000
AXPZ20 KNHC 112118
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED AUG 11 2010

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.

...SPECIAL FEATURE...

A TROUGH IS EMBEDDED IN THE ITCZ EXTENDING FROM 16N100W TO 
10N95W. A NEW 1010 MB AREA OF LOW PRES HAS DEVELOPED ALONG THIS 
TROUGH POSITIONED NEAR 13N98W. SCATTERED MODERATE AND ISOLATED 
STRONG CONVECTION EXISTS FROM 10N TO 15N BETWEEN 98W AND 103W. 
SW WINDS OF 20 TO 25 KT ARE FEEDING INTO THIS SYSTEM FROM S OF 
THE ITCZ TO 09N. THE CONVECTIVE ACTIVITY ASSOCIATED WITH THE LOW 
HAS BECOME A LITTLE BETTER ORGANIZED TODAY AND SOME SLOW 
DEVELOPMENT OF THE SYSTEM IS POSSIBLE DURING THE NEXT COUPLE OF 
DAYS AS IT MOVES TO THE WNW AT 7 TO 10 KT. THIS LOW HAS A MEDIUM 
CHANCE OF TROPICAL CYCLONE DEVELOPMENT IN THE NEXT 48 HOURS.

...ITCZ...

ITCZ AXIS IS ALONG 11N84W TO 15N95W AND THEN FROM 12N102W TO 
12N120W TO 10N140W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS FROM 07N TO 10N BETWEEN 78W AND 86W AND ALSO 
WITHIN A 90 NM RADIUS OF 15N94W.

...DISCUSSION...

AN UPPER LEVEL ANTICYCLONE LOCATED WELL W OF THE AREA NEAR 
17N152W OR JUST SE OF THE BIG ISLAND OF HAWAII IS LOSING ITS 
INFLUENCE ON THE DISCUSSION AREA AS AN ASSOCIATED UPPER RIDGE 
BARELY EXTENDS INTO THE AREA TO NEAR 15N137W. AN UPPER LEVEL 
TROUGH EXTENDS FROM N OF THE AREA NEAR SAN FRANCISCO BAY 
CALIFORNIA TO 32N132W THEN CONTINUES AS A SHEAR AXIS TO 24N136W 
TO 17N138W. VERY DRY AIR UNDER MODERATE TO STRONG SUBSIDENCE IS 
PRESENT ACROSS THE AREA N OF THE ITCZ AND W OF 125W AS SHOWN IN 
WATER VAPOR SATELLITE IMAGERY.

AN EXPANSIVE UPPER LEVEL ANTICYCLONE IS CENTERED OVER NW 
MEXICO NEAR 30N109W WITH AN UPPER RIDGE EXTENDING ACROSS CENTRAL 
BAJA CALIFORNIA TO A LARGE COL NEAR 17N134W. DIFFLUENT UPPER 
LEVEL NORTHEASTERLY WINDS ARE ADVECTING MID AND UPPER LEVEL 
MOISTURE WESTWARD FROM COASTAL MEXICO TO ALONG 122W N OF THE 
ITCZ TO 27N. 

AT THE SURFACE...A RIDGE AXIS IS OVER THE NW WATERS EXTENDING 
FROM 1031 MB HIGH PRES CENTERED WELL NW OF THE AREA NEAR 
46N142W. THE RIDGE ENTERS THE DISCUSSION AREA NEAR 32N137W AND 
CONTINUES THROUGH 25N130W TO 23N113W. DIURNALLY ENHANCED NW TO N 
WINDS OF 20 KT WILL CONTINUE TO OCCUR N OF 25N WITHIN 120 NM OF 
THE W COAST OF BAJA CALIFORNIA DURING THE EVENING HOURS THROUGH 
THE NEXT 18 HOURS DUE TO A TIGHT PRES GRADIENT BETWEEN THE RIDGE 
AND TROUGHING IN THE GULF OF CALIFORNIA.

A 1010 MB AREA OF LOW PRES IS CENTERED NEAR 18N110W AND IS 
NEARLY STATIONARY. THIS LOW HAS ABSORBED THE REMNANTS OF FORMER 
TROPICAL STORM ESTELLE. WINDS OF 20 KT WITH SEAS OF 8 TO 10 FT 
ARE OCCURRING WITHIN 90 NM OF THE CENTER...THEN WILL SHIFT TO 
WITHIN 180 NM OF THE CENTER IN THE S SEMICIRCLE FROM 24 TO 48 
HOURS.

A NEW SET OF LONG PERIOD SOUTHWESTERLY SWELL TO 8 FT WITH 
PERIODS OF 16 TO 18 SECONDS WILL PROPAGATE N OF THE EQUATOR AND 
INTO THE FAR SE WATERS S OF 05N BETWEEN 80W AND 86W BY 24 HOURS 
AND CONTINUING THROUGH 48 HOURS AS IT REACHES TO NEAR 08N.

$$
LEWITSKY