000
AXPZ20 KNHC 082121
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC WED APR 08 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 2000 UTC. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
          
THE ITCZ AXIS WAS ANALYZED FROM 03N92W TO 03N102W TO 05N109W TO 
02N125W TO 04N140W. SCATTERED MODERATE CONVECTION WAS WITHIN 150 
NM EITHER SIDE OF THE AXIS BETWEEN 104W-112W. 

...DISCUSSION... 

THE SUBTROPICAL HIGH HAS BEEN WEAKENED BY A DISSIPATING COLD 
FRONT THAT STRETCHES FROM PUERTO PENASCO ON THE GULF OF 
CALIFORNIA COAST INTO THE PACIFIC TO 29N123W. THE 1024 MB HIGH 
PRESSURE CENTER WAS ANALYZED NEAR 34N126W. A RIDGE AXIS EXTENDS 
FROM THIS SUBTROPICAL HIGH CENTER TO A 1022 MB HIGH S OF THE 
FRONT NEAR 27N127W TO 14N107W. RECENT ASCAT DATA SHOWS TRADE 
WINDS HAVE DIMINISHED TO A MODERATE TO FRESH BREEZE SW OF THE 
RIDGE AXIS. THE SUBTROPICAL HIGH IS EXPECTED TO WEAKEN FURTHER 
AND SHIFT SE AS A PROGRESSIVE COLD FRONT NW OF THE AREA 
ENCROACHES UPON IT. THIS SHOULD KEEP TRADE WINDS BELOW THE 
ADVISORY CRITERIA OF 20-25 KT THROUGH THE END OF THE FORECAST 
PERIOD FRIDAY AFTERNOON. WINDS SHOULD REMAIN A SOLID FRESH 
BREEZE AND HELP ENHANCE THE SEAS TO 9 FT OVER WATERS W OF 120W 
WHERE NW...NE AND SW SWELL ARE COMBINING. 

THE COLD FRONT ENCROACHING ON THE SUBTROPICAL HIGH IS FORECAST 
TO REACH THE NW FORECAST WATERS THU. WINDS ARE EXPECTED TO BE 
JUST BELOW ADVISORY CRITERIA BOTH AHEAD OF AND BEHIND THE FRONT 
THU. SEAS WILL SLOWLY BUILD ABOVE 8 FT BEHIND THE FRONT 
OVERNIGHT THU NIGHT. ALOFT...THE TROUGH SUPPORTING THIS COLD 
FRONT IS EXPECTED TO CUT OFF FROM THE NORTHERN STREAM BY THU 
NIGHT. A DEEP LAYERED LOW WILL MOVE INTO WATERS N OF 30N AROUND 
135W ON FRI. WINDS W OF THE LOW WILL INCREASE TO NEAR GALE FORCE 
AS SEAS BUILD AS HIGH AS 16 FT. 

SPLIT FLOW OVER THE CENTRAL PACIFIC HAS DIRECTED A 100 KT 
SOUTHWESTERLY JET ACROSS THE AREA FROM 18N140W TO GUAYMAS 
MEXICO. THIS JET IS PROPELLING TROPICAL MOISTURE ALOFT ACROSS 
THE FORECAST AREA. MULTI-LEVEL CLOUDINESS WITH SOME EMBEDDED 
SHOWERS CAN PRIMARILY BE FOUND WITHIN 270 NM EITHER SIDE OF A 
LINE FROM 08N140W TO 21N120W TO MAZATLAN. THIS PATTERN IS 
EXPECTED TO CHANGE LITTLE OVER THE NEXT TWO DAYS.

GAP WINDS...                                                    
GULF OF PAPAGAYO...THE PRESSURE GRADIENT BETWEEN RIDGING OVER 
THE WESTERN CARIBBEAN AND THE ITCZ TO THE SW IS SUPPORTING A 
FRESH TO STRONG NE BREEZE IN THE GULF OF PAPAGAYO. THE 
OBSERVATION AT LIBERIA COSTA RICA WAS 20 KT AT 2000 UTC AND HAS 
HOVERED AROUND 20-25 KT FOR THE PAST SEVERAL HOURS. THE PRESSURE 
GRADIENT WILL WEAKEN SLIGHTLY THROUGH THE REMAINDER OF THE 
FORECAST PERIOD. WINDS ARE FORECAST TO DIP BELOW ADVISORY 
CRITERIA THIS EVENING AT THE DIURNAL MINIMUM OF DRAINAGE FLOW 
OFF THE LAND ONLY TO RETURN IN THE MORNING HOURS THU BUT HUG 
CLOSER TO THE COAST. WINDS WILL DROP OFF AGAIN THU AFTERNOON AND 
RETURN TO ADVISORY CRITERIA FRI MORNING BEFORE DROPPING OFF 
AGAIN. 

GULF OF CALIFORNIA...A BRIEF PULSE OF NW WINDS AT ADVISORY 
CRITERIA IS EXPECTED IN THE GULF OF CALIFORNIA N OF 24N E OF 
109W THU EVENING. 

$$
SCHAUER