[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 231811
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI SEP 23 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...SPECIAL FEATURES...

RITA IS NOW A CATEGORY THREE HURRICANE. ITS CENTER AT
23/1800 UTC IS NEAR 27.8N 92.2W MOVING NORTHWEST 9 KT.
THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 931 MB. THE
MAXIMUM SUSTAINED WIND SPEEDS ARE 110 KT WITH GUSTS
TO 125 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/
WMO HEADERS MIATCMAT3/WTNT23 KNHC AND THE PUBLIC ADVISORY UNDER
HEADERS MIATCPAT3/WTNT33 KNHC FOR MORE DETAILS. THIS POSITION
ALSO IS ABOUT 165 NM SOUTHEAST OF GALVESTON TEXAS...AND ABOUT
150 NM SOUTHEAST OF PORT ARTHUR TEXAS. THE EYE APPEARS TO BE
FILLING IN BASED ON SATELLITE IMAGERY. THIS CORRESPONDS WELL
WITH THE FACT THAT RITA HAS BEEN WEAKENING IN WIND SPEED.
THE NUMEROUS STRONG SHOWERS AND THUNDERSTORMS AROUND RITA
ARE WITHIN 125 NM IN THE EASTERN SEMICIRCLE, AND WITHIN
60 TO 120 NM OF THE CENTER IN THE SOUTHWESTERN QUADRANT.

THE CENTER OF TROPICAL STORM PHILIPPE AT 23/1800 UTC IS NEAR
30.5N 63.6W MOVING WEST 13 KT. THIS POSITION ALSO IS ABOUT
140 MILES/260 KM SOUTH-SOUTHEAST OF BERMUDA.  THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1005 MB. THE MAXIMUM SUSTAINED
WIND SPEEDS ARE 35 KT WITH GUSTS TO 45 KT. SEE THE LATEST NHC
FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC
FOR MORE DETAILS. PHILIPPE IS CAUGHT IN THE FLOW AROUND A LARGER
DEEP-LAYER CYCLONIC CIRCULATION CENTERED ABOUT 200 NM TO THE
SOUTH. PHILIPPE NOW HAS THE APPEARANCE OF AN EMBEDDED LOW-LEVEL
VORTICITY MAXIMUM...AND MAY NOT HAVE A CLOSED CIRCULATION ANY
LONGER. THE THE OFFICIAL FORECAST CALLS FOR PHILIPPE TO BECOME
ABSORBED AND DISSIPATE WITHIN 24 HOURS SINCE THE LARGER
CIRCULATION TO THE SOUTH IS BECOMING THE DOMINANT WEATHER
SYSTEM. PHILIPPE COULD DISSIPATE EVEN SOONER IF PRESENT TRENDS
CONTINUE. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG
THUNDERSTORMS ARE FOUND FROM 30N TO 35N BETWEEN 53W AND 64W.
A SURFACE 1003 MB LOW PRESSURE CENTER HAS FORMED 27N63W.
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS
ARE FOUND FROM 22N TO 30N BETWEEN 60W AND 68W. OTHER SCATTERED
MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS CONTINUE FROM
20N TO 30N BETWEEN 50W AND 60W...AND SOUTHWESTWARD INTO THE
EASTERN CARIBBEAN SEA NORTH OF 15N BETWEEN 60W AND 64W.

...TROPICAL WAVES...

A SURFACE 1010 MB EASTERN ATLANTIC OCEAN LOW PRESSURE CENTER
IS NEAR 11N26W MOVING WEST 10 KT. SCATTERED MODERATE SHOWERS
TO ISOLATED STRONG THUNDERSTORMS...SOME FORMING IN THE VICINITY
OF THE ITCZ ALSO...ARE FOUND FROM 8N TO 16N BETWEEN 19W AND 31W.

ATLANTIC OCEAN TROPICAL WAVE IS ALONG 51W/52W SOUTH OF 20N
MOVING WEST 10 TO 15 KT. THIS WAVE IS MOVING THROUGH AN AREA
OF UPPER LEVEL ANTICYCLONIC FLOW...IN THE LARGE RIDGE WHICH IS
IMMEDIATELY EAST OF THE 28N61W MIDDLE TO UPPER LEVEL LOW CENTER.
A MIDDLE TO UPPER LEVEL TROUGH EXTENDS SOUTHWESTWARD FROM
31N61W...WHERE A LOW CENTER WAS YESTERDAY...TO 28N61W TO 24N63W
TO A DEVELOPING MIDDLE TO UPPER LEVEL LOW CENTER NEAR 20N65W...
THROUGH THE MONA PASSAGE TO 16N70W.

ATLANTIC OCEAN TROPICAL WAVE IS ALONG 59W/60W SOUTH OF 16N
MOVING WEST 10 TO 15 KT. THIS WAVE IS PASSING RIGHT UNDER THE
UPPER LEVEL RIDGE WHICH IS IMMEDIATELY EAST OF THE 31N61W-MONA
PASSAGE TROUGH...WITH UPPER LEVEL NORTHEASTERLY TO EASTERLY WIND
FLOW CUTTING ACROSS IT. THE SHOWERS AND THUNDERSTORMS IN THE
EASTERN CARIBBEAN SEA ARE MORE RELATED TO THE UPPER LEVEL TROUGH
RATHER THAN TO THE TROPICAL WAVE.

