[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 061053
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

HURRICANE MARIA IS CENTERED NEAR 33.3N 56.4W...OR 430 NM E OF
BERMUDA...AT 06/0900 UTC MOVING NNE AT 6 KT. MAXIMUM SUSTAINED
WIND SPEED IS 90 KT WITH GUSTS TO 110 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 970 MB. SEE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.
MARIA IS NOT AS WELL DEFINED AS 6 HOURS AGO. OUTFLOW IS BEING
SHEARED ON THE W SIDE AS THE SYSTEM APPROACHES THE STRONG
WESTERLIES AND COOLER WATERS. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 75/90 NM OF LINE 30N53W-34N56W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS COVER THE REMAINDER OF THE AREA
FROM 28N-35N BETWEEN 51W-57W.

TROPICAL STORM NATE IS CENTERED NEAR 28.6N 66.6W... OR ABOUT 240
NM SOUTH-SOUTHWEST OF BERMUDA...AT 06/0900 UTC DRIFTING W NEAR 2
KT. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC
FOR MORE DETAILS. THE CENTER IS IN THE NW PORTION OF THE DEEPEST
CONVECTION. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN A 45
NM RADIUS OF 29N66W. SCATTERED MODERATE/STRONG CONVECTION IS
FROM 26N-30N BETWEEN 61W-68W.

A 1009 MB LOW IS CENTERED OVER THE N BAHAMA ISLANDS OFF THE
COAST OF S FLORIDA NEAR 26N78W AND IS NEARLY STATIONARY. THE
CENTER OF CIRCULATION IS NOT THAT WELL DEFINED ON THE MIAMI
RADAR IMAGERY BUT DOES APPEAR TO BECOMING BETTER ORGANIZED OVER
THE PAST 6 HOURS. LOW IS BENEATH THE W SIDE OF A BROAD UPPER
HIGH PRODUCING S SHEAR OVER THE SYSTEM. CONVECTION HAS DEEPENED
OVER THE PAST 6 HOURS. SCATTERED STRONG CONVECTION IS WITHIN
30/45 NM OF LINE 26N77W-28N78W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION COVERS THE AREA WITHIN 75 NM OF LINE FROM
25N79W-31N76W INCLUDING THE ISLANDS OF ABACO AND GRAND BAHAMA.
THE LOW IS EXPECTED TO DRIFT N TO NW BENEATH AN UPPER LEVEL HIGH
AND BE NEAR OR OVER FLORIDA DURING THE NEXT SEVERAL DAYS.
TROPICAL CYCLONE DEVELOPMENT IS POSSIBLE WITHIN THE NEXT DAY OR
SO AS UPPER LEVEL WINDS BECOME MORE FAVORABLE.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE IS ALONG 32W S OF 21N MOVING W 15 KT WITH A
1010 MB LOW CENTERED NEAR 13N. THE LOW APPEARS LITTLE BETTER ON
THE FIRST VISIBLE SATELLITE IMAGES THIS MORNING. WAVE
CIRCULATION ENCOMPASSES AN THE AREA FROM JUST W OF THE CAPE
VERDE ISLANDS TO 35W. CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE WITHIN 90/120 NM OF LINE 12N36W-20N28W.

CENTRAL ATLC TROPICAL WAVE IS ALONG 45W/46W S OF 18N MOVING W 15
KT. THE WAVE HAS VIRTUALLY NO SIGNATURE IN SATELLITE IMAGERY BUT
IT IS PLACED SOMEWHAT ALONG THE LEADING EDGE OF THE AFRICAN DUST
SURGE. NO ASSOCIATED DEEP CONVECTION.

E CARIBBEAN TROPICAL WAVE MOVING THROUGH THE LESSER ANTILLES
ALONG 61W/62W MOVING W 10-15 KT. WAVE IS UNDER EASTERLY VERTICAL
SHEAR WHICH HAS DISPLACED THE MAJORITY OF THE CONVECTION TO W OF
THE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
WITHIN A 60/75 NM RADIUS OF 12.5N64W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE FROM 12N-18N BETWEEN 60W-63W INCLUDING MOST OF
THE LESSER ANTILLES ISLANDS.

