000
AXPZ20 KNHC 170358
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN JAN 17 2010

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 
0315 UTC.

...ITCZ...

THE ITCZ AXIS EXTENDS FROM 03N77W TO 09N104W TO 04N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 
120 NM EITHER SIDE OF A LINE FROM 08N120W TO 05N132W.
 
...DISCUSSION...

AN UPPER TROUGH EXTENDS FROM 32N116W TO 20N124W TO BEYOND 
12N140W WITH UPPER MOISTURE NOTED N OF 22N WITHIN ABOUT 600 NM E 
OF THE TROUGH AXIS...EXTENDING OVER NORTHERN OLD MEXICO W OF 
110W AND OVER MOST OF ARIZONA AND NEW MEXICO. A SHORTWAVE RIDGE 
IS BUILDING EASTWARD ALONG 22N W OF THE UPPER TROUGH AND IS 
ACCOMPANIED BY DRY UPPER AIR OVER MOST OF THE DISCUSSION AREA S 
OF 24N W OF THE UPPER TROUGH AXIS.

AN UPPER CYCLONE IS LIFTING NE OVER THE LOUISIANA WHILE TRAILING 
AN UPPER TROUGH S TO OVER THE YUCATAN PENINSULA. FURTHER S...A 
TROPICAL ANTICYCLONE IS ESTIMATED NEAR 07N125W WITH SHORTWAVE 
RIDGE EXTENDING NE ACROSS OLD MEXICO TO A CREST NEAR 27N107W... 
AND IS BASICALLY SEPARATING THE PREVIOUSLY MENTIONED UPPER 
TROUGHS WITH THE PREVIOUSLY MENTIONED MOISTURE SPREADING E 
ACROSS THE RIDGE. A SECOND SHORTWAVE RIDGE COVERS THE DEEP 
TROPICS TO THE S OF 18N E OF 100W. UPPER DIFFLUENCE IS ENHANCING 
CONVECTION ALONG THE ITCZ BETWEEN 120W AND 132W WITH THE 
RESULTANT DEBRIS MOISTURE QUICKLY EVAPORATING. OTHERWISE A BAND 
OF VERY DRY UPPER AIR IS ADVECTED ALONG THE NW PERIPHERY OF THIS 
RIDGE COVERING THE UPPER LEVELS OF THE TROPICS SE OF A LINE FROM 
10N140W TO 21N107W TO 21N80W AND IS SUPPRESSING CONVECTION.

AT THE LOW LEVELS A FRONTAL TROUGH IS LOSING IDENTITY FROM 
32N124W TO 24N137W. LARGE NW SWELLS ARE PROPAGATING SE OVER THE 
THE ENTIRE AREA W OF 85W....MIXING WITH NE TRADE SWELLS AND ALSO 
MIXING WITH SOUTHERLY SWELL MOVING N ACROSS THE EQUATOR OVER THE 
AREA S OF 10N W OF 83W. A STRONG COLD FRONT WILL ENTER THE NW 
PORTION SUN NIGHT ACCOMPANIED BY WESTERLY WINDS TOM 30 KT AND A 
NEW TRAIN OF NW SWELLS DRIVING COMBINED SEAS TO ABOUT 25 FT 
ALONG 30N BETWEEN 130W AND 140W MON NIGHT. 
 
GAP WINDS...N AND NE WINDS AT 20 TO 30 KT...SEAS BUILDING 
BRIEFLY TO 11 FT...ARE EXPECTED THROUGH THE GULF OF TEHUANTEPEC 
THROUGH SUN THEN DIMINISHING TO 20 TO 25 KT SUN NIGHT AND TO 15 
TO 20 KT LATE MON.  NE WINDS AT 15 TO 20 KT IN AND DOWNSTREAM OF 
THE GULF PAPAGAYO WILL INCREASE TO 25 TO 30 KT DURING THE MID 
MORNING SUN AND MON THEN DIMINISH TO 15 TO 20 KT MON NIGHT. 
N WINDS WILL PULSE TO 20 KT IN THE GULF OF PANAMA THROUGH MON.   

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
NELSON