[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 220603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU SEP 22 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
0315 UTC.

...SPECIAL FEATURES...

HURRICANE RITA IS CENTERED NEAR 24.8N 87.6W OR ABOUT 470 NM ESE
OF GALVESTON TEXAS AND 560 NM ESE OF CORPUS CHRISTI TEXAS
22/0600 UTC MOVING WNW AT 8 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 898 MB. MAXIMUM SUSTAINED WIND SPEED IS 150 KT WITH
GUSTS TO 185 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 A
STRONG CATEGORY 5 HURRICANE ON THE SAFFIR-SIMPSON SCALE WITH A
SMALL SYMMETRICAL EYE. THIS MAKES RITA THE THIRD MOST INTENSE
HURRICANE IN TERMS OF PRESSURE FOR THE ATLANTIC BASIN. BROAD
NEARLY SYMMETRICAL OUTFLOW IS IN QUADRANTS. THE CORE OF THE
NUMEROUS STRONG CONVECTION IS WITHIN 90 NM OF THE CENTER IN ALL
QUADRANTS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION
COVERS THE AREA FROM 22.5N-27.5N BETWEEN 83W-90W. SCATTERED
MODERATE/STRONG CONVECTION TRAILS RITA EXTENDING FROM THE MAJOR
PORTION OF CONVECTION NEAR 22.5N85W THROUGH THE YUCATAN CHANNEL
TO 20.5N86W. OUTER RAINBANDS OF SCATTERED SHOWERS/THUNDERSTORMS
EXTEND EVEN FURTHER OUT BETWEEN THE N COAST OF THE YUCATAN
PENINSULA TO THE N GULF COAST FROM OVER FLORIDA TO 92W.

TROPICAL STORM PHILIPPE IS CENTERED NEAR 22.4N 57.0W OR 417 NM
NE OF THE LEEWARD ISLANDS AT 22/0300 UTC MOVING N AT 10 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED
WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC
FOR MORE DETAILS. UPPER LEVEL LOW CENTERED TO THE W NEAR 22N63W
CONTINUES TO DOMINATE PHILIPPE DRAWING IN DRY UPPER AIR TO OVER
THE W PORTION OF PHILIPPE. WESTERLY SHEAR CONTINUES TO WEAKEN
PHILIPPE AS WELL. THUS...CONVECTION IS TO THE E OF THE CENTER.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN
90/120 NM OF LINE 16N58W 21N54W 26N56W.

...TROPICAL WAVES...

A 1008 MB LOW WAS ANALYZED AT 21/1800 UTC OFF THE COAST OF
AFRICA. AT 22/0000 UTC THE LOW IS CENTERED 13N20W MOVING W NEAR
10 KT. WEAK LOW LEVEL CIRCULATION IS OBSERVED ON INFRARED
SATELLITE IMAGERY. NO ASSOCIATED SHOWERS/CONVECTION.

CENTRAL ATLC TROPICAL WAVE IS ALONG 39W/40W S OF 18N MOVING W
10-15 KT. WELL-DEFINED SIGNATURE CURVATURE IS OBSERVED ON
INFRARED SATELLITE IMAGERY. WAVE IS BENEATH THE E EDGE OF AN
UPPER RIDGE WITH ENOUGH DIFFLUENCE TO GENERATE SMALL CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 10N-15N
BETWEEN 38W-45W.

W ATLC TROPICAL WAVE IS ALONG 50W/51W S OF 154 MOVING W 10-15
KT. WAVE IS BENEATH A BROAD UPPER RIDGE WITH PREDOMINANTLY NE
FLOW MASKING ANY SIGNATURE ON SATELLITE IMAGERY. NO ASSOCIATED
DEEP CONVECTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N21W 6N31W 7N46W 9N62W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 45/60 NM OF LINE
6N20W8N16W THEN N ALONG THE COAST OF AFRICA TO 12N17W.

...DISCUSSION...