W CARIBBEAN TROPICAL WAVE OVER CENTRAL AMERICA IS ALONG 89W S OF
18N MOVING W 15 KT. WAVE IS INLAND OVER CENTRAL AMERICA.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 19N W OF 84W
TO INLAND OVER CENTRAL AMERICA AND THE YUCATAN.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 16N17W 12N30W 9N45W 13N62W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM
ALONG THE COAST OF AFRICA S OF 7N W OF 10W...WITHIN 45 NM OF 31W
FROM 11N-13.5N. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE
WITHIN 120 NM OF LINE FROM 6N37W ACROSS THE ITCZ AXIS TO 17N56W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER LEVEL TROUGH EXTENDS THROUGH AN UPPER LOW OVER THE E
LOUISIANA NEAR 30N90W S INTO THE CENTRAL GULF N OF 23N W OF 87W.
THE TROUGH CONTINUES TO ADVECT DRY AIR OVER THE NW GULF AND
TROPICAL MOISTURE IS BEING ADVECTED N OVER THE THE FAR E GULF
AND FLORIDA BY A LARGE UPPER HIGH ANCHORED IN THE W ATLC. WEAK
UPPER INVERTED TROUGH EXTENDS FROM S/CENTRAL MEXICO SE BELOW THE
BAY OF CAMPECHE GENERATING SCATTERED SHOWERS/THUNDERSTORMS OVER
THE S GULF S OF LINE FROM THE FLORIDA KEYS 23N90W TO 21N OVER
THE BAY OF CAMPECHE. A WEAK 1012 MB SURFACE LOW IS A REFLECTION
OF THE UPPER TROUGH CENTERED NEAR 21N94W. LIGHT TO MODERATE NE
TO E SURFACE WINDS COVER THE GULF WITH SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS N OF 23N FROM 85W-92W. MOISTURE LEVELS
ARE EXPECTED TO INCREASE OVER THE NEXT COUPLE OF DAYS AS S FLOW
REDEVELOPS.

CARIBBEAN...
MID/UPPER LEVEL LOW REMAINS OVER THE NW CARIBBEAN NEAR 21N85W
AND WAS TRIGGERING SHOWERS/THUNDERSTORMS N OF THE CYCLONIC FLOW
OVER THE SE GULF. AN MID/UPPER HIGH IS IN THE SW CARIBBEAN NEAR
11N81W WHICH PULLING TROPICAL MOISTURE ACROSS CENTRAL AMERICA
OVER THE W CARIBBEAN W OF 80W. THE CENTRAL PORTION OF THE
CARIBBEAN IS UNDER THE INFLUENCE OF A DRY AIR MASS THAT IS
SUPPRESSING MOST THUNDERSTORM ACTIVITY. SCATTERED MODERATE/
STRONG CONVECTION IS S OF 12NW OF 80W TO INLAND OVER COSTA RICA.
SHOWERS/THUNDERSTORMS ARE MOVING ACROSS THE LESSER ANTILLES IN
ASSOCIATED WITH ANOTHER TROPICAL WAVE. MOISTURE WILL CONTINUE TO
INCREASE OVER THE E CARIBBEAN THROUGH THURSDAY...INCREASING THE
CHANGES FOR SCATTERED THUNDERSTORMS E OF 70W...BUT DRY AIR WILL
REMAIN ENTRENCHED OVER THE W PART OF THE AREA AND KEEP
THUNDERSTORMS HUGGING THE COAST OF PANAMA AND COSTA RICA.

WEST ATLANTIC...
HURRICANE MARIA...TROPICAL STROM NATE...AND THE 1010 MB LOW OVER
THE N BAHAMAS ARE STRUNG ACROSS THE W ATLC BENEATH A VERY BROAD
UPPER RIDGE THAT ENCOMPASSES THEM. SEE SPECIAL FEATURES ABOVE
FOR FURTHER DISCUSSION.

EAST/CENTRAL ATLANTIC...
SHARP MID/UPPER TROUGH COVERS THE CENTRAL ATLC WITH THE AXIS
THROUGH 32N42W SSW ALONG 23N47W INTO THE TROPICS NEAR 15N51W.
BACK SIDE OF THE TROUGH IS SERVING AS AN OUTFLOW CHANNEL FOR
HURRICANE MARIA...WITH UPPER LEVEL CIRRUS EXPANDING OUT THE SE
SIDE OF THE STORM. AN UPPER RIDGE EXTENDS S INTO THE FAR W
TROPICAL ATLC THROUGH 24N60W TO 11N59W. A LARGE UPPER HIGH IS
ANCHORED OFF AFRICA NEAR 18N25W WITH FLOW W OF 40W ENCOMPASSING
THE E ATLC. BROAD SW FLOW IS SKIRTING UP THE N SIDE OF THE
RIDGE AND IS ACTUALLY PICKING UP SOME OF THE DUST WHICH MOVED
OFF THE AFRICAN COAST AND RETURNING IT N AND E ACROSS MADEIRA
ISLAND TOWARDS MOROCCO.

$$
WALLACE



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