[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 300540
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE AUG 30 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURES...

HURRICANE KATRINA WAS DOWNGRADED TO TROPICAL STORM AT 30/0000
UTC. TROPICAL STORM KATRINA IS CENTERED NEAR 33.5N 88.5W AT
30/0300 UTC NEAR COLLUMBUS MISSISSIPPI MOVING NNE AT 19 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 973 MB. MAXIMUM SUSTAINED
WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. SEE THE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC
AND THE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32
KNHC FOR MORE DETAILS. KATRINA CONTINUES TO MOVE INLAND ACROSS
MISSISSIPPI WITH THE SHOWERS/THUNDERSTORMS OVER N MISSISSIPPI...
ALABAMA...AND TENNESSEE. FEEDER BANDS WITH THUNDERSTORMS REMAIN
ALONG THE N GULF COAST AND ACROSS THE FLORIDA PANHANDLE. THESE
BANDS WILL CONTINUE TO MOVE N ACROSS ALABAMA AND GEORGIA.

A BROAD 1008 MB ATLC TROPICAL SURFACE LOW IS CENTERED NEAR
10N34W MOVING W 15-20 KT. THIS LOW HAS NOT BECOME BETTER
ORGANIZED THAN EARLIER THIS EVENING BUT STILL HAS THE POTENTIAL
FOR FURTHER DEVELOPMENT WITHIN THE NEXT DAY OR TWO. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 90/120 NM OF
LINE 15N29W-13N36W-9N38W.

...TROPICAL WAVES...

A 1010 MB LOW...FORMERLY T.D. THIRTEEN...IS W OF THE LEEWARD
ISLANDS NEAR 18N54W MOVING W 10 KT. SCATTERED MODERATE/STRONG
CONVECTION IS N OF THE LOW WITHIN 90 NM OF LINE 22N53W-19N56W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS W OF THE LOW
WITHIN A 60 NM RADIUS OF 19N57.5W.

WEAK CARIBBEAN TROPICAL WAVE IS CENTERED ALONG 69W S OF 18N
MOVING W 10-15 KT WITH LITTLE SIGNATURE CURVATURE OBSERVED. NO
ASSOCIATED SHOWERS/CONVECTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 16N16W 10N31W 7N45W 9N61W.
SCATTERED/NUMEROUS STRONG CONVECTION IS MOVING OFF AFRICA FROM
7N-11N E OF 17W TO JUST INLAND OVER AFRICA. SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS INLAND AND ALONG THE IMMEDIATE
COAST OF AFRICA FROM 11N-17N. SIMILAR CONVECTION IS WITHIN 90 NM
S OF THE AXIS FROM 36W-38W AND WITHIN 60 NM OF 9N FROM 23W-26W.

...DISCUSSION...

GULF OF MEXICO...
KATRINA HAS BEEN THE MAIN WEATHER MAKER OF THE PAST FEW DAYS AND
IS MOVING WELL INLAND OVER THE SE UNITED STATES. IN ITS
WAKE...OUTFLOW FROM THE STORM REMAINS OF THE E GULF WITH ITS
ASSOCIATED UPPER LEVEL MOISTURE WITHIN 150 NM FROM THE FLORIDA
PANHANDLE/PENINSULA TO THE BAY OF CAMPECHE. AT THE UPPER
LEVELS...THE BROAD UPPER HIGH ASSOCIATED WITH KATRINA IS
SITUATED OVER GEORGIA WITH THE UPPER LEVEL FLOW COVERING THE E
GULF E OF 92W. A BROAD MID/UPPER LEVEL TROUGH EXTENDS FROM THE
CENTRAL UNITED STATES INTO TEXAS AND N MEXICO JUST COVERING THE
NW GULF. THIS IS GIVING THE W GULF DRYING AIR AND CLEARING
SKIES.

CARIBBEAN SEA...
THE BROAD UPPER HIGH FROM THE GULF IS COVERING THE NW CARIBBEAN
N OF 15N W OF 70W WITH STRONG UPPER LEVEL WINDS MOSTLY FROM THE
E. THIS IS FORCING UPPER LEVEL DEBRIS CLOUDS...FROM AFTERNOON
THUNDERSTORMS OVER CUBA AND HAITI...OVER THE NW CARIBBEAN. AN
INVERTED MID/UPPER LEVEL TROUGH EXTENDS FROM THE ABC ISLANDS NNE
TO OVER PUERTO RICO/VIRGIN ISLANDS. THIS IS GIVING THE E
CARIBBEAN STRONG SUBSIDENCE AND DRY UPPER AIR. THE TROPICAL WAVE
IS IN THIS VICINITY AND THUS HAS NO ASSOCIATED SHOWERS/
CONVECTION. THE SW CARIBBEAN IS UNDER STRONG EASTERLY FLOW WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 13N.

ATLANTIC OCEAN...
THE BROAD UPPER HIGH OVER THE GULF EXTENDS INTO THE W ATLC WITH
N TO NE WINDS W OF 68W. THIS IS BRING OUTFLOW FROM KATRINA OUT
OVER THE AREA WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS NE
OF THE BAHAMAS FROM 24N-30N BETWEEN 70W-76W. MID/UPPER LEVEL
TROUGH EXTENDS FROM AN UPPER LOW S OF BERMUDA NEAR 29N64W SSW TO
THE MONA PASSAGE. AT THE BASE OF THE TROUGH...SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE FROM NW PUERTO RICO THROUGH THE MONA
PASSAGE TO ALONG THE N COAST OF THE DOMINICAN REPUBLIC E OF 70W.
A SECOND SHORTER UPPER TROUGH IS JUST TO THE E EXTENDING FROM
31N56W SSW TO 25N59W WITH AN AREA OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION WITHIN 90 NM OF LINE 25N60W-33N57W. BROAD
MID/UPPER LEVEL HIGH IS SITUATED JUST TO THE NE OF THE 1010 MB
LOW IN TROPICAL LOW/WAVE SECTION ABOVE. THE RIDGE AXIS EXTENDS
FROM THE WINDWARD ISLANDS NEAR 12N62W TO 32N46W. THIS IS
GENERATING AN  AREA OF SCATTERED STRONG CONVECTION FROM 24N-28N
BETWEEN 49W-52W AND A SWATH OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION WITHIN 120 NM OF LINE 25N46W-32N51W. THIS IS
LEAVING THE S/CENTRAL ATLC WITH MODERATE/STRONG SUBSIDENCE AND
DRY AIR WITHIN 300/400 NM OF LINE FROM 20N43W SW TO OVER SOUTH
AMERICA NEAR 4N51W. OVER THE NE ATLC...A MID/UPPER LOW IS MOVING
NE OUT OF THE REGION AND NOW COVERS THE AREA N OF 29N E OF 31W
TO THE CANARY ISLANDS. THE REMAINDER OF THE E ATLC IS UNDER
UPPER LEVEL RIDGING EXTENDING FROM INLAND OVER AFRICA W ALONG
16N/17N E OF 40W. THE 1008 MB LOW IN THE SPECIAL FEATURES
SECTION IS AT THE LEADING EDGE OF THE RIDGE AXIS PUSHING INTO
THE DRIER AIR TO THE WEST.

$$
WALLACE


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