000
AXPZ20 KNHC 251530
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT AUG 25 2007

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 
1500 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 82W MOVING W AT 15 KT. AN AREA OF 
SCATTERED MODERATE CONVECTION PERSISTS DOWNSHEAR OF THE WAVE 
FROM 8N TO 10N BETWEEN 85W AND 88W. WEAK MIDLEVEL ROTATION IS 
NOTED ON VISIBLE SATELLITE IMAGERY THIS MORNING.

TROPICAL WAVE PREVIOUSLY ALONG 90W N OF 5N HAS BEEN RELOCATED TO 
95W BASED ON WEAK CYCLONIC TURING AND ONGOING SCATTERED MODERATE 
CONVECTION FROM 9N TO 11N BETWEEN 93W AND 97W. SURFACE LOW PRES 
1009 MB IS CENTERED ALONG THE WAVE NEAR 13N96W. 

...ITCZ...
ITCZ AXIS IS ALONG 11N85W 14N95W 14N114W 8N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WITHIN 180 NM EITHER SIDE OF 
LINE 6N83W 12N99W 13N116W AND WITHIN 15 NM EITHER SIDE OF LINE 
11N116W 11N124W 8N135W.

...DISCUSSION...

E OF 120W...WEAK UPPER LOW IS CENTERED ALONG THE MEXICAN COAST 
NEAR 20N105W...BETWEEN A BROAD UPPER ANTICYCLONE OVER NW MEXICO 
AND A WEAKER UPPER ANTICYCLONE OVER SOUTHERN MEXICO. ELY SHEAR 
DOMINATES THE MID AND UPPER LEVELS S OF 15N ON THE SRN EDGE OF 
THE UPPER ANTICYCLONE. AT THE SURFACE...QUIKSCAT IMAGERY SHOWS 
MODERATE TO FRESH SWLY FLOW PERSISTING S OF THE 
ITCZ...ACCOMPANIED BY MODERATE TO LARGE SLY SWELL. VARIOUS MODEL 
GUIDANCE SUGGESTS SOME DEVELOPMENT OF THE LOW PRES OFF SRN 
MEXICO AND THE CONVECTIVE CLUSTER WITH THE MID LEVEL ROTATION 
OFF COSTA RICA. HOWEVER...SOME IF THIS PROJECTED DEVELOPMENT MAY 
BE SPURIOUS AND ATTRIBUTABLE TO CONVECTIVE FEEDBACK IN THE 
MODELS. UPPER LEVELS FAVOR CONTINUED MODEST CONVECTION IN ELY 
SHEAR OVER THE NEXT COUPLE OF DAYS...BUT NO SIGNIFICANT TROPICAL 
DEVELOPMENT IS EXPECTED.

W OF 120W...MID AND UPPER LEVELS REMAIN DRY N OF THE ITCZ 
ASSOCIATED WITH A BROAD UPPER ANTICYCLONE CENTERED NEAR 26N127W. 
THIS IS SUPPRESSING ANY SIGNIFICANT CONVECTIVE DEVELOPMENT EVEN 
ALONG THE ITCZ. EARLY VISIBLE SATELLITE IMAGERY SHOWS 
STRATOCUMULUS FIELDS N OF 20N...AS WELL AS S OF THE ITCZ 
ASSOCIATED WITH MODERATE TO FRESH CROSS EQUATORIAL FLOW. A WEAK 
SURFACE TROUGH EXTENDS FROM 21N126W TO LOW PRES 1010 MB  
CENTERED NEAR 17N132W TO 14N138W. DRY AIR IS KEEPING CONVECTION 
ANEMIC...AND SCATTEROMETER AND ALTIMETER DATA IN THE AREA SHOW 
GENERALLY LIGHT WINDS AND SEAS. 

$$
CHRISTENSEN