000
AXPZ20 KNHC 180332
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED APR 18 2007

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 
0315 UTC.

...ITCZ...

AXIS 4N77W 11N106W 3N140W. SCATTERED MODERATE ISOLATED STRONG 
WITHIN 120 NM EITHER SIDE OF LINE 5N83W 7N91W AND WITHIN 60 NM 
OF 8N97W AND 12N104W.

...DISCUSSION...

AN UPPER SHORTWAVE TROUGH IS SWINGING SE INTO THE NW PORTION 
ALONG 32N117W 27N140W WITH DRY AIR NOTED WITHIN 120 NM NW OF THE 
TROUGH. AN UPPER CYCLONE AT 25N129W WITH THE TROUGH S TO A BASE 
AT 9N129W. AN UPPER ANTICYCLONE IS AT 15N84W WITH A RIDGE W TO A 
CREST ALONG POINTS 13N125W 25N120W 28N117W 31N90W. ASSOCIATED 
UPPER DIFFLUENCE ENHANCED ITCZ CONVECTION BETWEEN 96W AND 121W. 
THE RESULTANT DEBRIS MOISTURE IS ADVECTED NE UNDER THE RIDGE 
INTO A MOISTURE PLUME THAT TURNS EASTWARD ACROSS OLD MEXICO AND 
THE NORTHERN GULF OF MEXICO. OTHERWISE DRY UPPER AIR IS NOTED 
OVER THE W PORTION OF THE DISCUSSION AREA AND E OF 95W. 

AT THE LOW LEVELS A RIDGE EXTENDS INTO THE AREA ALONG 32N140W 
11N105W. THE ITCZ IS STRETCHED N TO NEAR 11N108W. NW WINDS IN 
THE SEA OF CORTEZ THIS AFTERNOON IS ALSO EXPECTED TO DIMINISH 
LATER TONIGHT.

$$
NELSON