000
AXPZ20 KNHC 251553
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI DEC 25 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...ITCZ...
ITCZ AXIS IS ALONG 07N77W TO 10N85W TO 05N97W TO 08N110W TO 
05N120W TO 05N140W. ISOLATED STRONG CONVECTION IS NOTED WITHIN 
150 NM OF 04N78W AND ALSO WITHIN 30 NM OF 08N128W. ISOLATED 
MODERATE OBSERVED FROM 05N TO 09N E OF 92W.

...DISCUSSION...
A SERIES OF UPPER LEVEL TROUGHS DOMINATE THE WESTERN PORTION OF 
THE DISCUSSION AREA. THE FIRST TROUGH AXIS IS NOTED ALONG 
32N120W TO 16N130W TO 03N132W. THE SECOND TROUGH IS CURRENTLY 
JUST W OF THE AREA ALONG 32N138W TO 25N148W. A SHORTWAVE RIDGE 
SEPARATES THESE TWO TROUGHS...ORIGINATING FROM AN ANTICYCLONE W 
OF THE AREA AT 09N150W WITH A RIDGE EXTENDING NE TO A CREST AT 
29N133W. UPPER MOISTURE IS NOTED UNDER THE RIDGE...ROUGHLY FROM 
23N TO 30N W OF 130W...WHILE DRY UPPER AIR IS INDICATED S OF 23N 
W OF 130W.

FURTHER E AN UPPER TROUGH EXTENDS SW ACROSS THE W CARIBBEAN AND 
PANAMA AND COSTA RICA TO BASE OVER THE TROPICAL PACIFIC AT 
03N91W. AS PREVIOUSLY MENTIONED...ISOLATED CONVECTION IS FLARING 
OVER THE PACIFIC FROM 05N TO 09N E OF 92W WITH THE DEBRIS 
MOISTURE QUICKLY EVAPORATING NEAR THE CONVECTIVE CLUSTERS.
  
AN UPPER ANTICYCLONE IS CENTERED NEAR 03N108W WITH A RIDGE 
EXTENDING N TO A FLAT CREST LYING ALONG 25N114W TO 27N90W. 
BETWEEN THIS RIDGE AND THE DEEP UPPER TROUGH MENTIONED ABOVE IS 
A WEAK SURFACE TROUGH AND INTERMITTENT SURFACE LOW BOTH EMBEDDED 
WITHIN THE ITCZ...ROUGHLY WITHIN THE AREA FROM 03N TO 13N 
BETWEEN 125W AND 132W. CONVECTION IS OCCASIONALLY ENHANCED WITH 
THE ASSOCIATED DEBRIS MOISTURE ADVECTED NE UNDER THE RIDGE IN AN 
IMPRESSIVE PLUME WITHIN 480 NM EITHER SIDE OF LINE 07N120W TO 
25N99W. THE MOISTURE IS NOW EVAPORATING OVER THE UPPER LEVELS 
OVER THE N CENTRAL GULF OF MEXICO. OTHERWISE DRY UPPER AIR IS 
INDICATED OVER THE DISCUSSION AREA S OF 18N E OF 110W.
 
AT THE SURFACE...1022 MB HIGH PRES CENTERED NEAR 30N127W WITH A 
COLD FRONT JUST ENTERING THE NW PORTION. EASTERLY TRADES OF 20 
KT CONTINUE ALONG THE SOUTHERN PERIPHERY OF THE RIDGE WITH 
SOUTHERLY WINDS AT 20 TO 25 KT OVER THE NW WATERS IN ADVANCE OF 
AN APPROACHING COLD FRONT AND NW 20 TO 25 KT IN WAKE OF FRONT. 
NW SWELLS ALREADY PROPAGATING OVER MOST OF THE AREA W OF 112W 
WILL BE REINFORCED BY EVEN LARGER SWELLS ACCOMPANYING THIS NEW 
COLD FRONT.  

GULF OF CALIFORNIA...NORTHERLY FLOW AT 15 TO 20 KT IS EXPECTED 
TO DIMINISH BELOW 20 KT LATE TODAY.

GULF OF TEHUANTEPEC...NORTHERLY 20 KT WINDS 20 KT IN THE GULF 
WILL CONTINUE TO INCREASE TO 20 TO 30 KT SPREADING S TO ALONG 
13N LATER TODAY THEN DIMINISH TO 20 KT SAT AND BELOW 20 KT SAT 
NIGHT.

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