000 AXPZ20 KNHC 281006 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU MAR 28 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 FROM 04N92W WHERE SCATTEROMETER AND MODEL DATA INDICATE THAT IT TRANSITIONS TO THE ITCZ AXIS TO 02N105W TO 01N121W TO 01N140W. NO SIGNIFICANT CONVECTION IS NOTED. ...DISCUSSION... GULF OF TEHUANTEPEC...THE 0546 UTC HIGH RESOLUTION ASCAT PASS NICELY CAPTURED A SWATH OF N WINDS OF 30-40 KT ACROSS THE GULF. A WEAKENING PRES GRADEINT OVER SERN MEXICO AND THE ISTHMUS OF TEHUANTEPEC ASSOCIATED WITH NOW WEAKER HIGH PRES OVER THE GULF OF MEXICO WILL ALLOW FOR THE CURRENT GALE FORCE N-NE WINDS OF 30- 35 KT ACROSS AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC TO GRADUALLY DIMINISH TO 20-30 KT LATE THIS MORNING...AND TO 20-25 KT LATE THIS AFTERNOON AND EVENING. ALTHOUGH THE NORTHERLY WINDS WILL FURTHER DIMINISH TO 10 TO 15 KT EARLY THIS EVENING...ANOTHER SWD SURGE OF HIGH PRES ACROSS SERN TONIGHT WILL RESULT IN AN INCREASE OF N WINDS TO 20-25 KT LATE TONIGHT...AND CONTINUE THROUGH LATE MORNING ON FRI. ONE LAST SURGE OF N WINDS OF 15-20 KT IS EXPECTED LATE FRI NIGHT INTO MID MORNING ON SAT. MAX SEAS OF 14 FT IN THE GULF WILL SLOWLY SUBSIDE TO 10 FEET THIS AFTERNOON...AND LESS THAN 9 FT FRI. GULF OF PAPAGAYO...NE WINDS OF 20-25 KT ARE ONGOING THROUGHOUT THE GULF OF PAPAGAYO AND EXTENDING AS FAR W AS 09N93W. THE GRADIENT WILL INCREASE SUPPORTING 20 TO 30 KT BY DAYBREAK THIS MORNING WITH THE WESTERN EXTENT OF THE WINDS TO NEAR 08N95W...WITH SEAS GRADUALLY BUILDING TO 12 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 SLACKEN LATE SAT TO ALLOW FOR 15-20 KT WINDS. THESE WINDS WILL PULSATE AT 20-25 KT ARE EXPECTED LATE EACH NIGHT TILL JUST AFTER DAYBREAK EACH MORNING. GULF OF PANAMA...NORTHERLY WINDS OF 15-20 KT WILL PERSIST THROUGH LATE SAT THEN DIMINISH TO 10-15 KT SAT NIGHT. THE LARGE SWELLS GENERATED IN AND DOWNSTREAM OF THE GULFS OF TEHUANTEPEC AND PAPAGAYO WILL MERGE COVERING THE TROPICAL WATERS OVER AN AREA FROM 04N TO 11N BETWEEN 95W-115W BY FRI...WITH COMBINED SEAS OF 7 TO 10 FT. THESE SWELLS WILL PROPAGATE W OVER THE WEEKEND ACROSS THE WATERS FROM 04N TO 11N BETWEEN 95W AND 124W ON SAT. A NEGATIVE-TILTED UPPER TROUGH SWINGING EWD EXTENDS FROM A RATHER STRONG LOW N OF THE AT 40N140W SEWD TO 32N131W TO 26N125W TO NEAR 18N117W. IN ITS WAKE...THE UPPER FLOW IS ZONAL AND IS ADVECTING UPPER MOISTURE ACROSS THE AREA N OF ABOUT 15N WITH THE PLUME TURNING NE ACROSS THE SOUTHERN TIP OF THE BAJA PENINSULA AND THE SOUTHERN GULF OF CALIFORNIA...THEN CONTINUING NEWD ACROSS CENTRAL OLD MEXICO. AN UPPER TROUGH IS NOTED S OF 20N ALONG ROUGHLY 112W...AND CONTINUES TO SEPARATE THE UPPER FLOW OVER THE DEEP TROPICAL PORTION. WEAK UPPER DIFFLUENCE NEAR THE BASE OF THE TROUGH IS HELPING TO TRIGGER OFF WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ALONG AND NEAR THE ITCZ FROM 01N TO 06N BETWEEN 103W-118W. THE CLEARLY EVIDENT SW FLOW AHEAD OF THE TROUGH IS ADVECTING RESULTANT UPPER DEBRIS MOISTURE NEWD WITHIN 150 NM EITHER SIDE OF A LINE FROM 04N109W TO OVER OLD MEXICO NEAR 20N98W WHERE THE MOISTURE EVAPORATES IN A DRIER ATMOSPHERE. A BROAD UPPER RIDGE DOMINATES THE TROPICS E OF 105W...WITH WEAK UPPER DIFFLUENCE HELPING TO SET OFF CLUSTERS OF ISOLATED TO WIDELY SCATTERED TSTMS ALONG AND NEAR 05N. BROAD ANTICYCLONIC FLOW COVERS THE AREA SW OF THE FIRST UPPER TROUGH DESCRIBED IN THE FIRST PARAGRAPH. A STRONG JET STREAM BRANCH ENTERS THE AREA AT 26N140W...AND CONTINUES ENE TO 28N130W...AND ACROSS THE UPPER TROUGH TO NE OF THE AREA WHERE IT WEAKENS. EXTENSIVE OVERCAST TO BROKEN MULTILAYERED CLOUDS WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS ARE NOTED ALONG AND S OF THE JET STREAM BRANCH TO NEAR 17N. AT THE SURFACE...A SURFACE HIGH PRES CENTER OF 1020 MB ANALYZED AT 30N121W WILL WEAKEN SOME AS IT REMAINS STATIONARY THROUGH SAT. AN INTENSIFYING SURFACE LOW ASSOCIATED WITH THE UPPER LOW AT 40N140W WILL MOVE SE TO ACROSS THE NW WATERS ALONG A POSITION FROM 32N133W TO 24N140W BY EARLY THIS EVENING. THE SURFACE LOW IS FORECAST TO INTENSIFY INTO A GALE CENTER...AND REACH A POSITION NEAR 35N133W BY LATE TONIGHT...WITH THE COLD FRONT FROM 32N132W TO 23N140W. THE GALE CENTER THEN IS FORECAST TO LIFT NE AND WEAKEN DURING FRI...WITH THE COLD FRONT REACHING FROM 32N131W TO 22N140W. WINDS BEHIND THE FRONT ARE EXPECTED TO INCREASE TO 20-25 KT N OF 29N TONIGHT WITH POSSIBLE WINDS TO 30 KT ALONG 30N...BUT SHOULD BE BRIEF. LARGE NW SWELLS WILL MOVE INTO THE NW PORTION OF THE AREA BEHIND THE FRONT...WITH SEAS REACHING TO 11 FT LATE TONIGHT AND TO 12 OR 13 FT N OF 29N BETWEEN THE FRONT AND 137W LATE FRI NIGHT AND SAT. $$ AGUIRRE