000
AXPZ20 KNHC 260308
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE JUL 26 2011

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH 09N84W TO 09N97W TO 11N110W TO 10N113W. ITCZ AXIS 
10N113W TO 09N132W TO BEYOND 07N140W. SCATTERED MODERATE TO 
STRONG WITHIN 90 NM S OF THE MONSOON TROUGH BETWEEN 93W AND 
98W. SCATTERED MODERATE ISOLATED STRONG ELSEWHERE WITHIN 150 NM 
OF THE MONSOON TROUGH BETWEEN 93W AND 113W. SCATTERED MODERATE 
ISOLATED STRONG WITHIN 150 NM OF THE ITCZ BETWEEN 122W AND 140W. 

...DISCUSSION...
A MID/UPPER LEVEL RIDGE EXTENDS FROM THE SOUTHERN GREAT PLAINS 
ACROSS ARIZONA/S CALIFORNIA WWD INTO THE EPAC NEAR 30N122W. AN 
UPPER LEVEL ANTICYCLONE IS NOTED NEAR 22N133W WITH A RIDGE 
EXTENDING SW THROUGH 12N140W. THE RIDGES WERE SEPARATED BY AN 
UPPER LEVEL INVERTED UPPER TROUGH WHICH EXTENDED FROM 17N125W TO 
30N121W. AN EMBEDDED MID LEVEL CYCLONE NEAR 26N122W REPRESENTS 
THE REMNANT MID LEVEL CIRCULATION OF FORMER TROPICAL CYCLONE 
DORA WHICH IS NOW ANALYZED AS A SURFACE TROUGH ON THE 26/0000 
UTC SURFACE MAP. THE TROUGH EXTENDS FROM 28N115W TO 24N114W. A
MUCH EARLIER 1702 UTC ASCAT PASS CAPTURED THE TROUGH AXIS AND 
NOTED N TO NW WINDS OF 10 TO 15 KT ON THE WEST SIDE OF THE 
TROUGH...HOWEVER MORE RECENT SHIP REPORTS IN THE AREA SUGGEST 
THE TROUGH IS DISSIPATING. UPPER DIFFLUENCE ALONG THE SOUTHERN 
PERIPHERY OF THE RIDGES NOTED ABOVE IS ENHANCING THE CONVECTION 
ALONG THE ITCZ BETWEEN 100W AND 135W. A BROAD UPPER RIDGE 
EXTENDS W OVER THE TROPICAL PACIFIC E OF 90W AND IS HELPING TO 
INDUCE CONVECTION ALONG AND SOUTH OF THE MONSOON TROUGH. 

AT THE SURFACE A RIDGE EXTENDS FROM 32N140W TO 20N120W TO 
18N115W. SUBNORMAL TRADE WINDS ARE NOTED BETWEEN THE RIDGE AND 
THE ITCZ. 

CROSS EQUATORIAL SE SWELLS...RESULTING IN SEAS TO 9 FT...ARE 
PROPAGATING NWD ACROSS THE WATERS SW OF A LINE FROM 10N140W TO 
THE EQUATOR AT 94W. THIS SWELL TRAIN WILL GRADUALLY TRANSITION 
ACROSS THE AREA TUE...THEN DECAY WED AS A NEW SET OF CROSS 
EQUATORIAL SW SWELL MOVES NORTHWARD TO S OF 08N W OF 95W LATE 
WED AND THU RAISING SEAS TO UP TO 10 FT. 

GAP WINDS...NORTHERLY WINDS OF 20 KT ARE EXPECTED TO CONTINUE 
INTO THE GULF OF TEHUANTEPEC THROUGH THE TIME OF MAXIMUM 
DRAINAGE FLOW IN THE MORNING HOURS OF TUE...THEN REMAIN BELOW 20 
KT. WINDS HAVE DROPPED TO 10 TO 15 KT AT IXTEPEC IN THE STATE OF 
OAXACA MEXICO SUGGESTING THE TEHUANTEPEC WIND EVENT MAY BE CLOSE 
TO ENDING. 

NWP MODEL GUIDANCE SUGGESTS A GRADUAL INCREASE IN THE SW 
MONSOONAL FLOW MAINLY S OF 07N BETWEEN 82W AND 95W BEGINNING 
WED. EXPECT WINDS OF 20 KT WITH BUILDING SEAS OF AROUND 10 FT
IN SW SWELLS.

$$
COBB