000 AXNT20 KNHC 131747 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST WED DEC 13 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA... CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA... NORTHEASTERN 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... 6N9W 4N20W 4N30W 3N40W 3N44W INTO NORTHEASTERN BRAZIL NEAR 2N52W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS IN CLUSTERS FROM 4N TO 5N BETWEEN 15W AND 18W... FROM 2N TO 3N BETWEEN 24W AND 26W...AND FROM 4N TO 5N BETWEEN 26W AND 28W. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE ELSEWHERE FROM THE EQUATOR TO 7N BETWEEN THE PRIME MERIDIAN AND 43W. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE FROM BRAZIL TO FRENCH GUIANA FROM 1S TO 5N BETWEEN 50W AND 53W. ...DISCUSSION... THE GULF OF MEXICO... UPPER LEVEL SOUTHWESTERLY FLOW MOVES FROM THE EASTERN PACIFIC OCEAN ACROSS MEXICO NORTH OF 20N. THE FLOW OVER MEXICO SOUTH OF 20N IS NOT CONTINUOUS OR UNIFORM. THE DEEP LAYER TROUGH FROM THE CENTRAL U.S.A. TO THE GULF WATERS FROM 24 HOURS AGO HAS WEAKENED. DRY AIR COVERS THE MIDDLE TO UPPER LEVELS ACROSS THE OPEN GULF WATERS. THE GREATEST AMOUNT OF MOISTURE IS NORTH OF 25N EAST OF 90W CROSSING FLORIDA ROUGHLY NORTH OF LAKE OKEECHOBEE. SHOWERS ARE INLAND OVER FLORIDA FROM 27N TO 29N. A SURFACE TROUGH RUNS FROM THE HONDURAS COAST NEAR 16N86W TO THE NORTHEASTERN YUCATAN PENINSULA COAST TO 24N87W IN THE GULF OF MEXICO. ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS AND THUNDERSTORMS ARE SOUTH OF 25N BETWEEN 83W AND 87W. OTHER BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE PRECIPITATION ARE IN THE GULF WATERS SOUTH OF 28N EAST OF 89W. A STATIONARY FRONT EXTENDS THROUGH EAST CENTRAL LOUISIANA TO THE NORTHWESTERN GULF WATERS IS 250 NM EAST OF THE STATIONARY FRONT IN AN AREA OF A WEAK PRESSURE GRADIENT AND COMPARATIVELY LOWER SURFACE PRESSURES. AN UPPER LEVEL RIDGE STRETCHES FROM THE NORTHWESTERN CARIBBEAN SEA...TO SOUTH FLORIDA...BEYOND 31N74W IN THE ATLANTIC OCEAN. THE CARIBBEAN SEA... A SURFACE TROUGH RUNS FROM THE HONDURAS COAST NEAR 16N86W TO THE NORTHEASTERN YUCATAN PENINSULA COAST TO 24N87W IN THE GULF OF MEXICO. ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS AND THUNDERSTORMS ARE FROM 20N TO 25N BETWEEN 83W AND 87W. A SECOND SURFACE TROUGH EXTENDS FROM 40 TO 50 NM EAST OF EASTERN HONDURAS NEAR 16N83W...PASSING IN BETWEEN SAN ANDRES AND PROVIDENCIA TO 13N81W...TO 10N79W ABOUT 35 NM NORTH OF THE PANAMA COAST. STRONG SHOWERS AND THUNDERSTORMS ARE FROM 11N TO 13N BETWEEN 80W AND 82W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE FROM 14N TO 16N BETWEEN 80W AND 84W. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS ARE ELSEWHERE FROM 10N TO 18N BETWEEN 80W AND 84W. A FEW AREAS OF DISORGANIZED MIDDLE TO UPPER LEVEL CYCLONIC FLOW ARE IN THE ITCZ SOUTH AND SOUTHWEST OF PANAMA AND COSTA RICA. UPPER LEVEL SOUTHWESTERLY FLOW IS IN THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA AS SEEN ON WATER VAPOR IMAGERY AND 13/1500 UTC CIMSS SATELLITE DERIVED WIND DATA. NOT WELL DEFINED MIDDLE LEVEL CYCLONIC FLOW...FROM THE SATELLITE AND THE CIMSS DATA...IS UNDERNEATH THE HIGHER LEVEL SOUTHWESTERLY WINDS. AN UPPER LEVEL RIDGE IS MOVING SOUTHEASTWARD...FROM THE AREA OF THE NORTHERN AND WESTERN BAHAMAS TO THE TURKS AND CAICOS AND THE ATLANTIC OCEAN WATERS NORTH OF HISPANIOLA. ISOLATED MODERATE SHOWERS FROM 20N TO 22N BETWEEN 67W AND 69W. THE REST OF THE MIDDLE TO UPPER LEVEL FLOW EAST OF 70W IS MOVING TOWARD THE BASE OF A MIDDLE TO UPPER LEVEL TROUGH THAT ENDS IN THE EASTERN CARIBBEAN SEA FROM GRENADA TO ST.LUCIA. THE ATLANTIC OCEAN... A MIDDLE LEVEL CYCLONIC CIRCULATION CENTER IS STARTING TO FORM NEAR 27N69W IN DRY AIR AND UNDER THE NORTHERN EXTENSION OF THE CARIBBEAN SEA-31N74W RIDGE. A MIDDLE TO UPPER LEVEL TROUGH PASSES THROUGH 32N43W TO 23N49W TO THE EASTERN/SOUTHEASTERN CARIBBEAN SEA FROM GRENADA TO ST.LUCIA. WELL-DEVELOPED MIDDLE TO UPPER LEVEL DRY AIR IS NORTH OF 20N WEST OF 40W. THIS TROUGH SUPPORTS THE COLD FRONT THAT PASSES THROUGH 32N38W TO 24N45W TO 20N50W. A STATIONARY FRONT CONTINUES FROM 20N50W TO 19N61W. BROKEN MULTILAYERED CLOUDS ARE WITHIN 180 NM ON EITHER SIDE OF 17N42W 23N37W 28N37W BEYOND 32N37W. SHOWERS AND POSSIBLE THUNDERSTORMS ARE NORTH OF 20N IN THIS CLOUDINESS. STRATIFORM CLOUDS AND POSSIBLE PRECIPITATION ARE WEST OF 40W...MOVING SOUTHWARD. WHATEVER REMAINS OF THE UPPER LEVEL RIDGE FROM 24 HOURS AGO CONTINUES TO BEING SQUEEZED IN BETWEEN THE APPROACHING TROUGH AND THE CYCLONIC FLOW AROUND A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER NEAR 26N26W. CYCLONIC FLOW AROUND THIS CENTER ROUGHLY COVERS THE ATLANTIC WATERS FROM 20N TO 30N BETWEEN 20W AND 30W. UPPER LEVEL ANTICYCLONIC FLOW COVERS THE ATLANTIC WATERS NORTH OF 30N BETWEEN 16W AND 30W. MIDDLE TO UPPER LEVEL CYCLONIC FLOW FROM A CYCLONIC CENTER IN NORTHEASTERN ALGERIA STARTS TO IMPOSE ON THE ANTICYCLONE NORTH OF 30N BETWEEN 16W AND 30W. $$ MT