[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 210628 CCA
TWDAT

TROPICAL WEATHER DISCUSSION...CORRECTION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED SEP 21 2005

...CORRECTION TO PRESSURE FOR HURRICANE RITA...


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
0315 UTC.

...SPECIAL FEATURES...

HURRICANE RITA IS CENTERED NEAR 24.2N 84.0W...OR ABOUT 70 NM WSW
OF THE DRY TORTUGAS...125 NM W OF KEY WEST FLORIDA AND ABOUT 115
NM NW OF HAVANA CUBA AT 21/0600 UTC MOVING W AT 12 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 960 MB. MAXIMUM SUSTAINED
WIND SPEED IS 100 KT WITH GUSTS TO 120 KT. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC
AND THE PUBLIC ADVISORY UNDER HEADERS MIATCPAT3/WTNT33 KNHC FOR
MORE DETAILS. RITA IS NOW A CATEGORY 3...WHICH IS A MAJOR
HURRICANE ON THE SAFFIR-SIMPSON SCALE WITH A 25 NM WIDE EYE.
BROAD OUTFLOW IS APPARENT IN ALL BUT THE S SIDE OF THE
HURRICANE...LIMITED BY THE CLOSE PROXIMITY TO LAND. HEAVY
RAIN/THUNDERSTORMS CONTINUE TO SPREAD OVER S FLORIDA AND W CUBA
BUT WILL BE MOVING OUT LATER THIS MORNING INTO TODAY. NUMEROUS
STRONG CONVECTION IS WITHIN 60 NM OF THE CENTER. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION COVERS THE AREA FROM
22N-27N BETWEEN 78W-87W.

TROPICAL STORM PHILIPPE IS CENTERED NEAR 19.3N 57.6W OR 275 NM
ENE OF THE LEEWARD ISLANDS AT 21/0300 UTC MOVING NNW AT 5 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 994 MB. MAXIMUM SUSTAINED
WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC
FOR MORE DETAILS. UPPER LEVEL LOW IS DOMINATING THE AREA JUST N
OF PHILIPPE DRAWING IN DRY UPPER AIR INTO THE SYSTEM. WESTERLY
SHEAR CONTINUES TO WEAKEN PHILIPPE AS WELL. THUS...CONVECTION
HAS BECOME RAGGED OVER THE PAST SEVERAL HOURS. CLUSTERS OF
SCATTERED MODERATE WITH SMALL EMBEDDED CLUSTERS OF SCATTERED/
NUMEROUS STRONG CONVECTION COVERS THE AREA WITHIN 200 NM OF LINE
14N58W-22N53W.

...TROPICAL WAVES...

CENTRAL ATLC TROPICAL WAVE IS ALONG 34W S OF 16N MOVING W 10 KT.
WEAK SIGNATURE CURVATURE IS OBSERVED ON INFRARED SATELLITE
IMAGERY. WAVE IS BENEATH THE E EDGE OF AN UPPER RIDGE WITH
ENOUGH DIFFLUENCE TO GENERATE A SMALL AREA OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 13.5N-15N BETWEEN
33W-35W.

W ATLC TROPICAL WAVE IS ALONG 45W S OF 15N MOVING W 10 KT. WEAK
SIGNATURE CURVATURE IS OBSERVED ON INFRARED SATELLITE IMAGERY.
NO ASSOCIATED DEEP CONVECTION.

A 1012 MB LOW IS CENTERED NEAR 18N45W...PREVIOUSLY PART OF THE
TROPICAL JUST TO THE E...MOVING WNW 5-10 KT. THE LOW IS BEING
DRAWN INTO THE AREA SURROUNDING T.S. PHILIPPE. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60/75 NM OF LINE
16.5N44W-19N47.5W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N10W 6N22W 7N40W 14N57W 13N62W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 3N-10N
BETWEEN 10W-19W AND FROM 5N-10N BETWEEN 39W-48W.

...DISCUSSION...

GULF OF MEXICO...
RITA CONTINUES TO DOMINATE THE WEATHER PICTURE TONIGHT AS A
STRONG CAT 2 HURRICANE MOVING ACROSS THE SE GULF. WARM SEA
SURFACE TEMPERATURES AND FAVORABLE UPPER LEVEL CONDITIONS
DESTINIES RITA TO MAJOR HURRICANE STATUS WITHIN 24 HOURS. AT THE
UPPER LEVELS...AN UPPER HIGH IS CENTERED INLAND OVER CENTRAL
TEXAS AND SECOND NEAR HURRICANE RITA. A SMALL UPPER LOW IS OVER
THE SW GULF IN THE BAY OF CAMPECHE NEAR 21N92W WITH AN INVERTED
TROUGH EXTENDING N BETWEEN THE TWO UPPER HIGHS. DRY AIR REMAINS
OVER THE NW GULF. UPPER LEVEL MOISTURE AND DIFFLUENCE FROM AN
UPPER HIGH OVER THE E PACIFIC REGION IS GENERATING SCATTERED
SHOWERS OVER THE SW GULF S OF 24N W OF 92W. RITA WILL CONTINUE
TO MOVE ACROSS THE GULF FOR THE REMAINDER OF THE WEEK MAKING
LANDFALL OVER THE WEEKEND AND THE E GULF WILL CLEAR WITH PASSING
OF RITA.

