000
AXPZ20 KNHC 091528
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

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

MONSOON TROUGH AXIS EXTENDS FROM 09N78W TO 09N92W THEN ITCZ TO 
09N100W TO 05N115W TO 07N130W TO 06N140W. NUMEROUS MODERATE TO 
SCATTERED STRONG CONVECTION WITHIN 120 NM OFF COAST OF COLOMBIA 
FROM 04N TO 07N. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION WITHIN 90 NM S OF ITCZ BETWEEN 100W AND 105W.

...DISCUSSION...

A WEAK MID TO UPPER LEVEL SHORT WAVE TROUGH CONTINUES TO PUSH 
EASTWARD INTO NORTHERN BAJA AHEAD OF A DEEP LAYER RIDGE BUILDING 
ALONG ROUGHLY 135W. A RELATED 1024 MB SURFACE HIGH IS CENTERED 
NEAR 27N127W. SCATTEROMETER DATA OVER THE PREVIOUS SEVERAL HOURS 
HAVE INDICATED GENTLE TO MODERATE TRADE WIND FLOW FROM 10N TO 
20N W OF 110W S OF THE RIDGE. A WEAK SURFACE TROUGH MAY BE 
FORMING OVER THE NORTHERN GULF OF CALIFORNIA AS THE SHORT WAVE 
TRANSIT ALOFT. AN OSCAT PASS FROM 0730 UTC INDICATED NW TO N 
WINDS TO 20 KT IN THE SLIGHTLY TIGHTER GRADIENT BETWEEN THE 
COAST AND THE HIGH PRES TO THE WEST. THE HIGH PRES WILL MAINTAIN 
MOSTLY MODERATE TRADE WIND FLOW ACROSS THE WATERS FROM 10N TO 
20N W OF 110W INTO SAT.
 
A LARGE AREA OF MODERATE TO STRONG CONVECTION IS NOTED ALONG THE 
COAST OF COLOMBIA. THIS IS IN PART NORMAL NOCTURNAL ACTIVITY 
THAT FLARES ALONG THE COAST...BUT IS BEING GREATLY ENHANCED BY A 
SHARP LONG WAVE UPPER TROUGH EXTENDING FROM FLORIDA TO PANAMA. 
THIS TROUGH IS ONE OF THE FACTORS RELATED TO A CARIBBEAN 
WAVE/TROUGH ALONG 79W/80W.

LOOKING AHEAD...FORECAST MODELS ARE CURRENTLY DEPICTING AN 
INTERESTING SCENARIO TO FOLLOW OVER THE NEXT WEEK. THE KEY 
FEATURE TO WATCH IS THE CARIBBEAN 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.  
  
$$
CHRISTENSEN/AL