[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 251201
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU AUG 25 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN 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
1115 UTC.

...SPECIAL FEATURE...
HURRICANE IRENE IS CENTERED NEAR 25.5N 76.5W AT 25/1200 UTC OR
ABOUT 65 MI...105 KM ENE OF NASSAU...OR ABOUT 670 MI...1085 KM S
OF CAPE HATTERAS NORTH CAROLINA MOVING NW AT 10 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 950 MB. MAXIMUM SUSTAINED WIND SPEED
IS 100 KT WITH GUSTS TO 120 KT. PLEASE SEE THE LATEST
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER
MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADER MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.
SCATTERED MODERATE/STRONG CONVECTION IS FROM 23N-26N BETWEEN
73W-79W. SCATTERED TO HEAVY SHOWERS AND ISOLATED THUNDERSTORMS
COVER A BROAD AREA FROM 18N-24N BETWEEN 63W-78W AND FROM 24N-31N
BETWEEN 70W-79W. HURRICANE IRENE REMAINS A LARGE TROPICAL
CYCLONE WITH HURRICANE FORCE WINDS EXTENDING OUTWARD UP TO 60 NM
FROM THE CENTER AND TROPICAL STORM FORCE WINDS EXTENDING OUTWARD
UP TO 225 NM. IRENE IS EXPECTED TO PRODUCE RAINFALL
ACCUMULATIONS OF 6 TO 12 INCHES OVER THE BAHAMAS DURING THE NEXT
36 HOURS. RAINS WILL BE DIMINISHING ACROSS THE TURKS AND CAICOS
ISLANDS WITH ADDITIONAL RAINFALL AMOUNTS OF 1 TO 3 INCHES
POSSIBLE...BRINGING THE MAXIMUM STORM TOTAL TO 6 TO 12 INCHES.

THE 1007 MB LOW CENTERED SW OF THE CAPE VERDE ISLANDS WAS
UPGRADED TO TROPICAL DEPRESSION TEN AT 0900 UTC. TROPICAL
DEPRESSION TEN IS CENTERED NEAR 12.4N 30.4W AT 25/0900 UTC
MOVING W-NW AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007
MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT.
PLEASE SEE THE LATEST FORECAST/ADVISORY UNDER AWIPS/WMO HEADER
MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. T.D. TEN COULD BECOME A
TROPICAL STORM LATER TODAY. SCATTERED MODERATE/STRONG CONVECTION
IS WITHIN 75/90 NM OF LINE FROM 16N28W TO 13N33W. SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS COVER THE REMAINDER
OF THE AREA FROM 9N-13N BETWEEN 30W-35W.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA ENTERING THE E
TROPICAL ATLC NEAR 21N16W THROUGH T.D. TEN TO 9N39W. THE ITCZ
AXIS CONTINUES FROM 9N39W ALONG 7N47W 7N55W TO INLAND OVER SOUTH
AMERICA NEAR 8N60W. THE MONSOON TROUGH IS EXPECTED TO DETACH
FROM T.D. TEN OVER THE NEXT SEVERAL HOURS AS T.D. TEN BECOMES A
TROPICAL STORM. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE WITHIN 120 NM OF LINE FROM 15N51W TO 12N60W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 90/120 NM
ALONG THE COAST OF W AFRICA BETWEEN 11N-18N.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE DOMINATES THE W GULF W OF 90W ANCHORED OVER W
TEXAS. UPPER DIFFLUENCE OVER THE FAR NW GULF IS GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND OVER LOUISIANA
AND E TEXAS AND OVER THE GULF WATERS N OF 28N W OF 90W. AN UPPER
LOW IS OVER THE NE GULF NEAR 27N85W WITH AN UPPER TROUGH
EXTENDING S TO THE W YUCATAN CHANNEL. AN ABUNDANCE OF DEEP LAYER
MOISTURE COVERS THE GULF GENERATING ISOLATED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS DOTTING THE REMAINDER OF THE
GULF WATERS. HURRICANE IRENE CURRENTLY MOVING ACROSS THE BAHAMAS
AND WILL REACH THE NW BAHAMAS LATER TODAY WITH TROPICAL STORM
CONDITIONS EXPECTED TO REMAIN WELL E OF THE GULF WATERS. HOWEVER
THE TIGHTENING PRESSURE GRADIENT WILL INCREASE WINDS AND SEAS
OVER THE E GULF THU THROUGH LATE FRI. A WEAK COLD FRONT WILL
REACH THE N GULF COAST EARLY SAT.

CARIBBEAN SEA...
HURRICANE IRENE CONTINUES TO GENERATE SHOWERS/THUNDERSTORMS OVER
THE N CARIBBEAN...SEE SPECIAL FEATURES ABOVE. BROAD OUTFLOW FROM
HURRICANE IRENE REMAINS OVER THE E AND CENTRAL CARIBBEAN DRAWING
TROPICAL MOISTURE N ACROSS THE S CARIBBEAN AND GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 15N TO INLAND OVER
COLOMBIA BETWEEN 71W-76W AND S OF 13N TO OVER VENEZUELA BETWEEN
62W-66W. THIS UPPER FLOW IS ALSO RESPONSIBLE FOR THE HIGH DEBRIS
CLOUDS COVERING THE AREA E OF 80W. HURRICANE IRENE CURRENTLY
OVER THE BAHAMAS WILL REACH THE NW BAHAMAS LATER TODAY AND
FURTHER AWAY FROM THE CARIBBEAN. SURFACE RIDGE WILL BUILD SW
ACROSS E CARIBBEAN LATE SUN BRINGING A RETURN OF E-SE TRADE
WINDS E OF 75W.

ATLANTIC OCEAN...
THE PRIMARY CONCERN THIS MORNING CONTINUES TO BE HURRICANE IRENE
MOVING THROUGH THE BAHAMA ISLANDS...SEE SPECIAL FEATURES ABOVE.
THE UPPER RIDGE ASSOCIATED WITH HURRICANE IRENE COVERS THE W
ATLC W OF 65W. A LARGE UPPER LOW IS JUST TO THE E CENTERED NEAR
25N55W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
WITHIN 150 NM OF LINE FROM 28N52W TO 25N55W. A WEAK 1015 MB
SURFACE LOW IS CENTERED IN THE CENTRAL ATLC NEAR 23N47W
GENERATING SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM
23N-27N BETWEEN 43W-47W. THE REMAINDER OF THE ATLC BASIN N OF
25N E OF 65W IS DOMINATED BY A LARGE SURFACE RIDGE ANCHORED BY A
PAIR OF 1026 MB HIGHS N OF THE DISCUSSION AREA. HURRICANE IRENE
IS FORECAST TO INTENSIFY AS IT MOVES MORE N-NW ACROSS THE NW
BAHAMAS TODAY THEN N OF THE BAHAMAS TONIGHT INTO FRI BEFORE
MOVING OVER THE OUTER BANKS OF CAROLINA OVER THE WEEKEND.

ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
PAW




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