000
AXPZ20 KNHC 111521
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN OCT 11 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... 

LOW NEAR 16.5N108.5W OR ABOUT 300 NM SW OF MANZANILLO MEXICO. 
CENTRAL PRESSURE IS ESTIMATED TO BE 1007 MB. GOOD UPPER LEVEL 
OUTFLOW IS OBSERVED OVER THE SYSTEM. THUNDERSTORM ACTIVITY HAS 
CHANGED LITTLE DURING THE PAST FEW HOURS AND THERE HAS BEEN 
LITTLE OVERALL CHANGE IN ITS ORGANIZATION. A TROPICAL DEPRESSION 
COULD FORM LATER TODAY OR TONIGHT AS THE LOW MOVES SLOWLY 
NORTHWESTWARD. SCATTERED MODERATE TO STRONG CONVECTION IS 
LOCATED WITHIN 180 NM OF THE CENTER OVER THE WEST SEMICIRCLE OF 
THE LOW. THE LOW IS EXPECTED TO MAKE A SLOW NORTH TO NORTHWEST 
TRACK OVER THE NEXT 24 TO 48 HOURS.

...TROPICAL WAVE...

A TROPICAL WAVE IS ALONG 93W/94W FROM 03N TO 14N MOVING W AT 10 
TO 15 KT. THE WAVE IS MOVING W IN TANDEM WITH AN UPPER LEVEL LOW 
LOCATED WEST OF THE WAVE NEAR 11N98W. THE CIRCULATION ASSOCIATED 
WITH THE UPPER LOW EXTENDS OUT ABOUT 300 NM FROM THE CENTER. 
UPPER DIVERGENCE ON THE EAST SIDE OF THE UPPER LOW...ALONG WITH 
FRESH TO MODERATE SW FLOW S OF THE ITCZ ARE TOGETHER MAINTAINING 
CLUSTERS OF MOSTLY MODERATE CONVECTION WITHIN 90 NM EITHER SIDE 
OF THE TROPICAL WAVE. CURRENTLY SCATTERED MODERATE CONVECTION IS 
WITHIN 90 NM OF 14N94W AND SHOWS SOME SIGNS OF BEING ORGANIZED 
BY THE LOW LEVEL FLOW. OTHER MORE ISOLATED MODERATE CONVECTION 
IS WITH 90 NM OF THE WAVE AXIS IN THE ITCZ.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE ITCZ AXIS 
WAS CENTERED ALONG 06N77W TO 06N86W TO 12N93W TO 13N105W TO 
09N120W TO 13N134W TO 10N140W.  SCATTERED MODERATE TO STRONG 
CONVECTION IS WITHIN 120 NM OF THE POINT 05N79W. 


OTHER CONVECTION
A COUPLE OF AREAS OF CONVECTION ARE LOCATED JUST OFF THE COAST 
OF MEXICO. ONE IS SCATTERED MODERATE TO STRONG CONVECTION WITHIN 
90 NM OF THE POINT 18.5N105W. ALSO SCATTERED MODERATE TO STRONG 
CONVECTION IS WITHIN 100 NM OF THE POINT 22N107.5W.
 
...DISCUSSION...

DEEP LAYER TROUGH IS NORTH OF A LINE FROM 30N100W TO 20N115W TO 
22N140W. MOST OF THE AREA IS DRY AND CLOUD FREE IN THE MIDDLE 
AND UPPER LEVELS WITH OVERCAST STRATOCUMULUS IN THE LOWER  
LEVELS. A COLD FRONT IS OVER THE FAR NORTHWEST PART OF THE AREA 
THROUGH 32N136W TO 28N140W. MULTI LEVEL CLOUDS ARE NEAR THE 
FRONT AND A FEW SHOWERS ARE ALONG AND WITHIN 120 NM OF THE FRONT 
NORTH OF 30N. THE PATTERN IS FORECAST TO CONTINUE WITH 
SHORTWAVES MOVING THROUGH THE BROAD TROUGH.

EXCEPT FOR THE LOW MENTIONED IN THE TROPICAL WAVE SECTION BROAD 
ANTICYCLONIC FLOW IS OBSERVED ELSEWHERE IN THE AREA. THIS FLOW 
IS DIFFLUENT ALOFT EAST OF 115W AND NORTH OF THE ITCZ WITH AREAS 
OF MULTI LEVEL CLOUDS AND EMBEDDED AREAS OF CONVECTION.  

TROUGH IS WITHIN THE ITCZ FROM 16N132W TO 11N135W AND IS MOVING 
WEST 10 TO 15 KT. THERE IS ONLY ISOLATED MODERATE CONVECTION 
WITHIN THE ITCZ NEAR THE TROUGH.

WEAK SURFACE RIDGE IS NORTH OF 16N WEST OF 117W. ELSEWHERE 
EXCEPT FOR THE TROUGH AND LOW MENTIONED ABOVE A BROAD TROUGH 
COVERS THE AREA.

$$
LL