000
AXPZ20 KNHC 252140
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON SEP 25 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 
2130 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N78W 9N100W 10N120W 9N140W. 
SCATTERED MODERATE ISOLATED STRONG WITHIN 90-120 NM OF THE AXIS 
BETWEEN 105W AND 112W. SCATTERED MODERATE WITHIN 60 NM OF THE 
AXIS BETWEEN 123W AND 126W. 

TROPICAL WAVES/LOW PRESSURE...
1008 MB SURFACE LOW CENTERED NEAR 15N111W IS MOVING WWD 5-10 KT. 
CLUSTERS OF SCATTERED MODERATE ISOLATED STRONG CONVECTION ARE 
INDICATED PRIMARILY OVER THE W SEMICIRCLE OF THE LOW. VISIBLE 
SATELLITE IMAGERY REVEALS A RATHER DEFINED LOW LEVEL CIRCULATION 
SITUATED NEAR THE EDGE OF THE CLUSTERS OF DEEP CONVECTION.  

...DISCUSSION...
BROAD MID TO UPPER LEVEL TROUGH COVERS THE NW PORTION OF THE 
DISCUSSION AREA WITH TWO EMBEDDED CYCLONIC CIRCULATION CENTERS.
THE FIRST CENTERED JUST N OF THE DISCUSSION AREA NEAR 33N127W 
WAS NEARLY STATIONARY. THE SECOND...AND MORE VIGOROUS CENTER
WAS SWEEPING EWD INTO THE DISCUSSION AREA NEAR 29N142W AND WAS 
ACCOMPANIED BY AN AREA OF MID TO UPPER LEVEL MOISTURE N OF 23N 
W OF 130W. AXIS OF SUBTROPICAL JTST WAS CARVING OUT THE BASE OF 
THE TROUGH WITH SATELLITE DERIVED WINDS OF 80-100 KT NOTED. 
A BROAD MID-UPPER LEVEL RIDGE/LARGE ANTICYCLONE LIES TO THE SE 
OF THE TROUGH NOTED ABOVE OVER NORTH-CENTRAL MEXICO WITH 
RIDGING/ANTICYCLONIC FLOW  EXTENDING SWWD TO NEAR 17N120W. 
ANOTHER...BUT WEAKER NE-SW ELONGATED UPPER ANTICYCLONE IS 
CENTERED NEAR 16N125W. A SLIGHT WEAKNESS EXISTS BETWEEN THE TWO 
ANTICYCLONES. THE MOST ACTIVE WEATHER IN THE REGION IS A FEW 
HUNDRED MILES TO THE S AND SW OF THE SRN TIP OF THE BAJA WHERE 
SCATTERED MODERATE ISOLATED STRONG CONVECTION EXTENDS FROM 12N 
TO 16N BETWEEN 101W AND 106W...AND FROM 13N TO 17N BETWEEN 110W 
AND 116W. THE WESTERN AREA OF CONVECTION IS IN ASSOCIATION WITH 
THE 1008 MB LOW NOTED ABOVE. 

AT THE SURFACE...THE PACIFIC RIDGE IS RATHER WEAK DUE TO THE 
PRESENCE OF A BROAD 1013 MB LOW LOCATED NEAR 32N130W. THE 
RESULTING WEAK PRES GRAD HAS MANIFESTED ITSELF IN WEAKER THAN 
NORMAL TRADES WHICH ARE CONFINED TO THE AREA FROM 11N TO 18N W 
OF 120W. CROSS EQUATORIAL SLY WINDS S OF 6N W OF 100W ARE 
MOSTLY 15 TO 20 KT WITH SLY SWELL 8 TO 10 FT. IN THE EASTERN 
PORTION OF THE REGION...THE TAIL END OF THE GULF OF MEXICO FRONT 
EXTENDS ALONG THE E SLOPES OF THE SRN SIERRA MADRE. HIGH PRES IS 
BUILDING IN BEHIND THE FRONT...WITH A TIGHTENED SFC PRES GRAD 
PRODUCING WINDS 20 TO 25 KT ACROSS CENTRAL AND NRN MEXICO AND 
THE NW GULF. GFS SUGGESTS THAT THIS FRONT WILL CONTINUE TO PRESS 
SWD AND RESULT IN THE FIRST COLD AIR SURGE IN THE GULF OF 
TEHUANTEPEC WITHIN THE NEXT 12-18 HOURS. HOWEVER THIS EVENT IS 
EXPECTED TO BE WEAK WITH WINDS EVENTUALLY REACHING 20-25 KT
BY 36-48 HOURS. 
   
$$
COBB