000
AXPZ20 KNHC 180324
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT AUG 18 2007

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 
0315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 81.5W HAS BEEN MOVING W AT 17 KT THE PAST 24 
HOURS. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS ENHANCED 
IN THE E PAC WITHIN 30 NM 8N83.5W AND WITHIN 30 NM OF 11N81W.

TROPICAL WAVE ALONG 109W N OF 6N MOVING W AT 12 KT. THE WAVE IS 
NEAR A BROAD AREA OF LOW PRES ANALYZED AS A LOW PRES NEAR 
16N109W AND ESTIMATED AT 1007 MB. A LARGE AREA OF MODERATE 
CONVECTION WITH A FEW STRONG CELLS CONTINUES FROM 8N TO 21N 
BETWEEN 97W AND 115W. 

A TROPICAL WAVE ALONG 131.5W FROM 6N TO 16N HAS MOVED W AT 15 KT 
OVER THE PAST 24 HOURS BUT IS BECOMING DIFFICULT TO LOCATE. 
SCATTERED MODERATE CONVECTION IS ENHANCED ALONG THE ITCZ WITHIN 
15 NM 10N131W. 

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N83W 7N91W 16N109W 10N131W 11N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 60 
NM OF 8N83W AND FROM 8N TO 21N BETWEEN 97W AND 115W AND WITHIN 
30 NM EITHER SIDE OF LINE 9N130W 11N140W. 

...DISCUSSION...

A BROAD UPPER TROUGH DOMINATES THE E PAC WITH TWO SHORTWAVE 
TROUGHS EXTENDING S INTO THE DISCUSSION AREA SQUEEZED BETWEEN 
TWO UPPER RIDGES. ONE UPPER TROUGH IS ALONG 32N123W 21.5N128W 
16N137W. THE SECOND UPPER TROUGH IS ALONG 32N119W 25N122W TO AN 
UPPER CYCLONE AT 17N125W. AN UPPER ANTICYCLONE IS NEAR 24N143W 
WITH A RIDGE EXTENDING E TO A CREST NEAR 26N132W. AN UPPER 
ANTICYCLONE IS OVER OLD MEXICO NEAR 27N105W WITH A RIDGE SW TO A 
SHARP CREST AT 19N119W. DRY UPPER AIR IS NOTED OVER THE 
DISCUSSION AREA N OF 13N W OF 118W. UPPER DIFFLUENCE FROM THE 
RIDGE OVER MEXICO IS ENHANCING THE CONVECTION OVER THE PAC N OF 
THE ITCZ BETWEEN 96W AND 117W WITH THE RESULTANT DEBRIS MOISTURE 
REMAINING IN ROUGHLY THE SAME AREA. 

AN UPPER TROUGH EXTENDS S FROM A CYCLONE NEAR 26N79W TO ANOTHER 
SMALL UPPER CYCLONE AT 14N89W. THE UPPER FLOW IS NE OVER THE 
TROPICS E OF 105W.
 
ELSEWHERE AT THE LOW LEVELS A RIDGE EXTENDS ALONG 32N140W 
13N125W. 

$$
NELSON