000
AXPZ20 KNHC 121515
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED NOV 12 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 
1345 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS CAN BE FOUND ALONG THE 
LINE...06N78W TO 08N100W TO 07N115W TO 09N128W TO 07N140W. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION LIES WITHIN 
90 NM OF THE AXIS E OF 89W. SCATTERED MODERATE CONVECTION CAN BE 
FOUND WITHIN 90 NM OF THE AXIS BETWEEN 99W AND 103W...WITHIN 150 
NM S OF THE AXIS BETWEEN 117W AND 119W...AND WITHIN 60 NM OF THE 
AXIS BETWEEN 129W AND 135W. 
 
...DISCUSSION...
THE DEEP LAYERED TROUGH DIGGING SOUTHWARD THROUGH NORTHERN 
MEXICO WILL CONTINUE TO AMPLIFY AS IT GRADUALLY SHIFTS EASTWARD 
TOWARD THE GULF OF MEXICO OVER THE NEXT FEW DAYS.  SURFACE HIGH 
PRESSURE BEHIND THE ASSOCIATED COLD FRONT BUILDING S FROM THE 
GREAT BASIN INTO NW MEXICO COUPLED WITH CLIMATOLOGICAL LOW 
PRESSURE OVER THE GULF OF CALIFORNIA HAS INDUCED A STRONG ENOUGH 
PRESSURE GRADIENT TO SUPPORT WINDS OVER 20 KT IN THE GULF OF 
CALIFORNIA WHICH ARE EXPECTED TO PERSIST OVER THE NEXT DAY OR 
TWO.  FURTHERMORE...THE PRESSURE GRADIENT OVER NORTHERN WATERS 
BETWEEN THE GULF OF CALIFORNIA LOW PRESSURE AND THE SUBTROPICAL 
HIGH JUST N OF NW WATERS HAS INDUCED WINDS OVER 20 KT WHICH ARE 
EXPECTED TO SHIFT W THROUGH FRI AS THE SOUTHEASTERN EDGE OF THE 
WEAKENING DEEP LAYER ANTICYCLONE OVER THE E PACIFIC IS ERODED BY 
MID LEVEL ENERGY LEFT BEHIND BY THE TROUGH CURRENTLY DIGGING 
INTO NW MEXICO...ALLOWING FOR EXPANSION OF THE SURFACE TROUGHING 
OVER THE GULF OF CALIFORNIA WESTWARD.  

THE UPPER LEVEL ANTICYCLONE NEAR 10N120W IS EXPECTED TO WEAKEN 
AS THE UPPER TROUGH AMPLIFYING OVER NW MEXICO SWINGS ITS AXIS 
SOUTHEAST OVER FORECAST WATERS...BRINGING STRONG WESTERLY FLOW 
INTO THE NORTHEASTERN EDGE OF THE ANTICYCLONE AND SHIFTING THE 
ANTICYCLONE CENTER WNW.  EXPECT CONVECTION TO BE LIMITED OVER 
THE TROPICS UNDER STRONG SOUTHERLY UPPER LEVEL FLOW BOTH THROUGH 
SOUTHERN MEXICO E TO NEAR 85W ON THE LEADING EDGE OF THIS UPPER 
TROUGH AS WELL AS W OF 135W WHERE STRONG SOUTHERLY FLOW IS 
EXPECTED BETWEEN THE UPPER LOW E OF HAWAII AND THE WEAKENING 
ANTICYCLONE APPROACHING IT FROM THE SE.

$$
SCHAUER CLARK