000
AXPZ20 KNHC 232200
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE JUN 23 2009

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 
2130 UTC.

...SPECIAL FEATURE...
RECONNAISSANCE DATA INDICATE THAT ANDRES IS NOW A CATEGORY ONE  
HURRICANEON THE SAFFIR-SIMPSON SCALE. AT 2100 UTC...IT WAS 
CENTERED NEAR 18.6N 105.2W OR ABOUT 55 NM WEST-SOUTHWEST OF 
MANZANILLO MEXICO MOVING NW AT 11 KT. ESTIMATED MINIMUM CENTRAL 
PRESSURE IS 988 MB. MAXIMUM SUSTAINED WINDS ARE 65 KT WITH 
HIGHER GUSTS. THE INTENSITY FORECAST CALLS FOR SLIGHT WEAKENING 
DURING THE NEXT 12 HOURS...FOLLOWED BY MORE STEADY WEAKENING AS 
THE SYSTEM MOVES OVER COOLER WATERS AND INTO A MORE STABLE AIR 
MASS IN 36-48 HOURS. ANDRES IS FORECAST TO BE A REMNANT LOW IN 
ABOUT 72 HOURS. 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. 
ANDRES FORECAST TRACK IS PARALLEL AND CLOSE TO THE COASTLINE OF 
JALISCO TOWARD CABO CORRIENTES THEN WILL TURN MORE WEST- 
NORTHWESTWARD AS A RIDGE BUILDS WESTWARD. ANDRES IS EXPECTED TO 
PRODUCE TOTAL RAIN ACCUMULATIONS OF 3 TO 6 INCHES OVER PORTIONS 
OF WEST-CENTRAL MEXICO...WITH POSSIBLE ISOLATED MAXIMUM AMOUNTS 
OF 8 INCHES...AND COASTAL STORM SURGES OF 1 TO 3 FT ABOVE NORMAL 
TIDES IS POSSIBLE ALONG THIS COASTLINE AS ANDRES MOVES NW.

...ITCZ...
THE ITCZ AXIS IS ALONG 08N78W TO 15N98W TO 14N110W TO 11N121W TO 
08N130W TO 05N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 
150 NM S OF AXIS BETWEEN 85W AND 88W. SCATTERED MODERATE FROM 
10N TO 15N BETWEEN 95W AND 110W...AND FROM 07N TO 12N BETWEEN 
115W AND 128W. SCATTERED MODERATE ISOLATED STRONG CONVECTION 
WITHIN 60 NM NE QUADRANT OF LOW PRES 1010 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 LOCATED NEAR 34N152W SE TO  
THE BAJA COAST. SURFACE DATA AND A QSCAT PASS SHOWED 20 KT NE 
TRADES S OF THE RIDGE...MAINLY W OF 135W. 

FURTHER SOUTH...AN EARLIER QUIKSCAT DATA SHOWED A PERSISTENT 
WEAK LOW PRES AROUND 1010 MB EMBEDDED WITHIN THE ITCZ NEAR 
11N124W. A CLUSTER OF CONVECTION PERSISTS WITHIN 60 NM NE 
QUADRANT OF THIS LOW. A DIFFUENT PATTERN ALOFT IS ENHANCHING 
SCATTERED MODERATE CONVECTION ALONG THE ITCZ BETWEEN 115W AND 
128W. THE GFS COMPUTER MODEL SUGGESTS SLIGHT INCREASE IN WINDS 
AND SEAS ASSOCIATED WITH THIS LOW IN ABOUT 24 HOURS.  

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.

$$
GR/EC