000
AXPZ20 KNHC 210345
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN SEP 21 2008

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 
0230 UTC.

...SPECIAL FEATURES...

LOW PRES NEAR 13N98W 1007 MB HAS THE POTENTIAL FOR DEVELOPMENT 
OVER THE NEXT FEW DAYS.  THIS LOW IS ATTACHED TO A TROPICAL WAVE 
ALONG 98W AND IS ASSOCIATED WITH A BROADER REGION OF CYCLONIC 
FLOW THAT HAS ACQUIRED MORE CONVECTION OVER THE PAST 24 HOURS.  
CURRENTLY...SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 
210 NM NE AND 60 NM NW QUADRANTS AND ANOTHER REGION OF SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION ASSOCIATED WITH THE 
COMPLEX CAN BE FOUND WITHIN 60 NM OF THE MEXICAN COAST BETWEEN 
97W AND 103W.  THIS SYSTEM IS EXPECTED TO SLOWLY MOVE 
NW...PARALLELING THE MEXICAN COAST...OVER THE NEXT FEW DAYS.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 84W MOVING W 20 KT. CONVECTION ASSOCIATED 
WITH THE WAVE LIES MAINLY TO ITS W OVER CENTRAL AMERICA AND 
WITHIN WITHIN 90 NM OF THE COAST OF PANAMA BETWEEN 84W AND 86W.

TROPICAL WAVE ALONG 98W IS DESCRIBED IN THE SPECIAL FEATURES 
SECTION ABOVE.

A TROPICAL WAVE ALONG 107W FROM 03N TO 16N IS MOVING W 5 KT. 
THIS WAVE IS LOCATED WITHIN THE WESTERN PERIPHERY OF THE BROAD 
REGION OF CYCLONIC FLOW NOTED IN THE SPECIAL FEATURES SECTION 
AND HAS NO SIGNIFICANT CONVECTION ASSOCIATED WITH IT.

A TROPICAL WAVE ALONG 121W FROM 03N TO 16N IS NEARLY STATIONARY. 
A 1010 MB LOW IS ATTACHED TO THE WAVE AT 10N NEAR THE AXIS OF 
THE ITCZ.  SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 30 
NM S AND 90 NM N OF THE ITCZ AXIS BETWEEN 118W AND 125W.

...ITCZ...

THE ITCZ AXIS LIES ALONG 13N87W TO 14N96W TO 10N103W TO 10N120W 
TO 10N140W. SCATTERED MODERATE CONVECTION LIE WITHIN 120 NM S OF 
AXIS E OF 89W AS WELL AS WITHIN 30 NM S AND 90 NM N OF THE AXIS 
BETWEEN 118W AND 125W.

...DISCUSSION...

W OF 115W...
A WEAK MID LEVEL TROUGH CENTERED NEAR THE LINE FROM25N120W TO 
14N131W IS INHIBITING THE W PROGRESS OF THE TROPICAL WAVES W OF 
100W...WITH THE WAVE AT 121W NEARLY STATIONARY AT THIS TIME.  
ENHANCED CONVECTION CAN BE FOUND NEAR THIS WAVE AS PLENTIFUL 
MOISTURE IS ABLE TO LIFT UPWARD WITHOUT ENCOUNTERING MUCH 
SHEAR.  CONVERSELY...THE WAVE ALONG 107W HAS LITTLE CONVECTION 
AS IT LIES IN A REGION OF DOMINANTLY N LOW LEVEL FLOW N OF 10N 
AND UNDER 25 TO 30 KT EASTERLY UPPER LEVEL WINDS. ELSEWHERE N OF 
15N W OF 115W STRENGTHENING HIGH PRES AT THE SURFACE CAN BE 
FOUND AND SUBSIDENCE IS DOMINANT.  

E OF 115W...
A STRONG PRESSURE GRADIENT BETWEEN THE BUILDING SFC 
RIDGE OVER NW WATERS AND LOWER PRESSURE IN THE VICINITY OF THE 
NORTHERN GULF OF CALIFORNIA IS GENERATING N TO NW WINDS TO 20 KT 
AND SEAS TO 8 FT. 

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 19N98W.  STRONG NE 
WINDS TO 45 KT ON THE SE SIDE OF THIS SYSTEM ARE FUNNELING 
THROUGH CENTRAL AMERICA IN THE VICINITY OF A LINE FROM 14N88W TO 
06N94W. THIS STRONG FLOW SHOULD SLACKEN SOMEWHAT OVER THE NEXT 
COUPLE OF DAYS AS IT TRANSLATES WESTWARD...MAKING FOR A SLIGHTLY 
MORE FAVORABLE ENVIRONMENT FOR THE LOW PRES SYSTEM DESCRIBED IN 
THE SPECIAL FEATURES.  CURRENTLY...THIS SHEAR IS ESPECIALLY 
INHIBITING CONVECTION BETWEEN THIS LOW PRES SYSTEM AND THE 
TROPICAL WAVE ALONG 84W.
 
$$
SCHAUER CLARK