CARIBBEAN...
BROAD UPPER HIGH IS FIRMLY ESTABLISHED OVER THE SW CARIBBEAN
CENTERED ALONG THE COAST OF COLOMBIA NEAR 11N76W WITH FLOW
COVERING THE AREA S OF 17N W OF 69W. A WEAK 1009 MB LOW IS
ANALYZED NEAR 12N80W. TROPICAL MOISTURE IS BEING ADVECTED ACROSS
CENTRAL AMERICA OVER THE AREA AND GENERATING SCATTERED CLUSTERS
OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS. THE UPPER LOW THAT
HAD DOMINATED THE NW CARIBBEAN EARLIER THIS WEEK IS NOW A SHEAR
AXIS EXTENDING FROM HAITI ACROSS JAMAICA TO THE GULF OF
HONDURAS. THE REMAINDER OF THE NW CARIBBEAN IS UNDER THE
INFLUENCE OF HURRICANE RITA. THE UPPER HIGH ASSOCIATED WITH RITA
EXTENDS A RIDGE AXIS SE ACROSS THE BAHAMAS TO OVER THE E
CARIBBEAN TO NEAR 15N64W. THIS IS GENERATING SCATTERED SHOWERS/
THUNDERSTORMS OVER THE NE CARIBBEAN FROM 15N62W 15N68W TO THE
DOMINICAN REPUBLIC NEAR 18N71W. AN INDUCED UPPER INVERTED TROUGH
IS OVER THE SE CARIBBEAN BETWEEN THE RIDGE FROM ACROSS THE
BAHAMAS AND THE UPPER HIGH SE OF T.S. PHILIPPE. WET WEATHER
SHOULD REMAIN OVER THE NE CARIBBEAN UNTIL THE WEEKS END AS
MOISTURE FROM PHILIPPE LINGERS AND OVER THE SW CARIBBEAN.

ATLANTIC...
UPPER HIGH IN ASSOCIATED WITH HURRICANE RITA IS GIVING THE W
ATLC OUTFLOW FROM THE STORM WITH BROAD ANTICYCLONIC FLOW W OF
68W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION W OF 76W AND
WILL LINGER THROUGH THE MORNING HOURS THEN CLEAR AS RITA
CONTINUES ON ITS WESTWARD TRACK. AN UPPER LOW IS IN THE CENTRAL
ATLC NEAR 23N61W PROVIDING W SHEAR AND DRY UPPER AIR OVER T.S.
PHILIPPE. DRY AIR AND MODERATE/STRONG SUBSIDENCE ARE WITHIN 100
NM OF LINE FROM 22N58W 23N65W TO 25N67W THEN BROADENS TO WITHIN
250 NM TO 30N69W AND ENCOMPASSES THE AREA N OF 30N W OF 55W TO
OVER THE SE UNITED STATES. THIS IS GIVING MOST OF THE W ATLC E
OF THE BAHAMAS TO NEAR 60W FAIR WEATHER EXCEPT IN THE IMMEDIATE
VICINITY OF THE UPPER LOW WHERE SCATTERED SHOWERS ARE PRESENT.
AN UPPER HIGH SE OF PHILIPPE NEAR 14N56W EXTENDS A RIDGE NNE TO
32N45W PRODUCING BROAD AREA OF DIFFLUENCE WITH SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS OVER THE AREA FROM 15N-31N
BETWEEN 43W-59W. A 1012 MB LOW IS CENTERED BENEATH THIS AREA
NEAR 21N51W WITH A SURFACE TROUGH EXTENDING NNE TO 28N47W.
THIS IS DIVIDING THE SUBTROPICAL RIDGE WITH A RIDGE AXIS OVER
THE W ATLC EXTENDING FROM A 1022 MB HIGH NW OF BERMUDA S ALONG
70W AND A BROADER RIDGE OVER THE E ATLC FROM A 1027 MB HIGH SW
OF THE AZORES S ALONG 38W. OVER THE E ATLC...AN UPPER HIGH IS
LOCATED W OF THE CAPE VERDE ISLANDS NEAR 12N39W AND A SECOND E
OF THE CAPE VERDE ISLANDS OVER W AFRICA. THIS IS PRODUCING A COL
OVER THE ISLANDS THEMSELVES. AN UPPER TROUGH OVER THE NE ATLC
EXTENDS FROM AN UPPER LOW NEAR 34N21W SW TO 23N33W. THIS IS
PRODUCING A JET WITH WINDS OF 70-90 KT AROUND THE BASE OF THE
UPPER TROUGH THEN NE TO THE CANARY ISLANDS. YET ANOTHER SURGE OF
AFRICAN DUST IS MOVING OVER THE FAR E ATLC FROM 10N-25N E TO THE
CAPE VERDES...THUS DRYING THE AREA.

$$
WALLACE



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