000
AXPZ20 KNHC 120920
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT AUG 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 103W FROM 2N TO 16N MOVING W 12 KT. 
SCATTERED MODERATE TO STRONG CONVECTION ON THE ITCZ..SOME OF 
WHICH APPEAR TO BE A SQUALL LINE MOVING W 20 TO 25 KT. 

TROPICAL WAVE ALONG 139W FROM 3N TO 16N MOVING W 15 KT. A LARGE 
AREA OF MID CLOUDS BETWEEN 135W AND 140W. SCATTERED MODERATE TO 
STRONG CONVECTION ON THE ITCZ BULGING NWD BUT NO ORGANIZATION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG...9N77W 8N81W 10N89W 9N104W 13N128W 
10N140W. ISOLATED MODERATE CONVECTION NEAR 6N82W. CLUSTER OF 
STRONG NEAR 8N84W. SCATTERED MODERATE WITHIN 30 NM EITHER SIDE 
OF A LINE FROM 9N88W TO 9N105W. SCATTERED MODERATE FROM 12N119W 
TO 18N125W. SCATTERED MODERATE FROM 11N133W TO 13N140W. 

OTHER CONVECTION INCLUDE A CLUSTER OF STRONG CONVECTION WITHIN 
30 NM OF 13N91W AND ANOTHER CLUSTER OF STRONG NEAR 15N94W. 
ISOLATED MODERATE NEAR 14N94W.

...DISCUSSION...

A MID LEVEL TROUGH TO THE N OF THE AREA ALONG 120W CONTINUES TO 
MAINTAIN A WEAKNESS IN THE PRESSURE FIELD TONIGHT S OF 30N. THE 
MID LEVEL RIDGE OVER THE SW US AND NRN MEXICO REMAINS IN PLACE 
WITH A SECOND MID LEVEL RIDGE EXTENDING SE INTO THE NW PORTION 
OF THE REGION. MID LEVEL EASTERLIES ARE CONFINED TO S OF 20N. A 
WEAK INVERTED TROUGH WAS MOVING W ALONG 133W. ON THE SURFACE 
TONIGHT THE PACIFIC RIDGE WAS PRODUCING NE TRADES TO 20 KT N OF 
14N AND W OF 130W ACCORDING TO SSMI. NO QUIKSCAT PASS OVER THAT 
PORTION OF THE AREA TONIGHT. WINDS ALONG THE BAJA COAST TONIGHT 
WERE NWLY 10 TO 15 KT. GAP WINDS REMAIN LIGHT ALSO. CROSS 
EQUATORIAL SE WINDS W OF 100W S OF 5N WERE MOSTLY TO 20 KT. S OF 
5N E OF 100W WINDS WERE S TO SW TO 20 KT. SLY SWELL CONTINUED TO 
BLEED ACROSS THE EQUATOR WITH HEIGHTS TO 8 FT. 

LATER DAY 1 THE MID LEVEL TROUGH WILL REMAIN ALONG 120W WITH A 
WEAKNESS CONTINUING S OF 30N. THE RIDGE OVER THE SW WILL REMAIN 
IN PLACE WITH THE CENTER SHIFTING SW TO NRN MEXICO. A WEAK RIDGE 
OVER THE NW CORNER OF THE AREA WILL REMAIN IN PLACE. ON THE 
SURFACE LATER DAY 1 NE TRADES WILL INCREASE N OF 25N W OF 130W 
AS THE PRESSURE GRADIENT OF THE PACIFIC RIDGE STRENGTHENS SOME. 
THIS WILL ALSO INCREASE NLY WINDS N OF 26N BETWEEN 120W AND 130W 
TO 20 KT WITH AN INCREASE IN NLY SWELL TO 8 FT. WINDS ALONG THE 
BAJA COAST WILL REMAIN LIGHT. GAP WINDS REMAIN LIGHT. CROSS 
EQUATORIAL WINDS DECREASE TO MOSTLY 10 TO 15 KT WITH SLY SWELL 
TO 8 FT REMAINING. 

FOR DAY 2 THE GFS MODEL SHOWS SOME ENERGY DROPPING SWD IN THE 
MID LEVEL TROUGH THAT PERSISTS ALONG 120W. THIS ENERGY IN THE 
FORM OF A SHORTWAVE TROUGH WILL LOWER MID LEVEL HEIGHTS AS MOVES 
SWD DAY 2. LITTLE CHANGE TO THE MID LEVEL RIDGE OVER NRN MEXICO. 
MID LEVEL EASTERLIES WEAKEN SOME AND REMAIN S OF 15N. ON THE 
SURFACE DAY 2 THE PACIFIC RIDGE WEAKENS SOME AND NLY WINDS N OF 
26N ARE CONFINED TO BETWEEN 125W AND 130W. NLY SWELL WILL 
CONTINUE TO 8 FT. NE TRADES REMAIN ABOUT THE SAMEN OF 25N W OF 
130W. S OF 25N W OF 130W NE TRADES WILL BE TO 20 KT. WINDS ALONG 
THE BAJA COAST WILL REMAIN LIGHT DAY 2 AS WELL AS GAP WINDS 
ALONG THE CENTRAL AMERICAN COAST. CROSS EQUATORIAL WINDS WILL 
REMAIN STRONGEST S OF 5N W OF 125W AT 20 KT. ELSEWHERE MOSTLY S 
TO SW AT 10 TO 15 KT. SLY SWELL WILL CONTINUE CROSSING THE 
EQUATOR WITH LONG PERIOD SWELL TO 8 FT S OF 8N.  

$$
RRG