000
AXPZ20 KNHC 081514
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE SEP 08 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 FEATURES...

AT 08/1500 UTC...TROPICAL STORM LINDA IS LOCATED NEAR 15.2N 
128.4W MOVING W OR 275 DEG AT 2 KT. MAXIMUM SUSTAINED WIND SPEED 
IS 50 KT WITH GUSTS TO 60 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 
IS 997 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. NUMEROUS 
MODERATE WITH SCATTERED STRONG CONVECTION IS NOTED WITHIN 75 NM 
OF THE CENTER EXCEPT 120 NM N QUADRANT. ADDITIONAL STRENGTHENING 
IS FORECAST THROUGH WEDNESDAY BUT THE FORECAST KEEPS LINDA AS A 
TROPICAL STORM. SATELLITE IMAGERY SHOWS A SHARP WESTERN 
EDGE TO THE DEEP CONVECTIVE CLOUDS ASSOCIATED WITH 
LINDA...INDICATING THAT THE CYCLONE IS EXPERIENCING WESTERLY 
SHEAR.

...THE ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE 06N77W TO 
08N100W TO 08N120W TO 07N140W. SCATTERED MODERATE TO STRONG 
CONVECTION IS WITHIN THE AREA FROM 05N TO 07N EAST OF 85W. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN THE 
AREA 75 NM EITHER SIDE OF THE ITCZ AXIS FROM 98W TO 109W. 
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 120 NM OF THE 
POINT 06.5N115W. SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION IS WITHIN THE AREA 45 NM EITHER SIDE OF THE ITCZ AXIS 
WEST OF 136.5W.

...DISCUSSION...

A DEEP LAYER ANTICYCLONE LOCATED W OF 140W HAS A RIDGE EXTENDING 
EWD OVER THE WESTERN PORTION OF THE FORECAST REGION. THE RIDGE 
AND THE ASSOCIATED DRY STABLE AIR IN THE MIDDLE AND UPPER LEVELS 
OF THE ATMOSPHERE COVERS THE AREA N OF 10N AND W OF 130W.

A SHARP DEEP LAYER TROUGH EXTENDS FROM SE ARIZONA ACROSS CENTRAL 
BAJA CALIFORNIA TO 18N130W. ANOTHER UPPER LEVEL ANTICYCLONIC 
CIRCULATION IS CENTERED NEAR 15N116W. TROPICAL STORM LINDA IS 
MOVING AROUND THE WESTERN PERIPHERY OF THIS SYSTEM. THE THIRD 
MID/UPPER LEVEL HIGH IS OVER SOUTHERN MEXICO ALONG THE COAST OF 
THE BAY OF CAMPECHE AND IS ENHANCING CONVECTION N OF THE ITCZ 
BETWEEN 95W-105W. AN INVERTED UPPER LEVEL TROUGH WITH AXIS ALONG 
111W SEPARATES THE ABOVE MENTIONED ANTICYCLONES. 

A SURFACE RIDGE CONTINUES TO DOMINATE THE NORTHERN PORTION OF 
DISCUSSION AREA MAINLY N OF 20N W OF 115W. THE PRESSURE GRADIENT 
BETWEEN LINDA AND THE RIDGE IS PRODUCING A LARGE AREA OF NE 
WINDS 20 KT AND SEAS TO 9 FT PARTICULARLY FROM 15N TO 25N AND W 
OF 130W. THESE CONDITIONS ARE EXPECTED TO PERSIST DURING THE 
NEXT 48 HOURS. STRATOCUMULUS CLOUDS ARE OBSERVED N OF 15N W OF 
120W.

SWELLS FROM THE NW ARE IN THE NE PORTION OF THE AREA THROUGH 
TONIGHT. LATE IN THE WEEK...LONG PERIOD SWELLS OF 16 SECONDS  
WILL APPROACH THE NW PART OF THE AREA WITH SEAS TO 11 FT.

$$
LL