000
AXPZ20 KNHC 290243
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU OCT 29 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE FROM 07N78W 
TO 07N90W TO 12N110W TO 08N140W. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF THE POINT 07N88W.

OTHER CONVECTION NORTH OF THE ITCZ
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 75 
NM OF THE POINT 12N95.5W. SCATTERED MODERATE TO STRONG 
CONVECTION IS WITHIN THE AREA FROM 12N TO 17N FROM 99.5W TO 
102.5W.

...DISCUSSION...

STRONG DEEP LAYER TROUGH IS OVER MEXICO NORTH OF A LINE FROM THE 
MEXICAN GULF OF MEXICO COAST NEAR 25N TO THE MEXICAN PACIFIC 
OCEAN COAST NEAR 20N. THE TROUGH ALSO EXTENDS OVER THE NORTHEAST 
PART OF THE PACIFIC OCEAN AREA NORTH AND EAST OF A LINE THROUGH 
32N125W TO 20N115W TO 20N105W. THE TROUGH IS FORECAST TO PERSIST 
THROUGH MIDDAY FRIDAY THEN WEAKEN SOME AND MOVE EAST SATURDAY 
AND SUNDAY. A WEAKER TROUGH EXTENDS FROM THE MAIN TROUGH WEST 
SOUTHWEST OVER THE PACIFIC FROM NEAR THE COAST OF MEXICO AT 20N 
TO NEAR 10N140W. MOST OF THE AREA NORTHWEST OF THE TROUGH IS 
DOMINATED BY A LARGE ANTICYCLONE CENTERED NEAR 32N140W. DRY 
MIDDLE AND UPPER LEVELS INDICATES SUBSIDENCE IN THIS LARGE AREA 
EXCEPT FOR THIN BROKEN TO OVERCAST MIDDLE CLOUDS OVER NORTHWEST 
MEXICO AND OFFSHORE BAJA CALIFORNIA NORTH OF 28N WEST TO 125W.   
IN THE LOWER LEVELS OVERCAST STRATOCUMULUS IS NORTH OF 17N TO 
22N WEST OF 120W WITH BROKEN STRATOCUMULUS ELSEWHERE NORTH OF 
16N WEST OF 115W. WITHIN 300 NM SOUTHEAST AND SOUTH OF THE 
WEAKER TROUGH THE ATMOSPHERE IS MOIST IN THE DEEP LAYER WITH 
MULTI LEVEL CLOUDS FROM MOISTURE EMANATING FROM ITCZ CONVECTION. 
THE ITCZ CONVECTION HAS DIMINISHED IN THE LAST SEVERAL HOURS AND 
IS CONFINED TO THE WEST OF 133W.

NORTH OF 05N EAST OF 103W THE ATMOSPHERE IS DIFFLUENT ALOFT WITH 
DEEP LAYER MOISTURE WITH MULTI LEVEL CLOUDS AND EMBEDDED AREAS 
OF CONVECTION. WIDELY SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION IS NORTH OF 10N FROM 94W TO 103W.

A LARGE CYCLONIC CIRCULATION IS OVER THE WESTERN CARIBBEAN AND 
IS ASSOCIATED WITH DRY MIDDLE AND UPPER LEVELS AND CLEAR SKIES 
IN THE MIDDLE AND UPPER LEVELS. THIS FEATURE EXTENDS WESTWARD 
OVER NORTHERN CENTRAL AMERICA AND THE EASTERN PART OF MEXICO 
EAST OF 92W WITH SUPPRESSED CONVECTION OVER THIS AREA FROM 
NICARAGUA NORTH TO EAST MEXICO. FURTHER EAST OVER COSTA RICA AND 
PANAMA AND THE PACIFIC OCEAN NORTH OF A LINE FROM NORTHERN 
ECUADOR TO THE ITCZ NEAR 90W DIFFLUENT FLOW ALOFT IS ASSOCIATED 
WITH MULTI LEVEL CLOUDS AND EMBEDDED AREAS OF CONVECTION. 

STRONG SURFACE RIDGE IS NORTH OF 15N WEST OF 118W. STRONG NORTH 
TO NORTHEAST WINDS ARE ASSOCIATED WITH THE RIDGE WITH NEAR 30 
KNOT NORTHERLY WINDS OFF THE COAST OF NORTHERN MEXICO AND 
FURTHER NORTH GALE FORCE NORTHERLY WINDS NORTH OF 30N. THESE 
WINDS WILL BEGIN TO DIMINISH THURSDAY AS THE SURFACE HIGH 
WEAKENS AND CONTRACTS IN SIZE WHILE A COLD FRONT APPROACHES FROM 
THE NORTHWEST. ELSEWHERE AT THE SURFACE A BROAD TROUGH IS 
ANALYZED.
 
$$
LL