[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 290012
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT 28 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 1800 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 2345 UTC.

...SPECIAL FEATURES...
GASTON GETTING A LITTLE STRONGER...HURRICANE WARNINGS ISSUED
FOR SOUTH CAROLINA COAST...TROPICAL STORM GASTON CENTER NEAR
31.5N 79.1W...OR ABOUT 95 MILES/155 KM SOUTH-SOUTHEAST OF
CHARLESTON SOUTH CAROLINA...AT 29/0000 UTC...MOVING WEST 3 KT.
MAXIMUM SUSTAINED WIND SPEED 45 KT GUSTS 55 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE 996 MB. SEE THE LATEST NHC PUBLIC
ADVISORY OR FORECAST/ADVISORY ISSUED UNDER AWIPS/WMO HEADERS
MIATCPAT2/WTNT32 KNHC OR MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS.
NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 31N TO 33N
BETWEEN 78W AND 80W. WIDELY SCATTERED TO SCATTERED MODERATE/
ISOLATED STRONG SHOWERS AND THUNDERSTORMS FROM 30N TO 34N
BETWEEN 76W AND 80W.

CATEGORY FOUR HURRICANE FRANCES CENTER NEAR 17.4N 51.9W AT
29/0000 UTC MOVING NORTHWEST 8 KT. THIS IS THE SECOND CATEGORY
FOUR HURRICANE OF THE 2004 SEASON. MAXIMUM SUSTAINED WINDS ARE
115 KT GUSTS 140 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 948 MB.
SEE THE LATEST NHC FORECAST/ADVISORY ISSUED UNDER AWIPS/WMO
HEADERS MIATCMAT1/WTNT21 KNHC OR MIATCMAT2/WTNT22 KNHC FOR MORE
DETAILS. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 17N
TO 20N BETWEEN 51W AND 54W. FRANCES IS IN A LOW-SHEAR
ENVIRONMENT...MOVING INTO WATERS WHOSE TEMPERATURES ARE NEAR
29C...AND UPPER LEVEL ANTICYCLONIC OUTFLOW IS EXCELLENT IN
ALL QUADRANTS.

1013 MB LOW PRESSURE LOCATED NEAR 30N67W ABOUT 200 NM SOUTHWEST
OF BERMUDA. THIS SYSTEM COULD BECOME A TROPICAL DEPRESSION
DURING THE NEXT 24 HOURS. CELL OF STRONG SHOWERS/THUNDERSTORMS
WITHIN 30 NM RADIUS OF 30N68.5W. ISOLATED TO WIDELY SCATTERED
MODERATE TO LOCALLY STRONG SHOWERS AND THUNDERSTORMS ELSEWHERE
FROM 30N TO 31N BETWEEN 65W AND 68W.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 34W SOUTH OF 18N MOVING WEST 10-15 KT.
ISOLATED MODERATE TO LOCALLY STRONG ITCZ SHOWERS AND
THUNDERSTORMS FROM THE EQUATOR TO 10N BETWEEN 30W AND 42W.

WESTERN CARIBBEAN SEA TROPICAL WAVE ALONG 82W/84W SOUTH OF 18N
MOVING WEST 15-20 KT. SHOWERS AND THUNDERSTORMS IN WESTERN
TWO-THIRDS OF NICARAGUA...IN WESTERN COSTA RICA...AND IN EASTERN
AND WESTERN HONDURAS JUST MIGHT BE RELATED TO DIURNAL HEATING...
NOT NECESSARILY JUST ASSOCIATED WITH THE WAVE.

...ITCZ...
ITCZ LEAVES AFRICA IN SOUTHERN SENEGAL ALONG 16W/17W TO 8N32W
TO 6N40W TO 8N50W TO THE NORTHEASTERN VENEZUELA COAST NEAR
10N62W. ISOLATED MODERATE TO LOCALLY STRONG SHOWERS AND
THUNDERSTORMS WITHIN 120 TO 180 NM ON EITHER SIDE OF AXIS EAST
OF 30W.

...DISCUSSION...
GULF OF MEXICO...
UPPER LEVEL SOUTHWESTERLY WIND FLOW RUNS FROM NORTH CENTRAL
MEXICO...THROUGH CENTRAL TEXAS AND BEYOND NORTHEAST TEXAS.
BROAD CYCLONIC FLOW COVERS THE GULF WATERS. WEAK SURFACE
PRESSURE GRADIENT. ISOLATED MODERATE TO LOCALLY STRONG SHOWERS
AND THUNDERSTORMS FROM THE GULF WATERS NEAR 26N NORTHWARD
BETWEEN 86W AND 99W. A SURFACE COLD FRONT IS MOVING THROUGH
NORTHEASTERN TEXAS...OUTFLOW BOUNDARIES ARE TO ITS EAST AND
SOUTHEAST. MILD 1017 MB SURFACE HIGH PRESSURE CENTER NEAR
24N89W IN THE CENTRAL GULF OF MEXICO.

CARIBBEAN SEA...
MIDDLE TO UPPER LEVEL TROUGH COVERS THE AREA EAST OF 80W WITH
THE BASE NEAR 13N74W. UPPER LEVEL NORTHWESTERLY WIND FLOW COVERS
THE AREA WEST OF 80W. STRONG SHOWERS/THUNDERSTORMS JUST NORTH OF
PUERTO RICO BETWEEN 66W AND 67W...OVER NORTHWESTERN DOMINICAN
REPUBLIC AND EASTERN HAITI...AND ON CARIBBEAN SIDE OF
SOUTHEASTERN END OF CUBA BETWEEN 76W AND 79W.

SUBTROPICAL ATLANTIC OCEAN...
TROPICAL STORM GASTON IS OFF THE SOUTH CAROLINA COAST.
AN 1013 MB LOW PRESSURE CENTER IS ABOUT 200 NM SOUTHWEST OF
BERMUDA. THIS SYSTEM COULD BECOME A TROPICAL DEPRESSION DURING
THE NEXT 24 HOURS. MIDDLE TO UPPER LEVEL TROUGH FROM A CYCLONIC
CIRCULATION CENTER NEAR 37N37W...TO 32N34W AND 21N31W...WITH THE
PART SOUTH OF 33N EMBEDDED IN MIDDLE TO UPPER LEVEL DRY AIR.
SURFACE RIDGE 17N43W TO 24N42W BEYOND 32N38W. ONE MIDDLE TO
UPPER LEVEL CYCLONIC CENTER IS NEAR 27N62W WHILE ANOTHER ONE
IS NEAR 27N71W. THE UPPER LEVEL ANTICYCLONIC OUTFLOW FROM
T.S. GASTON IS BEING FED INTO THE CYCLONIC FLOW AROUND THE
27N71W CYCLONIC CENTER.

TROPICAL ATLANTIC...
HURRICANE FRANCES CONTINUES TO BE THE MAIN WEATHER MAKER IN THE
DEEP TROPICS. BROAD UPPER LEVEL ANTICYCLONIC FLOW NORTH OF 15N
EAST OF 30W.

$$
MT



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