000
AXPZ20 KNHC 231545
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE JUN 23 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURE...
TROPICAL STORM ANDRES WAS CENTERED NEAR 18.0N 104.4W OR ABOUT 70 
MILES S OF MANZANILLO MEXICO AT 1500 UTC MOVING NW AT 10 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 990 MB. MAXIMUM SUSTAINED 
WINDS 60 KT GUSTS 75 KT. SEE LATEST NHC PUBLIC ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCPEP/WTPZ32 KNHC AND THE FULL FORECAST 
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2 WTPZ22 KNHC FOR MORE 
DETAILS. STRONG CONVECTION PERSISTS WITHIN 30 NM OF THE CENTER 
OF ANDRES...ALTHOUGH THIS HAS REMAINED MOSTLY OFF THE COAST 
OVER THE PAST SEVERAL HOURS. ANDRES FORECAST TRACK IS PARALLEL 
AND CLOSE TO THE COASTLINE N OF MANZANILLO TOWARD CABO 
CORRIENTES. HEAVY RAINFALL UP TO 8 INCHES...AND COASTAL STORM 
SURGES OF 1 TO 3 FT ABOVE NORMAL TIDES IS POSSIBLE ALONG THIS 
COASTLINE AS ANDRES MOVES NW.

...ITCZ...
AXIS IS ALONG 08N83W TO 06N88W TO 17N100W TO 08N140W. SCATTERED 
MODERATE CONVECTION WITHIN 60 NM S OF AXIS BETWEEN 85W AND 95W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 60 NM NE 
QUADRANT OF LOW PRES 1009 MB ALONG ITCZ NEAR 11N124W.

...DISCUSSION...
SHORT WAVE ENERGY IS ROUNDING THE BASE OF A MID TO UPPER LEVEL 
TROUGH EXTENDING FROM NORTHERN CALIFORNIA TO 30N130W TO 25N125W. 
THE UPPER PATTERN STAGNATES OVER THE NEXT COUPLE OF DAYS AS THE 
TROUGH CUTS OFF INTO AN UPPER LOW...EAST OF A GENERALLY 
STATIONARY UPPER RIDGE ALONG 145W. AT THE SURFACE...A RIDGE 
EXTENDS FROM A 1028 MB SURFACE HIGH N OF HAWAII...EASTWARD TO 
THE BAJA COAST. A SHIP OBSERVATION SHOWED 20 KT NE TRADES S OF 
THE RIDGE...MAINLY W OF 135W. SHIP OBSERVATIONS ALONG WITH A 04Z 
ASCAT PASS INDICATED 20 KT NE WINDS SOUTH OF THE OPENING TO THE 
GULF OF CALIFORNIA BETWEEN THE SURFACE RIDGE AND T.S. ANDRES.

A WEAK UPPER ANTICYCLONE IS NOTED SE OF THE MID/UPPER 
TROUGH...AND TO THE NORTH OF ANDRES...NEAR 20N110W WITH AN UPPER 
RIDGE EXTENDING WEST TOWARD 20N125W. UPPER LEVEL NORTHERLY FLOW 
BETWEEN THIS FEATURE AND AN ELONGATED UPPER TROUGH CENTERED OVER 
NE MEXICO IS PROVIDING SOME NORTHERLY SHEAR TO ANDRES AS 
EVIDENCED BY WISPS OF CIRRUS STREAMING SOUTHWESTWARD FROM THE 
STORM...AND A SLIGHTLY FLATTENED APPEARANCE ON THE NE SIDE OF 
THE CONVECTION.  

FURTHER SOUTH...EVENING QUIKSCAT DATA SHOWED A PERSISTENT WEAK 
LOW PRES AROUND 1009 MB EMBEDDED WITHIN THE ITCZ NEAR 10N125W. A 
CLUSTER OF CONVECTION CONTINUES ON THE NE QUADRANT OF THIS 
LOW...ENHANCED IN PART BY WEAK UPPER DIVERGENCE TO THE SOUTHEAST 
OF THE UPPER TROUGH. THIS CONVECTION WILL LIKELY PERSIST 
ALTHOUGH BE LIMITED IN EXTENT DUE TO GENERALLY DRY MID AND UPPER 
LEVEL CONDITIONS. 

SCATTEROMETER ALSO INDICATED A BROAD AREA OF FRESH TO MODERATE 
SOUTHERLY FLOW INTO THE ITCZ E OF 120W. THIS IS AIDING MODEST 
CONVECTIVE DEVELOPMENT ALONG THE ITCZ. THIS CONVECTION REMAINS 
FAIRLY WEAK DUE TO WEAK UPPER SUPPORT...GENERALLY NE FLOW ALOFT.

ASIDE FROM THE DEVELOPMENT AND TRACK OF T.S. ANDRES...LITTLE 
CHANGE IS EXPECTED IN CONDITIONS OVER THE NEXT 2 TO 3 DAYS.

$$
CHRISTENSEN