[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 062347
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE SEP 06 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION SIXTEEN CENTERED NEAR 27.0N 78.4W...OR 30 NM
NNE OF FREEPORT BAHAMAS...AT 07/0000 UTC DRIFTING N. MAXIMUM
SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 35 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE 1008 MB. SEE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC AND THE
PUBLIC ADVISORY UNDER HEADERS MIATCPAT1/WTNT31 KNHC FOR MORE
DETAILS. T.D. SIXTEEN IS AN ASYMMETRICAL SYSTEM IN WHICH
PRACTICALLY ALL THE CONVECTIVE ACTIVITY IS LOCATED N OF THE
CENTER HUGGING THE SOUTHEAST U.S. COASTLINE. WSR-88D IMAGERY
FROM MELBOURNE AND JACKSONVILLE SHOWS SOME HEAVY RAIN BANDS
CURRENTLY MOVING ONSHORE THE FLORIDA EAST COAST FROM MELBOURNE
TO BRUNSWICK GEORGIA...SPREADING W AND THINNING OUT N OF TAMPA
BAY. SCATTERED MODERATE/STRONG CONVECTION IS FROM 26.5N-31.5N
BETWEEN 75W-82W. T.D. SIXTEEN IS EXPECTED TO MOVE SLOWLY NWD AND
PARALLEL THE FLORIDA COAST FOR THE NEXT SEVERAL DAYS AND COULD
PRODUCE ISOLATED AMOUNTS UP TO 15 INCHES OF RAIN.

HURRICANE MARIA CENTERED NEAR 34.3N 55.1W...OR 500 NM ENE OF
BERMUDA...AT 06/2100 UTC MOVING NE 6 KT. MAXIMUM SUSTAINED WIND
SPEEDS HAVE DECREASED TO 70 KT WITH GUSTS TO 85 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE 982 MB. SEE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE
DETAILS. MARIA IS NEARING THE MID-LATITUDE WESTERLIES AND HAS
BEGUN TO FEEL THE INFLUENCE OF W/SWLY SHEAR. THE LOW-LEVEL
CIRCULATION LOOKS AS IF IT IS BEGINNING TO DECOUPLE FROM THE
MID-LEVEL CIRCULATION AND THE DEEPEST CONVECTION...ALMOST BEING
LEFT BEHIND AND BECOMING SLIGHTLY EXPOSED. CONVECTION NEAR THE
CENTER HAS BEEN WEAKENING BUT NEW CLUSTERS HAVE BEEN REFORMING
OVER THE N AND E SEMICIRCLES. SCATTERED MODERATE/STRONG
CONVECTION FROM 29N-37N BETWEEN 50W-56W.

TROPICAL STORM NATE CENTERED NEAR 28.7N 66.7W...OR 240 NM SSW OF
BERMUDA...AT 06/2100 UTC WITH STATIONARY MOVEMENT. MAXIMUM
SUSTAINED WIND SPEED 50 KT WITH GUSTS TO 60 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE 997 MB. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC
FOR MORE DETAILS. DEEP CONVECTION HAS MAINTAINED IMPRESSIVE
INTENSITY OVER THE PAST SEVERAL HOURS WITH A TIGHTLY-WOUND BAND
WRAPPING AROUND THE E AND N SIDES OF THE CENTER. THE STRUCTURE
HAS BECOME INCREASINGLY CIRCULAR DUE TO AN UPPER LEVEL
ANTICYCLONE SITTING EXACTLY OVER THE SYSTEM...AND PROVIDING
EXCELLENT OUTFLOW IN ALL BUT THE S QUADRANT. THE STRONGEST
CONVECTION IS ABOUT 100 NM S OF BERMUDA AT THE MOMENT...BUT
COULD BEGIN TO SPREAD OVER THE ISLAND OVER THE NEXT COUPLE OF
DAYS AS NATE DRIFTS TO THE N AND E. NUMEROUS MODERATE/STRONG
CONVECTION FROM 26N-31N BETWEEN 63W-69W.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ALONG 34W S OF 23N MOVING W 10-15 KT
WITH A 1012 MB LOW NEAR 15N. THE WAVE HAS A WELL-DEFINED AND
SHARP LOW-LEVEL CIRCULATION ALTHOUGH THE ATTACHED LOW HAS BECOME
INCREASINGLY MORE DIFFUSE. A LARGE SWATH OF SAHARAN DUST
EXTENDING W OF 50W JUST ABOUT COMPLETELY ENSHROUDS THE WAVE WITH
THE EXCEPTION OF AN AREA ABOUT 550 NM E OF THE AXIS WHERE
TROPICAL MOISTURE IS BEING LIFTED N IN THE CIRCULATION.
CONVECTION IS MEAGER WITH ONLY ISOLATED SHOWERS/TSTMS FROM
12N-21N BETWEEN 31W-38W.

TROPICAL WAVE ALONG 48W/49W S OF 18N MOVING W 15 KT. THE WAVE
LIES ROUGHLY ALONG THE LEADING EDGE OF THE WIDESPREAD SAHARAN
DUST OUTBREAK BUT REALLY LACKS MUCH OF AN IDENTIFIABLE
CIRCULATION. ISOLATED SHOWERS FROM 10N-14N BETWEEN 45W-50W.

