000
AXPZ20 KNHC 192147
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN AUG 19 2007

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 91.5W HAS BEEN MOVING W AT 15 KT OVER THE 
PAST 48 HOURS. ONLY ISOLATED MODERATE CONVECTION IS NOTED FROM 
6N TO 12N WITHIN 90 NM OF THE AXIS.

A TROPICAL WAVE ALONG 140W HAS MOVED W AT 12 KT OVER THE PAST 24 
HOURS AND CURRENTLY LACK CONVECTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N85W 7N95W 11N100W 15N115W 
11N140W. SCATTERED MODERATE CONVECTION NOTED WITHIN 180 NM OF 
LINE 6N83W 9N98W AND WITHIN 360 NM EITHER SIDE OF LINE 9N103W 
17N115W.

...DISCUSSION...

AN UPPER TROUGH DOMINATES THE E PAC EXTENDING S INTO THE 
DISCUSSION AREA FROM 32N128W TO AN UPPER CYCLONE NEAR 
17N134W...WITH THIS TROUGH SQUEEZED BETWEEN TWO UPPER RIDGES. 
THE PARENT UPPER ANTICYCLONE TO ITS W IS NEAR 22N150W WITH A 
RIDGE EXTENDING E TO A CREST NEAR 24N137W. AN UPPER ANTICYCLONE 
IS OVER THE OLD MEXICO AND ARIZONA BORDER NEAR 31N111W WITH A 
RIDGE EXTENDING SW TO A CREST ALONG POINTS 15N115W 20N128W 
31N123W. UPPER DIFFLUENCE FROM THIS RIDGE IS ENHANCING THE 
CONVECTION OVER THE PAC TO THE N OF THE ITCZ BETWEEN 105W AND 
120W...WITH THE RESULTANT DEBRIS MOISTURE REMAINING UNDER THE 
ENVELOPE OF ANTICYCLONIC FLOW...EXCEPT SOME OF THE ITCZ DEBRIS 
MOISTURE IS ADVECTED SW TO NEAR THE EQUATOR BETWEEN 100W AND 
120W. OTHERWISE...DRY UPPER AIR IS NOTED OVER THE DISCUSSION 
AREA N OF 12N W OF 126W. 

AN UPPER CYCLONE OVER THE CENTRAL GULF OF MEXICO IS NEAR 26N90W
AND CONTINUES W WHILE TRAILING A TROUGH S TO NEAR 17N98W. THE 
ENVELOPE OF ANTICYCLONIC UPPER FLOW ASSOCIATED WITH HURRICANE 
DEAN EXTENDS S INTO THE PAC WATERS N OF 5N E OF 88W...OTHERWISE 
THE UPPER FLOW IS NE OVER THE TROPICS DEEP TROPICAL E PAC...S OF 
9N E OF 135W. 

A SURFACE LOW IS NEAR 22.3N114.3W ESTIMATED AT 1006 MB AND IS 
DRIFTING NW TOWARDS COOLER SEA SURFACE TEMPERATURES. THE SURFACE 
LOW IS EXPOSED E OF CONVECTION NOTED NEAR 21N118.5W. A RIDGE 
EXTENDS ALONG 30N140W 24N124W. 

$$
NELSON