000
AXPZ20 KNHC 110309
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED APR 11 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

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

THE MONSOON TROUGH IS ALONG 03N103W TO 02N116W. THE 
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 02N116W TO 
04N131W TO 02N140W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS FROM 02N TO 05N BETWEEN 97W AND 103W. SCATTERED 
MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF A LINE FROM 
06N109W TO 04N121W.

...DISCUSSION...

A MIDDLE TO UPPER LEVEL TROUGH IS APPROACHING THE WEST COAST OF 
THE U.S. WITH TROUGH AXIS EXTENDING FROM WELL NORTH OF THE AREA 
NEAR 44N132W TO 28N124W THEN S-SW OVER THE NORTHWESTERN PORTION 
OF THE DISCUSSION AREA TO 20N140W. A 1005 MB SURFACE LOW IS 
CENTERED NEAR 39N132W WITH A SURFACE TROUGH ANALYZED FROM 
32N121W TO 22N124W. A SMALL AREA OF 20 KT NW WINDS IS LOCATED N 
OF 28N BETWEEN 130W AND 134W...HOWEVER MUCH OF THE REMAINDER OF 
THE AREA N OF 15N CONTAIN WINDS LESS THAN 20 KT WITH SEAS NOTED 
IN THE RANGE OF 8 TO 10 FT IN NW SWELL...HIGHEST SEAS PRIMARILY 
FOUND N OF 23N W OF 130W. OTHERWISE SOUTH OF THE INFLUENCE OF 
THE UPPER LEVEL TROUGH WEST-SOUTHWESTERLY FLOW ALOFT DOMINATES 
BETWEEN THE TROUGH AND AN ANTICYCLONIC CIRCULATION CENTERED NEAR 
06N121W. A 420 NM WIDE SWATH OF MIDDLE TO UPPER LEVEL MOISTURE 
IS NOTED ON WATER VAPOR IMAGERY STREAMING EAST-NORTHEAST FROM 
12N140W TO 19N120W TO OVER THE SOUTHERN BAJA CALIFORNIA 
PENINSULA AND NW MEXICO INTO THE U.S. DESERT SOUTHWEST. BENEATH 
THIS RELATIVELY MOIST AIRSTREAM LIES A SURFACE RIDGE EXTENDING 
FROM 17N105W TO 20N128W. THIS RIDGE IS AN EXTENSION OF A 
STRONGER HIGH PRESSURE AREA SITUATED NORTH OF THE HAWAIIAN 
ISLANDS AS A 1026 MB HIGH CENTERED NEAR 31N160W THAT CONTINUES 
TO BUILD EAST-SOUTHEAST.

ON THE SOUTHERN PERIPHERY OF THIS RIDGE...20 KT NE TRADES ARE 
OCCURRING FROM 04N TO 15N W OF 129W WITH SEAS IN THE RANGE OF 8 
TO 10 FT IN MIXED SW AND NW SWELL. THIS AREA OF TRADES IS 
FORECAST TO GRADUALLY EXPAND EASTWARD OVER THE NEXT 36 TO 48 
HOURS AS THE RIDGE SHIFTS SOUTH AND THEN WESTWARD THROUGH LATE 
THURSDAY MERGING WITH THE APPROACHING STRONGER CENTRAL PACIFIC 
RIDGE MENTIONED ABOVE.

N-NE WINDS ASSOCIATED WITH THE GULF OF TEHUANTEPEC AND 
DOWNSTREAM OF THAT REGION ARE EXPECTED TO PERSIST THROUGH 
11/1800 UTC AND TAPER OFF THEREAFTER BELOW 20 KT AS SURFACE 
RIDGING CURRENTLY OVER THE GULF OF MEXICO SHIFTS EAST AND SE 
RETURN FLOW RE-ESTABLISHES ITSELF. WINDS MAY DECREASE BELOW 20 
KT PRIOR TO TOMORROW AFTERNOON BUT LEFT IN THE FORECAST DUE TO 
POSSIBLE PEAK OVERNIGHT AND EARLY MORNING DRAINAGE FLOW.

$$

HUFFMAN