000 AXPZ20 KNHC 130912 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI MAY 13 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 0800 UTC. ...INTERTROPICAL CONVERGENCE ZONE... THE MONSOON TROUGH WAS ANALYZED FROM 09N96W TO 10N108W...THEN CONTINUED FROM LOW PRES NEAR 10N114W 1007 MB TO 06N118W TO 06N120W. THE ITCZ AXIS WAS ANALYZED FROM 06N120W TO 05N125W TO 02N130W...THEN CONTINUED FROM 04N136W TO 04N140W. ISOLATED MODERATE CONVECTION WAS FROM 04.5N-10.5N BETWEEN 95.5W-110W. SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 45 NM E SEMICIRCLE...150 NM SW QUADRANT AND 90 NM NW QUADRANT OF LOW PRES NEAR 10N114W AS WELL AS BETWEEN 90 NM-240 NM NE QUADRANT. ...DISCUSSION... THE 1018 MB SUBTROPICAL HIGH WAS ANALYZED NEAR 31N128W WITH A RIDGE AXIS EXTENDING SE THROUGH 27N124W TO NEAR 19N108W. THE SUBTROPICAL HIGH HAS BEEN WEAKENED BY A DEEP-LAYERED LOW TO ITS NW...WELL N OF THE AREA. THE LOW EXTENDS A WEAKENING STATIONARY FRONT INTO THE FORECAST AREA FROM 32N133W TO 25N140W THAT IS EXPECTED TO DISSIPATE TONIGHT. THE HIGH WILL CONTINUE TO WEAKEN AS THE LOW PASSES N OF IT TODAY AND TONIGHT BEFORE GRADUALLY COMBINING WITH SURFACE HIGH PRES MOVING IN BEHIND THE LOW SAT INTO SAT NIGHT. TRADE WINDS ARE CURRENTLY A MODERATE TO FRESH BREEZE OVER MUCH OF THE PACIFIC SW OF THE RIDGE AXIS. THE AREA OF FRESH NE TRADE WINDS SHOULD EXPAND AS THE HIGH PRES SYSTEMS COMBINE SAT AND SAT NIGHT. THE 0444 UTC ASCAT-A PASS CAPTURED THE BROAD LOW-LEVEL CIRCULATION ASSOCIATED WITH THE 1007 MB LOW PRES SYSTEM ANALYZED NEAR 10N114W. THE ASCAT PASS SHOWED A FRESH TO STRONG BREEZE WITHIN 60 NM NE AND SW QUADRANTS AS WELL AS WITHIN 150 NM NW QUADRANT. THIS LOW IS FORECAST TO GRADUALLY WEAKEN AS IT MOVES W- SW AROUND 12 KT OVER THE NEXT DAY OR SO. WINDS NEAR THE LOW ARE EXPECTED TO DIP BELOW 20-25 KT TONIGHT AS THE PRES GRADIENT RELAXES A BIT. HOWEVER...AS MENTIONED ABOVE...THE AREA OF FRESH TRADE WINDS WILL EXPAND SAT AND SAT NIGHT AS THE RIDGE TO THE N STRENGTHENS. THE AREA OF LOW PRES SHOULD CONTINUE TO CONVERGE LOW-LEVEL MOISTURE AND SUPPORT CONVECTION THROUGH THE END OF THE PERIOD EARLY SUN. GAP WINDS... GULF OF CALIFORNIA...THE AFOREMENTIONED DEEP-LAYER LOW ENCROACHING UPON THE SUBTROPICAL HIGH WILL MOVE INTO THE WESTERN UNITED STATES SAT AND SEND A COLD FRONT THROUGH THE GREAT BASIN LATE SAT THROUGH EARLY SUN. THE GRADIENT WILL BUILD BETWEEN HIGH PRES BEHIND THE FRONT AND LOWER PRES TO THE S OVER WESTERN MEXICO...WITH A FRESH TO STRONG S-SW BREEZE EXPECTED OVER THE GULF OF CALIFORNIA N OF 30N BY THE END OF THE FORECAST PERIOD AT 06Z SUN. GULF OF TEHUANTEPEC...NORTHERLY FLOW IS BEING DIRECTED THROUGH CHIVELA PASS BETWEEN TROUGHING OVER THE SW GULF OF MEXICO AND HIGH PRES OVER NE MEXICO. NORTHERLY WINDS IN THE GULF OF TEHUANTEPEC ARE EXPECTED TO QUICKLY PICK UP TO 20-30 KT BY SUNRISE AS NOCTURNAL DRAINAGE FLOW ENHANCES THE WIND. BOTH THE NOCTURNAL DRAINAGE FLOW THROUGH CHIVELA PASS AND THE DIURNAL PROGRESSION OF TROUGHING MOVING NW OFF YUCATAN PENINSULA INTO THE SW GULF OF MEXICO WILL INFLUENCE THE WIND IN THE GULF OF TEHUANTEPEC...WITH THE STRONGEST WINDS EXPECTED TO REMAIN BELOW GALE FORCE AND OCCUR IN THE EARLY MORNING HOURS. SEAS ARE EXPECTED TO REACH 8 FT THIS MORNING...BUT SHOULD BUILD AS HIGH AS 11 FT SAT MORNING. THE PRES GRADIENT SHOULD RELAX SOME BY EARLY SUN MORNING...WITH WINDS TO 25 KT EXPECTED TO BE CONFINED N OF 15N AND SEAS LESS THAN 8 FT. GULF OF PAPAGAYO...NE TRADE WINDS IN THE SW CARIBBEAN WILL CONTINUE TO BLEED THROUGH CENTRAL AMERICA INTO THE GULF OF PAPAGAYO THROUGH THE FORECAST PERIOD. NOCTURNAL DRAINAGE FLOW WILL ENHANCE THE WINDS...WITH A FRESH TO STRONG BREEZE EXPECTED IN THE GULF OF PAPAGAYO IN THE MORNING HOURS THIS MORNING AND SAT MORNING BEFORE DIMINISHING. SEAS WILL REACH AS HIGH AS 8 FT. $$ SCHAUER