000
AXPZ20 KNHC 111549
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT OCT 11 2008

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1515 UTC.

...SPECIAL FEATURES...

HURRICANE NORBERT CENTERED NEAR 24.3N 111.9W AT 11/1500 UTC IS 
MOVING NNE AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 966 
MB. MAXIMUM SUSTAINED WIND SPEED IS 90 KT WITH GUSTS TO 110 KT.  
NORBERT IS BEING STEERED BY A MIDDLE/UPPER LEVEL TROUGH OVER THE 
WESTERN UNITED STATES. LANDFALL OVER THE BAJA CALIFORNIA 
PENINSULA IS IMMINENT AND NORBERT IS EXPECTED TO MAINTAIN 
HURRICANE STRENGTH AS IT MAKES LANDFALL OVER MAINLAND MEXICO.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS 
MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS.

TROPICAL STORM ODILE CENTERED NEAR 17.2N 101.7W AT 11/1500 UTC IS
MOVING WNW AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 996 
MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. 
ODILE IS FORECAST TO MOVE ALONG THE MEXICAN COAST THROUGH EARLY 
SUNDAY AND THEN TURN WESTWARD OR WEST-SOUTHWESTWARD INTO THE 
OPEN PACIFIC LATER SUNDAY THROUGH THURSDAY. THE STORM IS BEING 
STEERED BY A WELL-DEFINED MIDDLE/UPPER LEVEL ANTICYCLONIC 
CIRCULATION CENTERED OVER E MEXICO NEAR 24N98W. HEAVY RAINS AND 
THUNDERSTORMS ARE LOCATED ALONG THE MEXICAN COAST BETWEEN 101W 
AND 105W CONTINUING OFFSHORE UP TO 180 NM. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC 
FOR MORE DETAILS.

...TROPICAL WAVES...
A TROPICAL WAVE IS ANALYZED ALONG 89W N OF 09N INTO CENTRAL 
AMERICA AND IS MOVING W ABOUT 10 KT. THE WAVE IS WEAK AND THE 
ONLY CONVECTION ASSOCIATED WITH IT IS A SMALL BURST OF 
CONVECTION W OF THE AXIS NEAR 12N91W.

...ITCZ...

ITCZ AXIS ALONG 08N84W TO 10N94W TO 11N103W TO 09N124W TO 
10N137W. SCATTERED MODERATE CONVECTION IS LOCATED WITHIN 60 NM N 
AND 180 NM S OF THE AXIS BETWEEN 96W AND 127W. 

...DISCUSSION...

W OF 110W...
THE MIDDLE/UPPER LEVEL TROUGH DISCUSSED ABOVE IN ASSOCIATION 
WITH HURRICANE NORBERT COVERS THE AREA N OF 28N E OF 130W WITH 
THE AXIS ALONG 118W. A SOUTHWESTERLY JET LIES ON THE E SIDE OF 
THE TROUGH EXTENDING FROM 25N116W THROUGH THE CENTRAL BAJA 
CALIFORNIA PENINSULA AND INTO SE ARIZONA. ANOTHER MIDDLE/UPPER 
LEVEL TROUGH HAS ITS AXIS EXTENDING ALONG 133W FROM 12N TO 26N 
AND IS MOVING E ABOUT 10 KT. CYCLONIC FLOW IS LOCATED UP TO FIVE 
DEGREES EITHER SIDE OF THE TROUGH AXIS AND WATER VAPOR IMAGERY 
INDICATES STRONG SUBSIDENCE ASSOCIATED WITH THIS FEATURE. 
INCREASING SOUTHWESTERLY WINDS ALOFT ARE FORECAST OVER THE NEXT 
24 HOURS OVER THE AREA N OF 20N W OF 110W. A BROAD RIDGE PATTERN 
ALOFT COVERS THE AREA S OF ABOUT 22N BETWEEN 110W AND 130W. AT 
THE SURFACE A 1009 MB LOW IS LOCATED NEAR 13N124W AND IS NEARLY 
STATIONARY. THIS FEATURE IS IDENTIFIED AS A SWIRL OF LOW LEVEL 
CLOUDS N OF THE ITCZ AND MINIMAL CONVECTION IS ASSOCIATED WITH 
IT. RELATIVELY STRONG SURFACE PRESSURE GRADIENT IS LOCATED N OF 
24N W OF LINE FROM 24N125W TO 30N119W RESULTING IN NE WINDS OF 
20 TO 30 KT AND SEAS 10 TO 18 FT IN N SWELL. THE SEAS AS HIGH AS 
18 FEET ARE CONFIRMED BY A JASON ALTIMETER PASS AT 0940 UTC.

E OF 110W...
THE MAIN FEATURE ALOFT OVER THE E PART OF THE DISCUSSION AREA IS 
A WELL-DEFINED MIDDLE/UPPER LEVEL ANTICYCLONIC CIRCULATION 
CENTERED OVER E MEXICO NEAR 24N98W WITH RESULTING NE TO E FLOW 
EXTENDING S TO NEARLY THE EQUATOR BETWEEN 85W AND 110W. THE 
ANTICYCLONE IS FORECAST TO BECOME STRETCHED AND ELONGATED ON A 
NE TO SW AXIS OVER THE NEXT COUPLE OF DAYS.

$$
CAB