000
AXNT20 KNHC 021054
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI OCT 02 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 40W TO THE 
SOUTH OF 13N. STRONG ITCZ SHOWERS AND THUNDERSTORMS ARE
IN ONE OF THE CLUSTERS OF STRONG PRECIPITATION THAT COVERS THE 
AREA FROM 9N TO 13N BETWEEN 37W AND 41W. AN UPPER LEVEL TROUGH
IS ON TOP OF THIS AREA...ADDING TO THE PRECIPITATION.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 54W/55W TO THE SOUTH
OF 21N. IT IS NOT EASY TO SEE PRECIPITATION WITH THIS WAVE.
THE UPPER LEVEL TROUGH THAT IS TO THE EAST IS THE PRIMARY SOURCE
OF ATMOSPHERIC INSTABILITY NECESSARY FOR THE PRECIPITATION THAT
ALSO IS TO THE EAST OF THIS WAVE.

...THE ITCZ...

FROM 12N17W TO 7N30W 8N44W 11N55W...INTO NORTHEASTERN VENEZUELA 
NEAR 10N63W. STRONG SHOWERS AND THUNDERSTORMS IN INDIVIDUAL 
CLUSTERS WITHIN 180 NM ON EITHER SIDE OF 9N13W 9N30W 12N41W.

...DISCUSSION...

THE GULF OF MEXICO...
A DEEP LAYER TROUGH THAT IS DIGGING AND DIGGING AND TAKING UP 
LOTS OF SPACE THROUGHOUT THE CENTRAL U.S.A. IS SENDING A 
NORTHEAST-TO-SOUTHWEST ORIENTED UPPER LEVEL RIDGE TO COVER THE
AREA FROM THE FLORIDA PANHANDLE TO THE SOUTHWESTERN CORNER OF 
THE GULF OF MEXICO. THE DEEP LAYER TROUGH THAT HAS BEEN GUIDING
THE FIRST COLD FRONT OF THIS AUTUMN IS ALONG THE LINE THROUGH 
THE NORTHERN BAHAMAS TO ANDROS ISLAND BEYOND 18N80W IN THE 
CARIBBEAN SEA. THE TAIL END OF A STATIONARY FRONT COVERS THE 
SOUTH FLORIDA.

THE CARIBBEAN SEA...
A DEEP LAYER TROUGH EXTENDS FROM THE NORTHERN BAHAMAS ISLANDS
TO ANDROS ISLAND TO 18N80W...AND THEN DIVING SOUTHWARD TO 
14N81W.  UPPER LEVEL ANTICYCLONIC FLOW THAT IS TO THE SOUTH OF 
THE CYCLONIC ENVELOPE WITH THE TROUGH MOVES NORTHWARD FROM THE 
PART OF THE EASTERN PACIFIC OCEAN THAT IS TO THE SOUTH OF PANAMA 
AND IT IS DEFLECTED RAPIDLY EASTWARD. STRONG SHOWERS AND 
THUNDERSTORMS COVER THE CARIBBEAN SEA AND THE ATLANTIC OCEAN 
FROM JAMAICA...ACROSS EXTREME SOUTHEASTERN CUBA AND THE WINDWARD 
PASSAGE...TO THE BAHAMAS TO THE SOUTH OF 25N BETWEEN 71W AND 78W.
THE REMNANTS OF T.D. EIGHT HAVE MOVED INTO THE NORTHEASTERN 
CARIBBEAN SEA IN THE FORM OF A SURFACE TROUGH THAT IS ALONG 63W 
FROM 15N TO 20N. SHOWERS AND THUNDERSTORMS IN A FEW CLUSTERS 
COVER THE WATERS AND ISLANDS FROM 17N TO 18N BETWEEN 62W AND 64W.

THE ATLANTIC OCEAN...
THE DEEP LAYER TROUGH FROM THE WESTERN ATLANTIC OCEAN INTO THE 
CARIBBEAN SEA DOMINATES THE WEATHER NEWS. THE STATIONARY FRONT 
THAT THE TROUGH IS SUPPORTING GOES FROM 31N64W TO 28N70W TO THE
NORTHERN BAHAMAS TO ANDROS ISLAND BEYOND 18N80W IN THE CARIBBEAN 
SEA. STRONG SHOWERS AND THUNDERSTORMS COVER THE CARIBBEAN SEA 
AND THE ATLANTIC OCEAN FROM JAMAICA...ACROSS EXTREME 
SOUTHEASTERN CUBA AND THE WINDWARD PASSAGE...TO THE BAHAMAS TO 
THE SOUTH OF 25N BETWEEN 71W AND 78W. AN UPPER LEVEL TROUGH 
EXTENDS FROM A CYCLONIC CIRCULATION CENTER NEAR 24N48W TO 18N49W 
TO 10N49W. ISOLATED MODERATE SHOWERS COVER THE AREA FROM 10N
TO 22N BETWEEN 40W AND 52W. ISOLATED MODERATE SHOWERS ARE IN 
BETWEEN THE TWO TROUGHS TO THE NORTH OF 26N BETWEEN 46W AND 60W. 
NUMEROUS STRONG SHOWERS AND THUNDERSTORMS THAT ARE IN THE ITCZ 
ARE BEING ENHANCED BY THE FACT THAT THIS AREA HAPPENS TO BE AT 
THE BASE OF AN UPPER LEVEL TROUGH THAT EXTENDS FROM 24N33W TO 
17N35W TO 10N40W. BROAD LARGE-SCALE DEEP LAYER CYCLONIC FLOW 
COVERS THE ATLANTIC OCEAN TO THE NORTH OF 28N TO THE EAST OF 
50W. THIS EXTENSIVE AREA OF CYCLONIC FLOW SUPPORTS A DISSIPATING
COLD FRONT THAT PASSES THROUGH 31N23W 29N30W 29N47W. ISOLATED 
MODERATE SHOWERS COVER THE AREA FROM 25N TO 30N BETWEEN 26W
AND 40W.

$$
MT