[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040000
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT SEP 03 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...

KATIA WAS DOWNGRADED FROM A HURRICANE TO A TROPICAL STORM
AT 03/2100 UTC. THE CENTER OF T.S. KATIA AT 03/2100 UTC IS
NEAR 19.9N 56.8W. THIS POSITION IS ABOUT 335 NM TO THE EAST-
NORTHEAST OF THE NORTHEASTERN CARIBBEAN SEA ISLANDS. KATIA IS
MOVING WEST-NORTHWESTWARD 9 KT. THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 993 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 60 KT
WITH GUSTS TO 75 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. NUMEROUS STRONG CONVECTIVE
PRECIPITATION COVERS THE ATLANTIC OCEAN FROM 18N TO 21N BETWEEN
55W AND 59W. OTHER POSSIBLE RAINSHOWERS ARE IN THE ATLANTIC
OCEAN FROM 11N TO 25N BETWEEN 50W AND 60W. AN UPPER LEVEL TROUGH
EXTENDS FROM A CYCLONIC CIRCULATION CENTER THAT IS NEAR 32N53W
TO 27N59W TO 22N63W.

THE CENTER OF TROPICAL STORM LEE AT 04/0000 UTC IS NEAR
29.5N 92.4W. THIS POSITION IS ABOUT 50 MILES TO THE SOUTHWEST OF
MORGAN CITY LOUISIANA. LEE IS MOVING TOWARD THE NORTH-NORTHWEST
4 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 988 MB. THE
MAXIMUM SUSTAINED WIND SPEEDS ARE 45 KT WITH GUSTS TO 55 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
COASTAL WATERS AND SOUTHERN SECTIONS OF THE U.S.A. GULF OF
MEXICO COAST STATES FROM ALABAMA TO THE FLORIDA PANHANDLE...
MISSISSIPPI...LOUISIANA...AND THE UPPER TEXAS GULF COAST.
NUMEROUS STRONG CONVECTIVE PRECIPITATION COVERS THE GULF OF
MEXICO WATERS FROM 25N TO 28N BETWEEN 86W AND 88W...AND ALONG
THE NORTHWESTERN CORNER OF THE YUCATAN PENINSULA FROM 20N
TO 22N BETWEEN 90W AND 91W.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 21N33W 16N34W...TO
A 1010 MB LOW PRESSURE CENTER THAT IS NEAR 12N35W. ISOLATED
RAINSHOWERS ARE POSSIBLE FROM 10N TO 20N BETWEEN 30W AND 40W.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH PASSES THROUGH THE AFRICA COAST NEAR 18N16W
TO 11N18W 10N20W 11N25W 12N35W 9N37W 8N40W. THE ITCZ CONTINUES
FROM 8N40W TO 6N47W AND 6N52W. ISOLATED MODERATE CONVECTIVE
PRECIPITATION IS FROM 4N TO 13N BETWEEN AFRICA AND 30W...
AND FROM 1N TO 9N BETWEEN 30W AND 52W.

...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 THE FLORIDA PANHANDLE AND THE UPPER TEXAS GULF COAST.
WATER VAPOR IMAGERY SHOWS THAT COMPARATIVELY MUCH DRIER AIR
IS MOVING ACROSS THE REST OF TEXAS THAT IS AWAY FROM THE UPPER
TEXAS GULF COAST...INTO THE GULF WATERS...TO THE NORTH OF 25N
TO THE WEST OF 92W. PLEASE REFER TO THE SPECIAL FEATURES SECTION
FOR ALL THE INFORMATION ABOUT THIS SYSTEM. MOST IF NOT ALL THE
PRECIPITATION THAT IS OCCURRING IS EITHER DIRECTLY RELATED TO
TROPICAL STORM LEE AND/OR AT THE PERIPHERY OF THE LARGER-SCALE
FLOW THAT IS AROUND LEE. UPPER LEVEL NORTHERLY WIND FLOW MOVES
ACROSS FLORIDA...PART OF THE UPPER LEVEL ANTICYCLONIC FLOW THAT
IS SPIRALING AWAY FROM T.S. LEE.

