[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 060604
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST WED DEC 06 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC.

...THE ITCZ...
8N13W 6N20W 6N30W 5N40W TO THE EXTREME NORTHEASTERN COAST OF
BRAZIL FROM 1N TO 2N ALONG 51W. SCATTERED STRONG SHOWERS AND
THUNDERSTORMS FROM 4N TO 5N BETWEEN 27W AND 30W...AND FROM 3N
TO 6N BETWEEN 32W AND 37W. SCATTERED MODERATE SHOWERS TO
ISOLATED STRONG THUNDERSTORMS ARE FROM 4N TO 8N BETWEEN 38W
AND 44W. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS
ARE ELSEWHERE FROM THE EQUATOR TO BETWEEN THE PRIME MERIDIAN
AND 60W.

...DISCUSSION...
THE GULF OF MEXICO...
THE FRONTAL BOUNDARY WHICH HAS LASTED IN THE GULF OF MEXICO
SINCE LAST THURSDAY FINALLY IS OUT OF THE AREA. IT HAS SLOWED
DOWN ENOUGH DURING THE LAST FEW ANALYSES AND IS STATIONARY AT
THE MOMENT...FROM THE ATLANTIC OCEAN NEAR 28N70W...ACROSS THE
NORTHERN BAHAMAS...ACROSS WESTERN CUBA...INTO THE NORTHWESTERN
CARIBBEAN SEA...TO NORTHWESTERN COASTAL HONDURAS. BROKEN TO
OVERCAST LOW TO MIDDLE LEVEL CLOUDS COVER THE GULF WATERS AT
THIS TIME. THE UPPER FLOW OVER THE GULF HAS BECOME MOSTLY ZONAL
WITH JUST A SLIGHT ANTICYCLONIC FEEL...AROUND A RIDGE THAT HAS
FLATTENED FROM ITS ORIGIN NEAR NORTHEASTERN NICARAGUA.
THE SURFACE PATTERN REMAINS DOMINATED BY HIGH PRESSURE AND
ANTICYCLONIC FLOW...FROM HIGH PRESSURE CENTERS IN MISSISSIPPI
AND ALABAMA. THE SURFACE PRESSURE GRADIENT HAS RELAXED
SIGNIFICANTLY SINCE YESTERDAY...LEAVING LIGHTER NORTHEASTERLY
WINDS AND DIMINISHING SEAS ACROSS THE AREA. THE WINDS AND SEAS
WILL RELAX MORE INTO WEDNESDAY...BUT INCREASE THURSDAY AND
FRIDAY BEHIND THE NEXT COLD FRONT.

THE CARIBBEAN SEA...AND THE ATLANTIC OCEAN
SOUTH OF 25N WEST OF 50W...
UPPER LEVEL ANTICYCLONIC FLOW IS WEST OF 75W...FROM THE CENTRAL
CARIBBEAN SEA TO CENTRAL AMERICA. A MIDDLE TO UPPER LEVEL TROUGH
ORIGINATES FROM A NORTHEASTERN CARIBBEAN SEA 18N64W CYCLONIC
CIRCULATION CENTER TO THE SOUTH CENTRAL CARIBBEAN SEA. THIS IS
THE SAME CYCLONIC CENTER WHICH HAS BEEN MOVING WESTWARD...FROM
THE ATLANTIC OCEAN A FEW DAYS AGO TO THE CARIBBEAN SEA NOW.
MIDDLE TO UPPER LEVEL DRY AIR PREVAILS EVERYWHERE OVER THE
CARIBBEAN WATERS...EVEN IN CENTRAL AMERICA. ISOLATED MODERATE
SHOWERS TO LOCALLY STRONG THUNDERSTORMS FROM 14N TO 20N BETWEEN
60W AND 67W IN THE CARIBBEAN SEA...FROM 18N TO 27N BETWEEN
56W AND 62W IN THE ATLANTIC OCEAN...AND IN THE SOUTHEASTERN
CORNER OF THE AREA FROM 10N TO 13N BETWEEN 58W AND 63W.
AN UPPER LEVEL RIDGE RUNS FROM BRAZIL NEAR 2S47W TO 6N49W TO
14N50W TO 19N52W.

THE REST OF THE ATLANTIC OCEAN...
ANOTHER MIDDLE TO UPPER LEVEL TROUGH IS MOVING THROUGH THE
WESTERN ATLANTIC OCEAN. PRACTICALLY ALL OF THE CYCLONIC FLOW
WITH THIS TROUGH REALLY IS NORTH OF 30N BETWEEN 55W AND 80W.
THE SURFACE COLD FRONT FROM YESTERDAY STILL IS IN THE AREA...
PASSING THROUGH 32N59W TO 28N70W...PART OF THE OVERALL FRONTAL
BOUNDARY WHOSE ENDPOINT IS IN NORTHWESTERN COASTAL HONDURAS
IN THE CARIBBEAN SEA. A SURFACE TROUGH IS TO THE EAST OF THE
FRONTAL BOUNDARY...FROM 30N59W TO 25N67W TO 16N75W IN THE
CARIBBEAN SEA. THIS FEATURE IS SUPPORTED BY SURFACE
OBSERVATIONS. ISOLATED MODERATE SHOWERS AND POSSIBLE
THUNDERSTORMS ARE WITHIN 30 NM ON EITHER SIDE OF 26N64W
28N60W BEYOND 31N55W. BROAD UPPER LEVEL ANTICYCLONIC FLOW IS IN
THE ATLANTIC WATERS EAST AND NORTH OF THE CYCLONIC FLOW AROUND
THE MIDDLE TO UPPER LEVEL 17N64W CYCLONIC CENTER. A MIDDLE TO
UPPER LEVEL TROUGH RUNS FROM ONE CYCLONIC CIRCULATION CENTER
NEAR 22N27W TO 18N30W TO A SECOND CYCLONIC CIRCULATION CENTER
NEAR 16N37W.

$$
MT




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