000
AXPZ20 KNHC 041607
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON JUN 04 2007

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...SPECIAL FEATURE...

THE REMNANT CONVECTION OF TROPICAL STORM ALVIN FLARED OVER THE 
PAST FEW HOURS WITH A BROAD CYCLONIC CIRCULATION PULLING N OF 
THE ITCZ. CURRENTLY THE SYSTEM IS ANALYZED AS A SURFACE LOW PRES 
AT 11N123W 1006 MB. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS DECREASING WITHIN 90 NM OF 11N121W. IF CONVECTION 
FLARES AGAIN THIS AFTERNOON...AND PERSISTS...THIS LOW PRES 
SYSTEM MAY BECOME TROPICAL DEPRESSION ALVIN AGAIN. 

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N86W 12N95W 8N109W 11N124W 
5N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
WITHIN 90 NM OF THE COAST OF COLOMBIA FROM 3N TO 8N...AND ALSO 
WITHIN 120 NM EITHER SIDE OF LINE 13N97W 7N114W 11N122W 6N140W. 
ISOLATED MODERATE CONVECTION WAS OBSERVED ELSEWHERE N OF 10N E 
OF 99W.
 
DISCUSSION...

AN UPPER LEVEL TROUGH OVER THE NW PORTION OF THE DISCUSSION AREA 
HAS ITS MEAN AXIS FROM 32N133W TO A SMALL UPPER CYCLONE AT 
21N140W. THE ASSOCIATED SURFACE FRONT IS LOSING IDENTITY ALONG 
30N133W 26N140W. AN UPPER ANTICYCLONE IS CENTERED NEAR 28N120W 
WITH A SHORT WAVE RIDGE EXTENDING N TO WELL BEYOND 32N122W AND 
EFFECTIVELY SEPARATES THE UPSTREAM TROUGH MENTIONED ABOVE FROM A 
LONGWAVE TROUGH THAT DOMINATES CENTRAL N AMERICA...AND EXTENDS 
SW INTO THE AREA ALONG 32N100W 20N113W TO A SMALL UPPER CYCLONE 
CUTTING OFF AT 13N114W.

A TROPICAL UPPER ANTICYCLONE IS ILL-DEFINED NEAR 11N120W WITH A 
RIDGE EXTENDING W ACROSS THE REMNANTS OF TROPICAL STORM ALVIN TO 
A SHARP CREST OVER THE ITCZ NEAR 9N142W. THE ASSOCIATED UPPER 
DIFFLUENCE IS ENHANCING CONVECTION ALONG THE ITCZ BETWEEN 120W 
AND 132W...WITH MOST OF THE RESULTANT DEBRIS MOISTURE ADVECTED N 
TO ALONG 18N...WHERE IT EVAPORATES IN A LARGE AREA OF UPPER DRY 
AIR THAT IS NOTED FROM 18N-30N W OF 105W. 

A TROPICAL UPPER ANTICYCLONE OVER THE W CARIBBEAN EXTENDS W 
ACROSS CENTRAL AMERICA INTO THE E PAC TO A CREST AT 16N109W.
UPPER DIFFLUENCE ENHANCED CONVECTION OVER SE OLD MEXICO LAST 
NIGHT AND ALONG THE E PAC ITCZ BETWEEN 86W AND 106W. SOME OF THE 
DEBRIS MOISTURE IS ADVECTED S ACROSS THE EQUATOR AT 100W IN 
RESPONSE TO ANOTHER ANTICYCLONE NEAR 3S100W. THE REST OF THE 
DEBRIS MOISTURE SPREADS N ACROSS EASTERN OLD MEXICO AND OVER THE 
SW GULF OF MEXICO.
       
$$
FORECASTER NELSON/ROWLAND