000
AXPZ20 KNHC 312115
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT OCT 31 2009

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 INTERTROPICAL CONVERGENCE ZONE WAS CENTERED ALONG THE LINE...
...05N77W TO 08N100W TO 09N125W TO 06N135W TO 05N140W. SCATTERED 
MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF THE 
POINT 05.5N81.5W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM 
OF THE POINT 06N86.5W. SCATTERED MODERATE TO STRONG CONVECTION 
IS WITHIN 60 NM OF THE POINT 13N94W. SCATTERED MODERATE 
CONVECTION IS WITHIN 60 NM OF THE POINT 14N105W. SCATTERED 
MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN THE AREA FROM 
07N TO 10N FROM 119W TO 126W. SCATTERED MODERATE CONVECTION IS 
WITHIN 90 NM OF THE POINT 06N133W.

...DISCUSSION...

DEEP LAYER TROUGH THAT HAS BEEN OVER MEXICO NORTH OF 20N IS 
MOVING EAST OVER THE WESTERN GULF OF MEXICO. THE RESULT IS A 
VERY WEAK HEIGHT PATTERN WITH A BROAD CYCLONIC CIRCULATION 
CENTERED NEAR 22N133W. THIS CIRCULATION IS BRINGING SOME DEEP 
LAYER MOISTURE WITH BROKEN MOSTLY HIGH CLOUDS FROM ITCZ 
CONVECTION NORTHWARD WITHIN 200 NM EITHER SIDE OF A LINE FROM 
24N116W TO NEAR 08N132W. OTHERWISE WEST OF 106W THE AREA IS DRY 
AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS. IN THE LOWER 
LEVELS BROKEN STRATOCUMULUS IS NOTED WEST OF 122W AND FROM 20 TO 
25N WEST OF 115W. THE HEIGHT PATTERN IS FORECAST TO REMAIN WEAK 
THROUGH THE NEXT SEVERAL DAYS. 

EAST OF 106W NORTH OF THE ITCZ THE ATMOSPHERE IS DIFFLUENT ALOFT 
WITH MULTI LEVEL CLOUDS AND EMBEDDED AREAS OF CONVECTION.

MODERATE SURFACE RIDGE IS NORTH OF 15N WEST OF 110W. THE SURFACE 
HIGH IS FORECAST TO WEAKEN AND CONTRACT IN SIZE WHILE A COLD 
FRONT APPROACHES FROM THE NORTHWEST. ELSEWHERE AT THE SURFACE A 
BROAD TROUGH IS ANALYZED.

GAP WINDS...
HIGH PRES BUILDING OVER NORTHERN MEXICO IN THE WAKE OF A COLD 
FRONT OVER THE GULF OF MEXICO IS PUSHING NORTH TO NORTHEAST 
WINDS OF 20 TO 25 KT AND INCREASING TO 20 TO 35 KT TONIGHT 
THROUGH THE GULF OF TEHUANTEPEC. THIS SHOULD CONTINUE THROUGH 
MID WEEK AS THE HIGH IS REINFORCED. 

$$
LL