000 AXPZ20 KNHC 120946 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU MAY 12 2016 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... A MONSOON TROUGH EXTENDS W FROM THE CARIBBEAN COAST OF COLOMBIA AT 09N77W ACROSS PANAMA TO THE PACIFIC COAST OF COSTA RICA AT 10N85W...THEN DIPS SW THROUGH AN EMBEDDED 1009 MB LOW PRES AT 08N92W...THEN TURNS NW A SECOND A009 MB LOW AT 11N111W...THEN CONTINUES SW TO 07N125W WHERE SCATTEROMETER WINDS INDICATE AN ITCZ FORMS AND CONTINUES SW TO BEYOND 05N140W. ISOLATED MODERATE TO STRONG CONVECTION IS NOTED TO THE S OF THE LOW PRES AT 08N92W...FROM 04-08N BETWEEN 90-95W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED NEAR THE LOW PRES AT 11N111W WITHIN 90 NM EITHER SIDE OF A LINE FROM 13N107W TO 09N113W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED ALONG THE WESTERN SEGMENT OF THE MONSOON TROUGH AND ITCZ WITHIN 75 NM EITHER SIDE OF A LINE FROM 07N115W TO 07N126W TO 07N131W. ...DISCUSSION... N OF 15N E OF 120W... A N-S SURFACE TROUGH WILL DEVELOP ACROSS THE BAJA PENINSULA DURING THE AFTERNOON AND EARLY EVENING HOURS FOR THE NEXT FEW DAYS. GUIDANCE IS SUGGESTING THAT THE SOUTHERLY FLOW WILL INCREASE TO 20 TO 25 KT ACROSS THE GULF WATERS FROM 29.5N TO 31N W OF 113W ON SAT NIGHT. MODERATE NW WINDS ARE EXPECTED TO DEVELOP IN THE LATE AFTERNOONS WITHIN 180 NM W OF THE BAJA PENINSULA...AND PERSIST THROUGH SUNRISE EACH DAY THROUGH THE WEEKEND. THE PRESSURE GRADIENT IS EXPECTED TO TIGHTEN ON FRI NIGHT WITH MODERATE TO FRESH NW FLOW DEVELOPING ACROSS THE EPAC WATERS FROM 27-32N E OF 120W THROUGH SUN MORNING. THE GRADIENT WILL FURTHER TIGHTEN ON SUN AFTERNOON WITH FRESH NW FLOW ACROSS THE WATERS FROM 27-32N. A NW TO SE SURFACE RIDGE WILL MEANDER ACROSS THE TROPICAL WATERS ROUGHLY FROM NEAR 23N120W TO BEYOND 15N100W THROUGH THE UPCOMING WEEKEND. MODERATE-FRESH N-NE FLOW...SEAS 5-7 FT...IS EXPECTED S OF 17N BETWEEN 105-120W IN RESPONSE TO A TROPICAL LOW PRESSURE SYSTEM S OF THE AREA. OTHERWISE...LIGHT TO GENTLE ANTICYCLONIC FLOW AROUND THE QUASI-STATIONARY RIDGE IS EXPECTED ELSEWHERE ACROSS THE OPEN EPAC WATERS THROUGH THE WEEKEND. STRONG NORTHERLY DRAINAGE FLOW WILL DEVELOP LATE TONIGHT ACROSS AND JUST DOWNWIND OF THE GULF OF TEHUANTEPEC AND PERSIST INTO FRI MORNING. A MORE SIGNIFICANT EVENT IS EXPECTED ON FRI NIGHT INTO SAT MORNING WITH SEAS BUILDING TO PERHAPS 10 FT NEAR 15N95W. COMBINED SEAS OF 3-6 FT ARE CURRENTLY OBSERVED ACROSS THE OPEN PAC WATERS W OF 100W IN MIXING LONG-PERIOD CROSS EQUATORIAL S SWELL AND LONG PERIOD NW SWELL. S OF 15N E OF 110W... MODERATE-FRESH EASTERLY NOCTURNAL DRAINAGE FLOW EXPECTED ACROSS...AND JUST N OF THE GULF OF PAPAGAYO EACH NIGHT INTO EARLY NEXT WEEK. SCATTEROMETER WINDS DETECT A 1009 MB LOW ALONG THE MONSOON TROUGH NEAR 07N91W ACCOMPANIED BY LIGHT WINDS. THE LOW IS EXPECTED TO MOVE W AND GRADUALLY LOSE IDENTITY TODAY. GENTLE NORTHERLY FLOW IS EXPECTED N OF THE MONSOON TROUGH...AND MODERATE S FLOW EXPECTED S OF THE TROUGH AXIS. ELSEWHERE FROM THE EQUATOR TO 32N E OF 140W... A TROPICAL LOW IS ANALYZED NEAR 11N111W AND IS ESTIMATED AT 1009 MB. THE LOW IS FORECAST TO MOVE W TO NEAR 10N114W TONIGHT AND NEAR 09N118W ON FRI NIGHT. GUIDANCE HANGS ONTO THIS LOW THROUGH THE WEEKEND WITH AN ESTIMATED POSITION NEAR 06N128W ON SUN NIGHT. MODERATE-FRESH N-NE WINDS ARE EXPECTED WITHIN 300 NM OVER THE NW SEMICIRCLE OF THE LOW WITH SEAS BUILDING TO 9 FT. THE GRADIENT SHOULD TIGHTEN A LITTLE ON FRI NIGHT SUPPORTING STRONG N-NE WINDS BETWEEN 120 AND 240 NM NW OF THE LOW CENTER. A 1020 MB SURFACE HIGH AT 30N129W WILL SHIFT A LITTLE S TO NEAR 28N128W ON FRI. FRESH NE WINDS ARE NOTED ELSEWHERE ACROSS THE TROPICS BETWEEN THE RIDGE AND THE ITCZ...ALL TO THE W OF 110W...WITH SEAS OF 6-8 FT. LITTLE CHANGE EXPECTED THROUGH THE WEEKEND ACROSS THE WATERS W OF THE PREVIOUSLY DESCRIBED TROPICAL LOW. A COLD FRONT EXTENDS FROM 32N137W TO 26N140W AND IS PRECEDED BY MODERATE TO FRESH SOUTHERLY FLOW. THE SURFACE HIGH WILL BLOCK THE EASTWARD PROGRESSION OF THE COLD FRONT WHICH WILL STALL FROM ABOUT 32N132W TO 26N140W ON FRI. $$ NELSON