000
AXPZ20 KNHC 191505
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE AUG 19 2008

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1430 UTC.

...TROPICAL WAVES...

NONE.

...ITCZ...

ITCZ IS ALONG THE LINE...10N86W TO 09N96W TO 11N112W TO 11N128W 
TO 09N140W. SCATTERED MODERATE TO STRONG CONVECTION CAN BE FOUND 
S OF THE ITCZ WITHIN 120 NM OF 07N E OF 85W. SCATTERED MODERATE 
WITH ISOLATED STRONG CONVECTION CAN ALSO BE FOUND WITHIN 90 NM N 
AND 120 NM S OF THE ITCZ AXIS BETWEEN 125 AND 133W AS WELL AS 
WITHIN 300 NM S AND 150 NM N OF THE ITCZ AXIS BETWEEN 87W AND 
112W.

...DISCUSSION...

LOW...REMNANT OF ISELLE...18N120W 1009 MB MOVING SW 5-10 KNOTS. 
WELL DEFINED LOW LEVEL CIRCULATION. SHEAR DUE TO STRONG E FLOW 
ALOFT HAS PREVENTED CONVECTION TO ORGANIZED AROUND THE CENTER. 
CONVECTION IN THE WESTERN QUADRANT HAS CEASED FOR THE MOMENT... 
WITH SCATTERED MODERATE DEBRIS WITHIN 60 NM OF THE POINT 
18N122W. 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 24N138W.  
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. OVERCAST 
STRATOCUMULUS ARE WITHIN THIS AREA NORTH OF A LINE FROM 22N129W 
NE TO 28N115W. ELSEWHERE WITHIN THE TROUGH AREA PATCHES OF 
BROKEN TO OVERCAST STRATOCUMULUS ARE OBSERVED IN THE LOWER 
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 120 NM OF 
THE COAST BETWEEN 20N AND 23N. 

SIMILARLY...WEAK LOW TO MID LEVEL TROUGHING NEAR 90W N OF 13N 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 
WITHIN 120 NM OF THE COAST BETWEEN 88W AND 93W AS A RESULT.

LARGE LONG PERIOD SLY SWELLS MOVE ACROSS EQUATOR INTO E PAC S OF 
05N BEGINNING TODAY AND LASTING THROUGH AT LEAST 48 HOURS.

$$
SCHAUER CLARK