000
AXPZ20 KNHC 102119
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN MAY 10 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 06N105W TO 04N125W TO 06N130W TO 06N140W. SCATTERED MODERATE 
TO STRONG CONVECTION IS WITHIN THE AREA FROM 05N TO 07N FROM 90W 
TO 97W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 150 NM 
OF THE POINT 06N114W. SCATTERED MODERATE TO STRONG CONVECTION IS 
WITHIN 60 NM OF THE POINT 03N117W. SCATTERED MODERATE TO STRONG 
CONVECTION IS WITHIN THE AREA FROM 03N TO 05N FROM 121W TO 127W.

...DISCUSSION...

DEEP LAYER TROUGH IS OVER THE EASTERN PART OF THE AREA EAST OF A 
LINE THAT EXTENDS FROM THE YUCATAN PENINSULA NEAR 20N90W TO THE 
ITCZ NEAR 106W. THE AREAS IS DIFFLUENT ALOFT AND SUPPORTS 
ENHANCED ITCZ CONVECTION MOSTLY IN THE ITCZ AND OVER THE DAYTIME 
HEATED AREAS OF CENTRAL AMERICA/ THE RESULTING MULTI LEVEL 
CLOUDS FROM THE CONVECTION IS ADVECTING NORTHWARD ACROSS MOST OF 
CENTRAL AMERICA. 

A LARGE CYCLONIC CIRCULATION IS CENTERED NEAR 20N119W AND COVERS 
AN AREA WEST OF 106W NORTH OF THE ITCZ TO A LINE ACROSS 
NORTHERN MEXICO FROM NEAR 30N105W TO 25N125W TO THE ITCZ NEAR 
125W. MOST OF THIS AREA IS DRY AND CLOUD FREE IN THE MIDDLE AND 
UPPER LEVELS EXCEPT FOR THE AREA EAST OF 115W WHERE MOIST 
SOUTHERLY FLOW IS OBSERVED. THE MOISTURE EMANATES FROM ENHANCE 
CONVECTION IN THE ITCZ NEAR 115W. THE CONVECTION IS SUPPORTED BY 
BOTH DIFFLUENT AIR ALOFT AND BY SURFACE CONVERGENCE ASSOCIATED 
WITH A SURFACE TROUGH THAT EXTENDS FROM 11N113W TO 03N119W. THIS 
MOIST AIR IS FLOWING ACROSS MOST OF MEXICO EXCEPT FOR THE PART 
SOUTH OF 20N AND FROM 100W TO THE TROUGH MENTIONED ABOVE. CLOUDS 
ARE NOT PRESENT IN THIS MOIST FLOW BUT CONVECTION IS DEVELOPING 
AS THE AIR FLOWS OVER THE SIERRA MADRE OCCIDENTAL. 

A SMALLER CYCLONIC CIRCULATION IS LOCATED BEAR 26N133W AND IS 
MOVING NORTH ABOUT 20 KT. LITTLE WEATHER IS ASSOCIATED WITH THIS 
FEATURE.

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

MODERATE SURFACE RIDGE IS NORTH OF 17N WEST OF 120W WITH A 
WEAKER RIDGE ELSEWHERE NORTH OF 11N WEST OF 105W. EXCEPT FOR THE 
SURFACE TROUGH MENTIONED ABOVE WEAK TROUGH IS ANALYZED 
ELSEWHERE.

EASTERLY GAP WINDS IN THE GULF OF PAPAGAYO REGION WILL CONTINUE 
TO OCCASIONALLY BE 20 KT THROUGH THE NEXT SEVERAL DAYS. HIGHER 
WINDS SPEEDS WILL GENERALLY BE DURING THE NIGHTTIME HOURS.

$$
LL