000
AXPZ20 KNHC 100350
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN MAY 10 2009

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 
0300 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG A LINE FROM  
06N77W TO 06N105W TO 07N140W. SCATTERED MODERATE WITH ISOLATED 
STRONG CONVECTION IS WITHIN 60 NM OF THE POINT 06N109.5W. 
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 120 NM OF THE 
POINT 06N115W. SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION IS WITHIN THE AREA 120 NM EITHER SIDE OF THE ITCZ 
AXIS FROM 134W TO 140W.

...DISCUSSION...
DEEP LAYER TROUGH IS OVER THE EASTERN PART OF THE AREA WITH AN 
AXIS ALONG A LINE FROM EASTERN YUCATAN PENINSULA AND BELIZE TO 
THE ITCZ NEAR 100W. TO THE EAST OF THE AXIS DIFFLUENT FLOW IN 
THE MIDDLE AND UPPER LEVELS IS ENHANCING ITCZ CONVECTION WITH 
AREAS OF MULTI LEVEL CLOUDS AND DEEP LAYER MOISTURE FLOWING 
NORTHEAST OVER CENTRAL AMERICA. TO THE WEST OF THE AXIS TO 101W 
THE MIDDLE AND UPPER LEVELS ARE DRY AND MOSTLY CLOUD FREE WITH 
SUBSIDENCE EXCEPT FOR ISOLATED CONVECTIVE CELLS THAT EXIST IN 
SPITE OF THE SUBSIDENCE DUE TO THE INSTABILITY OF THE TROUGH 
WITH COLD AIR ALOFT. CONVECTION IS ALSO VERY ACTIVE OVER CENTRAL 
AMERICA NEAR THE TROUGH AXIS WITH THE DAYTIME HEATING FROM BELOW 
TRIGGERING CONVECTION.

A LARGE DEEP LAYER CYCLONIC CIRCULATION IS LOCATED NEAR 20N118W. 
THE CIRCULATION COVERS THE AREA NORTH OF THE ITCZ TO NEAR 28N 
FROM ABOUT 105W TO 130W. THE AREA W OF 105W TO A LINE FROM 
25N112W TO THE ITCZ NEAR 120W IS MOIST SOUTHERLY FLOW WITH AREAS 
OF MULTI LEVEL CLOUDS AND A COUPLE OF AREAS OF ENHANCED 
CONVECTION...ONE AREA IN THE ITCZ NEAR 115W AND SMALLER AREAS 
EMBEDDED IN THE FLOW. 

REMAINDER OF THE MIDDLE AND UPPER LEVELS IS BROAD ANTICYCLONIC 
FLOW.

MODERATE SURFACE RIDGE IS NORTH OF 17N W OF 120W ELSEWHERE NORTH 
OF THE ITCZ WEST OF 110W WEAK SURFACE RIDGE IS ANALYZED. A 
TROUGH IS ANALYZED WITHIN THE ITCZ ALONG 112W FROM 12N TO 04N 
WHERE ACTIVE CONVECTION IS LOCATED IN THE ITCZ. REMAINDER OF THE 
SURFACE IS ANALYZED AS A BROAD TROUGH.
 
GAP WINDS...THE RETURN OF STRONG TRADE WINDS IN THE WESTERN 
CARIBBEAN WILL ALLOW FOR EASTERLY FLOW TO BLEED THROUGH NORTHERN 
COSTA RICA AND SOUTHERN NICARAGUA THROUGH THE GULF OF 
PAPAGAYO...WITH OCCASIONAL 20 KT WINDS EXPECTED BY SUN MORNING. 

$$
LL