000
AXPZ20 KNHC 070932
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN SEP 07 2008

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...SPECIAL FEATURES...

TROPICAL STORM LOWELL CENTERED NEAR 16.6N 107.2W OR 220 NM SW OF 
MANZANILLO MEXICO AT 0900 UTC MOVING WNW OR 300 DEGREES AT 10 
KT. ESTIMATED CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED 
WINDS 35 KT WITH GUSTS TO 45 KT. SEE LATEST NHC PUBLIC ADVISORY 
UNDER AWIPS HEADER MIATCPEP3 OR WMO HEADER WTPZ33 KNHC AND THE 
FULL FORECAST ADVISORY UNDER AWIPS HEADER MIATCMEP3 OR WMO 
HEADER WTPZ23 KNHC FOR MORE DETAILS. NUMEROUS MODERATE ISOLATED 
STRONG CONVECTION CAN BE FOUND WITHIN 330 NM W SEMICIRCLE. 
LOWELL IS FORECAST TO GRADUALLY STRENGTHEN THROUGH MON AS IT 
MOVES NW.

...ITCZ...

ITCZ LIES ALONG 06N77W TO 06N84W TO 16N102W TO 09N116W TO 
09N125W TO 11N136W. SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION LIES WITHIN 120 NM N AND 150 NM S OF AXIS E OF 80W.

...DISCUSSION...

CHANGES ARE IN STORE FOR THE SYNOPTIC SCALE PATTERN OVER THE N 
WATERS DURING THE NEXT 2 DAYS. THE UPPER LEVEL ANTICYCLONE 
PRESENTLY NEAR 23N120W IS EXPECTED TO BE SHOVED TO THE W AS THE 
WEAK TROUGH CURRENTLY TO ITS N AMPLIFIES ALONG 125W. THIS 
TROUGHING SHOULD HELP STEER LOWELL ON A MORE N OF W TRACK...WITH 
THE SYSTEM ENCOUNTERING MORE VERTICAL WIND SHEAR AS IS 
APPROACHES THE AMPLIFYING TROUGH SOMETIME MON NIGHT OR TUE. AS 
THE UPPER TROUGH INTENSIFIES...SO SHOULD THE ANTICYCLONE TO ITS 
W MOVING ACROSS MAINLAND MEXICO TO NEAR THE MOUTH OF THE GULF OF 
CALIFORNIA BY TUE MORNING. LOWELL IS EXPECTED TO TRACK WITH THE 
REGION OF BROAD UPPER LEVEL DIFFLUENCE ON THE SW SIDE OF THIS 
ANTICYCLONE...BUT WILL BE ENCOUNTERING COOLER SEA SURFACE 
TEMPERATURES IN ADDITION TO THE INCREASED SHEAR BY MON 
NIGHT/TUE.  

MUCH OF THE DEEP TROPICAL MOISTURE E OF 120W IS EXPECTED TO BE 
OCCUPIED WITH LOWELL AND ITS ASSOCIATED MONSOON TROUGH TO ITS E 
ALONG THE SW MEXICAN COAST. TO THE S...PRECIPITABLE WATER VALUES 
ARE FORECAST TO BE RELATIVELY LOWER OVER MUCH OF CENTRAL AMERICA 
THIS PERIOD...WITH THE BEST CHANCE OF PRECIPITATION S OF 10N 
EXPECTED TO BE NEAR THE ITCZ W OF 95W WHERE LOW LEVEL MOISTURE 
WILL CONVERGE.

THE MEAN UPPER LEVEL ANTICYCLONIC FLOW N OF 15N AND W OF 120W 
WILL ALLOW FOR SUBSIDENCE OVER THAT REGION...WITH ONLY A SLIGHT 
POTENTIAL FOR SHOWERS IN THE FAR NW WATERS ON THE E EDGE OF THE 
UPPER LEVEL LOW CURRENTLY PINCHING OFF FROM THE TROUGHING 
STRETCHED N OF THE ANTICYCLONE. THIS UPPER LOW IS EXPECTED TO 
TRACK W TOWARD HAWAII OVER THE NEXT SEVERAL DAYS.

$$
SCHAUER CLARK