000
AXPZ20 KNHC 161538 CCA
TWDEP 

TROPICAL WEATHER DISCUSSION...UPDATED 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON OCT 16 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.

ADDED TEXT TO FURTHER DISCUSS HEAVY RAINFALL OVER SW MEXICO IN THE 
DISCUSSION.
 
...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 88W N OF 5N MOVING W NEAR 15 KT. SLIGHT LOW 
TO MID LEVEL CYCLONIC TURNING IS NOTED ON EARLY MORNING VIS IMAGES 
ABOUT THE AXIS S OF 12N. SCATTERED MODERATE CONVECTION IS MAINLY 
EMBEDDED IN THE ITCZ AND DISCUSSED IN THAT SECTION. DRY STABLE AIR 
ALOFT ON THE S PERIPHERY OF A STRONG RIDGE IN THE NW CARIBBEAN IS 
SUPPRESSING CONVECTION FROM FORMING NEAR THE NRN EXTENSION OF THE 
WAVE OVER CENTRAL AMERICA.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N86W 13N94W 16N102W 10N116W 11N140W. A 
LARGE AREA OF SCATTERED MODERATE CONVECTION ENHANCED BY OTHER 
FEATURES IS WITHIN 150 NM S OF THE AXIS BETWEEN 89W-97W. SIMILAR 
CONVECTION IS FROM 11N-20N BETWEEN 97W-109W. SEE DISCUSSION FOR MORE 
DETAILS. ISOLATED MODERATE IS WITHIN 120 NM N OF THE AXIS BETWEEN 
129W-131W. 

...DISCUSSION...

THE MOST ACTIVE WEATHER IN THE REGION IS E OF 110W BETWEEN 10N AND  
20N...WHICH INCLUDES SW MEXICO...WHERE A RATHER LARGE AREA OF 
SCATTERED MODERATE CONVECTION EXISTS. THIS UNSETTLED WEATHER IS 
ENHANCED BY SEVERAL FEATURES. THE CONTRIBUTING SURFACE FEATURES ARE 
THE ITCZ WHICH IS PERTURBED N IN THE AREA AND A TROPICAL WAVE ALONG 
88W. UPPER DIFFLUENCE IS A PRIMARY FACTOR WITH MOIST SW FLOW 
ADVECTING DEEP TROPICAL MOISTURE BETWEEN THE STRONG RIDGE CENTERED 
IN THE NW CARIBBEAN AND AN HIGHLY ELONGATED UPPER TROUGH WHICH 
ORIGINATES OVER THE WRN U.S. AND DIGS ACROSS THE E PAC FROM THE 
CENTRAL BAJA TO 20N120W. THESE LOCALLY HEAVY RAINFALL ARE LIKELY 
PRODUCING FLASH FLOODING AND POSSIBLE MUD SLIDES IN AREAS OF 
MOUNTAINOUS TERRAIN. THIS HEAVY RAINFALL WILL CONTINUE TO POSE A 
SIGNIFICANT HAZARD ACROSS SW MEXICO THROUGHOUT THE DAY. 

THE REMAINDER OF THE DISCUSSION AREA IS FAIRLY QUIET. A RIDGE/TROUGH 
UPPER LEVEL PATTERN EXISTS WITH THE UPPER ANTICYLONE CENTERED NEAR 
13N138W AND THE ELONGATED UPPER TROUGH TO ITS E WHICH IS DESCRIBED 
ABOVE. VERY DRY STABLE UPPER LEVEL AIR NOTED ON WATER VAPOR IMAGES 
COVERS THE AREA E OF 135W N OF 18N. ELSEWHERE AT THE SURFACE...A 
1021 MB HIGH IS LOCATED N OF THE AREA NEAR 25N141W WITH RIDGING 
EXTENDING SE TO NEAR 22N123W. A BROAD LOW PRES TROUGH IS ANALYZED 
ACROSS THE ERN PORTION OF THE AREA.

LOOKING AHEAD OVER THE NEXT FEW DAYS...GLOBAL MODELS FORECAST THE 
MID TO UPPER LEVEL TROUGH IN THE ERN PORTION OF THE AREA TO LIFT OUT 
AND A LARGE UPPER LOW TO FORM OVER THE WRN PORTION OF THE AREA BY 
MID-WEEK. THE SFC RIDGE IS FORECAST TO STRENGTHEN AND SHIFT SLIGHTLY 
TO THE SE. 

$$
CANGIALOSI