000
AXNT20 KNHC 160014
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT DEC 15 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO
THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING
INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL  
ANALYSIS...WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC

...ITCZ...
FROM THE COASTAL BOUNDARY OF LIBERIA AND SIERRA LEONE TO 4N30W 
TO 5N40W TO 3N50 AT THE EASTERN COAST OF FRENCH GUIANA.  
SCATTERED MODERATE THUNDERSTORMS FROM 4N-7N BETWEEN 33W-48W.  
ISOLATED MODERATE TO STRONG THUNDERSTORMS ELSEWHERE FROM EQUATOR 
TO 8N FROM 20W-50W.  ISOLATED MODERATE SHOWERS FROM 4N-6N 
BETWEEN 15W-33W AND FROM 48W-66W INCLUDING IN NORTHERN SECTIONS 
OF SURINAME...GUYANA...AND EASTERN VENEZUELA.

...DISCUSSION...
GULF OF MEXICO...
COLD FRONT EXTENDS FROM SOUTHEASTERN LOUISIANA THROUGH 26N90W TO 
COAST OF MEXICO AT 23N97W.  FRONT FORECAST TO MOVE THROUGH 
FLORIDA SUNDAY NIGHT INTO SOUTHWEST NORTH ATLANTIC LEAVING 
HEALTHY HIGH PRESSURE CENTER OVER GULF OF MEXICO WITH GALE FORCE 
WINDS WEST OF 90W TONIGHT.  SUSTAINED WINDS DIMINISH BELOW GALE 
FORCE SUN AND SUN NIGHT BUT STILL REMAIN 20-30 KT AND GUSTY.  

LOW PRESSURE CENTER...REMNANTS OF OLGA...NOW NEAR 24N88W  
FORECAST TO SHIFT NE AS IT IS ABSORBED BY COLD FRONT.  LINE OF 
SCATTERED MODERATE SHOWERS ISOLATED THUNDERSTORMS WITHIN 90 NM 
NORTHEAST QUADRANT OF LOW PRESSURE.  WIDELY SCATTERED MODERATE 
SHOWERS WITHIN 60 NM E OF LINE FROM 27N89W TO 30N87W AND WITHIN 
90 NM E OF COLD FRONT.

CARIBBEAN SEA...
MIDDLE TO UPPER LEVEL RIDGE AT 17N83W DOMINATES ENTIRE WESTERN 
BASIN WITH WEAK TROUGH HANGING FROM CYCLONIC VORTEX AT 18N60W TO 
12N72W SHARING EASTERN HALF.  WESTERN CARIBBEAN REMAINS VERY DRY 
UNDER RIDGE AND TROUGH AXIS ACROSS EASTERN HALF OF BASIN 
MAINTAIN MODERATE SUBSIDENCE IN FLOW ALOFT.  UPPER LEVEL 
MOISTURE CONFINED TO SOUTH OF 15N EAST OF 70W AS TROPICAL 
MOISTURE FROM ITCZ IS ADVECTED NE ON LEE SIDE OF UPPER TROUGH.

CONVERGING TRADES OVER MOUNTAINOUS NICARAGUA AND COSTA RICA 
PRODUCE MINOR CONVECTION AND SHOULD DIMINISH AS FLOW WEAKENS AND 
BECOME MORE SOUTHEAST WITH APPROACHING COLD FRONT TO YUCATAN 
PASSAGE.

ATLANTIC OCEAN...
UPPER LEVEL RIDGE OVER NORTHWESTERN CARIBBEAN MAINTAIN STUBBORN 
ANTICYCLONIC FLOW OVER ENTIRE SOUTHWESTERN NORTH ATLANTIC WITH 
PLENTY OF MOISTURE LADEN AIR MASS ADVECTING FROM THE NORTHWEST.
COLD FRONT...NOW OVER GULF OF MEXICO...ENTERS BASIN EARLY SUNDAY 
WITH GALE FORCE SW WINDS AHEAD OF BOUNDARY THROUGH SUN 
DIMINISHING SUN NIGHT.  
FARTHER INTO EAST ATLANTIC...MIDDLE TO UPPER LEVEL TROUGH PASSES 
THROUGH 31N11W TO 26N16W TO 18N28W...EAST OF MADEIRA ARCHIPELAGO 
...AND OVER CANARY ISLANDS APPROACHING MOROCCO.  UPPER LEVEL 
WEST-TO-SOUTHWEST WIND FLOW SOUTH OF 20N17W 17N33W 18N60W.

$$
WALLY BARNES