000
AXPZ20 KNHC 092142
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT MAY 09 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 
2100 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG A LINE FROM 06N77W 
TO 06N140W.  SCATTERED MODERATE CONVECTION IS WITHIN 90 NM OF 
THE POINT 05N95W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM 
OF THE POINT 06N98W. SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION IS WITHIN 60 NM OF THE POINT 05.5N108.5W. SCATTERED 
MODERATE CONVECTION IS WITHIN 60 NM OF 07.5N112W. SCATTERED 
MODERATE TO STRONG CONVECTION IS WITHIN 60 NM OF 05.5N114.5W. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN THE 
AREA 120 NM EITHER SIDE OF THE ITCZ AXIS FROM 133W TO 138W.

...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 IS 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.

A LARGE DEEP LAYER CYCLONIC CIRCULATION IS LOCATED NEAR 20N117W. 
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 AREA 
OF MULTI LEVEL CLOUDS AND A COUPLE OF AREAS OF ENHANCED 
CONVECTION...ONE AREA IN THE ITCZ NEAR 112W AND ANOTHER AREA 
NORTH OF THE ITCZ FROM 10N TO 15N BETWEEN 105W AND 110W. 

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 110W FROM 12N TO 05N. 
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