000 AXPZ20 KNHC 030351 TWDEP AXPZ20 KNHC DDHHMM TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI MAY 03 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 0300 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W FROM THE BORDER OF COLOMBIA AND PANAMA ACROSS CENTRAL PANAMA AND ACROSS SOUTHERN COSTA RICA TO THE PACIFIC AT 10N88W THEN TURNS WSW TO 09N96W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ AXIS CONTINUES SOUTHWESTERLY THROUGH 08N110W TO 05N126W TO BEYOND 05N140W. ISOLATED MODERATE AND STRONG CONVECTION IS OBSERVED S OF THE EASTERN SEGMENT OF THE MONSOON TROUGH AXIS ROUGHLY WITHIN 150 NM EITHER SIDE OF A LINE FROM 07N83W TO 09N100W...WITH THIS CONVECTION CONTINUING TO DECREASE IN BOTH COVERAGE AND INTENSITY. SCATTERED MODERATE ISOLATED STRONG CONVECTION APPEARS TO BE INTENSIFYING ALONG ASSOCIATED THE ITCZ WITHIN 120 NM EITHER SIDE OF A LINE FROM 10N112W TO 03N133W. ISOLATED MODERATE CONVECTION IS FLARING N OF THE ITCZ TO ALONG 10N BETWEEN 132W AND 140W. ...DISCUSSION... GULF OF TEHUANTEPEC...S TO SW WINDS AT 5 TO 10 KT ARE EXPECTED ACROSS THE GULF OF TEHUANTEPEC EARLY TONIGHT BUT NORTHERLY WINDS ARE EXPECTED TO BEGIN TO SURGE THROUGH THE CHEVILA PASS LATE TONIGHT...INITIALLY AT 20 TO 25 KT...BUT THEN GRADUALLY INCREASING TO 20 TO 30 KT BY FRI AFTERNOON WITH SEAS BUILDING TO 10 FT. THE N FLOW WILL FURTHER INCREASE TO MINIMAL GALE FORCE FRI EVENING...BUT THE GALE CONDITIONS SHOULD ONLY LAST ABOUT 9 HOURS AS GUIDANCE IS SUGGESTING THE NORTHERLY DRAINAGE FLOW WILL MAX AT ONLY 30 KT AT SUNRISE ON SAT. THESE STRONG WINDS WILL CREATE N-NE SWELL THAT WILL MIX WITH CROSS EQUATORIAL SOUTHERLY SWELL...WITH COMBINED SEAS EXPECTED TO BUILD BRIEFLY TO 14 FT NEAR 14.5N95W LATE FRI NIGHT. THE NNE WINDS WILL FURTHER DIMINISH AFTER SUNRISE SAT WITH ONLY 15 TO 20 KT EXPECTED BY MIDDAY SAT...WITH THESE CONDITIONS REACHING AS FAR S AS 10N98W...WITH THE ASSOCIATED SEAS ALREADY SUBSIDED TO A MAX OF 9 FT. EXPECT LIGHT...MOSTLY SW...WINDS ACROSS THE GULF OF TEHUANTEPEC ON SUN AND MON...EXCEPT BECOMING NORTHERLY AT 10 TO 15 KT BRIEFLY LATE SUN NIGHT AND MON NIGHTS. THE NE SWELL WILL GRADUALLY SUBSIDE TO 7 FT ON SUN NIGHT...WITH THE AREA OF NE SWELL CONTINUING TO PROPAGATE SW MIXING WITH CROSS EQUATORIAL SWELL WITH RESULTANT SEAS FINALLY SUBSIDING BELOW 6 FT ON MON NIGHT AND BELOW 5 FT ON TUE NIGHT. GULF OF CALIFORNIA...NW WINDS AT 20 TO 25 KT ARE OBSERVED ACROSS THE GULF WATERS N OF 27N WITH SEAS EXPECTED TO SOON BUILD TO 8 FT IN THE AREA OF LONG NW TO SE FETCH NEAR 30N. THE GRADIENT WILL BEGIN TO RELAX LATE TONIGHT INTO FRI WITH THE N FLOW FURTHER DIMINISHING AND BECOMING LIGHT AND VARIABLE...WITH SEAS SUBSIDING TO 2 FT OR LESS ON FRI NIGHT. THE LOW LEVEL FLOW WILL BECOME SOUTHERLY AGAIN ON SAT AND INCREASE TO 10 TO 15 KT WITH LITTLE CHANGE THEN EXPECTED THROUGH SUN NIGHT. THE SOUTHERLY WINDS WILL DIMINISH TO LIGHT AND VARIABLE ON AND TUE. GULF OF PAPAGAYO...LIGHT AND VARIABLE WINDS AND LONG PERIOD SW SWELL...WITH SEAS 3 TO 5 FT...ARE EXPECTED THROUGH SAT EVENING...THEN ENE DRAINAGE FLOW AT 10 TO 15 KT IS FORECAST BRIEFLY LATE EACH NIGHT INTO JUST AFTER SUNRISE EACH MORNING...WITH THESE CONDITIONS REPEATING THROUGH AT LEAST TUE MORNING. GULF OF PANAMA...LIGHT AND VARIABLE WINDS AT 5 TO 10 KT ARE EXPECTED THROUGH MON. A SMALL CLUSTER OF SCATTERED MODERATE CONVECTION IS ENHANCED WITHIN AN AREA OF UPPER DIFFLUENCE INDUCED BETWEEN THE W PERIPHERY OF AN UPPER RIDGE AND JUST AHEAD OF A DEEP LAYERED UPPER TROUGH...IN THE AREA N OF THE ITCZ ROUGHLY WITHIN 45 NM OF 11.5N129.5W. DENSE UPPER DEBRIS IS INDICATED OVER THE DISCUSSION AREA WITHIN ROUGHLY 300 NM EITHER SIDE OF A LINE FROM 15N124W TO 23N120W TO 29N124W. A BROAD SURFACE RIDGE DOMINATES THE SUBTROPICS WITH NW WINDS AT 10 TO 15 KT ALONG THE ENTIRE PACIFIC COAST OF THE BAJA CALIFORNIA PENINSULA...ACCOMPANIED BY COMBINED SEAS OF 5 TO 7 FT IN MIXING NW AND S-SW CROSS EQUATORIAL SWELL. THE COMBINED SEAS ARE EXPECTED TO GRADUALLY SUBSIDE...WITH 2 TO 3 FT EXPECTED ALONG THE WESTERN SHORE OF THE BAJA PENINSULA ON SAT THROUGH TUE. THE SURFACE RIDGE WILL SHIFT S TO ALONG 25N THIS WEEKEND ALLOWING A WEAK COLD FRONT TO SWEEP E ACROSS THE PACIFIC WATERS N OF 27N E OF 125W ON SAT AND SUN...ACCOMPANIED BY A 15 TO 20 KT GRADUAL SW-W-NW WIND SHIFT WITH SEAS EXPECTED TO MAX AT 7 FT. $$ NELSON