000
AXPZ20 KNHC 110930
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1005 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 09N83W TO 08N91W TO 10N101W THEN 
TRANSITIONS TO AN ITCZ WHICH EXTENDS WEST TO 10N110W TO 06N140W. 
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 60 NM OF THE 
ITCZ AXIS BETWEEN 109W AND 135W.

...DISCUSSION...

1028 MB HIGH PRES CENTERED NEAR 31N130W. PRES GRADIENT BETWEEN 
THE HIGH AND LOWER PRESSURE NEAR THE ITCZ MAINTAINING MODERATE 
TO FRESH TRADES N OF THE ITCZ TO 18N AND W OF 115W. THIS IS 
HELPING TO INCREASE CONVERGENCE INTO THE ITCZ AND PRODUCE THE 
ACTIVE CONVECTION ALONG THE ITCZ AS NOTED ABOVE. GENTLE TO 
MODERATE WINDS PREVAIL ELSEWHERE ACROSS THE FORECAST AREA. WITH 
WINDS GENERALLY 20 KT OR LESS...AND NO SIGNIFICANT SWELL MOVING 
THROUGH...SEAS REMAIN 5 TO 7 FT ACROSS MOST OF THE REGION. A 
WEAK LATE SEASON FRONT APPROACHING NW PART OF DISCUSSION AREA 
TONIGHT AND SUN WILL BECOME DIFFUSE AND WEAKEN INTO A TROUGH. 
THE SURFACE HIGH PRESSURE RIDGE WILL WEAKEN TONIGHT AS THIS 
BOUNDARY APPROACHES...THEN A STRONGER RIDGE WILL BUILD EASTWARD 
SUN AND MON BEHIND THE FRONTAL TROUGH. 

A TROUGH IN THE FAR SW CARIBBEAN WILL SLOWLY 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 GREAT DEAL OF UNCERTAINTY 
IN THE GLOBAL MODELS REGARDING THE STRENGTH OF THIS LOW. 
  
$$
MUNDELL