000
AXPZ20 KNHC 070307
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU MAY 07 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 IS ALONG THE LINE...04N77W TO 
04N90W TO 07N105W TO 06N140W. SCATTERED MODERATE WITH ISOLATED 
STRONG CONVECTION IS WITHIN 60 NM OF THE POINT 04N90W. SCATTERED 
MODERATE CONVECTION IS WITHIN 60 NM OF THE POINT 04N94.5W. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 90 
NM OF THE POINT 06N109W. SCATTERED MODERATE CONVECTION IS WITHIN 
THE AREA FROM 06.5N TO 08N FROM 118W TO 122W.

...DISCUSSION...

IN THE MIDDLE LEVELS A BROAD RIDGE IS NORTH OF 20N. A TROUGH IS 
ALONG 110W SOUTH OF THE BAJA CALIFORNIA PENINSULA. A CUT OFF LOW 
IS LOCATED NEAR 18N138W. THE RIDGE WILL CHANGE LITTLE AND THE 
TROUGH WILL MOVE WEST ABOUT 4 DEGREES A DAY OR ABOUT 10 KNOTS. 
THE CUT OFF LOW WILL MOVE NORTHWEST ABOUT 10 KNOTS. IN THE UPPER 
LEVELS BOTH THE TROUGH AND THE CUT OFF LOW HAVE A LARGER 
AMPLITUDE. THE TROUGH IN THE UPPER LEVELS WILL DRIFT A LITTLE 
WEST AND BY THE WEEKEND STILL BE NEAR 115W. THE CUT OFF LOW IN 
THE UPPER LEVELS WILL REMAIN SMALL AND MOVE NORTH THEN NORTHEAST 
AND REACH THE SOUTHERN CALIFORNIA COAST LATE FRIDAY. A PLUME OF 
UPPER LEVEL MOISTURE EXTENDS OVER THE NORTHEAST SEMICIRCLE OF 
THE CUT OFF LOW OUT TO ABOUT 500 NM. FEW CLOUDS ARE ASSOCIATED 
WITH THIS FEATURE. 

TO THE EAST OF THE TROUGH SOUTHERLY MOIST FLOW IS OVER THE AREA 
NORTH OF THE ITCZ. ISOLATED AREAS OF CONVECTION ARE NOTED IN 
THIS AREA AND PATCHY CLOUDS ARE ALSO OBSERVED ADVECTING 
NORTHWARD TOWARD SOUTHERN MEXICO AND CENTRAL AMERICA. 

A MODERATE HIGH PRESSURE IS CENTERED NEAR 30N134W WITH A 
MODERATE RIDGE NORTH OF 10N WEST OF 105W. THE RIDGE IS FORECAST 
TO STRENGTHEN FROM THE NORTH IN THE NEXT SEVERAL DAYS. 
ASSOCIATED TRADES WILL CONTRACT NORTHWARD AS THE RIDGE BUILDS 
FROM THE NORTH. REMAINDER OF THE AREA IS ANALYZED AS A BROAD 
TROUGH.

$$
LL