000 AXPZ20 KNHC 090945 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC MON MAY 09 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 SW FROM THE PACIFIC COAST OF NORTHERN COSTA RICA AT 11N86W TO 08N91W...THEN TURNS ABRUPTLY NW TO 12N97W...THEN W TO 12N105W...THEN IS BRIEFLY INTERRUPTED BY A SURFACE LOW PRESSURE AT 11.5N110W. SCATTEROMETER WINDS INDICATE AN ITCZ FORMS SW OF THE LOW AND CONTINUES WSW TO BEYOND 07N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 180 NM OVER THE N SEMICIRCLE OF THE LOW. SIMILAR CONVECTION IS NOTED OVER AND TO THE S OF THE MONSOON TROUGH WITHIN 150 NM OF 07N91W AND WITHIN 240 NM OF 09N103W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ALONG THE ITCZ WITHIN 60 NM OF 10N115W...AND WITHIN 90 NM OF 09N127W AND 07N138W. ...DISCUSSION... N OF 15N E OF 120W... A N-S SURFACE TROUGH WILL PERSIST ACROSS THE BAJA PENINSULA THIS WEEK...BECOMING MOST PRONOUNCED DURING THE LATE AFTERNOON AND EVENINGS. A NW TO SE SURFACE RIDGE WILL MEANDER ACROSS THE TROPICAL WATERS FROM NEAR 22N120W TO BEYOND 15N103W THIS WEEK. MODERATE NW WINDS ARE EXPECTED WITHIN 120 NM W OF THE BAJA PENINSULA THROUGH EARLY TUE...THEN THE GRADIENT WILL RELAX SOME WITH GENTLE-MODERATE NW FLOW FORECAST THROUGH THE REMAINDER OF THE WEEK. LIGHT TO GENTLE ANTICYCLONIC FLOW AROUND THE QUASI-STATIONARY RIDGE IS EXPECTED ELSEWHERE ACROSS THE OPEN EPAC WATERS W OF 97W THIS WEEK. LIGHT ONSHORE FLOW IS EXPECTED ACROSS THE GULF OF TEHUANTEPEC THROUGH THU EVENING...WITH GUIDANCE CONTINUING TO INDICATE THAT STRONG NORTHERLY DRAINAGE FLOW WILL DEVELOP LATE THU NIGHT...AND PERSIST THROUGH SUNRISE ON SAT BEFORE DIMINISHING. COMBINED SEAS OF 4-7 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. EXPECT BOTH THE SW AND NW SWELL COMPONENTS TO SUBSIDE THROUGH TONIGHT WITH 3-5 FT SEAS FORECAST ON TUE THROUGH SAT...EXCEPT INCREASING TO 5-6 FT ALONG 15N BETWEEN 110-120W ON THU NIGHT...WITH SEAS BUILDING TO 5-6 FT IN RESPONSE TO A TROPICAL LOW S OF THE AREA. S OF 15N E OF 110W... MODERATE E NOCTURNAL DRAINAGE EXPECTED ACROSS AND JUST N OF THE GULF OF PAPAGAYO TONIGHT AND AGAIN ON TUE NIGHT WITH SEAS BUILDING TO ABOUT 6 FT. A TROPICAL LOW IS ANALYZED NEAR 11N111W AND IS ESTIMATED AT 1010 MB. THE LOW IS FORECAST TO DRIFT SLOWLY WESTWARD FOR THE NEXT FEW DAYS WITH ASSOCIATED MODERATE CYCLONIC WINDS SHIFTING W OF 110W. OTHERWISE...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 RIDGE EXTENDS SE FROM NEAR 32N136W TO BEYOND 22N120W. 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 07-18N BETWEEN 129- 140W. THE GRADIENT WILL RELAX TODAY WITH THE SEAS SUBSIDING TO A MAX OF 7 FT TONIGHT. A WEAK 1010 MB TROPICAL LOW CURRENTLY NEAR 11N111W IS FORECAST TO MOVE SLOWLY W TO NEAR 10N113W ON WED NIGHT AND NEAR 10N117W ON FRI WITH THE PRESSURE GRADIENT THEN SUPPORTING FRESH N-NE WINDS WITHIN 300 NM OVER THE W SEMICIRCLE OF THE CENTER. THE NEXT COLD FRONT WILL REACH NEAR 30N140W ON WED...BUT ONLY ACCOMPANIED BY A MODERATE S-SW-NW WIND SHIFT. A SURFACE HIGH WILL BUILD ALONG THE RIDGE AXIS NEAR 29N128W ON THU BLOCKING THE EASTWARD PROGRESSION OF THE COLD FRONT WHICH IS EXPECTED TO STALL FROM ABOUT 32N131W TO 27N140W ON FRI. $$ NELSON