000
AXPZ20 KNHC 240922
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT JUL 24 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...

AXIS IS ALONG 13N88W TO 10N98W TO 13N103W TO 14N115W TO 11N130W 
TO 10N140W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF 
THE AXIS BETWEEN 106W AND 112W. SCATTERED MODERATE AND ISOLATED 
STRONG CONVECTION IS WITHIN 60 NM OF THE AXIS BETWEEN 113W AND 
119W...AND ALSO WITHIN 120 NM OF THE AXIS BETWEEN 128W AND 
137W.  

...DISCUSSION...

A SHARP UPPER LEVEL TROUGH PERSISTS N-NE TO S-SW ACROSS THE FAR 
NW PORTION OF THE AREA FROM 32N133W TO 23N140W. THE TROUGH IS 
BEING BLOCKED FROM PROGRESSING FURTHER TO THE E BY A BROAD AND 
NEARLY STATIONARY UPPER ANTICYCLONE POSITIONED NEAR 25N116W JUST 
W OF BAJA CALIFORNIA. AN UPPER RIDGE EXTENDS FROM THE 
ANTICYCLONE EXTENDING NW OF THE AREA TO NEAR POINT CONCEPTION 
CALIFORNIA. BOTH OF THESE UPPER LEVEL SYSTEMS ARE MAINTAINING 
DRY AND STABLE CONDITIONS WITH MODERATE TO STRONG SUBSIDENCE 
EVIDENT E OF 127W. 

A WELL DEFINED CYCLONIC VORTEX OVER THE WESTERN GULF OF MEXICO 
HAS A NARROW TROUGH EXTENDING S OVER THE YUCATAN PENINSULA TO 
NEAR THE GULF OF TEHUANTEPEC. MAINLY ZONAL FLOW/EASTERLIES EXIST 
OVER THE REMAINDER OF THE AREA EXTENDING FROM CENTRAL AMERICA TO 
125W WITH CORE WIND SPEEDS 50-55 KT JUST S OF 10N BETWEEN 100W 
AND 120W. MODERATE TO STRONG CONVECTION ALONG THE CENTRAL 
PORTION OF THE ITCZ IS PRODUCING DIFFLUENT FLOW OVER THE ITCZ 
BETWEEN 105W AND 135W.

AT THE SURFACE...1031 MB HIGH PRES WELL NW OF THE AREA HAS A 
RIDGE EXTENDING INTO THE AREA TO 21N115W WHILE AN ELONGATED LOW 
LEVEL CYCLONIC GYRE CONTINUES ACROSS CENTRAL MEXICO SW INTO THE 
EPAC...E OF 110W. WEAK WESTERLY WINDS PRODUCING LIGHT ONSHORE 
FLOW EXTEND ALL THE WAY TO ACROSS COSTA RICA AND PANAMA TO 
COLOMBIA. 

FRESH NW BREEZE WILL PERSIST WITHIN 90 NM OF THE W COAST OF BAJA 
CALIFORNIA FROM 24N-28N AS HIGH PRES DRIFTS E-SE. A TIGHTENING 
PRES GRADIENT MAY PRODUCE FRESH SOUTHERLY WINDS TO 20 KT IN THE 
GULF OF CALIFORNIA BY 42-48 HOURS AND BEYOND. 

OTHERWISE CROSS EQUATORIAL SOUTHERLY SWELL REACHING 8-10 FT WITH 
PERIODS OF 14-15 SECONDS CONTINUES TO AFFECT A LARGE PORTION OF 
THE SOUTHERN THIRD OF THE DISCUSSION AREA AND WILL PERSIST 
THROUGH 48 HOURS ACROSS THE SAME AREA.

$$
LEWITSKY