000
AXPZ20 KNHC 281518
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU SEP 28 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.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N82W 7N106W 12N122W 10N140W. 
SCATTERED MODERATE CONVECTION EXISTS FROM 7N-10N BETWEEN 
115W-124W. A LARGE AREA OF DISTURBED WEATHER LIES TO THE W OF 
140W.

TROPICAL WAVES/LOWS...
A TROPICAL WAVE IS ALONG 83W N OF 3N ACROSS COSTA RICA AND INTO 
THE WRN CARIBBEAN SEA MOVING W 15 KT. THERE IS SOME SLIGHT 
CYCLONIC VEERING IN THE WINDS NOTED IN THE REPORTING SFC 
OBSERVATIONS. SCATTERED MODERATE CONVECTION LIES FROM 8N-11N 
BETWEEN 82W-86W AND OFF THE WRN COLOMBIAN COAST FROM 6N-9N 
BETWEEN 78W-80W.

A 1010 MB LOW IS CENTERED NEAR 13N125W MOVING W NEAR 10 KT OVER 
THE PAST FEW DAYS. THIS LOW HAS BEEN ON A WEAKENING TREND WITH 
ONLY SMALL PATCHES OF SHOWERS AND TSTMS WITHIN 120 NM IN THE NRN 
SEMICIRCLE. THIS FEATURE IS IN A MARGINAL TO UNFAVORABLE 
ATMOSPHERIC ENVIRONMENT AND DEVELOPMENT IS NOT EXPECTED AS IT 
CONTINUES TO MOVE WESTWARD STEERED BY THE LOW-MID LEVEL FLOW.
  
...DISCUSSION...
A WELL DEFINED MID TO UPPER LEVEL TROUGH COVERS THE NW PORTION 
OF THE AREA EXTENDING FROM AN UPPER LOW NEAR 35N130W TO ANOTHER 
UPPER LOW NEAR 29N147W. THIS LARGE TROUGH HAS BEEN RELUCTANT TO 
PULL OUT OF THE AREA...BUT GFS DOES ANTICIPATE IT TO SLOWLY DO 
SO OVER THE NEXT SEVERAL DAYS. A LARGE NEARLY STATIONARY 
ANTICYCLONE IS CENTERED ABOUT 120 NM TO THE S OF THE SRN TIP OF 
THE BAJA NEAR 21N110W WITH RIDGING EXTENDING WESTWARD TO NEAR 
20N120W. ANOTHER LARGE NEARLY STATIONARY ANTICYCLONE IS CENTERED 
NEAR 12N140W WITH RIDGING EXTENDING EASTWARD TO 14N127W. A 
FAIRLY PRONOUNCED WEAKNESS EXISTS IN THE RIDGING INDUCED BY THE 
LARGE TROUGH TO THE N BETWEEN 120W-127W. A SLOW MOVING UPPER 
LEVEL LOW IS CENTERED NEAR 12N104W. IN TERMS OF MOISTURE...MUCH 
OF THE REGION IS FILLED WITH HIGH LEVEL MOISTURE...AT LEAST MORE 
SO THAN EARLIER THIS WEEK. HOWEVER...DEEP MOISTURE IS RATHER 
LIMITED TO WITHIN 180 NM OF THE UPPER LOW NEAR 12N104W AND THE 
ITCZ. 

AT THE SURFACE...A 1027 MB HIGH IS LOCATED NEAR 40N138W. THE 
TIGHTENED PRES GRADIENT BETWEEN THE HIGH PRES AND A 1012 MB LOW 
PRES NEAR 22N116W IS GENERATING FRESH NE TRADES FROM 13N AND 20N 
W OF 120W. THE COMBINATION OF HIGH PRESSURE OVER THE WESTERN 
GULF OF MEXICO AND THE APPROACHING TROPICAL WAVE HAS SET UP 
ANOTHER 20 KT GAP WINDS EVENT IN THE TEHUANTEPEC AREA. 

S OF 10N LIGHT TO MODERATE CROSS-EQUATORIAL SLY FLOW PERSISTS 
ACCOMPANIED BY MODERATE TO LARGE SW SWELL BETWEEN 92W AND 122W. 
THE SLY FLOW IS CONVERGING WITH DRAINAGE WINDS OFF PANAMANIAN 
AND COSTA RICAN COASTS ENHANCED BY THE TROPICAL WAVE TO TRIGGER 
MODERATE CONVECTION GENERALLY N OF 4N AND E OF 89W. 

$$
CANGIALOSI