000
AXPZ20 KNHC 192121
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN OCT 19 2008

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 
2100 UTC.

...ITCZ...

THE ITCZ AXIS IS ALONG THE LINE FROM 06N77W TO 06N105W TO 
07N140W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM OF THE 
POINT 06N80W. OTHERWISE THERE IS NOT MUCH CONVECTION ALONG THE 
ITCZ.

SCATTERED MODERATE CONVECTION WITHIN 60 NM OF THE POINT 
11N100.5W. THIS CONVECTION IS WELL NORTH OF THE ITCZ.

...DISCUSSION...

THE STRONG SURFACE PRESSURE GRADIENT OVER SOUTHERN MEXICO 
BETWEEN HIGH PRESSURE OVER THE WESTERN GULF OF MEXICO AND 
NORTHERN MEXICO AND LOW PRESSURE IN THE GULF OF HONDURAS AND A 
TROUGH WHICH EXTENDS SOUTHWESTWARD INTO THE PACIFIC NEAR 10N95W 
IS INDUCING A GALE FORCE WIND EVENT IN THE GULF OF TEHUANTEPEC 
WHICH SHOULD END EARLY MONDAY.  

UPPER LEVEL DIFFLUENCE BETWEEN AN ANTICYCLONE OVER THE CARIBBEAN 
AND RELATIVELY STRONG EASTERLY FLOW S OF 10N E OF 90W HAS 
ENHANCED CONVECTION SOUTH OF PANAMA AND WEST OF COLOMBIA. THIS 
CONVECTION HAS DECREASED IN INTENSITY DURING THE LAST 24 HOURS.  
CURRENTLY...SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 
120 NM OF THE POINT 06N80W.

OVER NW WATERS...DEEP LAYER TROUGH STRETCHED OVER NW WATERS 
NORTH OF A LINE THROUGH 32N115W TO 18N140W. THE MIDDLE LEVEL 
PART OF THE TROUGH WILL PASS EASTWARD INTO THE BAJA TONIGHT AND 
MONDAY AS IT IS INCORPORATED IN THE MIDDLE LATITUDE WESTERLIES. 
THE TROUGH WILL LEAVE BEHIND SOME VORTICITY NORTH OF 25N THROUGH 
THE NEXT SEVERAL DAYS. THIS FLOW PATTERN WILL CARRY THE MOISTURE 
ASSOCIATED WITH WEAKENING CONVECTION IN THE WESTERN PORTIONS OF 
THE ITCZ. THE AREA OF THE TROUGH IS CLOUD FREE IN THE MIDDLE AND 
UPPER LEVELS WITH BROKEN TO OVERCAST STRATOCUMULUS IN THE LOWER 
LEVELS. 

BROKEN TO OVERCAST STRATOCUMULUS IN THE LOWER LEVELS IS ALSO 
FOUND SOUTH OF THE ITCZ WITH CLEAR SKIES IN THE MIDDLE AND UPPER 
LEVELS.

MODERATE SURFACE RIDGE IS NORTH OF ABOUT 12N WEST OF 110W. THIS 
RIDGE IS FORECAST TO CHANGE LITTLE THROUGH 48 HOURS. ELSEWHERE A 
BROAD TROUGH IS ANALYZED.

$$
LL