000
AXPZ20 KNHC 110901
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1005 UTC THU JUL 11 2013

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 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...   
     
THE MONSOON TROUGH AXIS EXTENDS FROM 10N85W TO 10N110W TO 
06N120W. THE ITCZ EXTENDS FROM 06N120W TO 09N140W. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION IS NOTED WITHIN 210 NM S 
OF THE MONSOON TROUGH AXIS...AND S OF COSTA RICA...BETWEEN 83W 
AND 87W. SCATTERED MODERATE WITHIN 120 NM EITHER SIDE OF MONSOON 
TROUGH AXIS BETWEEN 95W AND 105W. SCATTERED MODERATE CONVECTION 
WITHIN 60 NM OF MONSOON TROUGH AXIS BETWEEN 111W AND 113W.

...DISCUSSION... 

A TROPICAL WAVE THAT HAD MOVED ACROSS THE GULF OF TEHUANTEPEC 
AND SOUTHERN MEXICO HAS BECOME DIFFUSE THIS MORNING. AN ASCAT 
PASS FROM 04 UTC INDICATED THE SUBTROPICAL RIDGE AXIS EXTENDING 
INTO THE AREA WHERE THE WAVE IS MOVING. IN ADDITION OBSERVATIONS 
FROM AROUND THE AREA SUPPORT RIDGING WHERE THE WAVE WOULD BE 
SITUATED...SHOWING THAT THE WAVE NO LONGER IS AT THE SURFACE AT 
LEAST N OF 12N. FARTHER SOUTH...THERE REMAINS LINGER EVIDENCE OF 
THE TROPICAL WAVE ALONG THE MONSOON TROUGH WHERE CYCLONIC 
TURNING EMBEDDED ALONG THE TROUGH BETWEEN 95W AND 100W ALONG WITH 
SMALL POCKETS OF CONVECTION. 

THE WEAK CYCLONIC TURNING ALONG THE MONSOON TROUGH WILL PROGRESS 
WEST TODAY AND DEVELOP SLIGHTLY. GLOBAL MODELS SHOW A WEAK 
TROUGH FORMING ALONG THE MONSOON TROUGH TODAY BETWEEN 100W AND 
110W...AND MERGING WITH A PAIR OF ADDITIONAL FARTHER WEST ALONG 
THE MONSOON TROUGH...ALREADY STARTING TO PRESENT THEMSELVES IN 
SCATTEROMETER DATA. LITTLE IMPACT IN TERMS OF WINDS...SEAS...OR 
WIDESPREAD ORGANIZED CONVECTION IS EXPECTED WITH ANY OF THE 
FEATURES AS THEY PROGRESS WESTWARD ALONG THE MONSOON TROUGH/ITCZ 
OVER THE NEXT SEVERAL DAYS.

FARTHER WEST...A TROUGH WAS NOTED YESTERDAY N OF THE ITCZ W OF 
135W. THIS HAS LIKELY SHIFTED W OF 140W SINCE THEN. WINDS OF 20 
TO 25 KT WERE NOTED IN AN ASCAT PASS FROM AROUND 18 UTC 
YESTERDAY...AND ALTIMETER DATA SHOWED SEAS IN EXCESS OF 8 FT IN 
THIS AREA AS WELL. WHILE THE WINDS ASSOCIATED WITH THE TROUGH 
ARE NO LONGER IN THE DISCUSSION AREA...IT IS LIKELY SEAS TO 8 FT 
WILL LINGER FROM 14N TO 17N W OF 138W FOR THE NEXT FEW HOURS 
THEN SHIFT W OF THE AREA AS WELL.

OVERALL...THE SUBTROPICAL RIDGE DOMINATES N OF 10N W OF 
110W...WITH WEAK TROUGHING ALONG THE MONSOON TROUGH/ITCZ. BY FRI 
THE PRES GRADIENT WILL NOT BE ENOUGH TO SUPPORT WINDS IN EXCESS 
OF 20 KT ANYWHERE IN THE DISCUSSION AREA...WITH NO SWELL OF 8 FT 
OR GREATER EXPECTED AS WELL. THIS RELATIVELY BENIGN PATTERN WILL 
LIKELY PERSIST THROUGH THE WEEKEND.

$$ 
CHRISTENSEN