[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 180624
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU 18 NOV 2004

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

BASED ON 0000 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 0545 UTC.

...ITCZ...

ITCZ 8N10W 7N30W 8N42W 6N55W AT THE COAST OF SURINAME...ACROSS
GUYANA...VENEZUELA AND COLOMBIA TO THE COLOMBIA PACIFIC COAST
NEAR 6N77W...TO 8N83W NEAR THE COSTA RICA/PANAMA BORDER.
SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS
IN CLUSTERS FROM 3N TO 4N WITHIN 15 NM ON EITHER SIDE OF 17W...
FROM 4N TO 8N BETWEEN 20W AND 26W...AND FROM 2N TO 4N BETWEEN
29W AND 32W. ISOLATED TO WIDELY SCATTERED MODERATE/LOCALLY
STRONG SHOWERS AND THUNDERSTORMS FROM 6N TO 12N BETWEEN 70W AND
82W.

...DISCUSSION...

THE GULF OF MEXICO...
HIGH LEVEL MOISTURE FROM THE EASTERN PACIFIC OCEAN IS MOVING
ACROSS MEXICO WITH FLOW FROM AN UPPER LEVEL RIDGE ALONG 111W.
MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER NOW IS IN
NORTH CENTRAL OKLAHOMA...WITH A TROUGH FROM THIS CENTER TO THE
MIDDLE TEXAS COASTAL WATERS NEAR 28N95W. UPPER LEVEL MOISTURE
AT THE TAIL END OF THE CYCLONIC FLOW OF THIS CENTER IS CAUGHT
UP IN THE UPPER LEVEL NORTHWESTERLY WIND FLOW OVER THE OPEN
GULF WATERS. SURFACE FRONTAL BOUNDARY IN TEXAS AND MEXICO
FROM 24N BEYOND 32N BETWEEN 94W AND 100W. ISOLATED TO WIDELY
SCATTERED MODERATE/LOCALLY STRONG SHOWERS...ALSO WITH A SQUALL
LINE...FROM 27N TO 30N BETWEEN 91W AND 96W IN THE GULF WATERS.
BROAD SURFACE ANTICYCLONIC FLOW ELSEWHERE. MIDDLE TO UPPER LEVEL
DRY AIR SOUTH OF 27N97W 25N90W 25N81W.

THE CARIBBEAN SEA...
UPPER LEVEL SOUTHWESTERLY WIND FLOW CONTINUES FROM NORTHERN
PARTS OF SOUTH AMERICA ACROSS THE OPEN CARIBBEAN WATERS. THIS
FLOW REGIME IS EAST AND SOUTHEAST OF A LINE FROM THE WINDWARD
PASSAGE TO THE EASTERN HONDURAS/NORTHEASTERN NICARAGUA BORDER.
HIGH LEVEL MOISTURE IS MOVING OVER/CUTTING INTO THE MIDDLE TO
UPPER LEVEL DRY AIR WHICH HAS BEEN IN PLACE IN THE NORTH CENTRAL
SECTION. THE SHOWERS AND THUNDERSTORMS SOUTH AND SOUTHEAST OF
16N60W 13N80W MAY BE MORE RELATED TO THE ITCZ THAN ANYTHING
ELSE...AND IN GENERAL...TO THE LEFT-OVER BROAD LOW PRESSURE
OF THE ATLANTIC-TO-CARIBBEAN SEA SURFACE TROUGH. MIDDLE TO UPPER
LEVEL TROUGH GOES FROM THE ATLANTIC OCEAN TO JUST WEST OF
JAMAICA...AND TO THE EASTERN HONDURAS/NORTHEASTERN NICARAGUA
BORDER. THIS TROUGH SUPPORTS THE SURFACE COLD FRONT THROUGH
18N60W TO 17N67W. SURFACE TROUGH 16N50W 12N60W TO NORTHWESTERN
VENEZUELA 11N70W. SHOWERS AND THUNDERSTORMS SOUTH AND SOUTHEAST
OF 16N60W 13N80W.

THE SUBTROPICAL ATLANTIC OCEAN...
CYCLONIC FLOW FROM THE DEEP LAYER TROUGH COVERS THE ATLANTIC
WATERS WEST OF 40W. THIS TROUGH EVENTUALLY WORKS ITS WAY INTO
THE CARIBBEAN SEA JUST WEST OF JAMAICA...AND TO THE EASTERN
HONDURAS/NORTHEASTERN NICARAGUA BORDER. THIS TROUGH SUPPORTS
THE SURFACE COLD FRONT THROUGH 32N40W 23N50W 18N60W 17N67W.
SURFACE TROUGH 30N37W 23N40W 16N50W 12N60W TO NORTHWESTERN
VENEZUELA 11N70W. A SECOND COLD FRONT IS MAKING ITS WAY INTO
THE AREA FROM THE NORTH...NOW THROUGH 32N57W 30N63W BEYOND
32N68W. MIDDLE TO UPPER LEVEL DRY AIR NORTH OF 20N WEST OF 40W.
ISOLATED MODERATE TO LOCALLY STRONG SHOWERS AND THUNDERSTORMS
WITHIN 60 TO 120 NM ON EITHER SIDE OF 32N35W 23N36W...AND WITHIN
60 NM ON EITHER SIDE OF 23N36W 20N43W 14N60W. NO DEEP CONVECTIVE
ACTIVITY YET WITH THE 32N57W 32N68W COLD FRONT.

THE TROPICAL ATLANTIC OCEAN...
SURFACE RIDGE 6N42W 21N31W BEYOND 32N27W. UPPER LEVEL
ANTICYCLONIC FLOW IMMEDIATELY EAST OF THE 40W CYCLONIC FLOW
REACHES THE CAPE VERDE ISLANDS...ANTICYCLONIC CENTER NEAR
18N42W. MIDDLE TO UPPER LEVEL TROUGH FROM 19N21W...OVER THE
CANARY ISLANDS...TO THE MADEIRA ISLANDS. UPPER LEVEL
ANTICYCLONIC FLOW IS OVER AFRICA EAST OF THIS 19N21W-TO-
CANARY ISLANDS TROUGH.

$$
MT


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