000 AXPZ20 KNHC 152123 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI MAY 15 2015 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 1945 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 10N84W TO 05N96W TO 07N107W TO 05N115W TO LOW PRES NEAR 10N124W 1010 MB TO LOW PRES NEAR 08N137W TO 07N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 120 NM SE OF THE AXIS E OF 90W AND ELSEWHERE FROM 01N-07N BETWEEN 82W-87W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS BETWEEN 45 NM AND 300 NM S OF THE AXIS BETWEEN 92W-103W. SCATTERED MODERATE CONVECTION WAS S OF THE AXIS TO 00N BETWEEN 111W-118W. SCATTERED MODERATE CONVECTION WAS WITHIN 180 NM SW QUADRANT OF LOW PRES NEAR 10N124W AND WITHIN 210 NM N QUADRANT OF LOW PRES NEAR 08N137W. ...DISCUSSION... A 1025 MB SUBTROPICAL HIGH CENTERED NEAR 31N145W EXTENDS A RIDGE SE THROUGH 23N133W TO NEAR 23N113W. THE PRESSURE GRADIENT BETWEEN THIS RIDGE AND LOW PRES SYSTEMS EMBEDDED IN THE MONSOON TROUGH NEAR 10N124W AND 08N137W IS GENERATING FRESH NE TRADE WINDS AS OBSERVED BY THE 1842 UTC ASCAT PASS. TRADES ARE EXPECTED TO REMAIN A FRESH BREEZE OVER W WATERS N OF THE MONSOON TROUGH THROUGH THE FORECAST PERIOD. A COLD FRONT IS APPROACHING THE SUBTROPICAL HIGH FROM THE NW. THE SUBTROPICAL HIGH WILL MERGE INTO THE SE SIDE OF A NEW HIGH BEHIND THE FRONT ON SAT. THE COLD FRONT WILL DIP S OF 32N OVER NW WATERS SAT EVENING AND STRETCH FROM 32N130W TO 29N133W TO 28N140W BY SUN AFTERNOON. WINDS NEAR THE FRONT ARE EXPECTED TO REMAIN BELOW A FRESH BREEZE AND SEAS TO 8 FT SHOULD BE CONFINED N OF 30N BEHIND THE FRONT. THE BULK OF THE DEEP CONVECTION IN THE PACIFIC CAN BE FOUND ALONG A LINE FROM CENTRAL COSTA RICA TO 02N100W TO 02N120W. THE AREA ALONG THIS LINE W OF 90W CORRESPONDS TO A REGION OF ABUNDANT MOISTURE AND LOW LEVEL SPEED CONVERGENCE. DIVERGENCE ASSOCIATED WITH THE REAR RIGHT QUADRANTS OF A SOUTHWESTERLY UPPER JET NEAR THE COAST OF COSTA RICA AND A NORTHERLY UPPER JET NEAR 03N100W IS ENHANCING CONVECTION BY LIFTING THE MOIST LOW LEVEL AIR UPWARD IN THE ATMOSPHERE. THE STRENGTH OF THE UPPER JETS IS EXPECTED TO WEAKEN OVER THE NEXT FEW DAYS BUT THE AREA OF CONVECTIVE ENHANCEMENT SHOULD REMAIN IN THE SAME GENERAL REGION. A 1010 MB LOW PRES SYSTEM NEAR 32N118W EXTENDS A COLD FRONT SW THROUGH 27N122W AND 26N129W THEN WEAKENS TO 30N137W. AN 1842 UTC RAPIDSCAT PASS SHOWS 20-25 KT WITHIN 75 NM EITHER SIDE OF THE LEADING EDGE OF THE FRONT FROM 27N-30N WITH WINDS TO NEAR GALE FORCE WITHIN 75 NM OF THE LOW CENTER. THE LOW WILL MOVE ONSHORE NEAR ENSENADA THIS EVENING BEFORE MOVING INTO THE NORTHERN GULF OF CALIFORNIA. ONCE INLAND...THE SYSTEM WILL WEAKEN OVER PACIFIC WATERS. THE COLD FRONT IS EXPECTED TO DISSIPATE BY SAT EVENING AS SEAS SUBSIDE BELOW 8 FT. GAP WINDS... GULF OF CALIFORNIA...THE 1744 UTC ASCAT PASS SHOWS WINDS HAVE DIMINISHED TO A FRESH SW BREEZE IN THE NORTHERN GULF OF CALIFORNIA. THIS BREAK IN THE FRESH TO STRONG SW FLOW N OF 29N SHOULD BE TEMPORARY...WITH CONDITIONS EXPECTED TO RESUME AHEAD OF THE COLD FRONT MOVING INTO THE NORTHERN GULF OF CALIFORNIA LATER TONIGHT. THE COLD FRONT WILL WEAKEN QUICKLY...WITH WINDS AND SEAS EXPECTED TO DIMINISH AROUND SUNRISE SAT. GULF OF PAPAGAYO...THE PRESSURE GRADIENT BETWEEN RIDGING OVER THE NW CARIBBEAN AND TROUGHING NEAR THE ITCZ WILL SUPPORT A FRESH TO STRONG BREEZE IN THE GULF OF PAPAGAYO BY THE EARLY MORNING HOURS SAT WITH THE ASSISTANCE OF NOCTURNAL DRAINAGE FLOW. THESE WINDS WILL DIMINISH AFTER SUNRISE. THE PRESSURE GRADIENT WILL SLACKEN ENOUGH BY SAT EVENING TO PREVENT WINDS FROM EXCEEDING A FRESH BREEZE ON SUN. $$ SCHAUER