000 AXPZ20 KNHC 100945 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE MAY 10 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 PACIFIC COAST OF COSTA RICA AT 09N84W TO 10N98W THEN TURNS NW TO 13N105W. THE TROUGH IS INTERRUPTED BY SEVERAL CYCLONIC SWIRLS BETWEEN 108-114W WITH A 1008 MB SURFACE LOW CURRENTLY ANALYZED NEAR 12N107W. THE MONSOON TROUGH REFORMS SW OF THE LOW NEAR 10N114W AND CONTINUES SW THROUGH 07N120W TO 07N128W WHERE SCATTEROMETER WINDS INDICATE AN ITCZ FORMS AND CONTINUES W TO BEYOND 05N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 150 NM OVER THE NW QUADRANT OF THE LOW. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED OVER AND TO THE S OF THE EASTERN SEGMENT OF THE MONSOON TROUGH WITHIN 120 NM EITHER SIDE OF A LINE FROM 04N86W TO 10N94W TO 10N104W... AND ALONG THE W SEGMENT OF THE MONSOON TROUGH WITHIN 150 NM OF A LINE FROM 11N112W TO 08N116W. ...DISCUSSION... N OF 15N E OF 120W... A N-S SURFACE TROUGH WILL PERSIST ACROSS THE BAJA PENINSULA THIS WEEK...BECOMING MOST PRONOUNCED DURING AFTERNOON AND EARLY EVENING DURING PEAK HEATING. A NW TO SE SURFACE RIDGE WILL MEANDER ACROSS THE TROPICAL WATERS FROM NEAR 23N120W TO BEYOND 15N103W THROUGH THE UPCOMING WEEKEND. MODERATE NW WINDS ARE EXPECTED TO DEVELOP IN THE LATE AFTERNOONS WITHIN 120 NM W OF THE BAJA PENINSULA. THE PRESSURE GRADIENT IS EXPECTED TO TIGHTEN ON SAT WITH MODERATE TO FRESH NW FLOW DEVELOPING ACROSS THE EPAC WATERS FROM 27-32N E OF 120W. LIGHT TO GENTLE ANTICYCLONIC FLOW IS EXPECTED AROUND THE QUASI- STATIONARY RIDGE ELSEWHERE ACROSS THE OPEN EPAC WATERS W OF 97W THIS WEEK...EXCEPT MODERATE N FLOW IS EXPECTED S OF 17N BETWEEN 105-120W IN RESPONSE TO A TROPICAL LOW PRESSURE SYSTEM CURRENTLY NEAR 12N107W. LIGHT ONSHORE FLOW IS EXPECTED ACROSS THE GULF OF TEHUANTEPEC THROUGH FRI EVENING...WITH GUIDANCE SUGGESTING THAT STRONG NORTHERLY DRAINAGE FLOW WILL DEVELOP LATE FRI NIGHT...AND PERSIST THROUGH SUNRISE ON SAT BEFORE DIMINISHING. 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 E NOCTURNAL DRAINAGE EXPECTED ACROSS AND JUST N OF THE GULF OF PAPAGAYO TONIGHT WITH SEAS BUILDING TO 6 FT. A TROPICAL LOW IS ANALYZED NEAR 12N107W AND IS ESTIMATED AT 1008 MB. THE LOW IS FORECAST TO MEANDER FOR A DAY OR SO ACCOMPANIED BY MODERATE CYCLONIC WINDS BEFORE SHIFTING W AND PASSING W OF 110W ON THU. OTHERWISE...GENTLE NORTHERLY FLOW IS EXPECTED N OF THE MONSOON TROUGH...AND MODERATE S FLOW IS EXPECTED S OF THE TROUGH AXIS. ELSEWHERE FROM THE EQUATOR TO 32N E OF 140W... A RIDGE EXTENDS SE FROM NEAR 32N132W TO BEYOND 23N120W. FRESH NE WINDS ARE NOTED ACROSS THE TROPICS BETWEEN THE RIDGE AND THE ITCZ ALL TO THE W OF 115W...WITH SEAS OF 7-8 FT CURRENTLY OBSERVED ACROSS THE TROPICAL WATERS FROM 07-11N BETWEEN 135- 140W. THE GRADIENT IS RELAXING AND THESE SEAS WILL SUBSIDE TO A MAX OF 7 FT TODAY. A WEAK 1008 MB TROPICAL LOW CURRENTLY NEAR 12N107W IS FORECAST TO MEANDER TONIGHT AND THEN MOVE W TO NEAR 11N109W ON WED NIGHT...THEN WEAKEN TO AN OPEN TROUGH FROM NEAR 14N110W TO 08N115W ON THU. HOWEVER...THE PRESSURE GRADIENT WILL SUPPORT FRESH N-NE WINDS WITHIN 300 NM OVER THE W SEMICIRCLE OF THE LOW CENTER...AND LATER TO THE W OF THE TROUGH AXIS. THE NEXT COLD FRONT WILL REACH NEAR 30N140W ON WED ACCOMPANIED BY A MODERATE-FRESH S-SW-NW WIND SHIFT. A SURFACE HIGH WILL SHIFT S ALONG 130W REACHING NEAR 28N ON THU BLOCKING THE EASTWARD PROGRESSION OF THE COLD FRONT...WHICH IS EXPECTED TO STALL FROM ABOUT 32N131W TO 26N140W ON FRI. $$ NELSON