[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 240601
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT SEP 24 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
0515 UTC.

...SPECIAL FEATURES...

HURRICANE RITA IS CENTERED NEAR 29.4N 93.5W...OR 25 NM SE OF
SABINE PASS AT THE BORDER OF TEXAS AND LOUISIANA...AT 24/0600
UTC MOVING NW 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 934
MB. MAXIMUM SUSTAINED WIND SPEED IS 105 KT WITH GUSTS TO 130 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. THE NORTHERN EYEWALL OF
RITA IS NOW REACHING THE SW COAST OF LOUISIANA AND LANDFALL IS
EXPECTED WITHIN THE NEXT 2-3 HOURS. INFRARED SATELLITE IMAGERY
INDICATES THAT THE EYE HAS BECOME A BIT OBSCURED WITH THE
DEEPEST CONVECTION MAINLY FOCUSED OVER THE N...W...AND S
QUADRANTS. AN UPPER LEVEL RIDGE IS LOCATED E OF THE HURRICANE
FROM W CUBA NWD INTO THE TENNESSEE VALLEY AND A LARGE CIRRUS
CANOPY IS OBSERVED RADIATING NWD AWAY FROM THE STORM INTO
CENTRAL ILLINOIS/INDIANA. NUMEROUS MODERATE/STRONG CONVECTION
FROM 27N-32N BETWEEN 90W-95W. RADAR IMAGERY SHOWS A LARGE SHIELD
OF VERY HEAVY RAIN STRETCHING NWD TO 32N TOWARDS NRN LOUISIANA
AND SE TEXAS WITH STRONG AND POSSIBLY TORNADIC SPIRAL BANDS
STILL ROTATING ACROSS AREAS NEAR THE WESTERN SUBURBS OF NEW
ORLEANS...HOUMA...AND BATON ROUGE. THE WESTERN END OF THE
RAINFALL ENDS JUST TO THE W OF HOUSTON. THE CORE OF RITA WILL BE
MOVING ONSHORE IN THE NEXT SEVERAL HOURS WITH THE STRONGEST
WINDS EXPECTED TO AFFECT CAMERON AND CALCASIEU PARISHES IN SW
LOUISIANA AND JEFFERSON AND ORANGE COUNTIES IN SE TEXAS. THIS
INCLUDES THE CITIES OF LAKE CHARLES...BEAUMONT... AND PORT
ARTHUR.

TROPICAL DEPRESSION PHILIPPE IS CENTERED NEAR 29.0N 64.0W...OR
205 NM SSE OF BERMUDA...AT 24/0300 UTC MOVING SSE 8 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB. MAXIMUM SUSTAINED
WIND SPEED IS 25 KT WITH GUSTS TO 35 KT. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC
FOR MORE DETAILS. THE LOW-LEVEL CENTER OF PHILIPPE HAS BECOME
COMPLETELY EXPOSED FROM ANY DEEP CONVECTION AND IS BECOMING
ABSORBED INTO A MUCH LARGER CYCLONIC CIRCULATION WITH 25-30 KT
WINDS EXTENDING 400-500 NM N AND E OF THE CENTER. PHILIPPE IS
LOCATED WITHIN STRONG SLY FLOW ON THE E SIDE OF A LARGE UPPER
LOW AND APPEARS TO HAVE FINALLY SUCCUMBED TO THE VERTICAL SHEAR.
AS SUCH...THIS HAS BEEN THE FINAL ADVISORY ISSUED BY THE
NATIONAL HURRICANE CENTER. SCATTERED MODERATE CONVECTION FROM
23N-30N BETWEEN 54W-61W. SCATTERED MODERATE FROM 31N-37N BETWEEN
60W-64W.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ALONG 31W S OF 18N MOVING W 15 KT
WITH AN ELONGATED 1011 MB LOW ALONG THE AXIS NEAR 11N31W.
ALTHOUGH THE LOW HAD A WELL-DEFINED SIGNATURE YESTERDAY...IT HAS
SINCE BECOME MORE ELONGATED AND THE ENTIRE FEATURE HAS A MORE
WAVE-LIKE APPEARANCE. AS SUCH...A TROPICAL WAVE SYMBOL WILL BE
ADDED TO THE 0600 UTC ANALYSIS (ALTHOUGH THE LOW HAS REALLY BEEN
ASSOCIATED WITH A WAVE ALL ALONG). ISOLATED TO WIDELY SCATTERED
MODERATE CONVECTION FROM 9N-15N BETWEEN 23W-36W.

TROPICAL WAVE LOCATED ABOUT 350 NM E OF THE LEEWARD/WINDWARD
ISLANDS ALONG 55W S OF 19N MOVING W 15 KT. A SLIGHT NE/SE WIND
SHIFT IS NOTED BETWEEN BUOYS 41100 AND 41040 WHICH SUGGESTS GOOD
PLACEMENT OF THE WAVE. DEEP CONVECTION HAS BEEN DEVELOPING NEAR
THE WAVE AXIS OVER THE PAST FEW HOURS WITH SCATTERED
MODERATE/STRONG NOW FROM 10N-15N BETWEEN 54W-59W. SOME OF THIS
ACTIVITY IS LIKELY TO SPREAD ACROSS THE LEEWARD AND WINDWARD
ISLANDS LATER TODAY AND TONIGHT...POSSIBLY LINGERING OVER THE
AREA FOR A GOOD PART OF THE START OF NEXT WEEK.

