000
AXPZ20 KNHC 071619
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI DEC 07 2007

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 
1530 UTC.
 
...ITCZ...
INTERTROPICAL CONVERGENCE ZONE AXIS ALONG 7N78W 9N90W 12N113W 
8N140W. SCATTERED MODERATE CONVECTION FROM 4N TO 6N BETWEEN 79W 
AND 83W.

...DISCUSSION...

AN UPPER RIDGE IS CENTERED NEAR 25N143W WITH A WEAKENING UPPER 
LOW TO ITS SOUTH NEAR 14N130W. THIS HAS SET UP A WEAK REX BLOCK 
ROUGHLY ALONG 135W. THIS IS RESULTING IN A MORE AMPLIFIED 
PATTERN OVERALL. A STRONG UPPER TROUGH TO THE EAST OF THE 
BUILDING UPPER RIDGE IS DIGGING INTO THE CENTRAL CALIFORNIA 
COAST THIS MORNING. AS THE UPPER TROUGH PUSHES EWD INTO THE 
ROCKIES THROUGH SAT...ANOTHER CUTOFF UPPER LOW NEAR 22N118W WILL 
OPEN UP AND LIFT OUT INTO THE SOUTHWEST U.S. A COLD FRONT 
ASSOCIATED WITH THE UPPER TROUGH IS MOVING INTO THE NORTHERN 
WATERS OFF THE BAJA COAST...FOLLOWED BY FRESH NLY FLOW AND LARGE 
SWELL. MEANWHILE...SLY FLOW ON THE EAST SIDE OF THE CUTOFF LOW 
NEAR BAJA IS SUSTAINING A WEAK SURFACE TROUGH THROUGH THE ITCZ 
ALONG ROUGHLY 112W. THIS IS ALSO DRAWING MOISTURE NWD SUPPORTING 
ISOLATED SHOWERS NEAR THE TROUGH. AS FAR AS SEAS GO...SHIPS 
REPORT MODERATE LARGE NLY SWELL ACROSS MOST OF THE DISCUSSION 
AREA THIS MORNING. TRENDS SHOW THE SWELL DECAYING BELOW 8 FT 
THROUGH TODAY IN ALL BUT THE AREA N OF 25N.

FOR THE WEEKEND AHEAD...THE RIDGE WILL BUILD ALONG ROUGHLY 
135W...AS THE TROUGH DEEPENS OVER THE SOUTHWEST U.S. THIS WILL 
TIGHTEN THE GRADIENT OFF THE CALIFORNIA COAST...WITH NLY WINDS 
PICKING UP AS FAR SOUTH AS OFF NRN BAJA. THIS WILL INVITE A NEW 
ROUND OF LARGE NLY SWELL TO START TO PUSH INTO THE WATERS W OF 
NRN BAJA BY SUN. IN ADDITION...THE BUILDING RIDGE STRENGTHENS 
THE SURFACE HIGH NW OF THE AREA...WHICH IN TURN ENHANCES TRADE 
WIND FLOW. FURTHER E...STRONGER ELY FLOW THIS WEEKEND OVER THE 
CARIBBEAN WILL PROMOTE FRESH ELY FLOW THROUGH THE GULF OF 
PAPAGAYO STARTING TOMORROW. A SURGE OF SLY FLOW S OF THE EQUATOR 
WILL INCREASE WINDS AND SEAS TO THE WEST OF THE GALAPAGOS SUN.

$$
CHRISTENSEN