000
AXPZ20 KNHC 200921
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI FEB 20 2009

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0915 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG THE LINE 07N78W 
TO 03N110W TO 04N120W TO 06N140W. SCATTERED MODERATE ISOLATED 
STRONG WITHIN 120 TO 180 NM N OF AXIS W OF 130W. 

...DISCUSSION...

RATHER SHARP MID-UPPER LEVEL TROUGH EXTENDS FROM A STRONG 
COMPLEX CUTOFF LOW CENTERED N OF THE WESTERN PART OF THE AREA 
NEAR 38N145W SW THROUGH THE NW CORNER OF THE AREA TO NEAR 
27N140W. STRONG UPPER LEVEL SUBSIDENCE WAS WRAPPING AROUND THE 
BASE OF THE TROUGH OVER THE FAR NW CORNER OF THE DISCUSSION 
AREA. ASSOCIATED MULTI LEVEL CLOUDS AND EMBEDDED CONVECTION IS N 
OF THE AREA. THE CUTOFF LOW AND TROUGH WILL CONTINUE THROUGH THE 
NEXT SEVERAL DAYS WITH THE TROUGH DIGGING THROUGH 48 HOURS THEN 
WEAKENING AND LIFTING OUT TO THE NE BEYOND 48 HOURS.

A BROAD FLAT MID-UPPER LEVEL RIDGE COVERS THE AREA S OF 25N W OF 
120W TO ALONG 150W. THE RIDGE WAS BUILDING NORTHWARD WITH TIME.
THE UPPER LEVEL FLOW WAS GENERALLY DIFFLUENT OVER THE S PORTION 
OF THE RIDGE TO ABOUT 15N WHICH WAS ENHANCING ITCZ CONVECTION 
BETWEEN 130W AND 140W AND RESULTING IN A PLUME OF MID-UPPER 
LEVEL MOISTURE ABOUT 480 NM EITHER SIDE OF A LINE FROM 15N140W 
TO 20N125W AND 240 NM EITHER SIDE OF THIS LINE TO BEYOND 
27N100W. A MID-UPPER TROUGH WAS LOCATED E OF THE RIDGE WITH AXIS
GENERALLY ALONG 110W AND EXTENDING DEEP INTO THE TROPICS. STRONG 
SUBSIDENCE/DRY AIR ALOFT WAS LOCATED WITHIN THE TROUGH AND 
ELSEWHERE OVER THE PACIFIC S OF 20N AND E OF 110W. 

SURFACE FRONTAL TROUGH IS OVER THE NORTHWEST PART OF THE AREA 
AND IS ASSOCIATED WITH THE MIDDLE AND UPPER LEVEL TROUGH AND 
CUTOFF. THE SURFACE TROUGH SHOULD CONTINUE THROUGH THE NEXT 
SEVERAL DAYS. OTHERWISE WEAK RIDGE IS NORTH OF 15N W OF 110W. 
REMAINDER OF THE AREA IS ANALYZED AS A BROAD SURFACE TROUGH 
CENTERED NEAR THE EQUATOR.

GAP NORTHEAST TO EAST WINDS IN AND WEST OF THE GULF OF PAPAGAYO 
OF 20 TO 25 KNOTS WILL INCREASE FURTHER OVER THE NEXT 18-24 
HOURS TO 20 TO 30 KT BEFORE DIMINISHING ON SATURDAY. GAP 
NORTHWESTERLY WINDS 20 TO 25 KT IN THE GULF OF CALIFORNIA WILL 
DIMINISH TO LESS THAN 20 KT WITHIN 24 HOURS. GAP NORTHERLY WINDS 
IN THE GULF OF TEHUANTEPEC REGION OF 20 KNOTS WILL BEGIN TONIGHT 
AND INCREASE RAPIDLY TO 20 TO 30 KNOTS FRIDAY THEN DIMINISH 
SATURDAY.

$$
COBB