000
AXPZ20 KNHC 072135
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT OCT 07 2006

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

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

...SPECIAL FEATURES...

1007 MB LOW PRESSURE CENTERED NEAR 10N115W. SCATTERED MODERATE 
CONVECTION IS EVIDENT WITHIN 180 NM OF THE CENTER OF THIS SYSTEM.

1006 MB LOW PRESSURE CENTERED NEAR 12N127W. NUMEROUS STRONG 
CONVECTION EVIDENT WITHIN 120 NM OF THE NE SEMICIRCLE OF THIS 
SYSTEM. SCATTERED MODERATE CONVECTION IS EVIDENT FROM 8N TO 16N 
BETWEEN 123W AND 127W.

...TROPICAL WAVES...

TROPICAL WAVE IS LOCATED ALONG 90W N OF 4N INTO CENTRAL AMERICA 
AND IS MOVING W 10 TO 15 KT. NO SIGNIFICANT CONVECTION NOTED 
WITH THIS FEATURE.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N78W 10N87W 8N99W 10N119W 12N127W 
10N140W. SCATTERED MODERATE CONVECTION WITH 120 NM OF THE AXIS 
BETWEEN 80W AND 88W...AND WITHIN 180 NM OF AXIS BETWEEN 93W AND 
102W. SCATTERED MODERATE CONVECTION FROM 5N TO 11N W OF 131W.

...DISCUSSION...
 
N OF 22N...
DOMINANT FEATURE CONTINUES TO BE BROAD UPPER LEVEL TROUGH 
EXTENDING FROM CENTRAL CALIFORNIA TO 22N130W. NW FLOW BETWEEN 
THE TROUGH AND AN UPPER RIDGE OVER 140W IS PROVIDING SUBSIDENT 
DRY AIR ACROSS THIS REGION. QUIKSCAT IMAGERY FROM THIS MORNING 
AND AVAILABLE SHIP OBSERVATIONS SHOW FRESH NE TRADES PERSISTING 
GENERALLY W OF 120W...BETWEEN THE SOUTHERN PERIPHERY OF 1030 MB 
OFF THE OREGON COAST AND DEEPENING LOW PRESSURE ALONG THE ITCZ. 
GFS SHOWS THIS RIDGE WEAKENING THROUGH MID WEEK AHEAD OF A 
FRONTAL BOUNDARY MIGRATING TO THE N. WHILE THIS MAY ALLOW WINDS 
TO SUBSIDE A LITTLE...MUCH WILL DEPEND ON POSSIBLE DEVELOPMENT 
OF LOW PRESSURE TO THE S. ELSEWHERE OFF THE BAJA COAST N OF 
25N...FRESH TO STRONG NW WINDS BETWEEN THE BOUNDARY LAYER HIGH 
TO THE NW AND 1012 MB LOW PRESSURE OVER THE SW U.S. WILL TONIGHT 
AS THE LOW WEAKENS AND LIFTS OUT. 

FROM 7N TO 22N...TWO STRONG UPPER ANTICYCLONES NOTED NEAR 
10N131W AND 12N110W. THESE ARE ASSOCIATED WITH SURFACE LOWS 
NOTED ABOVE...AND ARE PROVIDING HEALTHY UPPER EXHAUST ENHANCING 
CONVECTION OVER THE AREA. 50 TO 60 KT UPPER JET IS EVIDENT 
BETWEEN THESE FEATURES AND THE TROUGH TO THE NORTH...EXTENDING 
FROM 14N129W TO THE SOUTHERN TIP OF BAJA. UPPER SHEAR WEAKENS W 
OF 129W HOWEVER...S OF THE UPPER RIDGE. GLOBAL MODELS SHOW THESE 
FEATURES PERSISTING ALONG THE ITCZ FOR THE NEXT COUPLE OF DAYS. 
GFS SHOWS THEM WEAKENING AND RIDING TO THE NE IN THE SW SHEAR 
ALOFT.

S OF 7N...15 TO 20 KT CROSS EQUATORIAL FLOW PERSISTS WITH SWELL 
HEIGHTS GENERALLY BELOW 8 FT. GFS SHOWS LOW PRESSURE FORMING 
ALONG ITCZ ALONG 100W WITH SLIGHT INCREASE IN WINDS AND SEAS TO 
THE S.

GULF OF TEHUANTEPEC...1081 MB BOUNDARY LAYER HIGH REMAINS OVER 
CENTRAL MEXICO...WITH TROUGHING OVER WESTERN GULF AHEAD 
APPROACHING WAVE. COASTAL OBSERVATIONS FROM MMMT SHOW 20 TO 25 
KT SUSTAINED WINDS THROUGH THE GAP EARLIER TODAY. WINDS WILL 
GRADUALLY DIMINISH BY EARLY MONDAY AS THE TROUGH MOVES INTO THE 
AREA AND THE HIGH PRESSURE WEAKENS.   

$$
CHRISTENSEN