000
AXPZ20 KNHC 311522
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED DEC 31 2008

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...
THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...04N77W TO 
09N105W TO 07N115W TO 09N130W TO 08N140W. SCATTERED MODERATE 
WITH ISOLATED STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE OF 
THE LINE FROM 09N106W TO 06N115W. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION IS WITHIN 75 NM OF THE POINT 09N130W. 
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN THE 
AREA FROM 06N TO 12N W OF 135W.

...DISCUSSION...
PERSISTENT WEAK TROUGH IN THE WESTERLIES IS NORTH OF A LINE 
THROUGH 22N140W TO 27N125W TO 22N115W TO 25N105W TO 32N104W. 
A TROUGH WILL REMAIN ACROSS THE AREA GENERALLY NORTH OF 25N 
THROUGH AT LEAST 72 HOURS. LITTLE WEATHER IS ASSOCIATED WITH THE 
TROUGH EXCEPT FOR A SMALL AREA OF CLOUDS OVER CENTRAL MEXICO. 

THE REMAINDER OF THE AREA IS COVERED BY WEAK ANTICYCLONIC FLOW.
THIS FLOW IS SOMEWHAT DIVERGENT ALOFT WITH A LARGE AREA OF DEEP 
LAYER MOISTURE WITH BROKEN TO OVERCAST MULTI LEVEL CLOUDS IS 
SOUTH OF 22N WEST OF 114W. 

THE AREA EAST OF 115W SOUTH OF THE ITCZ IS DRY AND CLOUD FREE IN 
THE MIDDLE AND UPPER LEVELS WITH OVERCAST STRATOCUMULUS CLOUDS 
IN THE LOWER LEVELS.  EXCEPT FOR SOME ITCZ CONVECTION WEST OF 
100W THE AREA EAST OF 105W IS DRY AND CLOUD FREE IN THE MIDDLE 
AND UPPER LEVELS WITH ONLY SCATTERED CUMULUS CLOUDS NORTH OF THE 
ITCZ IN THE LOWER LEVELS AND THE STRATOCUMULUS SOUTH OF THE 
ITCZ.

TWO AREAS OF ENHANCED CONVECTION IN THE ITCZ ARE ASSOCIATED WITH 
UPPER LEVEL TROUGHS. ONE IS FROM 105W TO 115W THE OTHER IS WEST 
OF 135W. 

WEAK SURFACE RIDGE IS NORTH OF 13N WEST OF 115W. ELSEWHERE A 
BROAD TROUGH IS ANALYZED AT THE SURFACE.

GAP WINDS HAVE LESSENED IN THE GULF OF TEHUANTEPEC REGION BUT 
WILL INCREASE TO GALE FORCE BRIEFLY THURSDAY MORNING BEFORE 
FALLING TO LESS THAN 20 KT LATER THURSDAY.

GAP WINDS CONTINUE IN THE GULF OF PAPAGAYO REGION THROUGH AT 
LEAST THE NEXT 48 HOURS.

$$
LL