000
AXPZ20 KNHC 162215
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145  UTC.

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

A TROPICAL WAVE IS ALONG 90W N OF 4N IS MOVING W NEAR 15 KT. 
DEEP CONVECTION EARLIER NOTED WITH THE WAVE HAS WEAKENED DURING
THE AFTERNOON AND IS NOW SEEN AS ISOLATED SHOWERS AND TSTMS
EMBEDDED IN THE ITCZ FROM 5N-8N BETWEEN 90W-93W. 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 9N85W 15N99W 10N112W 10N120W 11N135W
10N140W. SCATTERED STRONG CONVECTION IS WITHIN 75 NM EITHER SIDE
OF THE AXIS BETWEEN 93W AND 101W. SCATTERED MODERATE ISOLATED
STRONG IS WITHIN 240 NM S OF THE AXIS BETWEEN 113W AND 118W. 
SCATTERED MODERATE IS WITHIN 180 NM S OF THE AXIS BETWEEN 80W 
AND 85W.


...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 90W. 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 
EXETNDS SOUTHWESTWARD ACROSS THE E PAC FROM THE CENTRAL BAJA TO 
19N117W WHERE AN ELONGATED MID/UPPER LEVEL CYCLONIC CIRCULATION 
ABOUT 180 NM IN DIAMETER IS NOTED. LOCALLY HEAVY RAINFALL ARE 
LIKELY PRODUCING FLASH FLOODING AND POSSIBLE MUD SLIDES IN AREAS 
OF MOUNTAINOUS TERRAIN THROUGH THE 12-24 HRS.

THE REMAINDER OF THE DISCUSSION AREA IS FAIRLY QUIET. A 
RIDGE/TROUGH UPPER LEVEL PATTERN EXISTS WITH THE UPPER 
ANTICYCLONE CENTERED NEAR 13N138W AND THE ELONGATED UPPER TROUGH 
TO ITS E AS DESCRIBED ABOVE. MODERATE TO STRONG SUBSIDENCE AND 
VERY DRY STABLE UPPER LEVEL AIR IS NOTED ON WATER VAPOR TO BE 
CONFINED TO N OF 18N. PATCHES OF MID TO UPPER LEVEL MOISTURE IS 
STREAMING ENE INTO THE WESTERN PART OF THE REGION AHEAD OF 
DEEP-LAYERED TROUGH WELL W OF 140W. ELSEWHERE AT THE SURFACE...A 
1022 MB HIGH IS LOCATED N OF THE AREA NEAR 33N141W WITH RIDGING 
EXTENDING SOUTHEASTWARD TO NEAR 22N125W. HIGH PRESSURE COVERS 
THE AREA N OF 20N W OF 121W. 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 
SLIGHTLY THROUGH WED THEN WEAKEN THU AND FRI.

$$
AGUIRRE