GULF OF MEXICO...
RITA CONTINUES TO DOMINATE THE WEATHER PICTURE TONIGHT AS A
STRONG CAT 5 HURRICANE MOVING ACROSS THE CENTRAL GULF. INTENSITY
OF RITA MAY FLUCTUATE OVER THE NEXT DAY OR SO BUT IS STILL
EXPECTED TO BE A MAJOR HURRICANE AT LANDFALL. AT THE UPPER
LEVELS...AN UPPER HIGH IS CENTERED NEAR HURRICANE RITA AND
DOMINATES THE GULF. A SMALL UPPER LOW IS OVER THE SW GULF JUST N
OF THE BAY OF CAMPECHE NEAR 21N95W WHICH IS GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90/120 NM ALONG THE COAST
OF MEXICO FROM 20N-22N. NOT MUCH DRY AIR REMAINS OVER THE W GULF
AS RITA CONTINUES ITS WESTWARD TRACK. RITA WILL CONTINUE TO MOVE
ACROSS THE GULF FOR THE REMAINDER OF THE WEEK MAKING LANDFALL
FRI INTO SAT ALONG THE TEXAS COAST.

CARIBBEAN...
BROAD MID/UPPER HIGH IS FIRMLY ESTABLISHED OVER THE SW CARIBBEAN
CENTERED NEAR 13N78W WITH FLOW COVERING THE AREA S OF 18N W OF
66W. A WEAK 1008 MB LOW IS ANALYZED NEAR 11N82W. TROPICAL
MOISTURE COVERS THE AREA GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 18N W OF 74W. THE NW CARIBBEAN IS UNDER THE
INFLUENCE OF HURRICANE RITA. THE UPPER HIGH ASSOCIATED WITH RITA
EXTENDS A RIDGE AXIS SE ACROSS CUBA TO OVER HISPANIOLA
GENERATING SCATTERED MODERATE/ISOLATED STRONG CONVECTION N OF
16N TO OVER S HAITI BETWEEN 71.5W-74.5W. BROAD UPPER LOW OVER
THE CENTRAL ATLC EXTENDS S OVER THE NE CARIBBEAN TO 15N E OF 68W
TO ACROSS THE LEEWARD ISLANDS.

ATLANTIC...
UPPER HIGH IN ASSOCIATED WITH HURRICANE RITA IS GIVING THE W
ATLC OUTFLOW FROM THE STORM WITH BROAD ANTICYCLONIC FLOW W OF
70W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE W
OF 78W S OF 31N ACROSS THE FLORIDA PENINSULA INCLUDING THE
STRAITS OF FLORIDA. BROAD UPPER LOW IS IN THE CENTRAL ATLC NEAR
22N63W PROVIDING W SHEAR AND DRY UPPER AIR INTO T.S. PHILIPPE.
DRY AIR AND MODERATE/STRONG SUBSIDENCE ARE WITHIN 90 NM OF LINE
FROM 24N58W 20N65W TO BEYOND 28N69W. THIS IS GIVING MOST OF THE
W ATLC FROM 66W-78W FAIR WEATHER. AN ELONGATED UPPER HIGH IS SE
OF PHILIPPE NEAR 14N56W EXTENDING A RIDGE NE TO BEYOND 32N45W
PRODUCING BROAD AREA OF DIFFLUENCE WITH SCATTERED SHOWERS/
THUNDERSTORMS OVER THE AREA FROM 15N-30N BETWEEN 46W-58W. A
SURFACE TROUGH EXTENDS FROM N OF PHILIPPE NEAR 26N57W NE TO
33N53W. THIS IS DIVIDING THE SUBTROPICAL RIDGE WITH A RIDGE AXIS
OVER THE W ATLC EXTENDING THROUGH BERMUDA WSW TO THE N BAHAMAS
AND A BROADER RIDGE OVER THE E ATLC FROM A 1025 MB HIGH SW OF
THE AZORES N OF 20N FROM AFRICA TO 50W. OVER THE E ATLC...AN
UPPER TROUGH OVER THE NE ATLC EXTENDS FROM AN UPPER LOW NEAR
MADEIRA ISLANDS SW TO 13N37W. THIS IS PRODUCING A JET WITH WINDS
OF 70-90 KT ON THE W SIDE TO THE BASE OF THE UPPER TROUGH. AN
UPPER HIGH IS LOCATED OVER W AFRICA WITH A RIDGE EXTENDING W TO
THE CAPE VERDE ISLANDS. ANOTHER SURGE OF AFRICAN DUST IS MOVING
OVER THE E ATLC FROM 10N-25N E ACROSS THE CAPE VERDE ISLANDS TO
NEAR 40W...THUS KEEPING THE AREA DRY.

$$
WALLACE


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