000
AXPZ20 KNHC 212129
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
2205 UTC TUE APR 21 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 
2100 UTC. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              

THE ITCZ AXIS EXTENDS FROM 05N100W TO 08N112W TO 06N140W. 
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN   
150 NM N OF THE AXIS BETWEEN 109W AND 118W...WITHIN 150 NM 
EITHER SIDE OF THE AXIS BETWEEN 127W AND 132W...AND ALSO WITHIN 
150 NM N OF THE AXIS W OF 132W.

A TROUGH EXTENDS FROM 06N87W TO 02N94W. SCATTERED MODERATE 
CONVECTION IS FROM 01N TO 06N BETWEEN 86W AND 94W.

...DISCUSSION... 

A SURFACE TROUGH IS SWINGING THROUGH THE NORTHERN WATERS 
EXTENDING FROM 30N120W TO 26N132W. WINDS ARE LIGHT TO MODERATE 
ON EITHER SIDE OF THE TROUGH. A COLD FRONT IS JUST NW OF THE 
DISCUSSION WATERS APPROACHING 32N140W AND IS SHOWING SIGNS OF 
STALLING. AN AREA OF NW SWELL IS OUTRUNNING THIS FRONT WITH SEAS 
OF 8-9 FT COVERING THE WATERS N OF A LINE FROM 30N125W TO 
23N140W. THIS SWELL WILL GRADUALLY PROPAGATE TO THE E-SE THROUGH 
THE NEXT 48 HOURS. MEANWHILE FRESH TO STRONG NORTHERLY WINDS 
WILL DEVELOP OFF OF THE U.S. CALIFORNIA COAST WHICH WILL SEND 
FRESH NORTHERLY SWELL SOUTHWARD MIXING WITH THE NW SWELL BY    
48 HOURS WHICH WILL BUILD COMBINED SEAS UP TO 12 FT NEAR 30N125W 
BY EARLY THU.

BROAD SURFACE RIDGING IS IN PLACE FROM 30N140W TO 25N130W TO 
20N108W. THE PRESSURE GRADIENT S-SW OF THIS RIDGE AND TO THE N 
OF THE ITCZ WHERE LOWER PRESSURES ARE IS ENOUGH TO SUPPORT AN 
AREA OF FRESH TO STRONG NE TRADES FROM 09N TO 15N W OF 136W AS 
INDICATED BY A RECENT ASCAT-B SCATTEROMETER PASS. A RECENT 
ALTIMETER SATELLITE PASS MEASURED A SURROUNDING AREA OF 8-9 FT 
SEAS OVER THE FAR W CENTRAL WATERS. THE TRADES AND SWELL WILL 
PERSIST THROUGH THE NEXT 48 HOURS.

GULF OF CALIFORNIA...A SURFACE TROUGH IS LOCATED IN THE FAR NW 
CORNER OF THE GULF AND A 1740 UTC ASCAT SCATTEROMETER PASS 
MEASURED FRESH TO STRONG S-SW WINDS N OF 30N E OF THE TROUGH. 
THIS TROUGHING WILL WEAKEN THEN RE-STRENGTHEN THROUGH THE NEXT 
48 HOURS WITH THE FRESH TO STRONG SOUTHERLY FLOW PULSING EACH 
DAY IN RESPONSE. SEAS MAY BRIEFLY BUILD TO 8 FT JUST E OF 
THE TROUGH DURING THE STRONGEST WINDS.
 
THE GULF OF PAPAGAYO...GAP WINDS ARE EXPECTED TO PULSE TO 15-20 
KT ACROSS THE IMMEDIATE GULF AND DOWNSTREAM TONIGHT...AND THEN 
INCREASE FURTHER TO 20-25 KT WED NIGHT THROUGH THU MORNING WHEN 
SEAS WILL BUILD TO 6-8 FT.

$$
LEWITSKY