000
AXPZ20 KNHC 220340
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU JAN 22 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 
0115 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE LIES ALONG A LINE FROM 05N77W 
TO 03N90W TO 06N115W TO 04N130W TO 05N140W. THERE IS NO 
SIGNIFICANT CONVECTION CURRENTLY ASSOCIATED WITH THE ITCZ.

...DISCUSSION...

A GALE WARNING IS IN EFFECT FOR THE GULF OF TEHUANTEPEC.  THE 
QUIKSCAT PASS FROM 1246 UTC...NEAR THE PEAK OF THE EVENT... 
SHOWED GALE FORCE WINDS AS FAR AS 120 NM FROM THE COAST WITH 
WIND SPEEDS AS HIGH AS 50 KT.  HOWEVER...THE BULK OF THE 
NON-RAIN FLAGGED RETURNS SUGGESTED WINDS TO 45 KT.  ANOTHER 
QUIKSCAT PASS SHOULD BE AVAILABLE JUST AFTER THE ISSUANCE OF 
THIS PRODUCT.  SHIP DPKZ REPORTED 21 KT SUSTAINED WINDS WELL 
DOWNSTREAM NEAR 12N99W AT 0000 UTC...SO THE WIND FIELD HAS 
EXPANDED WEST SOMEWHAT SINCE THE 1246 UTC QUIKSCAT PASS.  WINDS 
ARE EXPECTED TO GRADUALLY DIMINISH BELOW GALE FORCE THU MORNING 
AND DROP BELOW 20 KT FRI AFTERNOON.  

TO THE SOUTH...A MORE RECENT QUIKSCAT PASS...2336 UTC...SHOWS 
WINDS IN THE GULF OF PAPAGAYO REMAINING IN THE 20 TO 25 KT 
RANGE.  THIS PASS JUST MISSED THE GULF OF FONSECA WHERE WINDS ON 
AN EARLIER ASCAT PASS WERE ALSO IN THIS RANGE.  THIS GENERAL 
AREA OF WIND IS EXPECTED TO EXPAND WEST A BIT THU BEFORE 
CONTRACTING AND WEAKENING AS THE PRESSURE GRADIENT BETWEEN THE 
DISSIPATING HIGH PRESSURE OVER CENTRAL AMERICA AND LOW PRESSURE 
OVER COLOMBIA SLACKENS.  

EVEN FARTHER SOUTH...THE MOST RECENT QUIKSCAT PASS SHOWS WINDS 
IN THE GULF OF PANAMA HAVE INCREASED TO 20 KT AS THE DISSIPATING 
COLD FRONT OVER THE WESTERN CARIBBEAN MOVES SOUTHWARD TOWARD 
PANAMA.  WINDS HERE SHOULD REMAIN IN THE 15 TO 20 KT RANGE 
TROUGH MID DAY THU.

A DEEP LAYERED LOW PRESSURE SYSTEM HAS A SURFACE REFLECTION 
CENTERED NEAR 29N123W.  THE ASCAT PASS FROM 1736 UTC SHOWED 
WINDS IN THE 20 TO 25 KT RANGE PRIMARILY WITHIN 180 NM N 
SEMICIRCLE OF THE LOW.  WINDS SHOULD DIMINISH WITH THIS SYSTEM 
OVER FORECAST WATERS AS IT IS GRADUALLY OVERTAKEN BY ANOTHER 
DEEP LAYERED LOW PRESSURE SYSTEM NW OF THE AREA.  EXPECT THE LOW 
CURRENTLY OVER FORECAST WATERS TO BE FORCED NORTHEASTWARD TOWARD 
CALIFORNIA OVER THE NEXT TWO DAYS.  THE COLD FRONT ASSOCIATED 
WITH THE LOW NW OF THE FORECAST AREA WILL MOVE INTO NW WATERS 
OVERNIGHT TONIGHT.  LONG PERIOD NW SWELL...IN THE 16 TO 18 
SECOND RANGE...WILL MOVE INTO NW WATERS AND PUSH AHEAD OF THE 
FRONT...REACHING NORTHERN BAJA CALIFORNIA LATE FRI.  SEAS ARE 
EXPECTED TO BE AS HIGH AS 15 TO 17 FT IN NW WATERS BEHIND THE 
FRONT ON FRI.  

SCATTERED MODERATE CONVECTION CAN CURRENTLY BE FOUND WITHIN 90 
NM W AND 150 NM E OF A SURFACE TROUGH THAT LIES FROM 07N113W TO 
14N112W.  THIS CONVECTION IS ASSOCIATED WITH A BROAD AREA OF 
UPPER LEVEL DIFFLUENCE ON THE SE EDGE OF THE UPPER TROUGH FROM 
30N124W TO 10N117W...THE SAME TROUGH SUPPORTING THE SURFACE LOW 
NEAR 29N123W.  THE NORTHERN PORTION OF THIS TROUGH IS EXPECTED 
TO MOVE INTO NW MEXICO OVERNIGHT THU NIGHT WHILE SOME MID TO 
UPPER LEVEL ENERGY WILL BE LEFT BEHIND S OF 20N AND IS EXPECTED 
TO BE DRAWN WEST TOWARD THE AFOREMENTIONED DEEP LAYER TROUGH 
APPROACHING FROM THE NW FRI/SAT.  THE BEST CHANCE OF CONVECTION 
WILL REMAIN S OF 15N...WHERE MOISTURE IS MORE PLENTIFUL... 
BETWEEN 95W AND 120W AS THE LINGERING MID TO UPPER LEVEL ENERGY 
AND RESULTING TROUGHING AND DIFFLUENCE WILL BE SLOWER TO MOVE 
OVER THE NEXT DAY OR TWO THAN THE N EDGE OF THE TROUGH.

$$
SCHAUER CLARK