[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 181053
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI SEP 18 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 22W/23W TO THE
SOUTH OF 16N MOVING WESTWARD 10 TO 15 KT. STRONG SHOWERS AND
THUNDERSTORMS ARE FROM 17N TO 18N BETWEEN 20W AND 24W.
DISORGANIZED ISOLATED MODERATE SHOWERS WITHIN 300 NM
TO THE WEST OF THE WAVE FROM 13N TO 17N.

A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 87W TO THE SOUTH
OF 20N MOVING WESTWARD 10 TO 15 KT. ANY PRECIPITATION THAT WAS
ON TOP OF CENTRAL AMERICA SIX HOURS AGO EITHER HAS DIMINISHED
AND/OR IT HAS BEEN PUSHED INTO THE COASTAL WATERS OF EASTERN
PACIFIC OCEAN.

...THE ITCZ...

14N24W 13N36W 11N41W 9N50W INTO NORTHEASTERN VENEZUELA NEAR
8N62W. ISOLATED MODERATE SHOWERS FROM 9N TO 12N BETWEEN 27W AND
32W...FROM 7N TO 11N BETWEEN 39W AND 45W...AND FROM 8N TO 11N
BETWEEN 56W AND 60W.

...DISCUSSION...

THE GULF OF MEXICO...
A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH SOUTHERN
MISSISSIPPI/SOUTHEASTERN LOUISIANA INTO THE WEST CENTRAL GULF
OF MEXICO AND THE SOUTHWESTERN CORNER OF THE AREA. MULTIPLE
TROUGHS ARE BETWEEN 90W AND THE TEXAS COAST. SHOWERS ARE WITHIN
15 NM TO 30 NM ON EITHER SIDE OF 27N93W 29N90W. ISOLATED MODERATE
SHOWERS ARE ELSEWHERE TO THE EAST OF THE LINE FROM THE WESTERN
FLORIDA PANHANDLE TO 21N97W AT THE MEXICO COAST. AN UPPER LEVEL
RIDGE PASSES THROUGH NORTHEASTERN FLORIDA INTO THE SOUTHEASTERN
GULF OF MEXICO TO THE YUCATAN PENINSULA.

THE CARIBBEAN SEA...
AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 15N77W...
ABOUT 180 NM TO THE SOUTH OF JAMAICA. CYCLONIC FLOW COVERS THE
WHOLE AREA TO THE WEST OF 70W. DISORGANIZED SHOWERS AND POSSIBLE
THUNDERSTORMS IN INDIVIDUAL CLUSTERS ARE BETWEEN 70W AND 82W IN
THE LARGE-SCALE CYCLONIC FLOW. DEBRIS CLOUDS AND MOISTURE THAT
HAVE SPUN AWAY FROM THE 15N77W CENTER HAVE MOVED INTO THE
CARIBBEAN SEA TO THE EAST OF 70W. ISOLATED MODERATE SHOWERS
ARE TO THE EAST OF 70W.

THE ATLANTIC OCEAN...
THE DEEP LAYER WESTERN ATLANTIC OCEAN TROUGH THAT WAS SUPPORTING
THE SURFACE TROUGH HAS BEEN ERODED AWAY. IT HAS BEEN REPLACED BY
UPPER LEVEL ANTICYCLONIC FLOW...AND SLOWLY-ENCROACHING UPPER
LEVEL CYCLONIC FLOW FROM THE CENTRAL ATLANTIC OCEAN. A SURFACE
TROUGH REMAINS ALONG 31N72W TO 28N76W TO THE SOUTHEASTERN COAST
OF FLORIDA NEAR MIAMI. ISOLATED MODERATE SHOWERS ARE WITHIN
30 NM ON EITHER SIDE OF 32N68W 29N74W...ACROSS SOUTHERN ANDROS
ISLAND TO 23N78W AT THE CUBA COAST. AN UPPER LEVEL CYCLONIC
CIRCULATION CENTER IS NEAR 22N58W. THIS FEATURE HAS BEEN MOVING
WESTWARD DURING THE LAST FEW DAYS. CYCLONIC FLOW AROUND THIS
CENTER COVERS THE AREA FROM 14N TO 30N BETWEEN 46W AND 70W. THE
1012 MB LOW PRESSURE CENTER THAT IS NEAR 25N64W IS THE REMNANT
OF HURRICANE FRED. A TROUGH GOES FROM 28N63W TO THE REMNANT LOW
CENTER...AND THEN TO 22N64W. ONE CELL OF PRECIPITATION COVERS
THE AREA FROM 24N TO 25N BETWEEN 65W AND 66W. OTHER POSSIBLE
SHOWERS COVER THE AREA FROM 20N TO 30N BETWEEN 60W AND 70W.
THE CHANCE OF THE REMNANT OF FRED DEVELOPING INTO A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS IS LOW. DISORGANIZED SHOWERS
AND THUNDERSTORMS STILL ARE ABOUT 700 NM TO THE EAST-SOUTHEAST
OF THE REMNANT OF FRED...COVERING THE AREA FROM 18N TO 20N
BETWEEN 53W AND 56W. OTHER POSSIBLE SHOWERS ARE ELSEWHERE FROM
18N TO 28N BETWEEN 50W AND 70W. AN UPPER LEVEL TROUGH PASSES
OVER THE MADEIRA ARCHIPELAGO TO 26N26W TO 16N40W. A 1010 MB LOW
PRESSURE CENTER IS NEAR 13N38W. NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS COVER THE AREA FROM 11N TO 14N BETWEEN 35W AND
38W. THE CHANCE OF THE 13N38W MB LOW PRESSURE CENTER DEVELOPING
INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS IS LOW.

$$
MT





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