000
AXPZ20 KNHC 202126
TWDEP 

TWDEP 

TROPICAL WEATHER DISCUSSION                                   
NWS NATIONAL HURRICANE CENTER MIAMI FL                        
2205 UTC WED MAR 20 2013

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 
2045 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 08N78W TO 03N100W. THE ITCZ 
CONTINUES FROM 03N100W TO 03N120W TO 01N140W. SCATTERED MODERATE 
TO STRONG CONVECTION IS NOTED FROM 04N TO 07N BETWEEN 83W AND 
90W. SCATTERED MODERATE CONVECTION IS WITHIN 75 NM N OF TROUGH 
BETWEEN 90W AND 92W. SIMILAR CONVECTION IS WITHIN 120 NM N OF 
AXIS BETWEEN 115W AND 122W. A CLUSTER OF MODERATE TO ISOLATED 
STRONG CONVECTION IS WITHIN 45 NM OF 05N114W.  

...DISCUSSION... 

DISSIPATING HIGH PRESSURE 1022 MB CENTERED NEAR 30N122W EXTENDS 
A RIDGE SE ACROSS THE N WATERS TO NEAR 17N114W. A LIGHT TO 
GENTLE BREEZE IS NOTED OVER THE N-CENTRAL WATERS UNDER THE 
INFLUENCE OF THIS SYSTEM. THE WEAKER PRES GRADIENT ON THE 
SOUTHERN PERIPHERY OF THIS RIDGE IS ONLY ALLOWING FOR WEAK NE 
TRADE WINDS OF ABOUT 15-20 KT TO PERSIST ACROSS THE CENTRAL AND 
WESTERN PORTIONS OF THE DISCUSSION AREA. THE MOST RECENT WINDSAT 
PASS CONFIRMED THE PRESENCE OF THESE WIND SPEEDS.

SEAS ARE GENERALLY UNDER 8 FT ACROSS MUCH OF THE FORECAST 
REGION. AN AREA OF 8 FT SEAS CAN BE FOUND FROM 05N TO 10N 
BETWEEN 119W AND 130W DUE TO PRIMARILY A SW SWELL COMPONENT. 

THE AREA OF MODERATE TO FRESH WINDS WILL DIMINISH TONIGHT AS THE 
SUBTROPICAL HIGH REORGANIZES WELL TO THE NW OF ITS CURRENT 
POSITION. HOWEVER...THE LEADING EDGE OF A NEW CROSS-EQUATORIAL 
SW SWELL TRAIN WITH PERIODS IN EXCESS OF 20 SECONDS WILL HELP 
KEEP SEAS TO 8 FT.

A WEAKENING COLD FRONT STRETCHES FROM 30N134W TO 25N140W. IT IS 
FORECAST TO DISSIPATE BY THIS EVENING. WINDS OF 20 KT OR LESS 
AND SEAS LESS THAN 8 FT ARE ASSOCIATED WITH THIS FRONT. 

THE PRESSURE GRADIENT WILL INCREASE OVERNIGHT THU NIGHT OFF THE 
COAST OF BAJA CALIFORNIA IN RESPONSE TO THE REORGANIZING 
SUBTROPICAL HIGH AND INCREASED TROUGHING OVER THE INTERMOUNTAIN 
WESTERN U.S. THIS WILL BRING A FRESH TO STRONG N-NW BREEZE TO NE 
FORECAST WATERS OFF BAJA CALIFORNIA NORTE...WITH SEAS BUILDING 
TO AROUND 12 FT BY FRI AFTERNOON.  

$$
GR