000
AXPZ20 KNHC 042121
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU SEP 04 2008

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED FROM 11N84W TO 11N110W TO 11N120W TO 
07N140W. THE AXIS IS SOMEWHAT ILL-DEFINED E OF 115W DUE TO 
STRONG LOW-LEVEL SW/W FLOW FEEDING INTO THE MONSOON TROUGH OFF 
THE COAST OF MEXICO. NUMEROUS MODERATE/ISOLATED STRONG 
CONVECTION FROM 06N-15N BETWEEN 82W-100W. NUMEROUS MODERATE/ 
STRONG FROM 13N-19N BETWEEN 103W-107W.

...DISCUSSION...

TROPICS...
A STRONG MONSOON TROUGH IS LOCATED LIES JUST OFFSHORE THE COAST 
OF MEXICO AND CENTRAL AMERICA...ROUGHLY FROM COSTA RICA UP THE 
COAST TO PUERTO VALLARTA MEXICO. SW TO W WINDS ARE ACCELERATING 
N OF 05N TOWARDS THE TROUGH WITH LOW-LEVEL SPEED CONVERGENCE 
PRODUCING WIDESPREAD CONVECTIVE ACTIVITY OFF THE COAST ALONG THE 
LENGTH OF THE TROUGH AXIS. SHARP CYCLONIC TURNING HAS DEVELOPED 
ALONG THE TROUGH NEAR 15N102W...WHICH MAY INDICATE THAT AN AREA 
OF LOW PRESSURE IS DEVELOPING. A CLUSTER OF STRONG TSTMS HAS 
DEVELOPED NEAR THIS FEATURE...AS DESCRIBED ABOVE WITH THE ITCZ. 
W OF 115W...THE ITCZ AXIS IS MORE WELL-DEFINED DUE TO PRONOUNCED 
CONVERGENCE BETWEEN THE CROSS-EQUATORIAL FLOW AND THE EASTERLY 
TRADES. HOWEVER...LIMITED MOISTURE IS ONLY PRODUCING SCATTERED 
SHOWERS ALONG THE AXIS WITH NO AREA OF DEEP CONVECTION. IN 
GENERAL...UPPER LEVEL WINDS ARE NE/EASTERLY OVER THE 
REGION...ADVECTING MOISTURE OUTFLOW FROM THE COASTAL CONVECTION 
WWD TO NEAR 120W.

SOUTHERLY 7-9 FT SWELLS HAVE BEEN SUBSIDING WITH MUCH OF THE 
AREA. HOWEVER...A NEW SWELL TRAIN IS EXPECTED TO CROSS THE 
EQUATOR...AND COMBINED WITH THE STRONG MONSOON FLOW SHOULD BEGIN 
TO PRODUCE 8-11 FT WAVES WITH SW SWELL BY SAT OR SUN.

SUBTROPICS...
A STRONG UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 22N112W WITH 
AN ELONGATED RIDGE AXIS EXTENDING FROM N/CNTRL MEXICO TO 
19N140W. AN UPPER TROUGH AXIS CONTINUES TO SIT FROM 30N136W TO 
21N140W AND CONFLUENCE CONTINUES TO PRODUCE MODERATE/STRONG 
SUBSIDENCE NW OF A LINE FROM THE SRN TIP OF BAJA CALIFORNIA TO 
10N140W. THE 1009 MB REMNANT LOW OF KARINA IS LOCATED NEAR 
20N115W...ABOUT 290 NM WSW OF CABO SAN LUCAS MEXICO...IS NOT 
PRODUCING ANY MORE DEEP CONVECTION AND ONLY CONSISTS OF A SWIRL 
OF LOW CLOUDS WITH SOME EMBEDDED SHOWERS WITHIN 120 NM OF ITS 
CENTER.

GALE FORCE WINDS OFF THE CALIFORNIA COAST CONTINUE TO PRODUCE 
8-11 FT N/NORTHEASTERLY SWELLS WHICH HAVE PROPAGATED INTO THE 
AREA NW OF A LINE FROM 30N120W TO 20N140W. THESE SWELLS ARE 
EXPECTED TO SUBSIDE WITHIN THE NEXT 24 HRS...LEAVING A SMALL 
AREA OF LINGERING SWELLS OVER THE NW PART OF THE AREA FOR THE 
NEXT COUPLE OF DAYS.

$$
BERG