[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 242356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED AUG 25 2010

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING
INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL
ANALYSIS...WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM DANIELLE AT 24/12100 UTC IS NEAR
17.5N 48.2W...OR ABOUT 780 NM...E OF THE LESSER
ANTILLES...MOVING W 16 KT. THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 993 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 60 KT
WITH GUSTS TO 75 KT. DANIELLE HAS WEAKENED DURING THE PAST SIX
HOURS BUT RE-STRENGTHENING IS POSSIBLE DURING THE NEXT 48 HOURS.
NUMEROUS STRONG CONVECTION IS MAINLY W OF THE CENTER FROM
16N-19N BETWEEN 47W-50W. SCATTERED MODERATE/STRONG CONVECTION IS
ELSEWHERE FROM 14N-21N BETWEEN 46W-50W...WITH SCATTERED MODERATE
CONVECTION FROM 10N-15N BETWEEN 44W-50W. PLEASE READ THE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21
KNHC AND THE LATEST PUBLIC ADVISORY UNDER MIATCPAT1/WTNT31 KNHC
FOR MORE DETAILS.

A 1008 MB LOW IS SSW OF THE CAPE VERDE ISLANDS NEAR 13N25W
MOVING WNW NEAR 15 KT. THIS LOW IS STEADILY DEEPENING AND COULD
DEVELOP INTO A TROPICAL CYCLONE WITHIN THE NEXT 48 HOURS.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 12N-16N
BETWEEN 25W-28W. SCATTERED STRONG CONVECTION IS FROM 9N-11N
BETWEEN 28W-31W.

...TROPICAL WAVES...

TROPICAL WAVE IS OVER THE W ATLANTIC AND THE CENTRAL CARIBBEAN
FROM 27N70W ACROSS TURKS AND CAICOS...AND HAITI TO 18N72W TO NRN
VENEZUELA NEAR 12N71W MOVING W 15-20 KT. THE WAVE LIES AHEAD OF
A SMALL AREA OF ENHANCED MOISTURE OVER THE W ATLC WITHIN 200 NM
E OF THE AXIS...WHILE EMBEDDED WITHIN AN AREA OF MAXIMUM
MOISTURE MOVING ACROSS THE CENTRAL CARIBBEAN BETWEEN 68W-76W
EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS E OF THE AXIS FROM
14N-18N BETWEEN 64W-73W. STRONG CONVECTION HAS FLARED UP OVER
NRN HAITI...AND IS ALSO INLAND OVER NRN COLOMBIA FROM 10N-12N
BETWEEN 73W-75W.

...THE ITCZ...

ITCZ AXIS EXTENDS ALONG 9N28W TO 15N40W RESUMING NEAR 13N50W
11N60W ACROSS THE SE CARIBBEAN TO 12N70W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS MOVING OFF THE COAST OF
AFRICA FROM 9N-11N BETWEEN 13W-17W. STRONG CONVECTION IS FARTHER
INLAND OVER W AFRICA. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS ALSO ALONG NRN S AMERICA WITHIN 150 NM INLAND OF
THE COASTLINE BETWEEN 54W-71W.

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 2100 UTC...A FORMING STATIONARY FRONT LINES THE NRN GULF
COAST EXTENDING FROM A 1007 MB LOW OVER CENTRAL GEORGIA. A
SURFACE TROUGH IS AHEAD OF THE BOUNDARY OVER THE NW GULF OF
MEXICO ALONG 29N89W 26N93W 27N95W. SCATTERED
SHOWERS/THUNDERSTORMS ARE AHEAD OF THE SYSTEM COVERING MUCH OF
THE BASIN S OF 29N E OF 93W WITH AN AREA OF ISOLATED
SHOWERS/THUNDERSTORMS FROM 25N-29N BETWEEN 94W-97W. A SURFACE
TROUGH ALSO EXTENDS DOWN THE CENTRAL PORTION OF THE YUCATAN
PENINSULA ENHANCING STRONG SHOWERS/THUNDERSTORMS BETWEEN 88W-93W
S OF 23N. ONLY THE FAR SW CORNER OF THE BASIN REMAINS UNDER
SOMEWHAT FAIR CONDITIONS WITH HIGH CLOUD COVER. ALOFT...AN UPPER
LEVEL TROUGH EXTENDS DOWN THE ERN UNITED STATES SEABOARD
SUPPORTING THE LOW PRESSURE SYSTEM ACROSS THE NRN GULF. A WEAK
UPPER LEVEL RIDGE IS OVER LOUISIANA...WHILE MAINLY MOIST NELY
FLOW COVERS THE SRN HALF OF THE BASIN. A STRONG MOISTURE
GRADIENT IS EVIDENT IN WATER VAPOR IMAGERY ALONG THE FRONTAL
BOUNDARY ACROSS THE NRN GULF COINCIDING WITH THE NRN BOUNDARY OF
THE AREA OF SHOWER ACTIVITY ACROSS THE BASIN. EXPECT CONTINUED
SHOWER ACTIVITY ACROSS MUCH OF THE BASIN OVER THE NEXT 24 HRS.

