[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 060546
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURES...

HURRICANE MARIA IS CENTERED NEAR 32.9N 56.5W...OR 420 NM E OF
BERMUDA...AT 06/0300 UTC MOVING NNE AT 5 KT. MAXIMUM SUSTAINED
WIND SPEED IS 100 KT WITH GUSTS TO 120 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 960 MB. SEE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.
MARIA IS BEGINNING TO MOVE OUT OF THE MOST FAVORABLE ENVIRONMENT
FOR MAINTAINING THE CURRENT INTENSITY. OUTFLOW IS BEING SHEARED
ON THE SW SIDE AS THE SYSTEM APPROACHES THE STRONG WESTERLIES
AND WILL BE OVER COOLER WATERS IN NEXT 24 TO 36 HOURS. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS SYMMETRICAL WITHIN 90 NM
AROUND THE WELL DEFINED EYE. SIMILAR CONVECTION COVERS THE AREA
TO THE SE WITHIN 90 NM OF LINE 29N56W-32N52W. SCATTERED MODERATE
CONVECTION COVERS THE REMAINDER OF THE AREA WITHIN 150 NM OF
LINE 25N54W-32N54W-36N58W.

TROPICAL DEPRESSION FIFTEEN WAS UPGRADED TO TROPICAL STORM AT
06/0300 UTC. TROPICAL STORM NATE IS CENTERED NEAR 28.0N 66.8W...
OR ABOUT 280 NM SOUTH-SOUTHWEST OF BERMUDA...AT 06/0300 UTC
DRIFTING W NEAR 2 KT. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH
GUSTS TO 45 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. DEEP CONVECTION WITH
COLDER CLOUD TOPS HAS BEEN MAINTAINED FOR THE PAST 6 HOURS. THE
SYSTEM WAS UPGRADED NOT SO MUCH ON SATELLITE APPEARANCE...BUT
BUOY DATA CLOSE TO THE CIRCULATION BUT NOT BENEATH THE DEEP
CONVECTION. SCATTERED MODERATE/STRONG CONVECTION IS FROM
26N-29.5N BETWEEN 63W-68W.

A 1010 MB LOW IS CENTERED OVER THE N BAHAMA ISLANDS OFF THE 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 NOT APPEAR TO BECOMING BETTER ORGANIZED
OVER THE PAST 6 HOURS. LOW IS BENEATH THE W SIDE OF AN UPPER
HIGH PRODUCING S SHEAR OVER THE SYSTEM. DEEP CONVECTION IS MORE
CONSOLIDATED OVER THE BAHAMA ISLANDS N OF LOW. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 26N-28.5N BETWEEN 76.5W-79.5W
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 30W/31W S OF 22N MOVING W 15 KT
WITH A 1009 MB LOW CENTERED NEAR 13N. THE LOW IS NOT WELL
DEFINED BUT THE WAVE CIRCULATION ENCOMPASSES AN THE AREA BETWEEN
THE CAPE VERDE ISLANDS TO 40W. CLUSTERS OF SCATTERED MODERATE/
STRONG CONVECTION FROM 12N-15N BETWEEN 27W-34W.

CENTRAL ATLC TROPICAL WAVE IS ALONG 44W 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.

TROPICAL WAVE ENTERING THE CARIBBEAN IS OVER THE LESSER ANTILLES
ALONG 60W/61W MOVING W 15-20 KT. WAVE IS UNDER EASTERLY VERTICAL
SHEAR WHICH HAS DISPLACED THE MAJORITY OF THE CONVECTION TO W OF
THE AXIS. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION ARE WITHIN 120/150 NM OF LINE 12N62W-22N59W INCLUDING
THE CENTRAL LESSER ANTILLES ISLANDS.

W CARIBBEAN TROPICAL WAVE OVER CENTRAL AMERICA IS ALONG 87W/88W
S OF 18N MOVING W 15 KT. WAVE IS ON THE S SIDE OF AN UPPER LOW
WHICH IS MASKING THE SIGNATURE CURVATURE. SCATTERED SHOWERS/
THUNDERSTORMS ARE S OF 19N W OF 83W TO INLAND OVER CENTRAL
AMERICA AND THE YUCATAN.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 16N17W 14N28W 10N40W 15N56W14N62W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS NW OF THE CAPE
VERDE ISLANDS WITHIN A 45/60 NM RADIUS OF 18.5N26.5W. CLUSTERS
OF SCATTERED MODERATE CONVECTION ARE FROM 3N-10N BETWEEN
33W-40W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER LEVEL TROUGH EXTENDS THROUGH AN UPPER LOW OVER THE
MISSISSIPPI DELTA S INTO THE CENTRAL GULF N OF 23N W OF 87W. THE
TROUGH CONTINUES TO ADVECT DRY AIR OVER THE NW GULF WITH
TROPICAL MOISTURE 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/ISOLATED THUNDERSTORMS
OVER S MEXICO AND THE W BAY OF CAMPECHE. A WEAK 1011 MB SURFACE
LOW IS A REFLECTION OF THE UPPER TROUGH CENTERED NEAR 20N94W.
LIGHT TO MODERATE NE SURFACE WINDS COVER THE GULF WITH ISOLATED
SHOWERS N OF 25N E OF 91W. THE 1010 MB LOW OVER THE BAHAMAS AND
THE UPPER LEVEL HIGH OVER THE W ATLC ARE PUSHING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS INTO THE STRAITS OF FLORIDA S OF
25N E OF 84W. MOISTURE LEVELS ARE EXPECTED TO INCREASE OVER THE
NEXT COUPLE OF DAYS AS S FLOW REDEVELOPS.

CARIBBEAN...
MID/UPPER LEVEL LOW IS LOCATED OVER THE GULF OF HONDURAS/YUCATAN
COAST NEAR 20N86W AND WAS TRIGGERING SHOWERS/THUNDERSTORMS BEING
ENHANCED BY THE CLOSE PROXIMITY OF THE TROPICAL WAVE. OVERALL...
THE BULK OF THE CARIBBEAN IS UNDER THE INFLUENCE OF A DRY AIR
MASS THAT IS SUPPRESSING MOST THUNDERSTORM ACTIVITY. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF LINE FROM
OFF THE PANAMA COAST NEAR 10N80W TO OVER NICARAGUA NEAR
11.5N84W. 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 32N40W SSW ALONG 24N48W INTO THE TROPICS NEAR 16N50W.
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
TROPIC ATLC THROUGH 24N58W TO 10N60W. A LARGE UPPER HIGH IS
ANCHORED OFF AFRICA NEAR 19N20W 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 NE PAST MADEIRA ISLAND
TOWARDS MOROCCO.

$$
WALLACE


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