000
AXPZ20 KNHC 280243
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED OCT 28 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 CENTERED ALONG...06N77W TO 
12N100W TO 11N120W TO 08N140W. SCATTERED MODERATE TO STRONG 
CONVECTION IS OVER THE GULF OF PANAMA. SCATTERED MODERATE TO 
STRONG CONVECTION IS WITHIN THE AREA N OF 05N FROM 80W TO 81.5W. 
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 100 NM OF THE 
POINT 12N95W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 
75 NM OF THE POINT 14N101W. SCATTERED MODERATE TO STRONG 
CONVECTION IS WITHIN 60 NM OF THE POINT 12N105W. SCATTERED 
MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 60 NM EITHER 
SIDE OF THE ITCZ AXIS W OF 135W.

...DISCUSSION...

DEEP LAYER LONGWAVE TROUGH AXIS EXTENDS FROM THE NORTHEAST COAST 
OF MEXICO AT 25N TO 18N105W TO 15N123W TO 11N127W TO 11N140W. 
MOST OF THE AREA NORTHWEST OF THE TROUGH AXIS IS DRY AND CLOUD 
FREE IN THE MIDDLE AND UPPER LEVELS. OVERCAST STRATOCUMULUS IS N 
OF 19N W OF 120W WITH CLEAR SKIES IN THE LOWER LEVELS ELSEWHERE 
NORTHWEST OF THE TROUGH AXIS. THE EXCEPTION TO THIS IS MOSTLY 
HIGH BROKEN CLOUDS OVER THE UNITED STATES FROM WEST TEXAS 
WESTWARD. THIS AREA IS DOMINATED BY A LARGE DEEP LAYER 
ANTICYCLONE CENTERED NEAR 33N141W. THE DEEP LAYER TROUGH IS 
CONFINED TO OVER THE NORTHEAST PART OF THE PACIFIC OCEAN AREA 
AND MEXICO NORTH OF 20N. THIS PATTERN IS FORECAST TO REMAIN WITH 
THE TROUGH STRENGTHENING SOME AND THE RIDGE WEAKENING SOME OVER 
THE NEXT SEVERAL DAYS.

TO THE SOUTHEAST OF THE TROUGH AXIS A MOIST REGION EXTENDS 
ABOUT 360 NM SOUTH OF THE TROUGH AXIS WEST OF 110W. SOME OF 
THIS AREA IS THE ITCZ. EAST OF 110W TO 90W THE ATMOSPHERE IS 
MOIST IN THE DEEP LAYER NORTH OF THE ITCZ WITH MULTI LEVEL 
OVERCAST CLOUDS WITH EMBEDDED AREAS OF CONVECTION. FROM ABOUT 
83W TO 91W THE ATMOSPHERE IS DRY IN THE MIDDLE AND UPPER LEVELS 
WITH SCATTERED TO BROKEN CUMULUS IN THE LOWER LEVELS.

STRONG SURFACE RIDGE IS NORTH OF 15N WEST OF 117W. NORTHEASTERLY 
WINDS OF 20 TO 25 KT ARE OVER THE NORTHWEST QUARTER OF THE 
PACIFIC OCEAN REGION DUE TO THE STRONG HIGH PRESSURE. WINDS WILL 
GUST TO 30 KNOTS NEAR 30N WITH GALE CONDITIONS FURTHER NORTH OFF 
THE CALIFORNIA COAST. AS THE RIDGE WEAKENS THESE WINDS WILL 
BEGIN TO DIMINISH LATER WEDNESDAY. ELSEWHERE A BROAD TROUGH IS 
ANALYZED AT THE SURFACE CENTERED AROUND THE ITCZ.
 
$$
LL