000
AXPZ20 KNHC 081608
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI SEP 8 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 81W N OF 5N MOVING W 15 KT. CYCLONIC TURNING 
NOTED ALONG THE AXIS AT 9N WITH CONVECTION ENHANCED WITHIN 120 
NM OF THE AXIS AT 9N. CONVECTION ALSO ENHANCED OVER THE SW 
CARIBBEAN ALONG THE AXIS AT 13N.

TROPICAL WAVE ALONG 91W MOVING W 12 KT. CYCLONIC TURNING NOTED 
WITHIN THE ITCZ AT 6N. BROAD CYCLONIC TURNING ALSO EVIDENT N OF 
9N TO THE COAST OF MEXICO ALONG THE AXIS WITH SCATTERED MODERATE 
TO STRONG CONVECTION ENHANCED ALONG 10N BUT CURRENTLY 
DECREASING. SCATTERED MODERATE TO STRONG CONVECTION ALSO ENHANCED
WITHIN 150 NM OF 13.5N92W.

...ITCZ...

ITCZ AXIS 9N84W 10N91W 7N100W 12N114W 11N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 150 NM EITHER 
SIDE OF LINE 4N78W 13N123W. ISOLATED MODERATE AND STRONG 
OBSERVED WITHIN 180 NM EITHER SIDE OF LINE 14N131W 10N140W.

...DISCUSSION...

AN UPPER LEVEL CYCLONE HAS CUT OFF AT 20N136W AND IS DRIFTING W 
WITH TIME. THIS CYCLONE IS EXPECTED TO WEAKEN TONIGHT AS IT 
MERGES WITH AN UPPER SHORTWAVE TROUGH SWINGING E SE INTO THE NW 
PORTION OF THE DISCUSSION AREA. GLOBAL MODELS SUGGEST THE MERGED 
TROUGH WILL STALL ROUGHLY ALONG 140W SAT...THEN RETROGRESS 
SLIGHTLY W WITH ANOTHER CUT OFF UPPER CYCLONE DEVELOPING NEAR 
19N146W SAT NIGHT. 

AN UPPER ANTICYCLONE IS CENTERED OVER OLD MEXICO NEAR 21N102W 
RIDGING W NW TO A FAIRLY SHARP CREST NEAR 27N123W. THE 
ANTICYCLONE IS EXPECTED TO SHIFT NW OVER THE SEA OF CORTEZ SAT 
WITH ITS RIDGE BUILDING W NW TO NEAR 30N140W...AND EFFECTIVELY 
BLOCKING THE EASTWARD PROGRESS OF THE SHORTWAVE DISCUSSED 
PREVIOUSLY. A RIDGE IS ALSO EXPECTED TO BUILD SW TO NEAR 
11N133W...ALSO BLOCKING THE EASTWARD PROGRESS THE UPPER TROUGH 
AXIS...BUT ALLOWING THE TROUGH TO DIG S...LYING N TO S ALONG 
140W OVER THE TROPICAL WATERS N OF 8N BY LATE SAT. CURRENTLY A 
BAND OF VERY DRY UPPER AIR IS INDICATED WITHIN 90 NM EITHER SIDE 
OF LINE 25N110W 30N122W 26N131W SURROUNDED BY DRY UPPER AIR 
ELSEWHERE N OF 18N W OF 112W.    

A LONG WAVE TROUGH DOMINATING EASTERN N AMERICA HAS ITS MEAN 
AXIS EXTENDING S SW ACROSS THE CENTRAL GULF OF MEXICO ALONG 
32N87W TO A BASE OVER THE BAY OF CAMPECHE AT 20N92W. IMMEDIATELY 
TO THE SE...AN UPPER ANTICYCLONE IS AT 17N86W RIDGING W ACROSS 
CENTRAL AMERICA INTO THE TROPICAL E PAC OVER THE GULF OF 
TEHUANTEPEC. ASSOCIATED UPPER DIFFLUENCE HAS ENHANCED CONVECTION 
ALONG THE TROPICAL WAVE AT 91W...WITH SOME OF THE DEBRIS 
MOISTURE ALREADY SPREADING N ACROSS THE ISTHMUS OF TEHUANTEPEC 
AND OVER THE EASTERN BAY OF CAMPECHE. 

TO FURTHER CONFUSE THE UPPER FLOW OVER THE TROPICAL E PAC E OF 
110W...A SMALL UPPER CYCLONE IS NOTED OVER THE SW CARIBBEAN AT 
13N83W WITH ITS ENVELOPE OF UPPER CYCLONIC FLOW EXPANDING S OVER 
COSTA RICA ATTM. FURTHER SE...A LARGE ANTICYCLONE NEAR 5S57W 
RIDGES NW OFF THE COAST OF COLOMBIA INTO THE E PAC CRESTING AT 
7N82W.

THE UPPER LEVELS ARE MOIST N OF THE ITCZ E OF 95W. A BAND OF DRY 
UPPER AIR INDICATED WITHIN 90 NM EITHER SIDE OF LINE 11N93W 
16N107W.     

AT THE LOW LEVELS...LOW PRES...REMNANTS OF TROPICAL CYCLONE 
KRISTY...NEAR 15N132W 1009 DRIFTING W. BURSTS OF STRONG 
CONVECTION CONTINUE...MAINLY OVER THE W QUADRANT...WHILE 
ISOLATED MODERATE CONVECTION FLARES ELSEWHERE WITHIN 60 NM OF 
THE CENTER. OTHERWISE A RIDGE EXTENDS ACROSS THE NW PORTION 
ALONG 30N140W 20N120W. 
 
$$
NELSON