000
AXPZ20 KNHC 250337
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN JAN 25 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0145 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG AN AXIS FROM 
04N77W TO 02N95W TO 02N114W TO 06N132W TO 06N140W. SCATTERED 
MODERATE CONVECTION CAN BE FOUND WITHIN 75 NM OF AXIS FROM 85W 
TO 90W.


...DISCUSSION...
A VERY COMPLICATED PATTERN IS TAKING SHAPE OVER THE EASTERN 
PACIFIC.  THE HIGHLY AMPLIFIED TROUGH CURRENTLY STRETCHED ACROSS 
NW WATERS IS CUTTING OFF FROM THE NORTHERN STREAM FLOW...BUT NOT 
BEFORE ACQUIRING MORE UPPER ENERGY FROM THE NORTHERN STREAM.  AS 
IT CUTS OFF...EXPECT THIS DEEP LAYERED LOW TO MOVE SOUTHWARD. AT 
THE SURFACE...THE LOW WILL WEAKEN OVER THE NEXT TWO DAYS AS IT 
IS FORCED SOUTHWARD BY HIGH PRESSURE BUILDING TO IT NW.  WINDS 
BETWEEN THE TWO SURFACE SYSTEMS WILL BE IN THE 20 TO 30 KT RANGE 
OVER NW WATERS.  NW SWELL GENERATED BY THIS LOW CURRENTLY 
DOMINATES FORECAST WATERS.  AT THE SAME TIME...STRONG UPPER 
LEVEL DIFFLUENCE BETWEEN THE REAR RIGHT QUADRANT OF THE 
SOUTHWESTERLY JET ON THE NE SIDE OF THE LOW AND LEFT FRONT 
QUADRANT OF THE APPROACHING WEST-NORTHWESTERLY JET ON THE SOUTH 
SIDE OF THE LOW WILL LIKELY BE A SIGNIFICANT FOCUS FOR 
CONVECTION AND MODEL GUIDANCE AGREES ON A SURFACE LOW DEVELOPING 
IN THIS REGION SUN/MON.  PRECIPITABLE WATER VALUES ARE ON THE 
RISE HERE... AND ISOLATED MODERATE CONVECTION HAS ALREADY BEGUN 
FROM 13N TO 24N BETWEEN 117W AND 124W IN THE DIFFLUENT REGION ON 
THE SE SIDE OF THE UPPER LOW. 

THE ASCAT PASS AT 1634 UTC SHOWED WINDS BUILDING IN THE MOUTH 
OF THE GULF OF CALIFORNIA AS THE PRESSURE GRADIENT BUILDS 
BETWEEN LOW PRES ALONG THE EAST COAST OF THE GULF AND THE HIGH 
PRESSURE OFF THE COAST OF BAJA CALIFORNIA THAT IS CURRENTLY 
BEING SQUEEZED EASTWARD BY THE LOW OVER NW WATERS.  SHIP ZCDU9 
REPORTED 22 KT OF NORTHERLY WIND AT 0100 UTC IN THE MOUTH OF THE 
GULF NEAR 21N108W.  THESE WINDS SHOULD DIMINISH TOMORROW 
AFTERNOON.  LOOK FOR WINDS TO 20 KT INDUCED BY THE SAME GRADIENT 
TO KICK UP EARLY SUN MORNING AND LAST INTO MON ALONG THE WEST 
COAST OF BAJA CALIFORNIA.

OVER SE WATERS...THE WAS SCATTERED MODERATE CONVECTION ALONG 
THE ITCZ NEAR THE COASTS OF COLOMBIA AND ECUADOR EARLIER 
TODAY...WITH QUIKSCAT SHOWING WINDS IN THE 20 TO 25 KT 
RANGE...CAN NOW BE FOUND FARTHER OFFSHORE WITHIN 75 NM OF THE 
ITCZ AXIS FROM 85W TO 90W. THE QUIKSCAT PASS FROM 0000 UTC 
SHOWED MOSTLY RAIN FLAGGED RETURNS HERE.  THE UPPER LEVEL 
ANTICYCLONE OVER COLOMBIA/VENEZUELA IS INDUCING DIFFLUENT FLOW 
BETWEEN IT AND THE NE UPPER LEVEL WINDS FARTHER S ALONG THE 
COAST OF ECUADOR...ALLOWING FOR THIS CONVECTION.  THE 
ANTICYCLONE...ALONG WITH THE CONVECTION...IS EXPECTED TO 
CONTINUE SHIFTING WESTWARD TONIGHT...BUT WILL ENCOUNTER STRONGER 
SOUTHERLY FLOW WEST OF THE ANTICYCLONE SUN/MON THAT WILL INHIBIT 
CONVECTION.

GAP WINDS...SHIP ZCDF4 REPORTED NORTH WINDS AT 29 KT AS IT 
TRAVERSED THE GULF OF TEHUANTEPEC AT BOTH 0000 UTC AND 0100 
UTC.  MODEL GUIDANCE IS SLOW TO PICK UP ON THE INCREASE IN WINDS 
HERE.  THE WIND FIELD WILL EXPAND SOUTH-SOUTHWEST OF THE GULF OF 
TEHUANTEPEC THROUGH SUN MORNING...FAILING TO MEET GALE FORCE.  
WINDS ARE EXCEPTED TO REMAIN ELEVATED OVER 20 KT HERE THE NEXT 
FEW DAYS.

FARTHER S...THE QUIKSCAT PASS FROM 2357 UTC CONFIRMED WINDS IN 
THE 20 TO 30 KT RANGE IN THE GULF OF PAPAGAYO.  THE WIND FIELD 
IS EXPECTED TO EXPAND WESTWARD HERE THE NEXT TWO DAYS AS HIGH 
PRESSURE BUILDS OVER CENTRAL AMERICA AND TRADE WINDS IN THE 
WESTERN CARIBBEAN TURN SLIGHTLY MORE NORTHERLY AND STRONGER.  
WINDS WILL ALSO BLEED FROM THE WESTERN CARIBBEAN THROUGH PANAMA 
FARTHER SOUTH INTO THE PACIFIC BY MON AFTERNOON.

$$
SCHAUER CLARK