000
AXPZ20 KNHC 240303
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JUN 24 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0330 UTC.

...SPECIAL FEATURE...
AT 0300 UTC...ANDRES IS CENTERED NEAR 19.1N 106.0W OR ABOUT 110 
NM W OF MANZANILLO MEXICO MOVING NW AT 9 KT. ESTIMATED 
MINIMUM CENTRAL PRESSURE IS 990 MB. MAXIMUM SUSTAINED WINDS ARE 
60 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. THE NOAA WAVE WATCH III COMPUTER MODEL SHOWS A MAXIMUM 
SEA HEIGHT OF 20 FT TO THE NE QUADRANT OF ANDRES VERY CLOSE TO 
THE MEXICAN COASTLINE. THE CITY OF MANZANILLO IN THE STATE OF 
COLIMA HAS REPORTED HEAVY RAIN AND GUSTY WINDS OF 40 KT DUE TO 
THE PROXIMITY OF ANDRES. 

...ITCZ...
THE ITCZ AXIS IS 08N78W TO 10N91W TO 15N102W TO 14N112W TO 
06N140W. SCATTERED MODERATE CONVECTION IS WITHIN 160 NM S OF 
AXIS BETWEEN 82W AND 86W. SIMILAR CONVECTION IS ALSO FOUND FROM 
07N TO 12N BETWEEN 112W AND 122W WITH A CLUSTER OF SCATTERED 
MODERATE/ISOLATED STRONG WITHIN 80 NM E SEMICIRCLE OF LOW PRES 
1010 MB ALONG ITCZ NEAR 11N123W.  

...DISCUSSION...
ALOFT...A DEEP LAYERED TROUGH EXTENDS FROM AN UPPER-LEVEL LOW 
LOCATED NEAR 32N125W TO NEAR 24N137W WHILE ANDRES IS MOVING 
AROUND THE PERIPHERY OF A RIDGE ANCHORED ON A HIGH OVER THE GULF 
OF CALIFORNIA NEAR 27N111W. THE RIDGE IS FORECAST TO BUILD WWD 
AS THE UPPER-LEVEL LOW MOVES NEWD REACHING THE COAST OF 
CALIFORNIA LATE THU. UPPER LEVEL N-NE FLOW BETWEEN THE RIDGE  
AND AN ELONGATED UPPER TROUGH CENTERED OVER MEXICO IS PROVIDING 
MODERATE NORTHEASTERLY SHEAR TO ANDRES. 

AT THE SURFACE...A RIDGE EXTENDS FROM A 1028 MB SURFACE HIGH 
LOCATED NEAR 34N152W SE TO THE BAJA CALIFORNIA COAST. SURFACE 
DATA AND AN EARLIER QSCAT PASS SHOWED 20 KT NE TRADES S OF THE 
RIDGE...MAINLY W OF 130W. THE PRES GRADIENT BETWEEN THE RIDGE 
AND A TROUGH OF LOW PRES OVER MAINLAND MEXICO IS PRODUCING NW TO 
N WINDS OF 20 KT N OF 25N BETWEEN 120W TO 130W WITH SIGNIFICANT 
WAVE HEIGHTS OF UP TO 9 FT IN NW SWELL. A SHIP...WFLG...JUST N 
OF AREA IS REPORTING 13 FT. THESE CONDITIONS ARE EXPECTED TO 
PERSIST DURING THE NEXT 36 TO 48 HOURS.   

FURTHER SOUTH...AN EARLIER QUIKSCAT DATA SHOWED A PERSISTENT 
WEAK LOW PRES AROUND 1010 MB EMBEDDED WITHIN THE ITCZ NEAR 
11N123W. CONVECTION CONTINUES TO FLARE UP NEAR THE LOW CENTER 
PARTICULARLY TO THE EAST. A DIFFLUENT PATTERN ALOFT IS ENHANCING 
THIS CONVECTIVE ACTIVITY. THE GFS COMPUTER MODEL SUGGESTS A 
MODEST INCREASE IN WINDS AND SEAS ASSOCIATED WITH THIS LOW IN 
ABOUT 24 HOURS.  

$$
GR