000
AXPZ20 KNHC 140345
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JAN 14 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 
0330 UTC.

...ITCZ...

ITCZ IS CENTERED ALONG 6N78W 6N86W 6N95W 8N110W 9N120W 6N135W
5N140W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM N OF THE
AXIS BETWEEN 82W-86W.

...DISCUSSION...

THE REGION REMAINS IN BETWEEN TWO RATHER LARGE SCALE FEATURES.
THE FIRST IS THE TAIL END OF BROAD UPPER LEVEL TROUGHING 
CENTERED OVER MID-WEST REGION OF THE UNITED STATES WHICH REACHES 
INTO THE FAR EASTERN SECTION OF THE AREA TO N OF ABOUT 22N AND E 
OF 118W. W OF THE TROUGH...THE AREA IS UNDER MID AND UPPER LEVEL 
RIDGING PRESENT N OF 22N WITH AN ANTICYCLONIC CENTER NEAR 
32N125W. A RIDGE EXTENDS FROM THIS ANTICYCLONE TO WELL NW OF THE 
REGION. THE SECOND FEATURE IS A RATHER EXTENSIVE DEEP LAYER 
TROUGH DIGGING SWD JUST W OF THE AREA ALONG 142W IN RESPONSE TO 
LOW PRES WELL NW OF THE AREA. THE ASSOCIATED SURFACE COLD FRONT
IS ALSO WELL W OF THE AREA TO THE NW OF THE HAWAIIAN ISLANDS...
HOWEVER...STRONG SOUTHERLY FLOW AHEAD OF THIS SYSTEM IS BEING
OBSERVED JUST TO THE NW OF THE AREA AS REVEALED IN SHIP 
OBSERVATIONS FROM DURING THE AFTERNOON AND EARLY EVENING HOURS. 
DATA INFERRED FROM SATELLITE-DERIVED WINDS SHOWS MODERATE TO 
STRONG UPPER LEVEL WINDS AHEAD OF TROUGH AXIS NOW ENCROACHING TO 
THE FAR WESTERN PORTION OF THE REGION. THESE WINDS ARE 
TRANSPORTING DEEP TROPICAL MOISTURE IN THE FORM OF HIGH LEVEL 
CLOUDS NWD TO THE GENERAL AREA OF THE GULF OF ALASKA. THE MAIN 
ENERGY WITH THE TROUGH IS FORECAST TO PASS N OF THE AREA WITHIN 
THE NEXT 48-72 HOURS WHILE THE COLD FRONT IS ALSO EXPECTED TO 
STAY N OF THE AREA. THE MAIN PROBLEM...HOWEVER...WILL BE LONG 
PERIOD NW SWELLS GENERATED BY THE PARENT LOW OF THIS SYSTEM ARE 
FORECAST TO MIGRATE INTO THE NW SECTION OF THE REGION BY THE END 
OF THE WEEK WITH POSSIBLE MAXIMUM HEIGHTS OF 15 OR 15 FT IN THE 
FAR NW CORNER.

ELSEWHERE...A WEAK UPPER LEVEL CYCLONIC CIRCULATION IS LOCATED
NEAR 25N129W WITH A TROUGH SE THROUGH 21N125W TO 16N122W TO 
12N119W TO 8N115W  TO 7N108W. MODERATE TO STRONG SW FLOW E OF 
THE UPPER TROUGH BECOMES CONFLUENT ALONG 22N E OF 118W OR ALONG 
THE BASE OF THE BROAD UPPER LEVEL TROUGH OVER THE EASTERN PART 
OF THE AREA. A JET STREAM BRANCH WITH MAXIMUM WINDS OF 60-80 KT 
ROUNDS THE BASE OF THE THIS TROUGH. POSSIBLE HIGH LEVEL 
TURBULENCE IN TRANSVERSE BANDING OF CIRRUS CLOUDS IS NOTED FROM 
10N TO 20N E OF THE 117W. THE CONFLUENT FLOW ASSOCIATED WITH THE 
BROAD UPPER LEVEL TROUGH IS RESULTING IN MODERATE TO STRONG 
SUBSIDENCE INDUCING DRY STABLE AIR OVER MUCH OF THE AREA N OF 
22N E OF 135W. BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE 
AREA S OF 20N AND TO THE W OF THE ABOVE MENTIONED TROUGH.

AT THE SURFACE...HIGH PRES RIDGING SWD OVER NORTHERN AND CENTRAL 
MEXICO IS CREATING A TIGHT PRES GRADIENT JUST INLAND THE GULF
OF TEHUANTEPEC EARLY THIS EVENING. STORM FORCE WINDS ARE FORECAST
TO OCCUR IN THE GULF OF TEHUANTEPEC BEGINNING TONIGHT AND ENDING
BY WED NIGHT. HOWEVER...GALE FORCE WINDS ARE EXPECTED TO REMAIN
IN THE GULF THROUGH THE NEXT 48 HOURS WITH LATEST MODEL WIND 
GUIDANCE SUGGESTING THAT THESE CONDITIONS MAY INCREASE ONCE 
AGAIN BY THE END OF THE WEEK.
 
NE WINDS TO 20 KT THROUGH THE GULF OF PAPAGAYO ARE EXPECTED TO 
INCREASE TO 20-25 KT IN 24 HOURS AND CONTINUE THROUGH 48 HOURS
AS STRONG CARIBBEAN TRADE WINDS CHANNEL W ACROSS CENTRAL AMERICA.
ELSEWHERE HIGH PRES COVERS THE AREA N OF ABOUT 17N W OF 110W.

$$
AGUIRRE