THE CARIBBEAN SEA...

AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 19N66W...
FROM 20 TO 25 NM TO THE NORTH-NORTHEAST OF PUERTO RICO.
ISOLATED MODERATE CONVECTIVE PRECIPITATION HAS BEEN OCCURRING
IN THE NORTHERN HALF OF PUERTO RICO...AND WITHIN 30 NM OR SO
IN THE WATERS THAT ARE TO THE NORTH OF PUERTO RICO. OTHER
ISOLATED MODERATE CONVECTIVE PRECIPITATION IS POSSIBLE TO THE
EAST OF 70W...IN BROAD UPPER LEVEL SLIGHTLY CYCLONIC WIND FLOW.
RAINSHOWERS AND THUNDERSTORMS FROM AFTERNOON HEATING HAVE BEEN
OCCURRING FROM CUBA TO WESTERN JAMAICA...AND IN THE WATERS OF
THE NORTHWESTERN CORNER OF THE AREA THAT ARE TO THE NORTH OF
17N TO THE WEST OF JAMAICA. THE CLOUD TOPS THAT ARE ASSOCIATED
WITH THIS PRECIPITATION ARE BEING SHEARED BY THE UPPER LEVEL
NORTHEASTERLY WIND FLOW THAT IS CROSSING FLORIDA...CUBA...AND
ULTIMATELY MOVING ACROSS THE NORTHWESTERN CORNER OF THE AREA
AND BEYOND CENTRAL AMERICA. AN UPPER LEVEL TROUGH PASSES THROUGH
THE WINDWARD PASSAGE TO 15N79W. ISOLATED MODERATE TO STRONG
RAINSHOWERS AND THUNDERSTORMS HAVE BEEN OCCURRING ACROSS
HISPANIOLA. THE COMPARATIVELY STRONGEST PRECIPITATION CONTINUES
NOW IN HAITI NEAR 19N72W. THE MONSOON TROUGH PASSES THROUGH
13N74W TO 10N80W...ACROSS THE NICARAGUA/COSTA RICA BORDER...AND
INTO THE EASTERN PACIFIC OCEAN. BROKEN TO OVERCAST MULTILAYERED
CLOUDS AND POSSIBLE ISOLATED MODERATE CONVECTIVE PRECIPITATION
ARE TO THE SOUTH OF 13N TO THE WEST OF 74W.

THE ATLANTIC OCEAN...

TROPICAL STORM KATIA IS MOVING NORTHWESTWARD...AWAY FROM THE
NORTHEASTERN CARIBBEAN SEA. AN UPPER LEVEL TROUGH PASSES THROUGH
32N71W TO 27N74W BEYOND THE WINDWARD PASSAGE...INTO THE
CARIBBEAN SEA. AN UPPER LEVEL TROUGH EXTENDS FROM A CYCLONIC
CIRCULATION CENTER THAT IS NEAR 32N53W TO 27N59W TO 22N63W.
ISOLATED MODERATE CONVECTIVE PRECIPITATION COVERS THE ATLANTIC
OCEAN TO THE NORTH OF THE CARIBBEAN SEA ISLANDS BETWEEN THE TWO
TROUGHS. AN UPPER LEVEL TROUGH EXTENDS FROM A 29N28W CYCLONIC
CIRCULATION CENTER TO 19N32W. RAINSHOWERS ARE POSSIBLE FROM 20N
TO 30N BETWEEN 20W AND 30W. SURFACE ANTICYCLONIC WIND FLOW
COVERS THE ATLANTIC OCEAN TO THE NORTH OF 23N BETWEEN AFRICA AND
63W...MOVING AROUND A 1024 MB HIGH PRESSURE CENTER THAT IS NEAR
33N44W.

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

$$
MT




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