000
AXPZ20 KNHC 132157
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED MAY 13 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...ITCZ...

THE ITCZ AXIS IS ALONG POINTS 08N78W TO 08N90W TO 10N105W TO 
05N133W TO 05N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOTED WITHIN 120 NM EITHER SIDE OF LINE FROM 
06N77W TO 08N95W TO 14N101W AND ALSO WITHIN 150 NM OF 07N104W. 
ISOLATED MODERATE AND STRONG CLUSTERS WERE NOTED FROM 07N TO 13N 
BETWEEN 110W AND 135W. 

...DISCUSSION...

ALOFT...AN UPPER CYCLONE IS NEAR 24N136W WITH A TROUGH E TO 
ANOTHER CYCLONE AT 18N122W. A BROAD UPPER TROUGH IS ALONG 
32N110W TO 27N125W. AN UPPER ANTICYCLONE IS CENTERED NEAR 
27N132W SURROUNDED BY UPPER MOISTURE WITHIN 180 NM OF ITS 
CENTER. OTHERWISE DRY UPPER AIR IS INDICATED N OF 14N W OF
118W AND ALONG THE TROUGH N OF 26N BETWEEN 118W AND 104W. 

A SECOND UPPER ANTICYCLONE IS NEAR 12N99W WITH A RIDGE EXTENDING 
N NE TO OVER CENTRAL LOUISIANA. AN UPPER RIDGE EXTENDS W ACROSS 
VENEZUELA AND COLOMBIA OVER THE TROPICAL E PACIFIC TO A SHARP 
CREST AT 09N84W. AN BROAD UPPER TROUGH EXTENDS SW ACROSS THE NW 
CARIBBEAN ALONG 16N86W TO 09N91W SEPARATING THE TWO 
ANTICYCLONES. UPPER DIFFLUENCE IS ENHANCING CONVECTION ALONG THE 
ITCZ BETWEEN 96W AND 112W WITH THE DEBRIS MOISTURE ADVECTED N 
OVER OLD MEXICO BETWEEN 94W AND 104W AND SPILLING OVER THE UPPER 
LEVELS OF THE WESTERN GULF OF MEXICO. CONVECTION ALONG THE ITCZ 
IS ALSO ENHANCED BETWEEN 96W AND 81W WITH MOST OF THE DEBRIS 
MOISTURE SPREADING NE ACROSS COSTA RICA AND PANAMA AND THE SW 
CARIBBEAN TURNING E AND CONTINUING E ACROSS THE ENTIRE E 
CARIBBEAN.
       
AT THE LOW LEVELS...A RIDGE EXTENDS SE ALONG 32N135W TO 17N105W. 
NORTHERLY WINDS TO 20 KT ARE NE OF THE RIDGE OVER THE AREA N OF 
24N BETWEEN 125W AND 118W. THE GRADIENT IS EXPECTED TO TIGHTEN 
FURTHER INCREASE THE N WINDS TO 20 TO 25 KT WITH SEAS BUILDING 
TO 12 FT WITH CONDITIONS SPREADING S TO ALONG 22N ON FRI. A 
SMALL AREA OF NE TRADES TO 20 KT ARE OBSERVED S OF THE RIDGE 
FROM 09N TO 15N W OF 125W AND EXPECTED TO DIMINISH THU.      

GULF OF PAPAGAYO GAP...NE WINDS IN THE W CARIBBEAN ARE 
OCCASIONALLY SURGING THROUGH THE GULF OF PAPAGAYO AT 20 
KT...ESPECIALLY BEGINNING LATE AT NIGHT TO MID MORNING. THESE 
CONDITIONS SHOULD DIMINISH THU.

$$
NELSON