[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081641
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE SEP 07 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1615 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM FRED AT 08/1500 UTC IS NEAR
11.9N 28.6W...OR ABOUT 345 MILES/555 KM TO THE SOUTHWEST OF
THE SOUTHERNMOST CAPE VERDE ISLANDS. FRED IS MOVING WEST 12 KT.
THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 994 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 55 KT WITH GUSTS TO 65 KT. PLEASE
READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT2/
WTNT32 KNHC FOR MORE DETAILS. TROPICAL STORM FORCE WINDS EXTEND
OUTWARD UP TO 105 MILES...165 KM FROM THE CENTER. STRONG SHOWERS
AND THUNDERSTORMS FROM 11N TO 13N BETWEEN 27W AND 29W. SCATTERED
MODERATE TO STRONG SHOWERS AND THUNDERSTORMS FROM 9N TO 12N
BETWEEN 28W AND 31W.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 60W/61W FROM 10N TO 17N
MOVING WEST ABOUT 15 KT. THIS WAVE HAS SEPARATED FROM THE REST
OF THE WAVE FROM 24 HOURS AGO. SHOWERS THAT COVER THE AREA FROM
MARTINIQUE TO ANTIGUA MAY BE MORE RELATED TO THE UPPER LEVEL
TROUGH WHOSE BASE REACHES 16N60W. A 1014 MB LOW PRESSURE CENTER
IS NEAR 19N57W. A TROUGH EXISTS FROM 22N56W TO THE LOW CENTER TO
17N58W. ISOLATED MODERATE SHOWERS WITHIN 180 NM ON EITHER SIDE OF
16N61W 18N57W 22N54W.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 79W TO THE SOUTH OF 19N
MOVING WESTWARD 15 KT. NO DEEP CONVECTIVE PRECIPITATION
ACCOMPANIES THIS WAVE.

...THE ITCZ...

THE ITCZ IS NOT DISTINCT TO THE EAST OF T.S. FRED.
IT STARTS MORE OR LESS NEAR 7N29W AND CONTINUES TO 5N40W 7N50W
9N59W. ISOLATED MODERATE SHOWERS WITHIN 30 NM TO 45 NM ON EITHER
SIDE OF 8N29W 5N33W 6N40W 5N50W. CONVECTIVE DEBRIS CLOUDS AND
POSSIBLE PRECIPITATION FROM 7N TO 17N BETWEEN AFRICA AND 20W.

...DISCUSSION...

THE GULF OF MEXICO...
A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH SOUTH
CAROLINA TO GEORGIA TO NORTH FLORIDA INTO THE NORTHEASTERN GULF
OF MEXICO. BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA
FROM MEXICO INTO THE GULF OF MEXICO TO THE EAST OF 101W ALL THE
WAY INTO THE STRAITS OF FLORIDA. A SURFACE TROUGH IS IN THE
SOUTHWESTERN GULF OF MEXICO FROM THE ISTHMUS OF TEHUANTEPEC
NEAR 17N93W TO 22N95W. THE STRONG SHOWERS AND THUNDERSTORMS THAT
SIX HOURS AGO WERE TO THE SOUTH OF 20N BETWEEN 92W AND 94W HAVE
DISSIPATED. THE AREA OF CYCLONIC FLOW AND ENERGY HAVE MOVED TO
THE NORTH AND RE-FORMED AS MODERATE SHOWERS FROM 20N TO 22N
BETWEEN 92W AND 94W. ISOLATED MODERATE SHOWERS ARE IN THE OPEN
GULF WATERS...TO THE SOUTH OF THE TROUGH FROM SOUTH CAROLINA
TO THE NORTHEASTERN GULF OF MEXICO...AND TO THE SOUTH OF THE
SURFACE TROUGH THAT HUGS THE NORTHERN GULF COAST FROM THE JUST
TO THE SOUTH OF THE FLORIDA PANHANDLE...TO SOUTHWESTERN
LOUISIANA...TO ALL OF COASTAL TEXAS.

THE ATLANTIC OCEAN TO THE WEST OF 60W...
AND THE CARIBBEAN SEA TO THE WEST OF 70W...
LARGE-SCALE UPPER LEVEL CYCLONIC FLOW COVERS THE ATLANTIC OCEAN
TO THE WEST OF 60W AND THE WESTERN CARIBBEAN SEA TO THE WEST OF
70W. THE CYCLONIC FLOW IS AROUND A TROUGH THAT PASSES THROUGH
31N68W 23N69W TO NORTHERN HISPANIOLA...INTO THE CARIBBEAN SEA
NEAR 15N80W BEYOND NORTHERN COSTA RICA. BROAD UPPER LEVEL
ANTICYCLONIC FLOW COVERS THE REST OF THE CARIBBEAN SEA TO THE
EAST OF THE TROUGH. A SURFACE TROUGH PASSES THROUGH 31N76W
27N78W ACROSS SOUTH FLORIDA INTO THE SOUTHEASTERN GULF OF MEXICO
NEAR 24N84W. ISOLATED MODERATE SHOWERS ARE TO THE NORTH OF 20N
TO THE WEST OF 60W.

THE REST OF THE CARIBBEAN SEA...
BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE REST OF
THE CARIBBEAN SEA TO THE EAST OF THE TROUGH. SHOWERS AND
THUNDERSTORMS ARE ON TOP OF THE EASTERN CARIBBEAN SEA ISLANDS
FROM MARTINIQUE TO ANTIGUA. THIS PRECIPITATION IS OCCURRING
AT THE BASE OF AN ATLANTIC OCEAN TROUGH THAT REACHES 16N60W.

THE REST OF THE ATLANTIC OCEAN TO THE EAST OF 60W...
A CENTRAL ATLANTIC OCEAN UPPER LEVEL TROUGH PASSES THROUGH
31N36W TO 27N40W TO 23N44W TO 20N50W TO 16N60W AT THE EDGE
OF THE EASTERN CARIBBEAN SEA. ISOLATED MODERATE SHOWERS AND
CONVECTIVE DEBRIS CLOUDS ARE TO THE NORTHWEST OF 24N52W 28N44W
BEYOND 32N36W. AN EASTERN ATLANTIC OCEAN UPPER LEVEL TROUGH
EXTENDS FROM A 32N10W CYCLONIC CENTER TO A 27N20W CYCLONIC
CENTER TO 23N24W. NO DEEP CONVECTIVE PRECIPITATION ACCOMPANIES
THIS TROUGH. BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA
TO THE SOUTH OF 21N TO THE EAST OF 40W...INCLUDING ON TOP OF
T.S. FRED. A SURFACE TROUGH IS ALONG 39W/40W FROM 14N TO 22N
DRIFTING WEST. THE LOW PRESSURE CENTER FROM SIX HOURS AGO HAS
WEAKENED. NO DEEP CONVECTIVE PRECIPITATION IS ASSOCIATED
WITH THIS TROUGH.

$$
MT





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