[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN SEP 04 2011

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...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...SPECIAL FEATURES...

THE CENTER OF CATEGORY TWO HURRICANE KATIA AT 04/2100 UTC IS
NEAR 22.7N 60.1W. THIS POSITION IS ABOUT 640 NM TO THE EAST
OF THE SOUTHEASTERN BAHAMAS. KATIA IS MOVING NORTHWESTWARD 10 KT.
THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 965 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 90 KT WITH GUSTS TO 110 KT. PLEASE
READ THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO
HEADER MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY
UNDER AWIPS/WMO HEADER MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS.
THE UPPER LEVEL ANTICYCLONIC OUTFLOW AROUND KATIA IS DEVELOPED
ENOUGH IN ORDER TO REACH 34N60W AND 26N45W. NUMEROUS STRONG
CONVECTIVE PRECIPITATION COVERS THE ATLANTIC OCEAN FROM 22N TO
23N BETWEEN 59W AND 62W. OTHER POSSIBLE RAINSHOWERS ARE IN THE
ATLANTIC OCEAN FROM 19N TO 25N BETWEEN 56W AND 63W...AND FROM
16N TO 20N BETWEEN 53W AND 55W.

TROPICAL STORM LEE IS INLAND IN SOUTH CENTRAL LOUISIANA. THE
CENTER OF LEE AT 05/0000 UTC IS NEAR 30.9N 91.8W. THIS POSITION
IS ABOUT 45 MILES TO THE SOUTHEAST OF ALEXANDRIA LOUISIANA...
AND ABOUT 45 MILES TO THE WEST-NORTHWEST OF BATON ROUGE
LOUISIANA. LEE IS MOVING NORTHWARD 5 KT. THE ESTIMATED MINIMUM
CENTRAL PRESSURE IS 989 MB. THE MAXIMUM SUSTAINED WIND SPEEDS
ARE 35 KT WITH GUSTS TO 45 KT. PLEASE READ THE LATEST
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER
MIATCPAT3/WTNT33 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADER MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.
RAINSHOWERS AND THUNDERSTORMS COVER THE GULF OF MEXICO TO THE
NORTH OF 25N BETWEEN FLORIDA AND 95W. MAXIMUM RAINFALL TOTALS
IN SOME OF THE U.S.A. GULF COAST STATES RANGE FROM 10 TO
15 INCHES...AND OTHER TOTALS RANGING FROM 5 TO 10 INCHES.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 16N27W 10N24W. NO
SIGNIFICANT DEEP CONVECTIVE PRECIPITATION ACCOMPANIES THIS WAVE.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 19N42W 13N39W.
AN UPPER LEVEL TROUGH EXTENDS FROM A 30N26W CYCLONIC CIRCULATION
CENTER TO 24N32W AND 15N40W. IT IS EASILY POSSIBLE THAT IT MAY
NOT BE EASY TO DIFFERENTIATE BETWEEN THE PRECIPITATION THAT ONLY
IS WITH THE WAVE AND THE PRECIPITATION THAT IS ASSOCIATED ONLY
WITH THE TROUGH. ISOLATED MODERATE CONVECTIVE PRECIPITATION IS
FROM 11N TO 20N BETWEEN 30W AND 45W.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH PASSES THROUGH THE AFRICA COAST NEAR 15N17W
TO 10N23W. THE ITCZ IS ALONG 8N43W 8N50W...INTO NORTHEASTERN
SURINAME NEAR 5N55W. SCATTERED MODERATE TO STRONG CONVECTIVE
PRECIPITATION IS FROM 5N TO 10N BETWEEN 25W AND 32W. ISOLATED
MODERATE CONVECTIVE PRECIPITATION COVERS THE AREA ELSEWHERE
TO THE SOUTH OF 10N.

...DISCUSSION...

THE GULF OF MEXICO...

