000
AXPZ20 KNHC 232143
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT JUL 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURE...

TROPICAL STORM DORA CENTERED NEAR 21.7N 112.6W OR 190 NM WSW OF 
CABO SAN LUCAS MEXICO AT 23/2100 UTC MOVING NW OR 305 DEGREES AT 
08 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB. MAXIMUM 
SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SEE LATEST 
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 
KNHC FOR MORE DETAILS. THE SUSTAINED WIND SPEED IS SET TO 45 KT 
BASED ON OBSERVATIONS FROM A NOAA HURRICANE HUNTER AIRCRAFT 
INVESTIGATING DORA. DORA IS EXPERIENCING LIGHT TO MODERATE 
NORTHEASTERLY VERTICAL WIND SHEAR WHICH WILL CONTINUE AS DORA 
PARALLELS THE COAST OF THE BAJA CALIFORNIA PENINSULA. SCATTERED 
MODERATE CONVECTION IS OCCURRING WITHIN 60-90 NM OF THE CENTER. 
DORA IS FORECAST TO WEAKEN TO A POST TROPICAL REMNANT LOW IN 
ABOUT 24 HOURS AS IT CONTINUES TO MOVE OVER COLDER SEA SURFACE 
TEMPERATURES. MEANWHILE LARGE SWELLS GENERATED BY DORA WILL 
AFFECT THE COAST OF SOUTHWESTERN MEXICO AND BAJA CALIFORNIA 
DURING THE NEXT COUPLE OF DAYS. THESE SWELLS WILL LIKELY CAUSE 
LIFE-THREATENING SURF AND RIP CURRENT CONDITIONS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH IS ALONG 09N84W TO 07N95W. THE INTERTROPICAL 
CONVERGENCE ZONE AXIS EXTENDS FROM 07N95W TO 09N107W THEN 
RESUMES NEAR 06N111W TO 10N130W TO 07N140W. NO ASSOCIATED 
SIGNIFICANT CONVECTION IS NOTED...ALTHOUGH ISOLATED TO SCATTERED 
MODERATE CONVECTION IS WITHIN 90-120 NM S OF A LINE FROM 05N79W 
TO 06N88W AND ALSO WITHIN 90-120 NM S OF A LINE FROM 12N117W TO 
13N130W.

...DISCUSSION...

AN UPPER LEVEL TROUGH IS INTRUDING ON THE FAR W PORTION OF THE 
AREA ALONG 140W/141W PRODUCING LIGHT TO MODERATE S TO SW WINDS 
EAST OF THIS UPPER FEATURE AT THE SURFACE. AN UPPER LEVEL 
ANTICYCLONE IS CENTERED NEAR 25N117W. UPPER LEVEL NE WINDS IN 
ASSOCIATION WITH THE CIRCULATION OF THIS ANTICYCLONE ARE 
IMPACTING TROPICAL STORM DORA AS DESCRIBED IN THE SPECIAL 
FEATURE SECTION ABOVE. AN UPPER LEVEL CYCLONE IS OVER THE DEEP 
TROPICAL PACIFIC NEAR 04N124W. AN ASSOCIATED UPPER LEVEL TROUGH 
EXTENDS ALONG 04N W OF 105W. OTHERWISE UPPER LEVEL ANTICYCLONIC 
FLOW DOMINATES THE MAJORITY OF THE REMAINDER OF THE TROPICAL NE 
PACIFIC. UPPER LEVEL DIFFLUENCE IS HELPING TO INDUCE MINIMAL 
CONVECTION AS DESCRIBED ABOVE.

ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS FROM 32N140W TO 
20N120W. NE TRADES TO THE S OF THE RIDGE HAVE DIMINISHED TO 
10-15 KT BASED ON A RECENT WINDSAT SCATTEROMETER PASS. THIS PASS 
ALSO CAPTURED 20 KT E-SE WINDS S OF 04N W OF 133W WHERE A 
TIGHTER PRES GRADIENT EXISTS. THESE WINDS WILL DIMINISH DURING 
THE NEXT 12-24 HOURS.

A WEAK TO MODERATE GULF OF PAPAGAYO GAP WIND EVENT WILL PERSIST 
THROUGH EARLY MON AS FRESH TRADE WIND FLOW IN THE SW CARIBBEAN 
FUNNELS THROUGH THE GAP. AN EARLIER WINDSAT SCATTEROMETER PASS 
ALONG WITH A FEW MORE RECENT SHIP OBSERVATIONS CONTINUE TO 
INDICATE 20 KT NE-E WINDS FROM 10N TO 12N ALL THE WAY TO 90W.

CROSS-EQUATORIAL SE SWELLS OF 8-9 FT ARE PROPAGATING ACROSS THE 
SW CORNER OF THE AREA SW OF A LINE FROM 10N140W TO 00N125W. 
THESE HIGHER SWELLS WILL PROPAGATE LITTLE BECOMING POSITIONED SW 
OF A LINE FROM 07N140W TO 00N120W IN 24 HOURS...THEN S OF 04N W 
OF 110W IN 48 HOURS.

$$
LEWITSKY