000
AXPZ20 KNHC 181536
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU MAR 18 2010

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 
1500 UTC.

...ITCZ...
AXIS IS ALONG 06N77W TO 03.5N94.5W TO 06N109W TO 02N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 240 NM S OF 
AXIS BETWEEN 81W AND 97W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WITHIN 90 NM EITHER SIDE OF AXIS BETWEEN 99W AND 
111W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 150 NM 
EITHER SIDE OF AXIS W OF 114W. 

...DISCUSSION...
IN THE UPPER LEVELS...A NEGATIVELY TILTED TROUGH IS APPROACHING 
THE WESTERN PORTION OF THE AREA N OF 20N WITH RIDGING PREVAILING 
ACROSS THE REMAINDER OF THE AREA N OF 20N. ACTIVE CONVECTION IN 
THE ITCZ IS MAINTAINING UPPER LEVEL RIDGING AND ENHANCED 
DIVERGENCE ALOFT. THIS ACTIVE CONVECTION IS ALSO HELPING TO 
TRIGGER A SERIES OF SHORT WAVE TROUGHS AND RIDGES BETWEEN 10N 
AND 20N. 

AT THE SURFACE...AS THE STRONG NEGATIVELY TILTED TROUGH AND ITS 
ASSOCIATED COLD FRONT SHIFT E TOWARD THE AREA...ONLY WEAK 
RIDGING PREVAILS ACROSS THE NORTHERN PART OF THE AREA. AS A 
RESULT...TRADES GREATER THAN 20 KT ARE CONFINED TO A LIMITED 
AREA FROM 05N TO 15N W OF 125W. THIS RIDGE WILL CONTINUE TO 
WEAKEN ENABLING THE COLD FRONT TO ENTER THE NW PART OF THE AREA 
ON FRI MORNING. NW SWELLS PREVAILING ACROSS THE AREA...MIXING 
WITH SUBSIDING SW SWELL IN THE SOUTHERN PART OF THE AREA...WILL 
CONTINUE TO GRADUALLY SUBSIDE...BUT REMAIN ABOVE 8 FT W OF 100W 
FOR THE REMAINDER OF THE FORECAST PERIOD. ANOTHER SET OF LONG 
PERIOD NW SWELLS WILL BE GENERATED BEHIND THE COLD FRONT AND 
WILL ENTER THE NW PART OF THE AREA FRI.

GALE FORCE WINDS CONTINUE OVER THE GULF OF TEHUANTEPEC. WITH 
HIGH PRESSURE SHIFTING E ACROSS THE GULF OF MEXICO...WINDS 
FUNNELING INTO THE GULF OF TEHUANTEPEC WILL DECREASE. AS A 
RESULT...WINDS ARE EXPECTED TO DIMINISH BELOW GALE FORCE 
TONIGHT...AND BELOW 20 KT FRI. STRONG WINDS ARE ALSO BLOWING 
ACROSS THE GULF OF PAPAGAYO...AND SHOULD CONTINUE THROUGH THE 
REMAINDER OF THE FORECAST PERIOD.

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

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AL