000
AXPZ20 KNHC 170228
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED MAY 18 2006

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0200 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N76W 9N100W 7N120W 6N140W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION WITHIN 180 NM N OF AXIS FROM 80W 
TO 87W AND WITHIN 180 NM S OF AXIS FROM 97W TO 102W.  WIDELY 
SCATTERED MODERATE CONVECTION WITHIN 200 NM EITHER SIDE OF AXIS FROM 
100W TO 125W.

...DISCUSSION...

N OF 20N...
MIDDLE TO UPPER LEVEL TROUGH...RIDGE...TROUGH PATTERN COVERS THE 
NORTHERN PORTION OF THE DISCUSSION AREA.  FROM W TO E...A LARGE AND 
VIGOROUS MID/UPPER LEVEL TROUGH LIES W OF 130W WITH ASSOCIATED MOIST 
SWLY MID/UPPER LEVEL FLOW COVERING MUST OF THE W PART OF THE AREA. A 
WEAK AND NARROW RIDGE EXTENDS N ALONG 123N.  FARTHER E...SMALL AND 
WEAKENING UPPER LEVEL LOW IS SEEN OVER N BAJA WITH ASSOCIATED TROUGH 
EXTENDING SWD ALONG THE GULF OF CALIFORNIA.  DIFFLUENT FLOW IS 
OBSERVED E OF THE TROUGH GENERATING CLOUDINESS AND SHOWERS/TSTMS 
OVER THE HIGHER TERRAIN OF INTERIOR MEXICO N OF 20N.  AT THE 
SURFACE...SUBTROPICAL RIDGE CONTINUES TO BUILD ACROSS THE AREA FROM 
32N130W 16N123W. ELSEWHERE...A COLD FRONT IS LOCATED W OF THE AREA 
AND IS EXPECTED TO MOVE INTO THE NW PART OF THE DISCUSSION WITHIN 24 
HOURS AS THE LARGE UPPER TROUGH SHARPENS AND A CUT-OFF LOW FORMS 
JUST NW OF THE AREA. THE RIDGE AND SOUTHERN CALIFORNIA TROUGH ARE 
FORECAST TO REMAIN NEAR STATIONARY. 

S OF 20N...
THE MAIN FEATURE OVER THE TROPICAL PACIFIC IS AN E/W ORIENTED 
RIDGE EXTENDING FROM 12N140W TO 16N110W.  MODERATE SUBSIDENCE IS 
OBSERVED ALONG THE RIDGE AXIS TO 10N CREATING MOSTLY FAIR CONDITIONS 
N OF THE ITCZ. ISOLATED TO WIDELY SCATTERED CLUSTERS OF CONVECTION 
ARE LOCATED ALONG THE ITCZ BUT THERE IS NO SIGNIFICANT UPPER SUPPORT 
FOR ENHANCED ACTIVITY.  FURTHER E...A SHARP MID/UPPER LEVEL TROUGH 
AXIS EXTENDS FROM THE SW COAST OF MEXICO JUST W OF ACAPULCO INTO THE 
PACIFIC ALONG 18N102W TO 12N106W. EAST OF THE TROUGH...A MOIST SWLY 
FLOW IS ADVECTING MID/HIGH LEVEL MOISTURE NWD ACROSS EASTERN 
MEXICO...CENTRAL AMERICA...NW CARIBBEAN AND INTO EASTERN GULF OF 
MEXICO. SOME OF THIS MOISTURE IS BEING ADVECTED FARTHER N AHEAD OF A 
STRONG TROUGH THAT IS MOVING SE ACROSS GULF OF MEXICO.  
ADDITIONALLY...DIFFLUENT FLOW ON THE EQUATORWARD SIDE OF THE TROUGH 
AXIS CONTINUES TO ENHANCE ITCZ CONVECTION BETWEEN 95W AND 105W. A 
SECOND AREA OF ENHANCED ITCZ CONVECTION IS LOCATED E OF 85W WHERE A 
MID/UPPER LEVEL HIGH IS CENTERED OVER COLOMBIA/VENEZUELA NEAR 
10N73W. ASSOCIATED RIDGE AXIS EXTENDS W ALONG 10N TO NEAR 100W. THE 
STRONGEST AND MOST NUMEROUS ACTIVITY CURRENTLY OVER COLOMBIA AND 
ALONG THE IMMEDIATE COAST AS WELL AS N OF THE AXIS TO OVER PANAMA. 

$$
WALLACE