000 AXPZ20 KNHC 282150 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 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 08N78W ACROSS PANAMA TO 08N84W...THEN TURNS SW TO 07N88W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ THEN CONTINUES SW TO 03N104W...THEN WIGGLES W BETWEEN 01N AND 03N TO BEYOND 01N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 60 NM EITHER SIDE OF A LINE FROM 07.5N87W TO 05N94W...AND WITHIN 30 NM EITHER SIDE OF A LINE FROM 02N118W TO 04N126W. ...DISCUSSION... GULF OF TEHUANTEPEC...WEAKENING HIGH PRESSURE OVER THE GULF OF MEXICO WILL MAINTAIN NORTHERLY WINDS AT 20 TO 25 KT TONIGHT LIKELY TO REACH 25 TO 30 KT BRIEFLY JUST BEFORE SUNRISE ON FRI...THEN DIMINISH THROUGHOUT FRI AND FRI EVENING...SURGING AGAIN TO 15 TO 20 KT LATE FRI NIGHT INTO SAT MORNING. LIGHT AND VARIABLE WINDS EXPECTED FROM SAT NIGHT THROUGH TUE NIGHT. GULF OF PAPAGAYO...ENE WINDS ARE AT 20 TO 30 KT THROUGHOUT THE GULF OF PAPAGAYO AND EXTENDING AS FAR W AS 08N94W...WITH MAX SEAS OF 12 FT NEAR 10N89W. THE GRADIENT WILL RELAX FRI AFTERNOON WITH WINDS DIMINISHING TO 20 TO 25 KT...BUT LIKELY INCREASE AGAIN TO 25 TO 30 KT LATE FRI NIGHT TILL JUST AFTER SUNRISE SAT. THE GRADIENT WILL RELAX ON SAT AFTERNOON 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 THROUGH AT LEAST WED.. GULF OF PANAMA...NORTHERLY WINDS AT 15 TO 20 KT WILL PERSIST THROUGH MID MORNING SAT THEN DIMINISH TO 10 TO 15 KT. THE LARGE SWELLS GENERATED IN AND DOWNSTREAM OF THE GULFS OF TEHUANTEPEC AND PAPAGAYO HAVE MERGED COVERING THE TROPICAL WATERS FROM 05N TO 12N BETWEEN 94W AND 109W...WITH COMBINED SEAS OF 7 TO 11 FT. THESE SWELLS WILL CONTINUE TO PROPAGATE WESTWARD AND AFFECT THE TROPICAL WATERS FROM 03N TO 11N BETWEEN 92W AND 115W ON FRI...FROM 02N TO 11N BETWEEN 92W AND 125W ON SAT...AND FROM 03N TO 11N BETWEEN 102W AND 128W ON SUN. THESE NE SWELLS WILL BEGIN TO MIX WITH NW ACROSS THE WATERS FROM 03N TO 15N BETWEEN 118W AND 140W ON MON. A DEEP LAYERED CYCLONE IS CUTTING OFF JUST N OF THE AREA AT 35N137W WITH THE UPPER FLOW ZONAL AGAIN ACROSS THE ENTIRE DISCUSSION AREA FROM 17N TO 32N. THIS STRONG UPPER LEVEL WESTERLY FLOW IS ADVECTING DENSE UPPER MOISTURE ACROSS THE BAJA CALIFORNIA PENINSULA AND THE GULF OF CALIFORNIA...CONTINUING NE ACROSS MOST OF OLD MEXICO...AND NOW OVER THE NW GULF OF MEXICO. AN UPPER TROUGH IS NOTED S OF 11N ALONG ROUGHLY 110W...AND CONTINUES TO SEPARATE THE UPPER FLOW OVER THE DEEP TROPICAL PORTION OF THE DISCUSSION AREA. A BROAD RIDGE IS NOTED OVER THE TROPICS S OF 13N W OF 120W...AND IS ACCOMPANIED BY VERY DRY UPPER AIR SUPPRESSING CONVECTION...EXCEPT FOR THE NARROW LINE ALONG THE ITCZ ALREADY DESCRIBED BETWEEN 118W AND 126W. A BROAD UPPER RIDGE ALSO DOMINATES THE TROPICS E OF 100W...WITH WEAK UPPER DIFFLUENCE ALONG THE RIDGE AXIS ENHANCING THE CONVECTIVE CLUSTERS PREVIOUSLY MENTIONED BETWEEN 87W AND 94W. A NARROWING AND THINNING TROPICAL MOISTURE PLUME IS STILL OBSERVED WITHIN 90 NM EITHER SIDE OF A LINE FROM 05N108W TO OVER OLD MEXICO AT 20N100W WHERE THE MOISTURE NOW MERGES INTO THE DENSE PLUME ADVECTED E ACROSS MEXICO. A SURFACE HIGH PRESSURE ANALYZED AT 31N121W WILL CONTINUE TO SHIFT NE ALLOWING A SERIES OF WEAK COLD FRONTS TO ROTATE AROUND THE DEEP LAYERED CYCLONE CENTERED JUST N OF THE AREA. THE FRONTS WILL MOVE INTO THE DISCUSSION AREA BUT ARE EXPECTED TO STALL ALONG ABOUT 134W. HOWEVER THE POST FRONTAL WESTERLY FLOW WILL INCREASE TO 20 TO 25 KT AND DRIVE LARGE NW SWELL INTO THE AREA...WITH COMBINED SEAS BUILDING 8 TO 13 FT W OF THE MERGED FRONTS OVER THE WEEKEND. $$ NELSON