000
AXPZ20 KNHC 102148
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE APR 10 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

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

THE MONSOON TROUGH IS ALONG 01N93W TO 01N102W TO 03N110W. THE 
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 03N110W TO 
01N117W TO 03N127W TO 02N134W. SCATTERED MODERATE CONVECTION IS 
FROM 00N TO 03N BETWEEN 98W AND 104W...AND WITHIN 60 NM EITHER 
SIDE OF A LINE FROM 07N109W TO 04N120W. 

...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 45N133W TO 28N127W THEN S-SW OVER THE NORTHEASTERN PORTION 
OF THE DISCUSSION AREA TO 20N140W. A 1004 MB SURFACE LOW IS 
CENTERED NEAR 40N133W WITH A DISSIPATING COLD FRONT ENTERING THE 
AREA NEAR 32N123W TO 22N126W. WINDS ASSOCIATED WITH THIS FRONT 
REMAIN BELOW 20 KT AS SEAS 8 TO 11 FT IN NW SWELL...HIGHEST SEAS 
PRIMARILY FOUND WEST OF THE FRONTAL BOUNDARY. OTHERWISE SOUTH OF 
THE INFLUENCE OF THE UPPER LEVEL TROUGH WEST-SOUTHWESTERLY FLOW 
ALOFT DOMINATES BETWEEN THE TROUGH AND AN ANTICYCLONIC 
CIRCULATION CENTERED NEAR 05N122W. A 420 NM WIDE SWATH OF MIDDLE 
TO UPPER LEVEL MOISTURE IS NOTED ON WATER VAPOR IMAGERY 
STREAMING EAST-NORTHEAST FROM 12N140W TO 19N122W TO OVER THE 
BAJA CALIFORNIA PENINSULA AND NW MEXICO INTO THE U.S. DESERT 
SOUTHWEST. BENEATH THIS RELATIVELY MOIST AIRSTREAM SITS A SLOWLY 
WEAKENING 1019 MB HIGH CENTERED NEAR 19N122W. THIS RIDGE IS AN 
EXTENSION OF A STRONGER HIGH PRESSURE SITUATED NORTH OF THE 
HAWAIIAN ISLANDS AS A 1027 MB HIGH CENTERED NEAR 32N160W THAT 
CONTINUES TO BUILD WEST-SOUTHWEST.

ON THE SOUTHERN PERIPHERY OF THIS RIDGE...20 KT NE TRADES ARE 
OCCURRING FROM 04N TO 12N W OF 127W WITH SEAS IN THE RANGE OF 8 
TO 9 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 
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 DECIDED TO LEAVE IN THE 
FORECAST DUE TO POSSIBLE PEAK OVERNIGHT AND EARLY MORNING 
DRAINAGE FLOW.

$$

HUFFMAN