000
AXPZ20 KNHC 181455
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON AUG 18 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...09N84W TO 10N102W TO 12N112W TO 11N120W 
TO 09N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION 
IS WITHIN THE AREA 150 NM S OF THE AXIS AND 90 NM N OF AXIS W OF 
133W AND WITHIN 150 NM BETWEEN 107W AND 121W. SCATTERED MODERATE 
CONVECTION IS FOUND WITHIN 120 NM N OF THE AXIS AND 180 NM S OF 
THE AXIS BETWEEN 86W AND 121W.

...DISCUSSION...

LOW...REMNANT OF ISELLE...LOCATED NEAR 19N116W WITH CENTRAL 
PRESSURE 1009 MB AND MOVING SLOWLY TO THE W. THE LOW LEVEL 
CIRCULATION CONTINUES TO BE WELL DEFINED WITH AN ASCAT PASS AT 
0535 UTC SHOWING WINDS IN EXCESS OF 25 KT WITHIN 150 NM N 
SEMICIRCLE. AN AREA OF MODERATE TO STRONG CONVECTION CONTINUES 
TO SUSTAIN ITSELF W OF THE LOW CENTER WITHIN 60 NM OF 19N199W. 
EASTERLY SHEAR OVER THE LOW HAS DISPLACED THIS CONVECTION FROM 
THE CENTER AND THE REMNANT OF ISELLE IS EXPECTED TO DIMINISH 
OVER THE NEXT SEVERAL DAYS DUE TO THIS SHEAR AND COOLER SEA 
SURFACE TEMPERATURES AS IT MOVES W. CURRENTLY...UPPER LEVEL 
DIFFLUENCE IS GREATEST TO THE S OF THE ISELLE REMNANT WHERE 
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION CAN BE FOUND 
BETWEEN 08N AND 14N BETWEEN 110W AND 121W. WIDESPREAD CONVECTION 
WILL BE MORE LIKELY TO TRACK W WITH THIS REGION OF BETTER 
DEFINED UPPER LEVEL DIFFLUENCE AS OPPOSED TO THE SURFACE LOW 
CENTER OVER THE NEXT DAY OR TWO.

A MID TO UPPER LEVEL TROUGH OVER NW WATERS IS EXPECTED TO LIFT 
NE INTO THE W COAST BUT LEAVE BEHIND AN UPPER LEVEL LOW THAT 
WILL RETROGRADE W OF 140W TUE INTO WED. AS THE TROUGH LIFTS 
OUT...THE ANTICYCLONE OVER NW MEXICO SHOULD PUSH W THROUGH THE 
BAJA ALONG 25N...CARRYING THE STRONG E FLOW ON ITS S EDGE 
FARTHER W INTO THE PACIFIC PRIMARILY BETWEEN 10N AND 20N E OF 
120W. SHEAR DUE TO THIS RELATIVELY STRONG E FLOW SHOULD ACT TO 
INHIBIT CONVECTION OVER THIS REGION. WEAK MID LEVEL SHORTWAVE 
ENERGY PASSING ALONG THE E AND SE EDGE OF THE ANTICYCLONE OVER 
MAINLAND MEXICO SHOULD HELP TRIGGER CONVECTION...ESPECIALLY WITH 
AFTERNOON HEATING...WITH DEBRIS POTENTIALLY BEING PUSHED W UNDER 
THE DOMINANT NE STEERING FLOW TOWARD THE COAST.

$$
SCHAUER CLARK