000
AXPZ20 KNHC 112129
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU DEC 11 2008

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 
2100 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE...ALSO KNOWN AS THE ITCZ... 
IS ALONG THE LINE...06N77W TO 08N100W TO 09N120W TO 06N140W.
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 90 
NM OF THE POINT 06N81W. SCATTERED MODERATE CONVECTION IS WITHIN 
60 NM OF THE POINTS 06N93W AND 08.5N106W. SCATTERED MODERATE 
CONVECTION IS WITHIN 90 NM OF THE POINT 10N121W. SCATTERED 
MODERATE CONVECTION IS WITHIN 75 NM OF THE POINT 13N122W.

...DISCUSSION...
PERSISTENT MIDDLE AND UPPER LEVEL TROUGH IS OVER THE AREA NORTH 
OF THE ITCZ WEST OF 118W. A DEEP LAYER CYCLONIC CIRCULATION IS 
EMBEDDED WITHIN THE AREA AND IS CENTERED NEAR 30N128W. THIS 
CIRCULATION IS ABOUT 600 NM IN DIAMETER. THE SOUTHERLY FLOW ON 
THE EASTERN FLANK OF THE LARGE TROUGH IS DIFLUENT IN THE MIDDLE 
AND UPPER LEVELS WITH A LARGE AREA OF MULTI LEVEL OVERCAST 
CLOUDS WEST OF 110W SOUTH OF 15N AND WEST OF 100W NORTH OF 15N 
TO 23N AND TO THE RIDGE LINE OF THE SIERRA MADRE ORIENTAL NORTH 
OF 23N. THE MOISTURE COMES FROM CONVECTION WITHIN THE ITCZ. SOME 
EMBEDDED CONVECTION IS WITHIN THIS AREA SOUTH OF 15N FROM 118W 
TO 124W.

ELSEWHERE BROAD ANTICYCLONIC FLOW IS NOTED IN THE MIDDLE AND 
UPPER LEVELS. 

OUTSIDE OF SOME ITCZ CONVECTION THE ARA SOUTH OF 15N EAST OF 
110W IS DRY AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS.

WEAK SURFACE RIDGE IS NORTH OF 15N WEST OF 110W. ELSEWHERE A 
BROAD TROUGH IS ANALYZED AT THE SURFACE.

STRONG N FLOW IS ACROSS SE MEXICO AND INTO THE GULF OF 
TEHUANTEPEC...WITH A MORNING QUIKSCAT PASS INDICATING WINDS 40 
TO 55 KT DIRECTLY DOWNWIND. THIS STRONG TEHUANTEPEC EVENT IS 
EXPECTED DURING THE NEXT 06 HOURS...WITH THE WIND DIMINISHING TO 
GALE FORCE AND THEN TO LESS THAN GALE FORCE IN 48 HOURS.

GAP WINDS WILL FLOW THROUGH PARTS OF CENTRAL AMERICA TONIGHT AND 
CONTINUE THROUGH 48 HOURS DOWNWIND OF THE GULF OF PAPAGAYO.
 
$$
LL