000 AXPZ20 KNHC 270244 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SAT APR 27 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0130 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM COLOMBIA NEAR 08N72W TO 04N78W TO 07N90W WHERE IT TRANSITIONS TO ITCZ...CONTINUING ON TO 09N110W TO 08N120W TO 09N130W TO BEYOND 06N140W. ISOLATED TO SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 120 NM S OF MONSOON TROUGH E OF 86W. SCATTERED MODERATE TO STRONG CONVECTION NOTED FROM 05N TO 14N BETWEEN 105W AND 115W. SCATTERED MODERATE CONVECTION NOTED WITHIN 240 NM N OF ITCZ BETWEEN 130W AND 135W. ...DISCUSSION... AT UPPER LEVELS...A BROAD AND RELATIVELY FLAT UPPER LEVEL RIDGE RESIDES OVER EASTERN PORTIONS OF THE AREA S OF 22N AND BETWEEN 80W AND 125W...CENTERED ON AN UPPER ANTICYCLONE NEAR 11N104W. ELSEWHERE...A BROAD AND COMPLEX TROUGH DOMINATES THE REST OF THE AREA W OF 125W...PRODUCING W TO SWLY FLOW ALOFT. MODEL GUIDANCE SUGGESTS THAT THE RIDGE WILL SHIFT SLIGHTLY W THROUGH THE WEEKEND AND BECOME CENTERED ALONG 110W BY SUNDAY EVENING. AT THE SURFACE...WEAK LOW PRES OFFSHORE OF THE SOUTHERN CALIFORNIA COAST CONTINUES TO WEAKEN FURTHER AND DRIFT NW THIS EVENING...ALLOWING A WEAK HIGH PRES RIDGE TO BUILD FROM A 1025 MB HIGH NEAR 36N128W S AND SE INTO THE DISCUSSION AREA...TO NEAR 14N99W. MODERATE NE TRADE WINDS 15-20 KT NOW PREVAIL FROM 15N S TO THE ITCZ...FROM 115W WESTWARD. ON SAT...THIS SUBTROPICAL RIDGE WILL BUILD S AND SE ACROSS THE FORECAST REGION...AND BEGIN TO INDUCE AN INCREASE IN THE TRADE WIND FLOW. MODEL GUIDANCE INDICATES THAT NE TRADE WINDS 20-25 KT WILL DEVELOP BY SAT AFTERNOON FROM 09N TO 15N W OF 125W AND PERSIST THROUGH SUNDAY...WITH SEAS BUILDING 8 TO 9 FT. OTHERWISE...WINDS ACROSS THE DISCUSSION AREA ARE EXPECTED TO REMAIN BELOW 25 KT OVER THE REMAINDER OF THE FORECAST WATERS THROUGH THE WEEKEND. DEEP CONVECTION CONTINUES ALONG AND N OF THE ITCZ FROM 05.5N TO 13N BETWEEN 105W AND 113W...ON THE E SIDE OF A LOW LEVEL TROUGH ALONG THE ITCZ AT 114W-115W. ACTIVE CONVECTION THROUGH THIS REGION THE PAST FEW DAYS HAS HELPED THE UPPER LEVEL RIDGE PREVAILING S OF 20N AND E OF 120W THE PAST FEW DAYS...TO EXPAND W AND NW TO 125W. GULF OF TEHUANTEPEC...VISIBLE SATELLITE IMAGERY LATE THIS AFTERNOON REVEALED FINE NARROW LINES OF LOW CLOUD MOVING DOWNSTREAM OF THE GULF OF TEHUANTEPEC TO 10N98W...WHICH DELINEATES THE PLUME OF NORTHERLY WINDS ASSOCIATED WITH A LATE SEASON GULF OF TEHUANTEPEC GAP WIND EVENT. NORTHERLY FLOW FROM THE GULF OF MEXICO THROUGH THE CHIVELA PASS HAS ENDED...AND THE GAP WINDS HAVE BEGUN TO DIMINISH THIS EVENING AND WILL END BY SATURDAY MORNING. DESPITE THE LIMITED DURATION AND FETCH...THE WINDS WILL MAINTAIN SEAS AS HIGH AS 9 FT DOWNSTREAM OF THE GULF OF TEHUANTEPEC EARLY TONIGHT BEFORE FALLING BELOW 8 FT AROUND SUNRISE. FARTHER SOUTHEAST...GAP WINDS ARE ALSO FUNNELING ACROSS CENTRAL AMERICA AND THROUGH THE GULF OF PAPAGAYO...WITH E-NE WINDS AROUND 20 KT EXTENDING DOWNSTREAM TO NEAR 10N90W PER A 1604 UTC ASCAT-A PASS. THESE GAP WINDS ARE EXPECTED TO INCREASE TO 20-25 KT LATE TONIGHT THROUGH THE EARLY MORNING HOURS DUE TO DRAINAGE FLOW ENHANCEMENT...THEN DECREASE TO 15-20 KT DURING THE DAY SATURDAY BEFORE DIMINISHING TO LESS THAN 20 KT BY SUNDAY MORNING. AFTERNOON SATELLITE IMAGERY ALSO SHOWED HAZY SKIES ACROSS THE NEAR AND OFFSHORE COASTAL WATERS OF SOUTHERN MEXICO AND THE CENTRAL AMERICAN NATIONS N OF 10N. THIS HAZE WAS RESULTANT FROM THE SMOKE FROM THE SEASONAL AGRICULTURAL BURNING GOING ON ACROSS THE REGION...DRIFTING W AND SW OVER THE OCEAN. BURNING IS LIKELY TO CONTINUE FOR THE NEXT SEVERAL DAYS AND WILL BE MONITORED FOR SIGNIFICANTLY REDUCED VISIBILITIES ACROSS THE REGIONAL WATERS. $$ STRIPLING