000
AXNT20 KNHC 301059
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED SEP 30 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1015 UTC.

...TROPICAL WAVES...

AN EASTERN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 26W/27W TO THE 
SOUTH OF 13N. ANY PRECIPITATION IS IN THE ITCZ FROM 4N TO 10N
BETWEEN 25W AND 33W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 44W/45W TO THE SOUTH
OF 18N. STRONG SHOWERS AND THUNDERSTORMS ARE FROM 9N TO 13N 
BETWEEN 45W AND 48W.

...THE ITCZ...

FROM 13N16W 9N26W 8N35W 9N45W 8N55W INTO NORTHEASTERN VENEZUELA 
NEAR 8N63W. SCATTERED MODERATE TO STRONG SHOWERS AND 
THUNDERSTORMS FROM 5N TO 10N BETWEEN 28W AND 33W. ISOLATED 
MODERATE SHOWERS ARE ELSEWHERE FROM 5N TO 7N BETWEEN AFRICA AND 
20W...ELSEWHERE FROM 4N TO 11N BETWEEN 24W AND 40W...AND FROM 
ELSEWHERE FROM 4N TO 13N BETWEEN 40W AND 60W. NOT ALL THE 
PRECIPITATION IN THIS AREA IS DIRECTLY RELATED TO THE ITCZ.
SOME OF IT IS RELATED TO INTERACTIONS WITH AT LEAST ONE UPPER 
LEVEL TROUGH FROM 22N40W TO 13N43W.

...DISCUSSION...

THE GULF OF MEXICO...
CYCLONIC FLOW FROM A DEEP LAYER TROUGH COVERS THE U.S.A. AND
THE GULF OF MEXICO TO THE NORTH OF 22N TO THE EAST OF 100W.
THIS TROUGH SUPPORTS A COLD FRONT THAT PASSES THROUGH 27N79W 
JUST TO THE NORTH OF THE BAHAMAS...TO JUST TO THE SOUTH OF
LAKE OKEECHOBEE...INTO THE CENTRAL GULF OF MEXICO...TO JUST
OFF THE LOWER TEXAS COAST. SHOWERS AND THUNDERSTORMS FROM
24N TO 27N BETWEEN THE FLORIDA WEST COAST AND 90W.

THE CARIBBEAN SEA...
THE SOUTHERN END OF AN UPPER LEVEL ATLANTIC OCEAN TROUGH PASSES 
ON TOP OF THE EASTERN DOMINICAN REPUBLIC TO 14N73W AND 10N77W. 
UPPER LEVEL ANTICYCLONIC COVERS THE AREA TO THE WEST OF THE 
TROUGH...TO THE WEST AND NORTHWEST OF THE LINE THAT RUNS FROM 
THE WINDWARD PASSAGE TO 11N81W...EVENTUALLY SWEEPING ACROSS 
SOUTHERN NICARAGUA. SHOWERS AND THUNDERSTORMS ARE TO THE WEST
OF THE LINE FROM 79W ALONG PANAMA TO NORTHEASTERN COASTAL
NICARAGUA...AND THEN FROM THE EASTERN COAST OF HONDURAS INTO
THE GULF OF HONDURAS. UPPER LEVEL SOUTHWESTERLY WIND FLOW IS 
SPREADING BROKEN TO OVERCAST MULTILAYERED CLOUDS ACROSS THE 
CARIBBEAN SEA THAT IS TO THE EAST OF THE TROUGH. 

THE ATLANTIC OCEAN...
CYCLONIC FLOW FROM A DEEP LAYER TROUGH COVERS THE U.S.A AND
THE GULF OF MEXICO TO THE NORTH OF 22N TO THE EAST OF 100W...
AND THE ATLANTIC OCEAN TO THE WEST OF 70W. THIS TROUGH SUPPORTS 
A COLD FRONT THAT PASSES THROUGH 32N71W IN THE ATLANTIC OCEAN
TO JUST TO THE SOUTH OF LAKE OKEECHOBEE FLORIDA AND BEYOND...
INTO THE CENTRAL GULF OF MEXICO. SHOWERS AND THUNDERSTORMS ARE
IN THE WATERS BETWEEN THE NORTHERN BAHAMAS AND FLORIDA...AND
TO THE NORTH OF 24N BETWEEN 70W AND 80W. A COLD FRONT FROM
A FEW DAYS AGO HAS WEAKENED INTO A TROUGH...THAT STRETCHES
FROM BERMUDA TO 29N70W...INTO THE NORTHERN BAHAMAS TO 25N77W.
REMNANT SHOWERS AND POSSIBLE THUNDERSTORMS ARE FROM 25N TO 30N
BETWEEN 60W AND 70W UNDER AN UPPER LEVEL RIDGE. AN UPPER LEVEL 
TROUGH PASSES THROUGH 31N57W TO 25N57W TO THE EASTERN DOMINICAN 
REPUBLIC. ISOLATED MODERATE SHOWERS FROM 27N NORTHWARD BETWEEN 
50W AND 60W. A SURFACE TROUGH THAT IS THE REMNANT OF T.D. EIGHT 
IS ALONG 53W FROM 15N TO 22N. SHOWERS AND POSSIBLE THUNDERSTORMS
COVER THE AREA FROM 19N TO 20N BETWEEN 52W AND 53W. AN EASTERN 
ATLANTIC OCEAN MIDDLE LEVEL TO UPPER LEVEL TROUGH SUPPORTS
A COLD FRONT THAT PASSES THROUGH 32N21W TO 28N30W 28N40W.
A STATIONARY FRONT CONTINUES FROM 28N40W TO 29N53W. ISOLATED 
MODERATE SHOWERS ARE WITHIN 30 NM TO 60 NM ON EITHER SIDE OF
THE FRONT. AN UPPER LEVEL TROUGH FROM 22N40W TO 13N43W.
SHOWERS FROM 20N TO 23N WITHIN 30 NM TO 60 NM ON EITHER SIDE
OF 40W.

$$
MT