[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 121047
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU 12 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 0600 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 1015 UTC.

...SPECIAL FEATURES...

TROPICAL STORM BONNIE IS CENTERED NEAR 28.4N 87.5W...OR ABOUT
175 MILES... 285 KM...WEST-SOUTHWEST OF APALACHICOLA FLORIDA
...AT 12/0900 UTC. IT IS MOVING NORTHEAST 14 KT. MAXIMUM
SUSTAINED WIND SPEED IS 45 KT GUSTS 55 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE 1010 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. BONNIE
IS A SMALL AND COMPACT STORM.  PRESSURES HAVE RECENTLY STARTED
TO FALL AGAIN...AND CONVECTION HAS INCREASED MOSTLY E OF THE
CENTER. AN UPPER LEVEL TROUGH IS APPROACHING T.S. BONNIE. THIS
TROUGH IS SET TO STEER T.S. BONNIE TO THE NORTHEAST TOWARDS THE
FLORIDA PANHANDLE.  NUMEROUS STRONG CONVECTION IS FROM 27N-30N
BETWEEN 85W-87W.  IN ADDITION...SCATTERED MODERATE CONVECTION
EXTENDS FROM 26N-31N BETWEEN 84W-88W.

HURRICANE CHARLEY IS CENTERED NEAR 18.6N 79.9W...OR ABOUT 100
MILES... 155 KM... EAST-SOUTHEAST OF GRAND CAYMAN...AT 12/0900
UTC. IT IS MOVING NORTHWEST 14 KT. MAXIMUM SUSTAIN WIND
SPEED IS 75 KT GUSTS 90 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
986 MB. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. CHARLEY IS NOW
AFFECTING BOTH JAMAICA AND THE CAYMAN ISLANDS WITH TROPICAL
STORM FORCE WINDS IN SQUALLS.  THE UPPER LEVEL OUTFLOW IS MOST
PRONOUNCED OVER THE EAST SEMICIRCLE.  CONDITIONS APPEAR TO BE
FAVORABLE FOR INTENSIFICATION.  NUMEROUS STRONG CONVECTION IS
FROM 18N-21N BETWEEN 78W-81W.  IN ADDITION...SCATTERED MODERATE
CONVECTION IS FROM 17N-22N BETWEEN 77W-83W.

...TROPICAL WAVES...

TROPICAL WAVE IS INTRODUCED ALONG THE COAST OF W AFRICA ALONG
16W SOUTH OF 18N MOVING WEST ABOUT 15 KT.  A 1008 MB LOW IS
FOUND ON THE WAVE AXIS NEAR 15N16W.  SCATTERED MODERATE TO
STRONG CONVECTION IS NOTED S OF THE LOW CENTER FROM 7N-12N
BETWEEN 13W-18W.

ANOTHER TROPICAL WAVE IS INTRODUCED ALONG 31W SOUTH OF 16N
MOVING WEST ABOUT 20 KT.  SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS FROM 6N-12N BETWEEN 31W-36W.

CENTRAL ATLANTIC TROPICAL WAVE IS ALONG 48W SOUTH OF 17N MOVING
WEST ABOUT 15 KT. SCATTERED MODERATE CONVECTION IS ALONG THE
ITCZ FROM 12N-14N BETWEEN 48W-50W.

TROPICAL WAVE IS OVER CENTRAL AMERICA...MOVING THROUGH SOUTHERN
MEXICO...ALONG 94W SOUTH OF 18N MOVING WEST 15 KT.  SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS FROM 15N-18N BETWEEN
93W-96W.

...ITCZ...

ITCZ AXIS IS ALONG 16N1W 12N15W 10N40W 9N60W 10N80W. NUMEROUS
STRONG CONVECTION IS ALONG THE COAST OF AFRICA FROM 9N-11N
BETWEEN 13W-17W. IN ADDITION TO CONVECTION NOTED WITH TROPICAL
WAVES...ISOLATED MODERATE CONVECTION IS FROM 9N-12N BETWEEN
37W-41W.

...DISCUSSION...

THE GULF OF MEXICO...
SEE TROPICAL STORM BONNIE ABOVE.  IN ADDITION A STATIONARY FRONT
IS OVER LOUISIANA AND S TEXAS ALONG 32N91W 28N96W 29N100W.  IN
THE UPPER LEVELS...A LONG WAVE TROUGH IS DIPPING INTO THE NW
GULF OF MEXICO N OF 26N AND W OF 90W MOVING E.  A SMALL
ANTICYCLONIC CIRCULATION IS OVER BONNIE FROM 25N-32N BETWEEN
80W-90W.  ANOTHER ANTICYCLONIC CIRCULATION IS OVER MEXICO AND
THE W GULF OF MEXICO FROM 15N-26N BETWEEN 94W-110W.  THE LONG
WAVE TROUGH IS FORECAST TO MOVE T.S. BONNIE NORTHEASTWARD TODAY.

THE CARIBBEAN SEA...
HURRICANE CHARLEY IS THE MAIN FEATURE IN THE CARIBBEAN.  SEE
ABOVE.  IN THE UPPER LEVELS...ANTICYCLONIC FLOW IS ABOVE CHARLEY
FROM 10N-26N BETWEEN 72W-83W.  A CYCLONIC CIRCULATION IS OVER
THE NW CARIBBEAN...W OF CHARLEY WITH CENTER NEAR 20N85W.
CYCLONIC FLOW AND SUBSIDENCE IS FROM 16W-25W BETWEEN 83W-90W.
THE TWO UPPER LEVEL SYSTEMS ARE MOVING W IN TANDEM.

THE SUBTROPICAL ATLANTIC OCEAN...
A 1018 MB LOW IS OVER THE CENTRAL ATLANTIC NEAR 33N48W.  A
STATIONARY FRONT EXTENDS SW FROM THIS LOW TO 31N60W 24N58W.  A
1025 MB HIGH IS OVER THE E ATLANTIC NEAR 33N29W.  IN THE UPPER
LEVELS...BROAD UPPER LEVEL ANTICYCLONIC FLOW IS IN THE ATLANTIC
NORTH OF 20N BETWEEN 55W-80W. MIDDLE OCEANIC TROUGH EXTENDS FROM
32N42W SOUTHWESTWARD TO THE LESSER ANTILLES...TO A COLD CORE
CYCLONIC CIRCULATION CENTER NEAR 24N51W...TO THE LESSER ANTILLES
NEAR GUADELOUPE. NO DEEP THUNDERSTORMS ARE NEAR THIS FEATURE.
BROAD UPPER LEVEL ANTICYCLONIC FLOW AND MIDDLE TO UPPER LEVEL
DRY AIR COVERS THE REST OF THE SUBTROPICAL ATLANTIC OCEAN.

THE TROPICAL ATLANTIC OCEAN...
WELL-DEFINED MIDDLE TO UPPER LEVEL RIDGE STRETCHES ACROSS THE
EASTERN HALF OF THE TROPICAL ATLC ALONG 20N/21N EAST OF 40W.
MIDDLE TO UPPER LEVEL TROUGH OVER THE CENTRAL ATLANTIC OCEAN
DISRUPTS THE WESTERN EXTENT OF THE RIDGE IN THE VICINITY OF
THE LESSER ANTILLES. DEEP EASTERLY FLOW PREVAILS S OF 20N
EAST OF 40W.

$$
FORMOSA


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