...ITCZ...

ITCZ 13N17W 11N23W...8N32W 6N40W 5N50W 5N59W. ISOLATED MODERATE
SHOWERS ARE WITHIN 45 TO 60 NM ON EITHER SIDE OF 8N27W 7N35W
6N41W 7N49W 7N59W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE
FOUND FROM 8N TO 11N BETWEEN 46W AND 51W. ISOLATED MODERATE
SHOWERS ARE ELSEWHERE FROM 4N TO 10N BETWEEN AFRICA AND 40W.

...DISCUSSION...

THE GULF OF MEXICO...
EVERYTHING SURROUNDING HURRICANE RITA TAKES UP ALL THE WEATHER
NEWS IN THE GULF OF MEXICO. MIDDLE TO UPPER LEVEL DRY AIR IS
SOUTH OF RITA, SOUTH OF 23N WEST OF 89W. UPPER LEVEL
ANTICYCLONIC FLOW GOES FROM THE BAHAMAS, ACROSS CUBA, INTO THE
OPEN CARIBBEAN SEA WEST OF THE ATLANTIC-TO-CARIBBEAN SEA MIDDLE
TO UPPER LEVEL TROUGH...AND THROUGH THE YUCATAN CHANNEL.

THE CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL TROUGH EXTENDS SOUTHWESTWARD FROM THE
ATLANTIC OCEAN NEAR 31N61W...WHERE A LOW CENTER WAS YESTERDAY...
TO A 28N61W MIDDLE TO UPPER LEVEL LOW CENTER...TO 24N63W TO
A DEVELOPING MIDDLE TO UPPER LEVEL LOW CENTER NEAR 20N65W...
THROUGH THE MONA PASSAGE TO 16N70W IN THE EASTERN CARIBBEAN SEA.
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS
CONTINUE IN THE EASTERN CARIBBEAN SEA NORTH OF 15N BETWEEN 60W
AND 64W. BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE REST OF
THE CARIBBEAN SEA WEST OF THIS TROUGH. ISOLATED MODERATE SHOWERS
AND THUNDERSTORMS...PROBABLY WITH THE ITCZ...ARE SOUTH OF 13N
BETWEEN 74W NEAR THE COAST OF COLOMBIA AND 78W.

THE ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH EXTENDS SOUTHWESTWARD FROM THE
ATLANTIC OCEAN NEAR 31N61W...WHERE A LOW CENTER WAS YESTERDAY...
TO A 28N61W MIDDLE TO UPPER LEVEL LOW CENTER...TO 24N63W TO
A DEVELOPING MIDDLE TO UPPER LEVEL LOW CENTER NEAR 20N65W...
THROUGH THE MONA PASSAGE TO 16N70W IN THE EASTERN CARIBBEAN SEA.
TROPICAL STORM PHILIPPE IS NEAR 31.1N 63.2W. PHILIPPE IS MOVING
AROUND THE 28N61W MIDDLE TO UPPER LEVEL LOW CENTER. ISOLATED
MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE FOUND FROM
30N TO 35N BETWEEN 53W AND 64W. A SURFACE 1003 MB LOW PRESSURE
CENTER HAS FORMED 27N63W. SCATTERED MODERATE SHOWERS TO ISOLATED
STRONG THUNDERSTORMS ARE FOUND FROM 22N TO 30N BETWEEN 60W AND
68W. OTHER SCATTERED MODERATE SHOWERS TO ISOLATED STRONG
THUNDERSTORMS CONTINUE FROM 20N TO 30N BETWEEN 50W AND 60W...
AND SOUTHWESTWARD INTO THE EASTERN CARIBBEAN SEA NORTH OF 15N
BETWEEN 60W AND 64W. UPPER LEVEL ANTICYCLONIC OUTFLOW CURVES
FROM THE EASTERN GULF OF MEXICO INTO THE SOUTHWESTERN NORTH
ATLANTIC OCEAN...EAST OF FLORIDA...DIVING SOUTHEASTWARD INTO
THE TROUGH WITH THE 31N61W-TO-MONA PASSAGE TROUGH. THE RIDGE,
EAST OF THE 28N61W LOW CENTER AND ACCOMPANYING TROUGH, RUNS
FROM 18N58W 26N53W BEYOND 33N53W. A MIDDLE TO UPPER LEVEL TROUGH
REALLY HAS BEEN DIGGING, FROM THE EASTERN ATLANTIC OCEAN TO THE
ITCZ, ABOUT 300 NM NORTH-NORTHEAST OF THE CLOSEST POINT ON THE
COAST OF NORTHEASTERN BRAZIL. THE TROUGH RUNS THROUGH 30N30W TO
18N34W TO WHAT APPEARS TO BE A DEVELOPING CYCLONIC CENTER NEAR
10N31W TO 2N38W.BROAD UPPER LEVEL ANTICYCLONIC FLOW IS NORTH OF
THE DEVELOPING CYCLONIC CENTER, EAST OF THE TROUGH.

$$
MT


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