000
AXPZ20 KNHC 261531
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 UTC THU MAR 12 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1515 UTC. 

...SPECIAL FEATURES...                                          
GALE WARNING...                                                 
A STRONG COLD FRONT WILL MOVE INTO THE GULF OF MEXICO THIS 
AFTERNOON WITH GALE FORCE WINDS IN THE GULF OF MEXICO STARTING 
FRI MORNING. THIS WILL TIGHTEN THE PRESSURE GRADIENT ACROSS 
SOUTHERN MEXICO RESULTING IN STRONG NORTHERLY WINDS THROUGH THE 
GULF OF TEHUANTEPEC BY FRI MORNING. NORTHERLY WINDS WILL 
INCREASE RAPIDLY TO GALE FORCE BY FRI AFTERNOON WITH SEAS 
BUILDING TO 17 FT BY EARLY SAT. WINDS WILL DECREASE TO BELOW 
GALE FORCE SAT AFTERNOON WITH STRONG WINDS CONTINUING INTO SUN. 
SEAS WILL SUBSIDE WITH THE END OF THE GALE FORCE WINDS. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
 
SURFACE TROUGH EXTENDS FROM 6N88W TO A 1012 MB LOW NEAR 5N97W 
WHERE THE MONSOON TROUGH BEGINS AND CONTINUES ALONG 4N107W TO 
5N113W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 8N135W TO 
7N140W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 5N-12N 
BETWEEN 116W-129W. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION IS WITHIN 120 NM S OF SURFACE TROUGH BETWEEN 90W-
93W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM OF LOW IN NW 
SEMICIRCLE AND WITHIN 90 NM EITHER SIDE OF MONSOON TROUGH 
BETWEEN 100W-106W.   

...DISCUSSION...                                                

AN UPPER TROUGH IS JUST W OF THE FAR NW PORTION OF THE 
DISCUSSION AREA. THIS UPPER TROUGH IS SUPPORTING A COLD FRONT 
THAT WILL ENTER THE AREA THIS AFTERNOON WITH SWELLS PUSHING IN 
THIS EVENING. THIS FRONT WILL MOVE SE TONIGHT AND DISSIPATE FRI 
MORNING. A BROAD UPPER RIDGE IS S OF 27N E OF 130W. AN UPPER 
TROUGH IS NE OF THE UPPER RIDGE N OF 27N E OF 120W TO OVER SW 
CONUS AND NW MEXICO. IN THE DEEP TROPICS AN UPPER RIDGE IS 
ANCHORED NEAR 7N107W WITH AN UPPER TROUGH TO THE E EXTENDING 
FROM CENTRAL AMERICA NEAR 14N92W TO 6N96W. THIS UPPER TROUGH IS 
SUPPORTING THE 1012 LOW IN THE MONSOON TROUGH SECTION ABOVE. A 
SURFACE RIDGE COVERS THE AREA N OF 15N W OF 115W TO THE COLD 
FRONT JUST NW OF THE AREA WITH A 1024 MB HIGH NEAR 35N129W.  

CURRENTLY THE ENTIRE AREA IS VOID OF STRONG WINDS WITH SOME AREA 
SWELLS BEING GENERATED. THE SURFACE RIDGE IS PRODUCING A WEAK 
PRESSURE GRADIENT WITH SWELLS TO 8 FT FROM 11N TO 15N BETWEEN 
126W TO 133W THAT WILL SUBSIDE THIS AFTERNOON THEN RETURN FRI 
AFTERNOON THROUGH THE WEEKEND. CROSS EQUATORIAL SWELLS TO 9 FT 
ARE REACHING TO 12N BETWEEN 92W AND 124W. THESE SEAS WILL 
CONTINUE TO SPREAD NORTHWARD AS WELL AS E OF THE GALAPAGOS 
ISLANDS FRI AND WILL SUBSIDE BY SAT AFTERNOON. A WAVE PERIOD OF 
18 TO 20 SEC EXTENDS FROM BAJA CALIFORNIA SUR TO THE EQUATOR. 
THIS PERIOD TRAIN WILL CONTINUE UP THE BAJA COAST THROUGH FRI 
WHILE THE AREA S OF BAJA RELAXES TO 16 TO 18 FT TO THE EQUATOR. 

$$ 
PAW