000 AXPZ20 KNHC 272157 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC WED MAR 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS NW FROM THE COAST OF COLOMBIA AT 06N75W ACROSS THE SOUTHERN TIP OF PANAMA...THEN TURNS SW TO 04N92W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ THEN EXTENDS SW TO 02N101W...THEN WIGGLES W TO NEAR 02N121W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 90 NM EITHER SIDE OF A LINE FROM 04.5N84W TO 05N90W...AND WITHIN 120 NM EITHER SIDE OF A LINE FROM 04N109W TO 02N114W TO 04N120W. ...DISCUSSION... GULF OF TEHUANTEPEC...A N TO S ORIENTATED SURFACE RIDGE EXTENDS FROM THE MISSISSIPPI DELTA S TO THE WESTERN BAY OF CAMPECHE WITH N WINDS CONTINUING TO SURGE THROUGH THE CHIVELA PASS INTO AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC AT 30 TO 40 KT...WITH MAXIMUM SEAS OF 17 FT NEAR 14N96W. THE GRADIENT WILL GRADUALLY RELAX TONIGHT WITH WINDS DIMINISHING TO A MINIMAL GALE WHICH WILL PERSIST THROUGH SUNRISE THU THEN QUICKLY DIMINISH TO 20 TO 25 KT LATE THU AFTERNOON. ALTHOUGH THE NORTHERLY WINDS WILL FURTHER DIMINISH TO 10 TO 15 KT THU EVENING... EXPECT ANOTHER N SURGE TO 20 TO 25 KT LATE THU NIGHT CONTINUING THROUGH SUNRISE FRI. ONE LAST SURGE AT ONLY 15 TO 20 KT IS EXPECTED LATE FRI NIGHT INTO MID MORNING ON SAT. LIGHT AND VARIABLE WINDS EXPECTED FROM SAT NIGHT THROUGH MON NIGHT. GULF OF PAPAGAYO...ENE WINDS ARE AT 20 TO 25 KT THROUGHOUT THE GULF OF PAPAGAYO AND EXTENDING AS FAR W AS 09N93W. THE GRADIENT WILL INCREASE SUPPORTING 20 TO 30 KT ON THU WITH THE WESTERN EXTENT NEAR 09N95W...WITH SEAS GRADUALLY BUILDING TO 11 FT. THE GRADIENT WILL WEAKEN THU NIGHT WITH WINDS DIMINISHING TO 20 TO 25 KT...WITH LITTLE CHANGE THEN EXPECTED THROUGH SAT. THE GRADIENT WILL RELAX ON SAT NIGHT WITH 15 TO 20 KT WINDS THE DOMINATE CONDITIONS...BUT PULSES AT 20 TO 25 KT ARE EXPECTED LATE EACH NIGHT TILL JUST AFTER SUNRISE EACH MORNING. GULF OF PANAMA...NORTHERLY WINDS AT 15 TO 20 KT WILL PERSIST THROUGH LATE SAT THEN DIMINISH TO 10 TO 15 KT SAT NIGHT. THE LARGE SWELLS GENERATED IN AND DOWNSTREAM OF THE GULFS OF TEHUANTEPEC AND PAPAGAYO WILL MERGE COVERING THE TROPICAL WATERS FROM 04 TO 11N BETWEEN 95W AND 115W BY FRI...WITH COMBINED SEAS OF 7 TO 10 FT. THESE SWELLS WILL PROPAGATE W OVER THE WEEKEND AFFECTING THE WATERS FROM 04N TO 11N BETWEEN 95W AND 120W ON SAT...AND BETWEEN 110W AND 130W ON SUN. A NEGATIVE TILT UPPER TROUGH IS SWINGING E ACROSS THE PORTION WITH ITS MEAN AXIS FROM 32N127W TO A BASE AT 18N117W. THE NEARLY ZONAL UPPER FLOW IS ADVECTING UPPER MOISTURE ACROSS THE AREA FROM 15N TO 25N WITH THE PLUME TURNING NE ACROSS THE SOUTHERN TIP OF THE BAJA PENINSULA AND THE SOUTHERN GULF OF CALIFORNIA...THEN CONTINUING NE ACROSS NW OLD MEXICO. AN UPPER TROUGH IS NOTED S OF 10N ALONG ROUGHLY 113W...AND CONTINUES TO SEPARATE THE UPPER FLOW OVER THE DEEP TROPICAL PORTION. WEAK UPPER DIFFLUENCE IS ENHANCING THE CONVECTION PREVIOUSLY MENTIONED BETWEEN 107W AND 122W...WITH THE RESULTANT UPPER DEBRIS MOISTURE ADVECTED NE WITHIN 180 NM EITHER SIDE OF A LINE FROM 05N110W TO OVER OLD MEXICO AT 18N100W WHERE THE MOISTURE SEEMS TO EVAPORATE. A BROAD UPPER RIDGE DOMINATES THE TROPICS E OF 105W...WITH WEAK UPPER DIFFLUENCE ALSO ENHANCING THE CONVECTIVE CLUSTERS NEAR 05N96W. A SURFACE HIGH PRESSURE ANALYZED AT 30N121W WILL CONTINUE TO SHIFT E ALLOWING A COLD FRONT TO MOVE INTO THE FAR NW WATERS TONIGHT. THE FRONT WILL REACH FROM 32N135W TO 28N133W TO 23N136W ON FRI AS THE POST FRONTAL FLOW INCREASES TO 20 TO 25 KT AND DRIVES LARGE NW SWELL INTO THE AREA WITH COMBINED SEAS BUILDING 7 TO 10 FT OVER THE WEEKEND. $$ NELSON