THE MAIN FOCUS OF INTEREST RIGHT NOW IS TROPICAL STORM LEE AND
ITS RAINY IMPACT ON THE U.S.A. GULF OF MEXICO COAST STATES
BETWEEN FLORIDA ALONG 83W AND THE UPPER TEXAS GULF COAST. UPPER
LEVEL NORTHERLY AND NORTHEASTERLY WINDS COVER THE GULF OF MEXICO
TO THE EAST OF 90W. THIS WIND FLOW IS A RESULT OF THE UPPER
LEVEL ANTICYCLONIC OUTFLOW THAT IS SPIRALING AWAY FROM LEE.
PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR ALL THE
INFORMATION ABOUT THIS SYSTEM. MEASURED RAINFALL AMOUNTS ALREADY
ARE RANGING FROM 10 TO 15 INCHES BETWEEN THE FLORIDA BIG BEND
AND SOUTHWESTERN LOUISIANA. FLOODING IS A MAJOR THREAT FOR MUCH
OF THE SOUTHEASTERN UNITED STATES. REFER TO FLOOD FORECASTS AND
HURRICANE LOCAL STATEMENTS ISSUED BY LOCAL NWS FORECAST OFFICES
FOR MORE DETAILED INFORMATION ON THESE THREATS. LEE IS FORECAST
TO DRIFT NORTHEASTWARD. A COLD FRONT IS EXPECTED TO MERGE WITH
LEE AND...AND THE FRONT WILL SWEEP THROUGH THE NORTHWESTERN GULF
OF MEXICO. COMPARATIVELY MUCH DRIER AIR THAT IS BEHIND THE FRONT
WILL PROVIDE FAIR CONDITIONS. THE EASTERN HALF OF THE GULF OF
MEXICO WILL REMAIN UNDER THE HIGH MOISTURE VALUES THAT ARE
ASSOCIATED WITH LEE.

THE CARIBBEAN SEA...

AN UPPER LEVEL TROUGH CUTS ACROSS THE BAHAMAS...SOUTHEASTERN
CUBA...THROUGH THE WINDWARD PASSAGE...ACROSS JAMAICA...INTO
THE AREA OF WESTERN NICARAGUA/SOUTHERN HONDURAS/AND POSSIBLY
EL SALVADOR. RAINSHOWERS AND THUNDERSTORMS FROM AFTERNOON
HEATING AND IN THE VICINITY OF THE TROUGH ARE FROM EAST TO WEST
IN HISPANIOLA AND CUBA...OFF THE NORTHWESTERN COAST OF
JAMAICA...AND FROM CENTRAL NICARAGUA TO SOUTHEASTERN AND WESTERN
HONDURAS. THE MONSOON TROUGH PASSES THROUGH 9N77W IN THE GULF
OF URABA ALONG THE COLOMBIA COAST...ACROSS PANAMA...BEYOND
NORTHWESTERN COSTA RICA INTO THE EASTERN PACIFIC OCEAN.
ISOLATED TO WIDELY SCATTERED MODERATE TO STRONG CONVECTIVE
PRECIPITATION IS IN PANAMA TO THE WEST OF 80W...AND IN
SOUTHERN COSTA RICA.

THE ATLANTIC OCEAN...

TROPICAL STORM KATIA IS MOVING NORTHWESTWARD...MORE OR LESS
PARALLEL TO BUT STILL ANYWHERE FROM AT LEAST 500 TO 600 NM TO
THE EAST OF THE BAHAMAS. AN UPPER LEVEL TROUGH REMAINS IN BETWEEN
THE CIRCULATION THAT IS AROUND KATIA...AND THE SOUTHEASTERN
U.S.A. ATLANTIC OCEAN COAST. THE TROUGH ROUGHLY PASSES THROUGH
33N69W TO 27N70W BEYOND THE WINDWARD PASSAGE INTO THE CARIBBEAN
SEA. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 19N42W 13N39W.
AN UPPER LEVEL TROUGH EXTENDS FROM A 30N26W CYCLONIC CIRCULATION
CENTER TO 24N32W AND 15N40W. IT IS EASILY POSSIBLE THAT IT MAY
NOT BE EASY TO DIFFERENTIATE BETWEEN THE PRECIPITATION THAT ONLY
IS WITH THE WAVE AND THE PRECIPITATION THAT IS ASSOCIATED ONLY
WITH THE TROUGH. ISOLATED MODERATE CONVECTIVE PRECIPITATION IS
FROM 11N TO 20N BETWEEN 30W AND 45W. SURFACE ANTICYCLONIC WIND
FLOW COVERS THE ATLANTIC OCEAN TO THE NORTH OF 22N BETWEEN
AFRICA AND 53W...MOVING AROUND A 1024 MB HIGH PRESSURE CENTER
THAT IS NEAR 33N47W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
MT





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