000
AXPZ20 KNHC 240319
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE MAY 24 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 
0245 UTC.
 
...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED FROM 09N80W TO 
10N100W TO 10N111W TO 06N120W TO 05N140W. SCATTERED MODERATE 
CONVECTION IS FROM 06N TO 10N BETWEEN 81W AND 92W. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION IS FROM 08N TO 12N 
BETWEEN 94W AND 103W. SCATTERED MODERATE CONVECTION IS FROM 06N 
TO 11N BETWEEN 111W AND 113W...AND FROM 04N TO 07N BETWEEN 122W 
AND 134W.   

...DISCUSSION...
A WEAK UPPER TROUGH N OF 30N ALONG 115W IS OVER S 
CALIFORNIA...FOLLOWED BY A WEAK UPPER RIDGE N OF 30N ALONG 135W 
THAT WILL SHIFT E. AN ASSOCIATED 1030 MB SURFACE HIGH PRES WILL 
WEAKEN THROUGH TUE AS A MID TO UPPER LEVEL SHORT WAVE TROUGH 
WILL DIG EASTWARD NORTH OF 30N THROUGH WED. 20 KT NW TO N WINDS 
PERSIST OFF THE BAJA COAST BETWEEN THE HIGH PRES AND LOW PRES 
OVER NW MEXICO. SEAS TO 10 FT IN NW SWELL ARE NOTED BY SHIP 
OBSERVATIONS OFF THE NORTHERN BAJA COAST. THE WINDS WILL BRIEFLY 
DIMINISH BY WED AFTER THE HIGH PRES WEAKENS...BUT INCREASE AGAIN 
LATER IN THE WEEK AS NEW HIGH PRES BUILDS TO THE WEST.

SCATTEROMETER DATA SHOW AN AREA OF FRESH TRADE WINDS FROM 10N TO 
20N W OF 130W. THESE WINDS WILL DIMINISH IN AREAL EXTENT THROUGH 
MID WEEK AS THE HIGH PRES TO THE NORTH WEAKENS. AN ALTIMETER 
PASS FROM 19Z SHOWED SEAS TO 8 FT IN THE AREA OF THE FRESH TRADE 
WINDS. LOOKING AHEAD TO LATE IN THE WEEK...HIGH PRES WILL BUILD 
BEHIND THE SHORT WAVE TROUGH...ALLOWING TRADES TO INCREASE AGAIN.

FURTHER SOUTH...AN UPPER TROUGH EXTENDS FROM A CUT OFF UPPER 
CYCLONE NEAR 18N140W TO 10N135W. DIVERGENCE ALOFT NEAR THE 
TROUGH AXIS IS ENHANCING MODEST CONVECTION OVER THE ITCZ BETWEEN 
125W AND 135W. 

RECENT SCATTEROMETER DATA ALSO SHOWED A SMALL CIRCULATION 
EMBEDDED WITHIN THE ITCZ NEAR 10N111W...WHERE LIGHT TO MODERATE 
NE TRADES MEET MODERATE SW FLOW TO THE SOUTH OF THE ITCZ. A 
SMALL AREA OF SCATTERED MODERATE CONVECTION IS EXPECTED TO 
WEAKEN AS IT DRIFTS W THROUGH THE REMAINDER OF THE WEEK.

CLUSTERS OF MODERATE TO STRONG CONVECTION ARE PULSING MAINLY N 
OF THE ITCZ BETWEEN 93W AND 103W. THIS IS IN AN AREA OF 
DIVERGENCE ALOFT BETWEEN AN UPPER ANTICYCLONE NEAR 18N105W AND A 
SHARP UPPER TROUGH EXTENDING FROM THE NW CARIBBEAN THROUGH 
NORTHERN CENTRAL AMERICA TO NEAR 09N90W. MODERATE SW FLOW S OF 
THE ITCZ IS PROVIDING LOW LEVEL CONVERGENCE TO SUPPORT 
CONVECTIVE DEVELOPMENT. 

$$
FORMOSA