000
AXPZ20 KNHC 110232
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
0405 UTC SAT MAY 11 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 09N84W TO 08N90W TO 10N102W 
WHERE LOW LEVEL WINDS SUGGEST A TRANSITION TO ITCZ WHICH EXTENDS 
TO 10N110W TO BEYOND 06N140W. NUMEROUS MODERATE TO STRONG 
CONVECTION WAS NOTED WITHIN 120 NM N AND 60 NM S OF MONSOON 
TROUGH BETWEEN 84W AND 87W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WAS NOTED WITHIN 90 NM OF AXIS W OF 110W.

...DISCUSSION...

HIGH PRES 1028 MB IS CENTERED N OF THE AREA NEAR 32N128W. THE 
PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE AREA AND LOWER 
PRESSURE IN THE VICINITY OF THE ITCZ IS MAINTAINING MODERATE TO 
FRESH TRADES N OF THE ITCZ TO 20N AND W OF 110W AS DEPICTED BY 
THE LATEST SCATTEROMETER PASSES. THIS IS HELPING TO INCREASE 
CONVERGENCE INTO THE ITCZ AND PRODUCE THE ACTIVE CONVECTION 
ALONG THE ITCZ AS NOTED ABOVE. OTHERWISE MAINLY GENTLE TO 
MODERATE WINDS PREVAIL ACROSS THE FORECAST AREA. WITH WINDS 
GENERALLY 20 KT OR LESS...AND NO SIGNIFICANT SWELL MOVING 
THROUGH THE AREA...SEAS REMAIN BELOW 8 FT. A WEAK LATE SEASON 
FRONTAL BOUNDARY WILL REACH AS FAR AS 30N140W LATE SAT BEFORE 
BECOMING DIFFUSE AND LIFTING NE. THE SURFACE HIGH PRESSURE AND 
ASSOCIATED RIDGE WILL WEAKEN SAT INTO SUN AS THIS BOUNDARY 
APPROACHES...THEN BECOME ABSORBED INTO A STRONGER RIDGE BUILDING 
BEHIND THE FRONT. 

A TROUGH IN THE FAR SW CARIBBEAN WILL MOVE ACROSS CENTRAL 
AMERICA THIS WEEKEND. GAP WIND FLOW ASSOCIATED WITH THIS FEATURE 
WILL INTERACT WITH THE MONSOON TROUGH TO HELP INCREASE LOW LEVEL 
VORTICITY WITHIN THE MONSOON TROUGH. GAP WINDS THROUGH THE GULF 
OF TEHUANTEPEC WILL BE INDUCED MON AND TUE BY THE TROUGH AS IT 
SHIFTS FARTHER WEST. THIS WILL FURTHER INCREASE LOW LEVEL 
VORTICITY WITHIN THE MONSOON TROUGH TUE AND WED. IT IS LIKELY A 
LOW WILL DEVELOP ALONG THE MONSOON TROUGH AS A RESULT OF THESE 
INTERACTIONS...THOUGH THERE IS STILL A LOT OF UNCERTAINTY TO THE 
STRENGTH OF THE LOW. 
  
$$
AL