E CARIBBEAN TROPICAL WAVE IS ANALYZED ALONG 63W S OF 18N MOVING
W 15 KT. UPPER AIR DATA FROM CAYENNE AND TRINIDAD BOTH INDICATE
WAVE PASSAGE OVER THE PAST 48 HRS AND SHORTWAVE IR IMAGERY
SUGGESTS THAT THE WAVE MAY BE A LITTLE FARTHER W NEAR 65W OR SO.
THIS WILL LIKELY BE ACCOUNTED FOR IN THE 0600 UTC ANALYSIS. THE
WAVE IS ESSENTIALLY DEVOID OF ANY DEEP CONVECTION AND ALSO
LACKS MUCH CLOUD COVER.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 12N15W 10N30W...THEN ALONG 10N34W
6N56W. SCATTERED MODERATE CONVECTION MOVING OFF THE COAST OF
GUINEA-BISSAU FROM 10N-12.5N BETWEEN 14W-18W. SCATTERED MODERATE
FROM 6N-12N BETWEEN 40W-50W. SCATTERED MODERATE STRETCHING FROM
LAKE MARACAIBO WWD ALONG COASTAL AREAS OF COLOMBIA THEN ACROSS
PANAMA...COSTA RICA...AND NICARAGUA.

...DISCUSSION...

GULF OF MEXICO...
THE CIRCULATION OF HURRICANE RITA TAKES UP A GOOD CHUNK OF THE
GULF OF MEXICO ALTHOUGH THE MOST INCLEMENT WEATHER IS LIMITED TO
PRIMARILY THE NW PART OF THE BASIN. DRY CONTINENTAL AIR HAS
WRAPPED AROUND THE W AND S SIDE OF THE HURRICANE AND IS
PRODUCING MAINLY FAIR WEATHER WITH SOME HIGH LEVEL CIRRUS S OF
24N W OF 90W TO THE BAY OF CAMPECHE. THE ATMOSPHERE IS A LITTLE
MORE MOIST E OF 90W DUE TO THE TROPICAL S/SE FLOW MOVING TOWARDS
RITA SO CLOUD COVER IS MORE ABUNDANT AND WIDELY SCATTERED
SHOWERS SPECKLE THE E GULF IN REMNANT SPIRAL BANDS. THE BULK OF
THE MOISTURE ASSOCIATED WITH RITA WILL MOVE INLAND DURING THE
NEXT 48 HRS ALTHOUGH A FEW LEFTOVER SHOWERS WILL STILL BE
POSSIBLE ESPECIALLY OVER THE N GULF WATERS THROUGH THE EARLY
PART OF NEXT WEEK. SEE SPECIAL FEATURES FOR FURTHER DISCUSSION
ON RITA.

CARIBBEAN...
AN UPPER LEVEL HIGH IS CENTERED OVER THE SE GULF OF MEXICO NEAR
24N83W WITH A RIDGE AXIS EXTENDING SE ACROSS W CUBA TO JAMAICA
AND 17N70W. A LARGE AREA OF CIRRUS HAS SPREAD ACROSS THE W HALF
OF THE CARIBBEAN CARRIED BY A STRONG 50 KT EASTERLY JET RACING
TOWARDS THE NICARAGUAN COAST. AN UPPER TROUGH AXIS STRETCHES
THROUGH THE MONA PASSAGE SW TO THE ABC ISLANDS AND DRIER AIR IS
BEING BROUGHT IN FROM THE E TOWARDS THIS TROUGH AXIS WHICH IS
KEEPING RELATIVELY NICE WEATHER OVER THE LESSER ANTILLES FOR THE
MOMENT. ISOLATED SHOWERS/TSTMS SPECKLE THE AREA FROM 16N-20N
BETWEEN 70W-78W EXTENDING FROM HISPANIOLA TO JAMAICA AND
SCATTERED MODERATE CONVECTION ALSO STRETCHES FROM NW VENEZUELA
THROUGH COLOMBIA TO CENTRAL AMERICA. A FEW TSTMS ARE ALSO
APPROACHING BARBADOS AHEAD OF TROPICAL WAVE ALONG 55W.

ATLANTIC...
A LARGE UPPER LEVEL LOW IS LOCATED OVER THE W ATLC NEAR 29N71W
WITH DRY AIR SURGING SWD N OF 24N BETWEEN 70W-80W. UPPER LEVEL
CIRRUS IS WRAPPING AROUND THE S SIDE OF THE LOW'S CIRCULATION
STRETCHING FROM FLORIDA TO THE SRN BAHAMAS THEN NEWD TO 28N68W.
FARTHER E...A LARGE UPPER HIGH IS CENTERED NEAR 23N57W AND
COVERS VIRTUALLY THE ENTIRE CENTRAL ATLANTIC. TROPICAL
DEPRESSION PHILIPPE IS EMBEDDED WITHIN THE STRONG SLY FLOW
BETWEEN THESE TWO FEATURES AND HAS SUCCUMBED TO THE DETRIMENTAL
SHEAR. A SECOND UPPER LOW IS CENTERED OVER THE E/CENTRAL ATLC
NEAR 16N37W AND IS SUPPORTING DIFFLUENT FLOW TO ITS W AS IT
SPLITS BETWEEN THE LOW AND HIGH. THIS ENVIRONMENT IS SUPPORTING
A STRONG CLUSTER OF CONVECTION NEAR THE TROPICAL WAVE ALONG
55W...SOME OF WHICH WILL LIKELY SPREAD ACROSS PARTS OF THE
WINDWARD/SRN LEEWARD ISLANDS. THE UPPER LOW IS PRODUCING STRONG
SLY SHEAR OVER THE TROPICAL WAVE ALONG 31W AND IS LIKELY
IMPEDING DEVELOPMENT AT THIS TIME. AN UPPER RIDGE POKES WWD FROM
AFRICA ALONG 20N AND IS SPREADING HIGH LEVEL CIRRUS FROM 10N-30N
E OF 34W.

$$
BERG


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