000 AXPZ20 KNHC 041559 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 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...AND REACHES THE PACIFIC COAST OF COSTA RICA AT 10N86W. IT CONTINUES NW TO 11N94W TO 13N105W AND DIPS SW TO AN EMBEDDED 1007 MB LOW AT 12N111W AND TO 09N123W WHERE SCATTEROMETER DATA INDICATES A TRANSITION TO AN ITCZ AXIS WHICH CONTINUES WESTWARD TO BEYOND 09N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF TROUGH BETWEEN 103W-109W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM S OF TROUGH E OF 87W. SCATTERED MODERATE ISOLATED/STRONG CONVECTION IS OBSERVED N OF THE MONSOON TROUGH...IN ASSOCIATION WITH A POSSIBLE WEAK LOW LEVEL...TROUGH FROM 13N TO 17N AND BETWEEN 118W-123W. SIMILAR ACTIVITY IS SEEN WITHIN 30 NM OF 11.5N131W. WIDELY SCATTERED TO ISOLATED SMALL CLUSTERS OF MODERATE CONVECTION IS ALONG AND WITHIN 75 NM TO 90 NM OF THE COAST OF CENTRAL AMERICA FROM PANAMA TO SOUTHERN NICARAGUA. ...DISCUSSION... A LONGWAVE UPPER TROUGH IS OVER WESTERN N AMERICA WITH ITS MEAN AXIS STRETCHING SOUTHWESTWARD INTO THE DISCUSSION AREA FROM 32N112W TO 30N123W. IT CONTINUES SW THROUGH A PAIR OF UPPER CYCLONES...ONE AT 27N128W AND THE OTHER AT 23N135W. THE TROUGH THEN TURNS SE THROUGH UPPER CYCLONES OVER THE DEEP TROPICS AT 12N132W...05N125W AND AT 01N118W. 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 140W-135W. A NARROW 90 NM WIDE MOISTURE PLUME IS OBSERVED AHEAD OF THE UPPER TROUGH FROM THE BAJA CALIFORNIA PENINSULA AT 27N112W NE TO WELL ACROSS THE CENTRAL U.S. OTHERWISE THE UPPER LEVELS REMAIN VERY DRY W OF A LINE FROM 32N108W TO 15N130W TO 12N140W. AN UPPER ANTICYCLONE IS OVER OLD MEXICO AT 22N106W WITH AN UPPER RIDGE EXTENDING NE ACROSS NORTHERN OLD MEXICO TO A SHARP CREST AT 30N95W. AN UPPER RIDGE ALSO EXTENDS SW FROM THIS ANTICYCLONE TO A CREST OVER THE DEEP TROPICAL PACIFIC NEAR 12N130W. WEAK UPPER DIFFLUENCE ALONG THE SOUTHERN PERIPHERY OF THIS RIDGE HAS ENHANCED CONVECTION BETWEEN 100W-109W ALONG THE LOWER LEVEL MONSOON TROUGH. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 120 NM OF THE EMBEDDED MONSOON TROUGH LOW AT 12N111W WITHIN 120 NM IN ITS NW QUADRANT...AND WITHIN 90 NM IN ITS NE QUADRANT. THE RESULTANT UPPER DEBRIS MOISTURE REMAINS TRAPPED WITHIN THE UPPER ANTICYCLONIC ENVELOPE. CONVECTION THAT DEVELOPED ALONG THE MEXICAN SIERRA MADRE OCCIDENTAL LAST NIGHT HAS MOSTLY DISSIPATED...HOWEVER THE DEBRIS MOISTURE IS CURRENTLY EVAPORATING ALONG THE PACIFIC COAST OF MEXICO FROM 18N-21N. AN UPPER TROUGH EXTENDS SW FROM EASTERN MEXICO TO 20N102W TO A BASE NEAR 17N102W. 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 LOCATED OVER THE NORTHERN YUCATAN PENINSULA...WITH ITS ANTICYCLONIC ENVELOPE EXTENDING S ACROSS THE TROPICAL EASTERN PACIFIC TO THE N OF 05N AND E OF 98W. THE ASSOCIATED UPPER DIFFLUENCE ENHANCED CONVECTION OVER CENTRAL AMERICA THU NIGHT...WITH THE MAJORITY OF THE CONVECTION ALREADY HAVING DISSIPATED. SOME OF THIS ACTIVITY IS STILL EVIDENT AS DESCRIBED ABOVE UNDER ITCZ/MONSOON TROUGH AS DESCRIBED ABOVE UNDER ITCZ/MONSOON TROUGH. DENSE DEBRIS MOISTURE IS ADVECTED S COVERING THE DISCUSSION AREA TO THE N OF 03N AND E OF 99W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION OBSERVED FROM 11N TO 16N BETWEEN 92W-98W IS ASSOCIATED WITH A POSSIBLE TROPICAL WAVE THAT WAS FORMERLY RELATED TO TROPICAL STORM KAREN IN THE GULF OF MEXICO. ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS FROM A 1030 MB HIGH CENTER WELL N OF THE AREA AT 30N137W SOUTHEASTWARD THROUGH 32N133W TO NEAR 22N121W. STRONG TO NEAR GALE FORCE NORTHERLY WINDS E OF THE RIDGE OVER THE WATER N OF 32N CONTINUE OVER QUITE AND EXPANSIVE FETCH AREA THAT IS RESULTING IN THE GENERATION OF LONG PERIOD MAINLY NW SWELLS. THESE SWELLS ARE BRINGING COMBINED SEAS OF 8-13 FT IN THIS AREA...AND SEAS OF 9 TO 12 FT IN THE NE CORNER OF THE DISCUSSION AREA AND SEAS OF 8-10 FT ELSEWHERE N OF 23N BETWEEN 117W-138W. AS THE GRADIENT N OF THE AREA DIMINISHES THROUGH SUN...THE SEAS OF 10-2 FT ARE FORECAST TO DECREASE TO 8 FT SAT AND TO 6-7 FT BY SAT EVENING. 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 INTO SAT MORNING...WITH SEAS BUILDING TO 8 FT. THE GRADIENT IS FORECAST TO RELAX SOME DURING SAT...WITH NW 20-25 KT WINDS EXPECTED TO SPREAD S ACROSS THE GULF WATERS N OF 26N BY SUN WITH SEAS TO AROUND 8 OR 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 DAYBREAK MON. $$ AGUIRRE