THE CARIBBEAN SEA...
STRONG CONVECTION HAS FLARED UP ACROSS CUBA MOST LIKELY DUE TO
DAYTIME HEATING AND INSTABILITY. SCATTERED SHOWERS/THUNDERSTORMS
ARE ALSO S OF CUBA FROM 19N-21N BETWEEN 82W-84W...AND ACROSS
JAMAICA. SIMILAR ACTIVITY IS S OF JAMAICA FROM 12N-17N BETWEEN
74W-81W. SOME OF THIS ACTIVITY IS ENHANCED BY A PORTION OF THE
ITCZ EXTENDING ACROSS SRN COAST RICA TO NRN COLOMBIA ALONG 9N83W
12N79W 12N74W. THIS AREA IS ALSO UNDER DIFFLUENCE ALOFT BETWEEN
A WEAK INVERTED UPPER LEVEL TROUGH ACROSS HONDURAS AND NICARAGUA
AND A WEAK UPPER LEVEL RIDGE COVERING THE SW CARIBBEAN. A
TROPICAL WAVE EXTENDS ACROSS HAITI TO NRN VENEZUELA SUPPORTING
SCATTERED SHOWERS/THUNDERSTORMS FROM 14N-18N BETWEEN
64W-73W...AND AN AREA OF STRONG SHOWERS/THUNDERSTORMS OVER NRN
HAITI AND NRN COLOMBIA. SOME OF THIS ACTIVITY IS ENHANCED BY
DIFFLUENCE ALOFT AROUND A WEAK UPPER LEVEL TROUGH EXTENDING FROM
NE VENEZUELA TO CENTRAL CUBA. SCATTERED SHOWERS/THUNDERSTORMS
ARE ALSO WITHIN 150 NM INLAND OF THE NRN S AMERICA COASTLINE DUE
TO SURFACE CONVERGENCE NEAR A PORTION OF THE ITCZ EXTENDING
ALONG 11N. EXPECT MOISTURE TO REMAIN ACROSS MUCH OF THE WRN HALF
OF THE BASIN WITH CONTINUED AREAS OF
SHOWERS/THUNDERSTORMS...WHILE DRIER CONDITIONS MOVE ACROSS THE
ERN CARIBBEAN ASSOCIATED WITH A SAHARAN AIR LAYER. SOME STATIONS
ACROSS THE LESSER ANTILLES ARE ALREADY REPORTING THE PRESENCE OF
DUST ASSOCIATED WITH THIS DRIER AIR MASS.

THE ATLANTIC OCEAN...
SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE NW BAHAMAS AND
OFF THE ERN UNITED STATES COASTLINE W OF 71W ASSOCIATED WITH A
DIFFLUENT ZONE ALOFT AROUND AN UPPER LEVEL TROUGH EXTENDING DOWN
THE ERN SEABOARD. A TROPICAL WAVE EXTENDS FROM NEAR 27N70W
ACROSS TURKS AND CAICOS INTO THE CENTRAL CARIBBEAN. POSSIBLE
ISOLATED SHOWERS ARE NEAR THE AXIS N OF HAITI WHILE SCATTERED
SHOWERS/THUNDERSTORMS HAVE FLARED UP OVER HAITI AND TO THE S.
THE REMAINDER OF THE BASIN IS DOMINATED BY SURFACE RIDGING
ANCHORED BY A 1022 MB HIGH NEAR 30N58W...AND A 1020 MB HIGH NEAR
30N30W. THE CIRCULATION OF DANIELLE...AND THE LOW PRESSURE
CENTER S OF THE CAPE VERDE ISLANDS CREATE WEAKNESSES IN THE
RIDGE. ALOFT...AN UPPER LEVEL RIDGE IS N OF THE ERN CARIBBEAN
CENTERED NEAR 27N65W. AN UPPER LEVEL TROUGH IS TO THE E NEAR
25N50W...TO THE NW OF DANIELLE. AN UPPER LEVEL RIDGE IS DIRECTLY
E OF DANIELLE BETWEEN 32W-45W. AN UPPER LEVEL TROUGH EXTENDS W
OF THE CANARY ISLANDS TO W OF THE CAPE VERDE ISLANDS.
FINALLY...AN UPPER LEVEL RIDGE IS CENTERED JUST OFF THE COAST OF
W AFRICA NEAR 19N18W.

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

$$
WALTON







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