[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 191820
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU 19 AUG 2004

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 1200 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 1745 UTC.

...SPECIAL FEATURE...

TROPICAL STORM DANIELLE CENTER NEAR 30.0N 37.4W...OR ABOUT
810 MILES/1305 KM SOUTHWEST OF THE AZORES...AT 19/1500 UTC...
MOVING EAST 3 KT. MAXIMUM SUSTAINED WIND SPEED 35 KT GUSTS
45 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 1007 MB. SEE LATEST
NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/
WTNT24 KNHC FOR MORE DETAILS. MIDDLE TO UPPER LEVEL CYCLONIC
FLOW FROM 28N TO 37N BETWEEN 38W AND 50W IS IMMEDIATELY TO THE
WEST OF DANIELLE. THE LOW LEVEL CENTER IS COMPLETELY EXPOSED.
SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS
FROM 30N TO 31.5N BETWEEN 36W AND 37W. OVERCAST MULTILAYERED
CLOUDS AND POSSIBLE PRECIPITATION ELSEWHERE FROM 31.5N TO 36N
BETWEEN 33W AND 38W. A LINE OF POSSIBLE SHOWERS IS ABOUT
15 TO 30 NM WIDE ALONG 19N44W 24N37W 27N35W 30N35W.

...TROPICAL WAVES...

TROPICAL WAVE NEARING THE CAPE VERDE ISLANDS ALONG 22W/23W
SOUTH OF 20N...MOVING WEST 10-15 KT. HOVMOELLER DIAGRAMS SHOW
A DISTINCT CLUSTER OF TSTMS MOVING ACROSS WEST AFRICA DURING
THE PAST SEVERAL DAYS...AND THE TIMESECTIONS FROM BAMAKO AND
DAKAR SHOW A WAVE PASSAGE PRIMARILY BELOW 800 MB. THE WAVE
APPEARS TO BE TILTED TO THE EAST WITH HEIGHT...WITH THE
LOW-LEVEL CIRCULATION ABOUT 100 NM AHEAD OF THE CONVECTION...
AND THIS SEEMS TO AGREE WITH THE VERTICAL SOUNDINGS FROM WEST
AFRICA. VISIBLE IMAGERY FROM MET-8 ALSO SHOWS A WELL-DEFINED
LOW-LEVEL CIRCULATION APPROACHING THE CAPE VERDES. STRONG
SHOWERS AND THUNDERSTORMS IN ONE CLUSTER FROM 9N TO 10N BETWEEN
23W AND 24W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS WEST OF
THE WAVE IN THE ITCZ IN INDIVIDUAL CLUSTERS WITHIN 30 TO 40 NM
ON EITHER SIDE OF 10N24W 10N26W 9N30W.

TROPICAL WAVE IN THE CENTRAL ATLANTIC OCEAN ALONG 46W/47W SOUTH
OF 16N MOVING WEST 20-25 KT. ISOLATED MODERATE TO LOCALLY
STRONG SHOWERS AND THUNDERSTORMS IN THE ITCZ FROM 6N TO 11N
BETWEEN 46W AND 57W.

TROPICAL WAVE JUST HAS ENTERED THE EASTERN CARIBBEAN SEA ALONG
60W/61W SOUTH OF 18N MOVING WEST 15 KT. ISOLATED MODERATE TO
LOCALLY STRONG SHOWERS AND THUNDERSTORMS FROM 8N TO 13N
BETWEEN 60W AND 65W.

TROPICAL WAVE...REMNANTS OF T.S. EARL...IN THE SOUTHWESTERN GULF
OF MEXICO...ALONG 93W/94W SOUTH OF 20N MOVING WEST 15 KT.
NO PRECIPITATION WITH THIS WAVE IN THE ATLANTIC BASIN.

...ITCZ...

ITCZ FROM SENEGAL NEAR 15N17W TO 9N30W TO 7N40W 6N50W 7N60W.
ELSEWHERE...POSSIBLE SHOWERS FROM 7N TO 8N BETWEEN 30W AND 36W.

...DISCUSSION...

THE GULF OF MEXICO...
THE 19/1500 UTC CIMSS SATELLITE DERIVED WIND DATA SHOW MIDDLE
TO UPPER LEVEL WESTERLY WIND FLOW IN MUCH OF THE GULF.
ISOLATED MODERATE SHOWERS AND THUNDERSTORMS IN AN AREA OF A
WEAK MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH AND A WEAK SURFACE
PRESSURE GRADIENT IN THE GULF WATERS...FROM 23N TO 28N BETWEEN
THE WESTERN FLORIDA COAST AND 93W. THE GFS AMPLIFIES THE
SHORTWAVE AND PUTS IT IN PHASE WITH ANOTHER SHORTWAVE NEAR THE
WESTERN TIP OF CUBA...AND THIS MAY BRING MORE WIDESPREAD
THUNDERSTORM ACTIVITY TO PARTS OF FLORIDA LATER THIS AFTERNOON.

THE CARIBBEAN SEA...
BROAD UPPER LEVEL ANTICYCLONIC FLOW IN THE NORTHWESTERN CORNER
OF THE AREA. MIDDLE TO UPPER LEVEL TROUGH FROM AN ATLANTIC
CYCLONIC CIRCULATION CENTER NEAR 23N64W TO THE EASTERN DOMINICAN
REPUBLIC NEAR 19N69W...TO 12N80W IN THE SOUTHWESTERN CORNER OF
THE AREA. MIDDLE TO UPPER LEVEL DRY AIR SURROUNDS MUCH OF THIS
TROUGH. SCATTERED STRONG SHOWERS AND THUNDERSTORMS IN THE
SOUTHWESTERN CARIBBEAN SEA...WITH THE ITCZ...ARE SOUTH OF 11N
BETWEEN 79W AND 84W. SCATTERED MODERATE TO ISOLATED STRONG
SHOWERS AND THUNDERSTORMS ARE IN SOUTHERN NICARAGUA ALSO...
PROBABLY RELATED TO THE ITCZ.

THE SUBTROPICAL ATLANTIC OCEAN...
MIDDLE TO UPPER LEVEL TROUGH FROM AN ATLANTIC CYCLONIC
CIRCULATION CENTER NEAR 23N64W TO THE EASTERN DOMINICAN REPUBLIC
NEAR 19N69W. ISOLATED MODERATE SHOWERS WITHIN 30 NM ON EITHER
SIDE OF 27N56W 24N63W 21N64W. BROAD MIDDLE TO UPPER LEVEL
ANTICYCLONIC FLOW IN THE ATLANTIC ELSEWHERE...AWAY FROM THE
CYCLONIC CENTER NEAR T.S. DANIELLE...IN MIDDLE TO UPPER LEVEL
DRY AIR...AND AWAY FROM THE 23N64W 19N69W TROUGH.

TROPICAL ATLANTIC...
BROAD UPPER LEVEL RIDGE EXTENDS FROM THE SUBTROPICS INTO THE
AREA ALONG 20N44W 16N60W NEAR THE LEEWARD ISLANDS...WITH DEEP
EASTERLY FLOW ACROSS THE ATLC BETWEEN 30W AND 50W.

$$
MT


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