000
AXPZ20 KNHC 100959
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT JAN 10 2009

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 
0845 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 07N75W TO 06N80W TO 04N100W TO 
08N132W TO 07N140W. SCATTERED MODERATE CONVECTION CAN BE FOUND 
WITHIN 150 NM N OF THE AXIS BETWEEN 126N AND 137W. 

...DISCUSSION...

EAST OF 120W...
THE TROUGH DIGGING SOUTHEASTWARD FROM THE SW U.S. INTO NORTHERN 
MEXICO IS OVERTAKING A WEAK UPPER LEVEL LOW NEAR 25N120W 
...HELPING TO RAPIDLY BREAKDOWN THE RIDGING OVER SOUTHERN 
MEXICO.  A STRONG SURFACE PRES GRADIENT BETWEEN THE COLD 
FRONT ASSOCIATED WITH THIS TROUGH AND HIGH PRES OVER THE E PAC 
IS BELIEVED TO ALREADY BE GENERATING GALE FORCE WINDS IN THE 
GULF OF CALIFORNIA.  THE QUIKSCAT PASS FROM 0124 UTC SHOWS THAT 
WINDS WERE IN THE 25 TO 30 KT RANGE AT THAT TIME.  SINCE 
THEN...THE COLD FRONT HAS MADE SIGNIFICANT SOUTHWARD 
PROGRESS...MOVING FROM SOUTHERN NEW MEXICO TO THE TX BIG BEND 
AND INCREASING THE PRESSURE GRADIENT SIGNIFICANTLY OVER THE 
NORTHERN GULF OF CALIFORNIA.  THE GALE IN THE GULF OF CALIFORNIA 
IS EXPECTED TO LAST INTO MON.  THE 0124 QUIKSCAT PASS ALSO 
SHOWED WINDS IN THE 20 TO 25 KT RANGE WITHIN 45 NM OF THE WEST 
COAST OF BAJA CALIFORNIA BETWEEN 26N AND 27N.  THIS AREA OF 
STRONG WINDS IS EXPECTED TO EXPAND AS THE FRONT PASSES SOUTHWARD 
TODAY...BUT SHOULD DIMINISH BELOW 20 KT BY MONDAY.

AS THE COLD FRONT PROGRESSES SOUTHWARD....IT WILL PASS INTO 
SOUTHERN MEXICO LATE SUNDAY...WITH GALE FORCE NORTHERLY WINDS 
EXPECTED TO BEGIN IN THE GULF OF TEHAUNTEPEC OVERNIGHT SUN 
NIGHT. SEAS SHOULD RAPIDLY BUILD TO OVER 12 FT EARLY MON.

TO THE SOUTH...NORTH TO NORTHEASTERLY WINDS IN THE 20 TO 25 KT 
RANGE CAN BE FOUND DOWNSTREAM OF THE GULF OF PAPAGAYO ACCORDING 
TO THE 2348 UTC QUIKSCAT PASS.  WINDS ABOVE 20 KT ARE EXPECTED 
TO CONTINUE THE NEXT FEW DAYS IN THE GULF OF PAPAGAYO WHERE A 
TIGHT PRESSURE GRADIENT BETWEEN LOW PRES OVER PANAMA/NORTHERN 
COLOMBIA AND HIGH PRES OVER GUATEMALA/HONDURAS IS EXPECTED TO 
REMAIN STRONG.  THE SAME QUIKSCAT PASS ALSO REVELED NORTH WINDS 
IN THE 20 TO 25 KT RANGE BLEEDING FROM THE CARIBBEAN INTO THE 
GULF OF PANAMA.  THESE WINDS ARE EXPECTED TO DIMINISH TODAY AS 
THE LOW LEVEL FLOW TAKES A MORE EASTERLY TURN.

WEST OF 120W...
THE UPPER LOW NEAR 26N136W WILL BE FORCED SLIGHTLY WESTWARD AS A 
STRONG...DEEP LAYERED RIDGE OF HIGH PRES AMPLIFIES NEAR 
40N130W...DRIVING A WEDGE BETWEEN THIS LOW AND THE TROUGH 
DIGGING SOUTHEASTWARD THROUGH THE SW U.S. AND NORTHERN MEXICO.  
CONVECTION OVER THE WEEKEND IS MOST LIKELY TO OCCUR SOUTH OF 
THIS LOW ALONG THE ITCZ WHERE UPPER LEVEL DIFFLUENCE WILL LIKELY 
BE STRONG BETWEEN THE SOUTHERLY FLOW ON THE EASTERN SIDE OF THE 
LOW AND THE WESTERLY 70 TO 90 KT JET S OF 08N.  CURRENTLY...THE 
DIFFLUENCE ALOFT ASSOCIATED WITH THE LEFT FRONT QUADRANT OF THIS 
JET IS GENERATING SCATTERED MODERATE CONVECTION WITHIN 150 NM OF 
16N120W.  THIS LOW IS NOT EXPECTED TO BE STRONG ENOUGH TO 
SIGNIFICANTLY DISRUPT THE EASTERLY FLOW AT THE SURFACE SOUTH OF 
THE HIGH PRES CENTERED NORTH OF THE FORECAST AREA.  THE UPPER 
LOW WILL BE FORCED NORTH ON MONDAY ON THE LEADING EDGE OF THE 
TROUGH EXPECTED TO PASS THROUGH THE HAWAIIAN ISLANDS OVER THE 
WEEKEND.

$$
SCHAUER CLARK