000
AXPZ20 KNHC 192148
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE AUG 19 2008

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 
2115 UTC.

...TROPICAL WAVES...

NONE.

...ITCZ...

ITCZ IS ALONG THE LINE...11N86W TO 09N95W TO 12N110W TO 12N130W 
TO 10N140W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION CAN 
BE FOUND FROM 04N TO 09N BETWEEN 81W AND 105W...FROM 10N TO 13N 
BETWEEN 89W AND 91W...AND FROM 10N TO 12N BETWEEN 100W AND 105W. 

...DISCUSSION...

LOW...REMNANT OF ISELLE...18N120W 1010 MB MOVING SW 5 KT. SHEAR 
DUE TO STRONG E FLOW ALOFT HAS LIMITED CONVECTION AROUND THE 
CENTER...BUT SCATTERED MODERATE TO ISOLATED STRONG CONVECTION 
CAN CURRENTLY BE FOUND WITHIN 180 NM W QUADRANT. THE LOW SHOULD 
PERSIST THROUGH AT LEAST 48 HOURS BUT DEVELOPMENT OF THE LOW IS 
NOT EXPECTED.  

MIDDLE AND UPPER LEVEL TROUGH IS STRETCHED ACROSS THE NW WATERS. 
THE TROUGH IS CURRENTLY PINCHING OFF AN UPPER LOW NEAR 23N140W.  
THIS LOW IS EXPECTED TO RETROGRADE W OUT OF THE AREA AS THE 
PARENT TROUGH MOVES NE INTO NORTH AMERICA. THIS AREA IS DRY AND 
CLOUD FREE IN THE MIDDLE AND UPPER LEVELS. 

OTHERWISE...THE FLOW IN THE MIDDLE AND UPPER LEVELS IS DOMINATED 
BY LARGE ANTICYCLONE CENTERED OVER NORTHWESTERN MEXICO AND 
FORECAST TO MOVE W ALONG 25N OVER THE NEXT FEW DAYS. A WEAK LOW 
TO MID LEVEL TROUGH IN THE MOUTH OF THE GULF OF CA IS SUPPORTING 
LOW LEVEL MOISTURE CONVERGENCE. THIS TROUGH IS IN A REGION OF 
WEAKER UPPER LEVEL FLOW NEAR THE CENTER OF THE ANTICYCLONE. THIS 
ENVIRONMENT HAS BEEN CONDUCIVE FOR CONVECTION...WITH SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION FOUND WITHIN 210 NM OF 
THE COAST BETWEEN 20N AND 23N. 

SIMILARLY...WEAK LOW TO MID LEVEL TROUGHING NEAR 90W N OF 10N IS 
ALSO SUPPORTING LOW LEVEL CONVERGENCE. DEEPER MOISTURE IS IN 
PLACE HERE...BUT THERE IS MORE SHEAR IN THIS REGION DUE TO THE 
STRONGER E FLOW ON THE S EDGE OF THE ANTICYCLONE. CURRENTLY... 
THERE IS SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION N OF 
10N WITHIN 120 NM W OF 90W AS A RESULT.

AFTERNOON THUNDERSTORMS OVER CENTRAL AMERICA ARE CURRENTLY 
PUSHING W TOWARD THE COAST FROM 08N TO 15N UNDER THE STRONG 
EASTERLY UPPER TO MID LEVEL FLOW.  

LARGE LONG PERIOD SLY SWELLS MOVING ACROSS EQUATOR INTO E PAC S 
OF 07N TONIGHT AND LASTING THROUGH 48 HOURS.

$$
SCHAUER CLARK