000
AXPZ20 KNHC 102143
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT JAN 10 2009

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 
2130 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 07N77W 05N80W 08N88W 05N113W 
07N140W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM OF THE 
AXIS BETWEEN 95W-104W AND N OF THE AXIS TO 14N BETWEEN 125W AND 
140W. 

...DISCUSSION...

E OF 120W...
A MID-UPPER LEVEL TROUGH IS ACROSS THE CENTRAL U.S. WITH ITS 
AXIS EXTENDING SW ACROSS NW MEXICO AND N BAJA. THIS FEATURE IS 
PROVIDING SUPPORT FOR A COLD FRONT THAT IS ENTERING THE GULF OF 
MEXICO AND EXTENDS INTO NE MEXICO. THE PRES DIFFERENCE BETWEEN A 
1046 MB HIGH OVER NEVADA AND THE REMNANTS OF THE FRONT OVER 
MEXICO...COMBINED WITH LOCAL TOPOGRAPHIC INFLUENCES...HAS 
CONTINUES GALE CONDITIONS IN THE N PORTION OF THE GULF OF 
CALIFORNIA. THE GALE WARNING CONTINUES THROUGH 48 HOURS AS THE 
SFC HIGH ONLY SLOWLY WEAKENS OVER THE GREAT BASIN.

STRONG WINDS IN THE CARIBBEAN CONTINUE TO GENERATE NE 20-25 KT 
WINDS DOWNWIND OF THE GULF OF PAPAGAYO. LITTLE CHANGE IS 
EXPECTED IN THIS REGIME OVER THE NEXT COUPLE OF DAYS AS TRADE 
WINDS REMAIN STRONG OVER THE S HALF OF THE CARIBBEAN. WINDS OVER 
THE GULF OF TEHUANTEPEC ARE LIGHT AND VARIABLE AT THE MOMENT. 
HOWEVER...THIS WILL CHANGE AS THE AFOREMENTIONED COLD FRONT 
PROGRESSES S OVER THE GULF OF MEXICO. THE FRONT IS EXPECTED TO 
SURGE THROUGH THE BAY OF CAMPECHE SUN SETTING UP ANOTHER GALE 
EVENT LATE SUN AND MON. THIS ENHANCED FLOW SHOULD DIMINISH BY 
SUN AS THE TRADES OVER THE S CARIBBEAN SHIFT FROM THE N/NE TO 
NE/E.

OTHERWISE...A WEAK TROUGH WITHIN ITCZ COUPLED WITH AN UPPER 
DIFFLUENT PATTERN IS PRODUCING SCATTERED MODERATE CONVECTION 
(OUTLINED IN ITCZ SECTION ABOVE).

W OF 120W...
A MID-UPPER LOW NEAR 25N138W IS BEING DRIVEN SLIGHTLY W AS A 
STRONG RIDGE AMPLIFIES TO ITS N. A JET ORIGINATES NEAR THE BASE 
OF THE ASSOCIATED UPPER TROUGH AND EXTENDS NE TO MEXICO. 
DIFFLUENCE ALOFT IS GENERATING SCATTERED MODERATE CONVECTION 
FROM 14N TO 21N BETWEEN 111W AND 118W. 

AT THE SURFACE...A RIDGE DOMINATES THE AREA N OF 15N W OF 110W 
ANCHORED BY A 1037 MB HIGH NEAR 40N131W. 

$$
WALLACE