000
AXPZ20 KNHC 131537
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU SEP 13 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 ALONG 79W N OF 7N IN THE BAY OF PANAMA MOVING W 5 
OT 10 KT. CONVECTION IS FLARING ON THE SOUTHERN END OF THE 
WAVE...GENERALLY N OF 6N AND W OF 80W. THE CONVECTION IS 
INTERACTING WITH THE COLOMBIAN PACIFIC COAST AND IS FURTHER 
ENHANCED BY SLY DIVERGENT FLOW ALOFT. 

TROPICAL WAVE ALONG 106W MOVING W 5-10 KT WITH A WEAK 1009 MB 
LOW ALONG THE AXIS NEAR 9N. THE FIRST VISIBLE IMAGES OF THE DAY 
SHOW BROAD LOW LEVEL TURNING AROUND THE LOW. CONVECTION REMAINS 
FAIRLY LIMITED HOWEVER.

TROPICAL WAVE ALONG 135W S OF 15N MOVING W 10 KT. A WEAK 
CIRCULATION IS ASSOCIATED WITH THIS WAVE WHERE IT INTERSECTS 
WITH THE ITCZ NEAR 11N. HOWEVER...NO SIGNIFICANT CONVECTION IS 
NOTED.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N83W 8N90W 13N101W 9N110W 11N114W 
13N122W 10N140W. SCATTERED MODERATE CONVECTION WITHIN 240 NM OF 
AXIS BETWEEN 93W AND 101W. SCATTERED MODERATE WITHIN 90 NM N OF 
AXIS BETWEEN 107W AND 111W. 

...DISCUSSION...

E OF 115W...
MODERATE TO FRESH SWLY CROSS EQUATORIAL FLOW IS PROVIDING 
SUFFICIENT LOW LEVEL CONVERGENCE TO SUPPORT THE SCATTERED 
MODERATE CONVECTION NOTED ABOVE ALONG THE ITCZ FROM 93W TO 101W. 
ELY SHEAR IS IMPACTING THIS CONVECTION S OF AN UPPER ANTICYCLONE 
EXTENDING ACROSS CENTRAL MEXICO. AN UPPER TROUGH IS SITUATED W 
OF THIS UPPER ANTICYCLONE AND S OF BAJA FROM 24N107W TO AS FAR 
SOUTH AS 14N112W. UPPER DIVERGENCE ON THE E SIDE OF THE TROUGH 
IS ENHANCING CONVECTION WITHIN 90 NM E OF A SURFACE LOW 1010 MB 
CENTERED NEAR 17N112W. WHILE THE ROTATION IS BETTER DEFINED THAN 
BEFORE...CONVECTION IS NOT IMPRESSIVE SO FAR. WHILE GLOBAL 
MODELS ARE MIXED ON WHETHER THIS WILL SIGNIFICANTLY DEVELOP OVER 
THE NEXT COUPLE OF DAYS...ANY DEVELOPMENT WILL BE SLOW. 

W OF 115W...
AN UPPER ANTICYCLONE OFF THE W COAST OF CENTRAL BAJA NEAR 
26N116W.UPPER RIDGE AXIS EXTENDS FROM THE UPPER ANTICYCLONE OFF 
CENTRAL BAJA TO 20N140W. AN UPPER TROUGH EXTENDS S OF THIS UPPER 
RIDGE AXIS FROM 20N 11N ALONG 126W. A SURFACE LOW 1010 MB IS 
CENTERED ALONG THE ITCZ NEAR 15N120W. CONVERGENCE AROUND THIS 
FEATURE ALONG WITH SOME MINOR UPPER ENHANCEMENT IS SPARKING 
SCATTERED GENERALLY LIGHT CONVECTION WITHIN 120 NM OF THE CENTER 
OF THE LOW. HOWEVER...GLOBAL MODELS DO NOT SHOW SIGNIFICANT 
DEVELOPMENT OF THIS SYSTEM AS IT HEADS INTO A MORE UNFAVORABLE 
ENVIRONMENT FURTHER TO THE NW. ELSEWHERE...DRY AIR ALONG WITH 
NWLY FLOW ALOFT ON THE THE SOUTH SIDE OF THE UPPER RIDGE AXIS 
ARE SUPPRESSING SIGNIFICANT CONVECTIVE DEVELOPMENT OVER THE 
REMAINDER OF THE AREA. AT THE SURFACE...HIGH PRES 1021 MB IS 
CENTERED NEAR 29N129W. MODERATE FRESH N AND NE WINDS ARE EVIDENT 
IN SCATTEROMETER AND SHIP DATA BETWEEN THE SURFACE HIGH AND LOW 
PRES ASSOCIATED WITH THE ITCZ AND TROPICAL WAVES...AND IS 
EXPECTED TO PERSIST FOR AT LEAST THE NEXT 48 HOURS.

$$
CHRISTENSEN