000
AXPZ20 KNHC 132205
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE JAN 13 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...ITCZ...

ITCZ IS CENTERED ALONG 6N77W 5N90W 7N100W 8N110W 8N121W 7N130W
5N140W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM N OF THE
AXIS BETWEEN 81W-85W.

...DISCUSSION...

THE CURRENT PATTERN IS DESCRIBED BY MAINLY TOW FEATURES. THE 
FIRST IS THE TAIL END OF BROAD UPPER LEVEL TROUGHING CENTERED 
OVER MID-WEST REGION OF THE UNITED STATES WITH ITS TAIL END 
REACHING SW TO THE FAR EASTERN SECTION OF THE AREA N OF ABOUT 
22N AND E OF 118W. W OF THE TROUGH MID AND UPPER LEVEL RIDGING 
IS PRESENT N OF 22N WITH AN ANTICYCLONIC CENTER NEAR 31N124W. A 
RIDGE EXTENDS FROM THIS ANTICYCLONE WELL NW OF THE REGION. AN 
UPPER LEVEL TROUGH EXTENDS 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. STRONG SOUTHERLY FLOW AHEAD OF THE NEXT FRONTAL SYSTEM IS 
OBSERVED IN SATELLITE-DERIVED WINDS TO COVER THE AREA W OF 135W. 
BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA S OF 20N AND 
W OF 120W.
 
AT THE SURFACE...A STRONG 1036 MB HIGH CENTER IS LOCATED OVER 
NORTHERN MEXICO. IT IS BRINGING A TIGHT PRES GRADIENT RESULTING 
IN GALE FORCE WINDS THROUGH THE GULF OF TEHAUNTEPEC. THESE WINDS 
ARE EXPECTED TO INCREASE TO STORM STRENGTH EARLY THIS 
EVENING...THEN DIMINISH BACK TO GALE FORCE IN ABOUT 24 HOURS. NE 
20 KT WINDS THROUGH THE GULF OF PAPAGAYO ARE EXPECTED TO 
INCREASE TO 20-25 KT IN ABOUT 48 HOURS. HIGH PRES COVERS THE 
AREA N OF ABOUT 17N W OF 115W.

$$
AGUIRRE