000
AXPZ20 KNHC 100236
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
0405 UTC FRI MAY 10 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 AXIS EXTENDS FROM 09N78W TO 08N94W WHERE LOW 
LEVEL WINDS SUGGEST A TRANSITION TO ITCZ WHICH EXTENDS TO 
10N120W TO 07N130W TO BEYOND 07N140W. SCATTERED MODERATE 
CONVECTION WAS NOTED WITHIN 120 NM S OF MONSOON TROUGH BETWEEN 
78W AND 83W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION 
WAS NOTED WITHIN 90 NM N AND 20 NM S OF ITCZ BETWEEN 120W AND 
126W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS 
NOTED WITHIN 60 NM N OF ITCZ BETWEEN 132W AND 138W.

...DISCUSSION...

HIGH PRESSURE IS CENTERED N OF THE AREA WITH SURFACE RIDGE 
EXTENDING SE TO NEAR 20N110W AND SW TO BEYOND 25N140W. LATEST 
SCATTEROMETER DATA INDICATE GENTLE TO MODERATE TRADE WIND FLOW 
GENERALLY S OF 20N W OF 110W. FRESH NW TO N WINDS TO 20 KT WERE 
NOTED JUST W OF THE BAJA CALIFORNIA PENINSULA WHERE THERE IS A 
LOCALLY TIGHTER PRESSURE GRADIENT BETWEEN THE RIDGE AND LOW 
PRESSURE OVER MAINLAND MEXICO. HIGH PRESSURE WILL BUILD SLIGHTLY 
OVER THE NEXT 24 HOURS...AND WILL FRESHEN TRADEWIND FLOW N OF 
THE ITCZ W OF 130W THROUGH SAT. THE FRESHENED WINDS WILL 
INCREASE SEAS TO 8 FT OVER THIS AREA FRI AND SAT. 
 
LOOKING AHEAD...FORECAST MODEL RUNS HAVE BEEN DEPICTING AN 
INTERESTING SCENARIO TO FOLLOW OVER THE NEXT WEEK. THE KEY 
FEATURE TO WATCH IS A CARIBBEAN WAVE/TROUGH... AND ITS 
INTERACTION WITH THE TOPOGRAPHY OF CENTRAL AMERICA AND THE 
MONSOON TROUGH IN THE EASTERN PACIFIC. THE SCENARIO DEPICTED BY 
MODEL GUIDANCE HAS THE WAVE/TROUGH IN THE CARIBBEAN SHIFTING 
WESTWARD ACROSS CENTRAL AMERICA INTO THE FAR E PACIFIC THIS 
WEEKEND. GAP WINDS THROUGH THE GULF OF PAPAGAYO ASSOCIATED WITH 
THE WAVE/TROUGH WILL INTERACT WITH THE MONSOON TROUGH AND HELP 
TO INCREASE LOW LEVEL VORTICITY WITHIN THE MONSOON TROUGH LATE 
THIS WEEKEND. GAP WINDS THROUGH THE GULF OF TEHUANTEPEC WILL BE 
INDUCED EARLY NEXT WEEK BY THE WAVE/TROUGH AS IT SHIFTS WESTWARD 
ACROSS THE FAR E PORTION OF THE NE PACIFIC WATERS. THIS GAP WIND 
EVENT WILL HELP FURTHER INCREASE LOW LEVEL VORTICITY WITHIN THE 
MONSOON TROUGH EARLY NEXT WEEK. LATEST MODEL GUIDANCE SUGGESTS 
THAT THE BACKGROUND ENVIRONMENT WILL BECOME MORE FAVORABLE FOR 
BAROTROPIC GROWTH OF THE DISTURBANCE WITHIN THE MONSOON TROUGH 
EARLY NEXT WEEK. THIS SYNOPTIC SCENARIO HAS BEEN SHOWN TO 
OCCASIONALLY PRODUCE TROPICAL CYCLOGENESIS IN THE TROPICAL 
EASTERN PACIFIC AND WILL BE INTERESTING TO WATCH THE EVOLUTION 
CURRENTLY BEING DEPICTED...TO VARYING DEGREES...BY ALL OF THE 
GLOBAL MODELS.  
  
$$
AL