000
AXPZ20 KNHC 040935
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI SEP 04 2009

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 
0930 UTC.

...SPECIAL FEATURES...

JIMENA HAS BEEN DOWNGRADED TO A TROPICAL DEPRESSION. AT 04/0900 
UTC...THE DEPRESSION IS NEAR 27.4N 111.6W...OR ABOUT 45 MILES... 
70 KM...EAST OF SANTA ROSALIA MEXICO DRIFTING SE OR 130 DEG AT 2 
KT. MAXIMUM SUSTAINED WINDS HAVE DECREASED TO 30 KT WITH GUSTS 
TO 40 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. 
THE FORECAST TRACK OF JIMENA CARRIES THE SYSTEM BACK ACROSS THE 
CENTRAL BAJA CALIFORNIA PENINSULA THROUGH SATURDAY AS A REMNANT 
LOW. JIMENA IS EXPECTED TO PRODUCE ADDITIONAL RAIN ACCUMULATIONS 
OF 1 TO 3 INCHES OVER PORTIONS OF WESTERN MEXICO AND THE CENTRAL 
PORTION OF THE BAJA PENINSULA DURING THE NEXT DAY OR SO.  
ISOLATED MAXIMUM STORM-TOTAL AMOUNTS OF UP TO 30 INCHES ARE 
POSSIBLE. HIGHER THAN NORMAL TIDE LEVELS ALONG PORTIONS OF THE 
COAST OF THE CENTRAL BAJA PENINSULA AND WESTERN MAINLAND MEXICO 
WILL GRADUALLY SUBSIDE TODAY. REFER TO THE NHC FORECAST/ADVISORY 
UNDER AWIPS/WMO HEADERS MIATCMEP3 WTPZ23 KNHC AND THE PUBLIC 
ADVISORY MIATCPEP3/WTPZ33 KNHC FOR MORE INFORMATION.

...THE ITCZ...
THE ITCZ AXIS IS ALONG 10N85W TO 08N100W TO 11N110W THEN FROM 
09N119W TO 11N136W. SCATTERED MODERATE CONVECTION TO ISOLATED 
STRONG CONVECTION WITHIN 80 NM S OF AXIS AND E OF 85W TO THE 
COAST OF COSTA RICA. SIMILAR CONVECTION IS ALSO SEEN NEAR 
9.5N106W. 

A 1009 MB LOW PRESSURE CENTER IS NEAR 12N113W IN THE ITCZ. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED FROM 
10 TO 18N BETWEEN 112W AND 118W. A SURFACE TROUGH BREAKS UP THE 
ITCZ AND EXTENDS FROM 15N136W TO 09N140W. SCATTERED MODERATE 
CONVECTION IS FROM 10N TO 13N W OF 137W. UPPER-LEVEL WINDS ARE 
FORECAST TO BECOME MORE CONDUCIVE FOR TROPICAL CYCLONE FORMATION 
DURING THE NEXT DAY OR TWO AS THE SYSTEM MOVES TO THE W-NW AT 
ABOUT 10 KT.   

...DISCUSSION...

AN UPPER ANTICYCLONE CENTER NEAR 22N125W COVERS THE NW PORTION 
OF THE AREA EXTENDING A RIDGE SW TO NEAR 14N140W AND MAINLY E TO 
NEAR SOUTHERN BAJA CALIFORNIA. STRONG UPPER LEVEL SUBSIDENCE AND 
THE IMPLIED DRY AIR MASS IS NOTED WITHIN THE RIDGE. ANOTHER 
ANTICYLONE IS CENTERED NEAR MANZANILLO MEXICO. THESE TWO 
FEATURES ARE PRODUCING A BELT OF ELY UPPER-LEVEL WINDS N OF 10N 
AND W OF 100W. 

AT THE SURFACE...A RIDGE DOMINATES THE NW CORNER OF THE FORECAST 
AREA.  

THE REMNANT LOW PRESSURE CENTER OF KEVIN...ANALYZED 1011 MB... 
IS NEAR 19N123W...MARKED BY A SWIRL OF LOW CLOUDS. THE LOW IS 
FORECAST TO DISSIPATE WITHIN 24 HOURS BUT A SFC TROUGH WILL 
PERSIST THROUGH 48 HOURS. 

GAP WINDS...EXPECT ELY WINDS NEAR 20 KT TO PULSE UP AND DOWN 
THROUGH THE GULF OF PAPAGAYO AND THEN DOWNSTREAM TO NEAR 89W 
DURING THE NEXT FEW DAY. WINDS IN THE GULF OF TEHUANTEPEC ARE 
EXPECTED TO OSCILLATE BETWEEN 20 AND 25 KT OVER THE NEXT 12 
HOURS.  

A MIXTURE OF SOUTH...SOUTHWEST...AND NORTHWESTERLY LONG PERIOD 
SWELL DOMINATES THE REGIONAL WATERS.

$$
GR