AN UPPER ANTICYCLONE IS CENTERED OVER THE SOUTHERN GULF OF CALIFORNIA AT 24N108W WITH A RIDGE EXTENDING N ACROSS NW OLD MEXICO. AN UPPER RIDGE ALSO EXTENDS SE TO A CREST OVER THE GULF OF TEHUANTEPEC...AND AN UPPER RIDGE ALSO EXTENDS SW TO A CREST AT 13N129W. UPPER DIFFLUENCE UNDER THE SOUTHERN PERIPHERY OF THIS ANTICYCLONE IS ENHANCING THE CONVECTION PREVIOUSLY MENTIONED ALONG THE COAST OF MEXICO...AND NEAR 14N118W. THE RESULTANT DEBRIS MOISTURE REMAINS UNDER THE UPPER ANTICYCLONIC ENVELOPE. AN ATLANTIC TUTT CONTINUES SW DISSECTING THE CARIBBEAN FROM NE TO SW AND CONTINUING SW ACROSS THE BORDER OF NICARAGUA AND HONDURAS TO BASE OVER THE DEEP TROPICAL PACIFIC AT 04N93W. CONVECTION ALONG THE EASTERN SEGMENT OF THE MONSOON TROUGH IS ENHANCED E OF THIS UPPER TROUGH AXIS...WITH THE HEAVIEST ACTIVITY ALREADY DESCRIBED OVER THE SW CARIBBEAN WHERE AN UPPER RIDGE ORIGINATING OVER S AMERICA IS ALSO CRESTING. THE UPPER DEBRIS MOISTURE IS ADVECTED S OVER THE TROPICAL PACIFIC TO THE NE OF A LINE FROM 01N79W TO 07N100W. ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS SE OVER THE DISCUSSION AREA TO THE N OF 19N W OF 125W. A WEAK TROUGH IS ANALYZED FROM 27N117W TO 21N123W. NORTHERLY WINDS AT 15-20 KT ARE ROTATING ANTICYCLONICALLY AROUND THE RIDGE ACROSS THE WATERS WITH COMBINED SEAS OF 7-11 FT IN MIXED NW AND SE SWELL NOTED ACROSS THE WATERS N OF 20N W OF 115W. THESE WINDS WILL GRADUALLY DIMINISH TO 5-15 KT BY MIDDAY SAT AS THE SEAS SUBSIDE TO 4-7 FT PRIMARILY IN MIXED NW AND SE SWELL. CROSS EQUATORIAL SE SWELL IS MIXING WITH N SWELL RESULTING IN COMBINED SEAS OF 6-9 FT ACROSS THE PACIFIC WATERS S OF 10N W OF 110W. THE AFFECTED AREA WILL SHRINK TO A STRIP ALONG 09N BETWEEN 108-117W ON SAT. GULF OF CALIFORNIA...A LOW LEVEL TROUGH IS NOTED OVER THE NORTHERN WATERS WITH THE SOUTHERLY FLOW AT 15-20 KT TO THE N OF 30N THIS MORNING. THE TROUGH WILL MOVE SE TO ALONG 28N WITH NORTHERLY FLOW BEHIND THE TROUGH AT 15-20 KT...SEAS 2-4 FT...ON FRI MORNING AND CONTINUING THROUGH SAT MORNING THEN DIMINISHING. $$ NELSON