000
AXPZ20 KNHC 160243
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC SAT MAY 16 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0030 UTC.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              

THE MONSOON TROUGH AXIS WAS ANALYZED FROM 10N84W TO 05N96W TO 
08N107W TO 05N115W TO LOW PRES NEAR 10N126W 1010 MB TO LOW PRES 
NEAR 08N137W 1011 MB TO 07N140W. SCATTERED MODERATE CONVECTION 
WAS S OF THE AXIS TO 03N BETWEEN 83W-90W. SCATTERED MODERATE 
CONVECTION WAS S OF THE AXIS TO 01N BETWEEN 99W-105W. SCATTERED 
MODERATE CONVECTION WAS N OF THE AXIS TO 09N BETWEEN 115W-119W. 
SCATTERED MODERATE CONVECTION WAS WITHIN 180 NM NW AND N 
QUADRANTS OF LOW PRES NEAR 08N137W.

...DISCUSSION...

A 1025 MB SUBTROPICAL HIGH CENTERED NEAR 31N146W EXTENDS A RIDGE 
SE THROUGH 23N133W TO NEAR 22N110W. THE PRESSURE GRADIENT 
BETWEEN THIS RIDGE AND LOW PRES SYSTEMS EMBEDDED IN THE MONSOON 
TROUGH NEAR 10N126W AND 08N137W IS GENERATING FRESH NE TRADE 
WINDS AS OBSERVED BY ASCAT PASSES FROM 1748 UTC TO 1928 UTC. 
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 03N100W TO 01N120W. 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 1007 MB LOW PRES SYSTEM NEAR 31N117W EXTENDS A COLD FRONT TO 
JUST S OF ENSENADA THEN TO 24N120W TO 25N135W AND THEN WEAKENS 
TO 30N138W. WINDS ARE BELIEVED TO HAVE DIMINISHED BELOW A FRESH 
TO STRONG BREEZE BEHIND THE FRONT. THE LOW WILL MOVE INLAND AND 
CARRY THE FRONT INTO THE NORTHERN GULF OF CALIFORNIA TONIGHT. 
ONCE INLAND...THE FRONT 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...AS MENTIONED ABOVE...THE LOW PRES SYSTEM 
AND COLD FRONT ALONG THE COAST OF BAJA CALIFORNIA SUR JUST S OF 
ENSENADA WILL MOVE THROUGH GULF OF CALIFORNIA N OF 29N BY 
SUNRISE SAT. SW WINDS TO NEAR GALE FORCE LIE AHEAD OF THE FRONT 
OVER THE GULF OF CALIFORNIA. 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