EAST CARIBBEAN TROPICAL WAVE ALONG 64W S OF 20N MOVING W 15 KT.
EVEN THOUGH THERE IS NO CLOSED CIRCULATION ALONG THE WAVE
ANYMORE...IT STILL HAS A SHARP SIGNATURE AND IS PRODUCING
CLUSTERS OF SHOWERS/TSTMS OVER THE NORTHERN LEEWARD ISLANDS.
SCATTERED MODERATE CONVECTION FROM 15N-19N BETWEEN 60W-63.5W
OVER THE ISLANDS FROM GUADELOUPE AND DOMINICA NWD TO ANGUILLA
AND ST. MAARTEN.

TROPICAL WAVE OVER THE BAY OF CAMPECHE ALONG 92W S OF 19N MOVING
W 15 KT. SCATTERED MODERATE CONVECTION MAINLY INLAND FROM
17N-20N BETWEEN 89W-94W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N12W 19N33W...THEN ALONG 13N36W
9N51W 18N59W...THEN ALONG 8N70W 10N80W 9N86W. SCATTERED MODERATE
CONVECTION FROM 5N-13N BETWEEN 11W-18W. SCATTERED MODERATE FROM
6N-12N BETWEEN 35W-42W.

...DISCUSSION...

GULF OF MEXICO...
A LARGE AND WELL-DEFINED UPPER LOW HAS DEVELOPED OVER THE
W/CENTRAL GULF NEAR 25N93W AND IS PULLING A COPIOUS PLUME OF
TROPICAL MOISTURE NWD FROM SRN MEXICO TOWARDS THE CENTRAL GULF
COAST. SCATTERED SHOWERS/TSTMS WITH EMBEDDED ISOLATED MODERATE
CONVECTION HAVE DEVELOPED NEAR AND TO THE E OF THE UPPER LOW
FROM 22N-28N BETWEEN 86W-96W. IN ADDITION...AN ILL-DEFINED 1010
MB LOW IS LOCATED IN THE BAY OF CAMPECHE NEAR 21N93W WITH A
TROUGH EXTENDING NE TO 23N87W AND THIS IS ALSO PRODUCING WIDELY
SCATTERED SHOWERS S OF 22N BETWEEN 92W-96W. THE LOW IS EXPECTED
TO DRIFT SLOWLY NW AND COULD BEGIN SPREADING MORE MOISTURE
INLAND OVER COASTAL MEXICO LATER IN THE WEEK.

CARIBBEAN...
A SMALL BUT PERSISTENT UPPER LEVEL LOW SITS NEAR THE ISLE OF
YOUTH JUST S OF CUBA NEAR 22N82W BUT DOES APPEAR TO BE WEAKENING
AS IT BECOMES PULLED INTO THE CIRCULATION OF THE LARGER GULF OF
MEXICO UPPER LOW. FARTHER S...AN UPPER HIGH IS CENTERED JUST N
OF PANAMA NEAR 10N81W AND IS PROVIDING A DIFFLUENT ENVIRONMENT
FOR WIDELY SCATTERED MODERATE CONVECTION OVER NICARAGUA...COSTA
RICA...AND PANAMA S OF 15N BETWEEN 81W-86W. THE CENTRAL
CARIBBEAN IS UNDER A LARGE PATCH OF DRY AIR BETWEEN 68W-79W AND
IS KEEPING SKIES MOSTLY CLEAR. INCREASED CLOUDINESS AND CLUSTERS
OF TSTMS ARE OVER THE E CARIBBEAN AND NRN LEEWARD ISLANDS DUE TO
A TROPICAL WAVE MOVING TOWARDS THE VIRGIN ISLANDS.

ATLANTIC...
A LARGE UPPER LEVEL HIGH IS CENTERED OVER T.S. NATE NEAR 29N66W
WITH A RIDGE RUNNING OVER THE W ATLC WATERS FROM 26N50W TO THE
FLORIDA/GEORGIA BORDER NEAR 31N83W. THE RIDGE IS DICTATING THE
ENVIRONMENT SURROUNDING NATE...T.D. SIXTEEN...AND HURRICANE
MARIA. SEE SPECIAL FEATURES ABOVE FOR FURTHER DISCUSSION.
FARTHER E...A SHARP UPPER TROUGH LIES ALONG 32N43W 14N51W WITH
AN UPPER LOW ABOUT TO CLOSE OFF NEAR 17N51W AND MOVING SLOWLY NW
ABOUT 5 KT. A STRONG 90 KT NORTHERLY JET IS SCREAMING DOWN THE W
SIDE OF THE TROUGH AND IS ADVECTING CIRRUS SWD TO ABOUT
10N...AND MAKING THE ENVIRONMENT INSANELY DISRUPTIVE FOR ANY
KIND OF TROPICAL DEVELOPMENT. A LARGE UPPER HIGH IS OVER THE E
ATLC NEAR 22N27W WITH A RIDGE EXTENDING SW TO 8N47W...AND IS
KEEPING DRY SAHARAN AIR CAPPED BENEATH THE TRADE WIND INVERSION.
A DIGGING UPPER LEVEL TROUGH IS MOVING SWD OVER SPAIN AND N
AFRICA AND THE TAIL END STRAGGLES ACROSS THE CANARY ISLANDS N OF
25N E OF 27W.

$$
BERG


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