000
AXPZ20 KNHC 090944
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1005 UTC THU MAY 09 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 
0830 UTC.

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

MONSOON TROUGH AXIS EXTENDS FROM 07N74W TO 05N78W TO 08.5N84W TO 
07N91W...THEN TRANSITIONS TO ITCZ...CONTINUING ON TO 08N104W TO 
06N112W TO 08N124W TO BEYOND 07N140W. SCATTERED TO NUMEROUS 
STRONG CONVECTION NOTED ALONG THE COLOMBIAN COAST FROM 02N TO 
06.5N E OF 80W. SCATTERED MODERATE CONVECTION NOTED WITHIN 180 
NM N AND 210 NM S OF ITCZ AXIS W OF 135W.

...DISCUSSION...

A RELATIVELY WEAK RIDGE OF HIGH PRESSURE PREVAILS ACROSS THE 
WATERS W OF 110W...CENTERED ON A PAIR OF 1023 MB HIGHS AT 
26N127W AND 30N134W RESPECTIVELY. THE LATEST OBSERVATIONS 
INDICATE MAINLY GENTLE TO LIGHT WINDS PREVAIL OVER THE FORECAST 
AREA...EXCEPT N OF THE ITCZ TO 15N W OF 130W...WHERE THE 
PRESSURE GRADIENT IS LOCALLY TIGHTER AND NE TRADES 15-20 KT  
PREVAIL. SEAS REMAIN BELOW 8 FT OVER THE ENTIRE FORECAST AREA. 
THE RIDGE WILL CONTINUE TO BUILD OVER THE NEXT 48 HOURS WHICH 
WILL INCREASE COVERAGE OF THE MODERATE TO FRESH TRADES OVER THE 
W PART OF THE AREA N OF THE ITCZ. THE LARGER COVERAGE OF FRESH 
TRADES WILL INCREASE SEAS TO 8 FT OVER THIS AREA THU AND FRI.  

LOOKING AHEAD...A COMPLEX SYNOPTIC SITUATION HAS HELPED DEVELOP 
A CARIBBEAN WAVE/TROUGH IN THE CENTRAL CARIBBEAN WATERS ALONG 
79W-80W. FORECAST MODELS ARE CURRENTLY DEPICTING AN INTERESTING 
SCENARIO TO FOLLOW OVER THE NEXT WEEK. THE KEY FEATURE TO WATCH 
IS THE WAVE/TROUGH AND HOW IT INTERACTS WITH THE MONSOON TROUGH 
IN THE E PACIFIC...AND GAP WIND FLOW THROUGH THE TOPOGRAPHY OF 
CENTRAL AMERICA THROUGH THE GULFS OF PAPAGAYO AND TEHUANTEPEC. 
THE LATEST 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 
WITH AND BEHIND 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 ALSO 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.  
  
$$
STRIPLING/AL