000
AXPZ20 KNHC 270336
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED SEP 27 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N78W 10N96W 14N110W 10N123W 9N140W. 
SCATTERED MODERATE WITHIN 180-210 NM OF THE AXIS BETWEEN 107W 
AND 115W...BETWEEN 120W AND 126W AND W OF 135W. 

TROPICAL WAVES/LOW PRESSURE...
A 1008 MB LOW IS CENTERED NEAR 12N118W MOVING W 5-10 KT. THE LOW 
LEVEL CIRCULATION IS BECOMING RATHER DIFFUSE AND MAY BE IN THE 
PROCESS OF DISSIPATING. LOW LEVEL CENTER CONTINUES TO BE MOSTLY 
EXPOSED ON THE E SIDE OF AN AREA OF SCATTERED MODERATE 
CONVECTION WHICH IS WITHIN 60 NM EITHER SIDE OF LINE 12.5N121W
14N120W. THE SYSTEM CONTINUES TO BE UNDER THE EFFECTS OF UPPER 
LEVEL EASTERLY SHEAR.
  
...DISCUSSION...
A WELL DEFINED MID/UPPER LEVEL TROUGH COVERS THE AREA N OF 
20N W OF 127W. A WELL DEFINED MID TO UPPER LEVEL CYCLONIC 
CIRCULATION NEAR 29N135W WAS MOVING ENE 10-15 KT AND WAS 
ACCOMPANIED BY DEEP LAYERED MOISTURE WITHIN 360 NM IN THE N 
SEMICIRCLE. THIS MOISTURE WAS LIFTING N OF THE AREA WITH TIME. 
A MID-LEVEL RIDGE LIES TO THE SOUTH OF THE TROUGH EXTENDING FROM 
AN ANTICYCLONE OVER WRN MEXICO NEAR 23N106W WITH RIDGING 
EXTENDING SOUTHWEST TO NEAR 15N125W. ANOTHER ANTICYCLONE IS 
LOCATED JUST W OF THE DISCUSSION AREA NEAR 12N143W. A MID/UPPER 
LEVEL TROUGH DROPS SOUTH-SOUTHEAST FROM THE LOW NEAR 29N135W 
THROUGH 19N131W TO 15N129W. A SMALL MOSTLY UPPER LEVEL CYCLONIC 
CIRCULATION MOVING W ABOUT 15 KT IS NEAR 12N96W. SLIGHT TO 
MODERATE SUBSIDENCE NOTED EAST AND SOUTHEAST OF THE LOW 
CONTINUES IS ALLOWING FOR ONLY ISOLATED MODERATE CONVECTION TO 
EXIST ELSEWHERE SOUTH OF 11N EAST OF 96W.

THE MOST ACTIVE WEATHER IN THE REGION IS IN THE EASTERN PORTION 
ASSOCIATED WITH THE 1008 MB LOW DISCUSSED ABOVE. UPPER LEVEL
DIVERGENCE ON THE SOUTHWEST PERIPHERY OF THE RIDGE OVER WESTERN
MEXICO IS AIDING CONVECTIVE DEVELOPMENT NEAR THE SURFACE LOW. 

AT THE SURFACE...SURFACE ANALYSES INDICATE A WEAKENING OF THE 
PRESSURE GRADIENT ALONG THE SIERRA MADRE AND A RESULTING 
SLACKENING OF THE WINDS IN THE GULF OF TEHUANTEPEC. THESE WINDS 
ARE EXPECTED TO DIMINISH WITHIN 36 HRS. 

A 1021 MB HIGH IS ANALYZED NEAR 29N127W WITH A RIDGE SOUTHEAST
TO 21N112W. GENERALLY WEAK HIGH PRESSURE COVERS THE AREA NORTH 
OF 19N...WITH A WEAK PRESSURE PATTERN FOUND ELSEWHERE.

$$
COBB