000
AXPZ20 KNHC 160249
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED MAY 16 2012

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 
0300 UTC.

...SPECIAL FEATURE...
TROPICAL STORM ALETTA CENTERED NEAR 11.7N 110.9W AT 16/0300 UTC 
MOVING WNW OR 285 DEG AT 9 KT. ESTIMATED MINIMUM CENTRAL PRES 
1003 MB. MAXIMUM SUSTAINED WINDS 40 KT GUSTS TO 50 KT. LITTLE 
CHANGE IN MOTION AND INTENSITY IS EXPECTED THE NEXT 24 HOURS. 
PLEASE REFER TO THE LATEST PUBLIC ADVISORY TCPEP1/WTPZ31 KNHC 
FOR MORE DETAILS. SCATTERED MODERATE TO STRONG CONVECTION IS 
WITHIN 150 NM NE SEMICIRCLE. ALETTA IS EXPECTED TO START TO 
WEAKEN IN ABOUT 24 HOURS AS GREATER VERTICAL SHEAR AND A MORE 
STABLE SURROUNDING ENVIRONMENT INHIBIT FURTHER DEVELOPMENT.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 10N85W TO 09N98W TO 13N108W... 
THEN RESUMES W OF TS ALETTA NEAR 08N110W TO TROUGH NEAR 06N125W. 
ITCZ EXTENDS FROM 05N127W TO 03N140W. SCATTERED MODERATE TO 
STRONG CONVECTION IS FROM 07N TO 11N BETWEEN 95W AND 108W. 
SCATTERED MODERATE CONVECTION IS WITHIN 45 NM OF 05N126W.

...DISCUSSION...
ACTIVE MONSOON TROUGH E OF 120W DOMINATES THE TROPICAL NE PACIFIC
THIS EVENING. IN ADDITION TO TS ALETTA CHURNING AWAY NEAR 111W A 
BROAD CYCLONIC CIRCULATION CENTERED AT 10N95W IS ACTING TO ANCHOR
AN UNUSUALLY ACTIVE START TO THE 2012 EAST PAC HURRICANE 
SEASON...WHICH OFFICIALLY BEGAN TUE. AN UPPER LEVEL ANTICYCLONE 
CENTERED NEAR 11N91W IS PROVIDING A FAVORABLE ENVIRONMENT FOR 
ACTIVE TSTMS EAST OF 113W. 

A SURFACE RIDGE EXTENDS SE FROM 1025 MB HIGH PRES NEAR 33N136W TO
AROUND 20N114W. A SURFACE TROUGH IS ANALYZED ALONG THE WEST COAST
OF MEXICO FROM 20N101W TO YUMA AZ. THE RESULTING PRES GRADIENT 
BETWEEN THE OCEANIC RIDGE AND THE CONTINENTAL TROUGH IS PRODUCING
AN AREA OF FRESH NW WINDS NEAR THE COAST OF BAJA CALIFORNIA N OF 
26N E OF 118W. THE PRES GRADIENT BETWEEN THE HIGH AND TS ALETTA 
IS ALSO PRODUCING AN AREA OF ENHANCED NE TRADES FROM 20N TO 23N 
BETWEEN 123W AND 129W. THE HIGH IS EXPECTED TO WEAKEN AND REMAIN 
NEARLY STATIONARY THROUGH WED. FRESH NW WINDS ARE EXPECTED TO 
REDEVELOP N OF 27N E OF 120W BY EARLY FRI. 

HIGH PRES BUILDING SOUTHWARD ALONG THE GULF COAST OF MEXICO WILL
INDUCE FRESH TO STRONG N-NE FLOW INTO THE GULF OF TEHUANTEPEC 
TONIGHT THROUGH EARLY FRI. ELSEWHERE OUTSIDE THE CLOSE PROXIMITY 
OF TS ALETTA...LIGHT TO MODERATE WINDS AND SEAS 7 FT OR LESS ARE 
EXPECTED THROUGH FRI.

$$
MUNDELL