000
AXPZ20 KNHC 100328
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE MAY 10 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...ITCZ...
THE AXIS IS ANALYZED FROM 09N85W TO 05N131W. SCATTERED MODERATE 
AND ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 180 NM EITHER 
SIDE OF A LINE FROM 08N83W TO 05N91W. AN EMBEDDED SURFACE LOW IS 
NEAR 09N86W AND IS ESTIMATED AT 1005 MB. ISOLATED MODERATE TO 
STRONG CONVECTION IS FLARING IN SMALL CLUSTERS FROM 06N TO 11N 
BETWEEN 93W TO 110W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS OBSERVED WITHIN THE AREA BOUNDED BY 06N TO 11N 
BETWEEN 110W AND 120W WITH AN EMBEDDED SURFACE LOW AT 08N116W 
ESTIMATED AT 1009 MB.  

...DISCUSSION...
AN UPPER LEVEL CYCLONE HAS CUT OFF NEAR 23N141W DRIFTING W AND 
SURROUNDED BY UPPER MOISTURE EXTENDING ABOUT 600 NM OVER THE E 
SEMICIRCLE. AN UPPER LEVEL LONG WAVE TROUGH EXTENDS S ALONG THE 
WESTERN CONUS CONTINUING S OVER THE PACIFIC TO BASE AT 21N117W. 
A SHORTWAVE TROUGH HAS ROTATED SE INTO THE LONGWAVE AND IS 
DIFFICULT TO DISTINGUISH FROM THE LARGER PATTERN. AN UPPER  
ANTICYCLONE IS JUST N OF THE AREA NEAR 33N144W. THE COMBINED 
UPPER LEVEL NORTHERLY FLOW W OF THE TROUGHS AND E OF THE 
ANTICYCLONE PUSHED A BAND OF UPPER MOISTURE S INTO THE 
DISCUSSION AREA...NOW WITHIN 60 NM OF POINTS 30N140W TO 28N124W 
WITH THIS BAND CONTINUING NE THROUGH THE LONGWAVE TROUGH AND 
ACROSS SE ARIZONA AND WESTERN NEW MEXICO FUELING INTO A 
CONVECTIVE LINE NOW DISSIPATING OVER THE CENTRAL CONUS. 

AN UPPER LEVEL ANTICYCLONE IS OVER THE DEEP TROPICAL PACIFIC AT 
06N131W AND ANOTHER IS CENTERED NEAR 07N117W. THE ASSOCIATED 
UPPER ANTICYCLONIC FLOW DOMINATES THE UPPER LEVELS S OF 20N 
BETWEEN 105W AND 132W...WITH THE ASSOCIATED DIFFLUENCE ENHANCING 
CONVECTION ALONG THE ITCZ AS PREVIOUSLY DESCRIBED. THE RESULTANT 
DEBRIS MOISTURE SPREADS N AND MERGES WITH A 600 NM WIDE TROPICAL 
MOISTURE PLUME...ORIGINATING IN THE CENTRAL PACIFIC...WITH THE 
MOISTURE PLUME CONTINUING NE OVER THE BAJA CALIFORNIA PENINSULA 
S OF 28N...AND ACROSS OLD MEXICO N OF 20N...AND ACROSS MOST OF 
TEXAS...WITH SOME OF THE MOISTURE TURNING E ACROSS THE WESTERN 
GULF OF MEXICO. ADDITIONAL MOISTURE FROM AFTERNOON CONVECTION 
OVER EASTERN OLD MEXICO IS ALSO CAUGHT UP IN THIS SOUTHWESTERLY 
UPPER FLOW. 

AN AREA OF UPPER DRY AIR IS NOTED OVER THE TROPICS S OF 18N 
BETWEEN 106W AND 96W AND IS SUPPRESSING CONVECTION TO A FEW 
SMALL CLUSTERS PREVIOUSLY MENTIONED ALONG THE ITCZ BETWEEN 93W 
AND 110W.

AN UPPER LEVEL ANTICYCLONE IS ESTIMATED NEAR 07N90W WITH A RIDGE 
EXTENDING NW TO WELL BEYOND 32N94W. THE ASSOCIATED UPPER 
DIFFLUENCE IS ENHANCING THE ITCZ CONVECTION PREVIOUSLY DESCRIBED 
TO THE E OF 95W. THE DEBRIS MOISTURE IS SPREADING N ACROSS THE 
CENTRAL AMERICA...THEN TURNING E ACROSS THE CENTRAL CARIBBEAN S 
OF 17N.

AT THE LOW LEVELS A SURFACE RIDGE EXTENDS ROUGHLY ALONG 30N140W 
TO 12N100W WITH THE RIDGE EXPECTED TO SHIFT EASTWARD AND EXTEND 
FROM 32N133W TO 12N104W WED NIGHT. THE GRADIENT NE OF THE RIDGE 
IS CURRENTLY SUPPORTING 15-20 KT NORTHERLY WINDS OVER THE 
PACIFIC WATERS WITHIN 150 NM W OF THE BAJA CALIFORNIA PENINSULA. 
EXPECT THESE CONDITIONS TO CONTINUE THROUGH TUE...THEN DIMINISH 
AS THE RIDGE SHIFTS EASTWARD ON WED. NE TRADES SW OF THE RIDGE 
ARE AT 15 FROM 10N TO 22N W OF 127W. THESE TRADES WILL 
STRENGTHEN SOMEWHAT ON WED IN THE AREA FROM 07N TO 12N W OF 
127W.   

CROSS EQUATORIAL SOUTHERLY SWELL RESULTING IN SEAS TO 8 FT WILL 
CONTINUE OVER THE DEEP TROPICS S OF 098N BETWEEN 105W AND 130W 
THROUGH TUE THEN SUBSIDE TO LESS THAN 8 FT WED.

$$
NELSON