000
AXPZ20 KNHC 171501
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE OCT 17 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 
1500 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 94W N OF 5N IS MOVING W ABOUT 10-15 KT. LITTLE 
EVIDENCE OF ANY LOW TO MID LEVEL CYCLONIC TURNING IS EVIDENT ON 
SATELLITE IMAGERY ABOUT THE WAVE AXIS. A SWIRL OF LOW CLOUDS EXISTS 
TO THE E OF THE AXIS NEAR 13N89W. MODERATE CONVECTION HAS INCREASED 
IN COVERAGE OVER THE PAST FEW HOURS AND IS SCATTERED WITHIN 240 NM 
EITHER SIDE OF THE WAVE AXIS. DRY STABLE AIR ALOFT...ON THE S 
PERIPHERY OF A STRONG RIDGE IN THE SW GULF...IS CONTINUING TO 
SUPPRESS CONVECTION NEAR THE NRN EXTENSION OF THE WAVE OVER S MEXICO 
AND ACROSS MUCH OF CENTRAL AMERICA.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N86W 12N97W 11N110W 8N126W 8N140W. 
BESIDES FOR THE CONVECTION DISCUSSED IN THE TROPICAL WAVE 
SECTION...ISOLATED MODERATE EXISTS FROM 9N-18N BETWEEN 99W-113W. 
SCATTERED MODERATE IS WITHIN 180 NM EITHER SIDE OF THE AXIS BETWEEN 
120W-130W.

...DISCUSSION...
THE MODERATE TO OCCASIONALLY STRONG CONVECTION THAT WAS OCCURRING 
ACROSS SW MEXICO YESTERDAY HAS DIMINISHED TODAY. HOWEVER...LEFTOVER 
AREAS OF ISOLATED MODERATE CONVECTION STILL EXISTS FROM 9N TO 18N 
BETWEEN 89W AND 113W. THE SURFACE FEATURES CONTRIBUTING TO THIS 
UNSETTLED WEATHER ARE THE ITCZ AND A TROPICAL WAVE WHICH HAS BECOME 
MORE ACTIVE ALONG 95W. UPPER DIFFLUENCE IS A PRIMARY FACTOR WITH 
MOIST SW FLOW ADVECTING TROPICAL MOISTURE BETWEEN A STRONG RIDGE IN 
THE SW GULF AND AN ELONGATED UPPER TROUGH WHICH EXTENDS FROM THE WRN 
U.S. SOUTHWESTWARD ACROSS THE E PAC FROM THE NRN BAJA TO NEAR 
16N122W. GFS SHOWS THIS AREA OF TROPICAL MOISTURE MIGRATING FURTHER 
S OVER THE NEXT FEW DAYS.

THE REMAINDER OF THE DISCUSSION AREA REMAINS FAIRLY QUIET. A LARGE 
ANTICYCLONE HAS DRIFTED W CENTERED NEAR 13N142W...WITH AN AMPLIFIED 
RIDGE AXIS EXTENDING NORTHWARD ALONG 143W. AN UPPER LOW APPEARS TO 
BE FORMING TO THE E OF THE RIDGE WEAKENING THE ERN EXTENT NEAR 
31N135W. FARTHER EAST...THE ELONGATED UPPER TROUGH MENTIONED ABOVE 
COVERS THE REGION BETWEEN 110W AND 125W. MODERATE TO STRONG 
SUBSIDENCE AND DRY STABLE UPPER LEVEL AIR ASSOCIATED WITH THE TROUGH 
IS NOTED ON WATER VAPOR IMAGES N OF 16N E OF 126W. ELSEWHERE AT THE 
SURFACE...A 1027 MB HIGH IS CENTERED NEAR 41N138W WITH RIDGING 
EXTENDING SOUTHEAST TO NEAR 22N120W. THIS SFC RIDGING IS INTERRUPTED 
BY A COLD FRONT WHICH EXTENDS FROM THE NRN BAJA MAINLY WESTWARD 
ALONG 28N124W 28N132W 30N140W. NO SHOWER ACTIVITY IS ALONG THE 
FRONT...LIKELY SUPPRESSED BY THE DRY AIR ABOVE THE BOUNDARY. 

LOOKING AHEAD OVER THE NEXT FEW DAYS...THE MID/UPPER LEVEL TROUGH IN 
THE ERN PORTION OF THE AREA IS FORECAST TO LIFT OUT. THE UPPER LOW 
WHICH HAS ALREADY STARTED TO FORM IN THE NW PORTION OF THE AREA IS 
FORECAST TO DIG S AND INCREASE IN SIZE ENCOMPASSING A LARGE AREA 
LATER THIS WEEK. THE SFC RIDGE WILL REMAIN NEARLY STATIONARY THRU 
THU THEN LIFT TO THE N FRI THROUGH SUN. IN TERMS OF TROPICAL 
DEVELOPMENT...GLOBAL MODELS SHOW LITTLE OR NO DEVELOPMENT AND DO NOT 
APPEAR TO BE IN MUCH AGREEMENT IN DEVELOPING ONE FEATURE.

$$
CANGIALOSI