000 AXPZ20 KNHC 040948 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI OCT 04 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS W ACROSS THE SW CARIBBEAN BETWEEN 10-11N FROM THE NW COAST OF COLOMBIA TO ACROSS CENTRAL COSTA RICA ALONG 10N...REACHING THE PACIFIC COAST OF COSTA RICA AT 10N85W...THEN CONTINUES NW TO 12N91W...THEN DIPS SW TO 10N97W...THEN NW AGAIN THROUGH AN EMBEDDED 1009 MB SURFACE LOW PRESSURE AT 12.5N110W. THE MONSOON TROUGH THEN CONTINUES WSW TO 11N126W WHERE SCATTEROMETER DATA INDICATES A TRANSITION TO AN ITCZ AXIS WHICH CONTINUES WESTWARD TO BEYOND 10.5N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ALONG THE COASTS OF PANAMA AND COSTA RICA WITHIN 30 NM EITHER SIDE OF A LINE FROM 07N83W TO 09N86W. SIMILAR CONVECTION IS NOTED S OF THE MONSOON TROUGH WITHIN 30 NM EITHER SIDE OF A LINE FROM 07.5N98W TO 11N104W TO 10N109W...AND NW OF THE EMBEDDED SURFACE LOW WITHIN 60 NM EITHER SIDE OF A LINE FROM 15.5N109W TO 16N121W TO 13N121W...AND ALONG THE ITCZ WITHIN 60 NM EITHER SIDE OF A LINE FROM 10N126W TO 12N134W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED N OF THE MONSOON TROUGH ALONG THE COAST OF CENTRAL AMERICA WITHIN 15 NM EITHER SIDE OF A LINE FROM 13N89W TO 15N94W. ...DISCUSSION... A LONGWAVE UPPER TROUGH IS OVER WESTERN N AMERICA WITH ITS MEAN AXIS CONTINUING SW INTO THE DISCUSSION AREA FROM 32N111W TO 30N123W AND CONTINUING SW THROUGH A PAIR OF UPPER CYCLONES AT 27N128W AND 23N137W...THEN THE UPPER TROUGH TURNS SE THROUGH UPPER CYCLONES OVER THE DEEP TROPICS AT 14N133W AND 07N124W AND 01N117W. THIS UPPER TROUGH AND SERIES OF UPPER CYCLONES SEPARATES THE UPPER FLOW OVER THE DISCUSSION AREA. W OF THESE TROUGHS IS AN UPPER RIDGE EXTENDING E INTO THE AREA ALONG 14N FROM 140-135W. A NARROW 90 NM WIDE MOISTURE PLUME IS OBSERVED AHEAD OF THE UPPER TROUGH FROM THE BAJA CALIFORNIA PENINSULA AT 27N112W TO BEYOND CENTRAL OKLAHOMA. OTHERWISE THE UPPER LEVELS APPEAR VERY DRY W OF A LINE FROM 32N108W TO 16N130W TO 12N140W. AN UPPER ANTICYCLONE IS OVER OLD MEXICO AT 23N104W WITH AN UPPER RIDGE EXTENDING NE ACROSS NORTHERN OLD MEXICO TO A SHARP CREST AT 29N96W. AN UPPER RIDGE ALSO EXTENDS SW FROM THIS ANTICYCLONE TO A CREST OVER THE DEEP TROPICAL PACIFIC AT 12N131W. WEAK UPPER DIFFLUENCE ALONG THE SOUTHERN PERIPHERY OF THIS RIDGE HAS ENHANCED CONVECTION BETWEEN 100-130W ALONG THE LOWER LEVEL MONSOON TROUGH...AND ITS EMBEDDED SURFACE LOW ALREADY MENTIONED. THE RESULTANT UPPER DEBRIS MOISTURE REMAINS TRAPPED WITHIN THE UPPER ANTICYCLONIC ENVELOPE. CONVECTION FLARED LATE THU ALONG THE MEXICAN SIERRA MADRE OCCIDENTAL...WITH THE DEBRIS MOISTURE CURRENTLY EVAPORATING ALONG THE PACIFIC COAST OF MEXICO FROM 18- 21N. AN UPPER CYCLONE IS OVER EASTERN OLD MEXICO AT 22N98W WITH AN UPPER TROUGH EXTENDING SW OVER THE PACIFIC THROUGH 18N102W TO A BASE NEAR 13N109W. THIS UPPER TROUGH SOMEWHAT SEPARATES THE UPPER FLOW OVER THE EASTERN PORTION OF THE DISCUSSION AREA FROM THE ANTICYCLONIC FLOW ASSOCIATED WITH ANOTHER LARGE ANTICYCLONE OVER THE NW CARIBBEAN NEAR 20N87W...WITH ITS ANTICYCLONIC ENVELOPE EXTENDING S ACROSS THE TROPICAL E-PACIFIC TO THE N OF 05N AND E OF 98W. THE ASSOCIATED UPPER DIFFLUENCE ENHANCED CONVECTION OVER CENTRAL AMERICA LATE THU...WITH REMNANTS OF THE CONVECTION STILL DISSIPATING OVER THE COASTAL PACIFIC WATERS AS PREVIOUSLY DESCRIBED. DENSE DEBRIS MOISTURE IS ADVECTED S COVERING THE DISCUSSION AREA TO THE N OF 03N AND E OF 99W. ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS FROM 32N131W TO 18N109W. STRONG NORTHERLY WINDS E OF THE RIDGE IS AT MINIMAL GALE FORCE ACROSS THE WATERS N OF 32N...WHILE AT 20-30 KT ACROSS THE DISCUSSION AREA FROM 29-32N BETWEEN 119-132W. LONG PERIOD NW SWELLS ARE MIXING WITH LONG PERIOD S SWELL...RESULTING IN COMBINED SEAS OF 8-13 FT IN THIS AREA. THE GRADIENT WILL RELAX LATER TODAY WITH THE ASSOCIATED ANTICYCLONIC WINDS DIMINISHING TO 5-15 KT ACROSS THE DISCUSSION WATERS...WITH COMBINED SEAS SUBSIDING TO 5-7 FT BY SUNRISE ON SAT. NW SWELLS ARE ALSO MIXING WITH THE CROSS-EQUATORIAL LONG PERIOD SWELL ACROSS THE TROPICAL WATERS BETWEEN 90-140W...WITH COMBINED SEAS TO 9 FT. THESE SEAS ARE EXPECTED TO SUBSIDE BELOW 8 FT LATE SAT. GULF OF CALIFORNIA...NW WINDS ARE EXPECTED TO INCREASE TO 20-25 KT ACROSS THE GULF OF CALIFORNIA WATERS TO THE N OF 30N THIS AFTERNOON...WITH SEAS BUILDING TO 6 FT ACROSS NW-SE LONG FETCH AREAS. THE GRADIENT WILL FURTHER TIGHTEN SUPPORTING NW 20-30 KT CONDITIONS N OF 29N TONIGHT...WITH SEAS BUILDING TO 8 FT. ALTHOUGH THE GRADIENT WILL RELAX SOME SAT MORNING...THE NW 20-25 KT FLOW WILL SPREAD S ACROSS THE GULF WATERS N OF 26N BY SAT EVENING WITH SEAS TO 9 FT IN EXPOSED LONG NW-SE FETCH AREAS. THE GRADIENT WILL FURTHER RELAX SUN NIGHT WITH WINDS DIMINISHING TO 10-15 KT ACROSS THE ENTIRE GULF OF CALIFORNIA BY SUNRISE MON. $$ NELSON