000
AXPZ20 KNHC 310916
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU DEC 31 2009

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 05N77W TO 
06N105W TO 07N140W. THERE IS NO SIGNIFICANT CONVECTION ALONG THE 
ITCZ.

...DISCUSSION...

THE FLOW PATTERN IN THE MIDDLE AND UPPER LEVELS WILL CHANGE 
LITTLE IN THE NEXT TWO DAYS. A RIDGE IS OVER THE WEST PART OF 
THE AREA. THE RIDGE IS NORTH OF THE ITCZ WEST OF 130W. THE RIDGE 
WILL WEAKEN AFTER DAY TWO. A DEEP LAYER TROUGH IS NORTH OF 15N 
EAST OF 130W TO A LINE THAT RUNS FROM THE SOUTHEAST PART OF 
TEXAS ACROSS CENTRAL MEXICO TO THE ITCZ NEAR 125W. THE DEEP 
LAYER TROUGH WILL REMAIN THROUGH THE NEXT SEVERAL DAYS. MOST OF 
THE TROUGH AND RIDGE AREA IS DRY AND CLOUD FREE IN THE MIDDLE 
AND UPPER LEVELS THE EXCEPTION IS OVER THE NORTHWEST PART WHERE 
MULTIPLE LEVEL CLOUDS ARE OBSERVED AHEAD OF A TROUGH WEST OF THE 
AREA. A PLUME OF DEEP LAYER MOISTURE EXTENDS ABOUT 500 NM EAST 
OF THE DEEP LAYER TROUGH WITH BROKEN TO OVERCAST MOSTLY HIGH 
CLOUDS OVER CENTRAL MEXICO. TO THE EAST OF THE TROUGH BROAD 
ANTICYCLONIC FLOW IS OBSERVED. THIS AREA IS ALSO DRY AND CLOUD 
FREE IN THE MIDDLE AND UPPER LEVELS EXCEPT FOR SOME ISOLATED 
CONVECTION NEAR THE ITCZ AND AN AREA OF CLOUDINESS NORTH OF THE 
ITCZ TO 12N FROM 97W TO 103W. ISOLATED SHOWERS ARE WITHIN THIS 
AREA.

DIFFLUENT UPPER FLOW OVER THE ITCZ FROM 110W TO 125W IS 
SPREADING MOISTURE FROM ITCZ CONVECTION OVER THE AREA SOUTH OF 
10N FROM 110W TO 125W. THE CONVECTION HAS DIMINISHED DURING THE 
LAST SIX HOURS BUT THE UPPER MOISTURE REMAINS.

SURFACE HIGH PRESSURE IS CENTERED NEAR 29N129W WITH A CENTRAL 
PRESSURE OF 1025 MB. ASSOCIATED MODERATE SURFACE RIDGE IS NORTH 
OF 12N WEST OF 107W. TRADE WINDS NORTH OF THE ITCZ WEST OF 110W 
ARE IN THE 20 TO 25 KT RANGE FROM NEAR THE ITCZ TO 20N.  
ELSEWHERE A BROAD TROUGH CENTERED ON THE ITCZ IS ANALYZED AT THE 
SURFACE.

GAP WINDS...
GULF OF TEHUANTEPEC...N WINDS OF 20 TO 25 KT ARE FORECAST TO 
DIMINISH DURING TODAY TO LESS THAN 20 KT TONIGHT THEN INCREASE 
AGAIN FRIDAY.

GULF OF PAPAGAYO...E WINDS OF 20 TO 25 KT AND BRIEFLY TO 30 KT 
ARE EXPECTED TO CONTINUE THROUGH FRIDAY NIGHT.

GULF OF CALIFORNIA...NW WINDS ARE EXPECTED TO INCREASE TO 20 KT 
TONIGHT. THESE WINDS ARE EXPECTED TO CONTINUE THROUGH FRIDAY 
THEN DIMINISH.

SEA CONDITIONS ARE DOMINATED BY LONG PERIOD NW SWELL (WAVE 
PERIODS OF UP TO 16 SECONDS) WITH SIGNIFICANT WAVE HEIGHTS AS 
HIGH AS 12 FT. 

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