[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 120621
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 0515 UTC.

...SPECIAL FEATURES...

TROPICAL STORM BONNIE IS CENTERED NEAR 27.7N 88.2W...OR ABOUT
240 MILES SOUTHWEST OF APALACHICOLA FLORIDA...AT 12/0600 UTC. IT
IS MOVING NORTHEAST 10 KT. MAXIMUM SUSTAINED WIND SPEED IS 50 KT
GUSTS 60 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 1007 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 RISEN...HOWEVER
CONVECTION HAS SLIGHTLY INCREASED. 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. THE UPPER LEVEL
WIND SHEAR IS EXPECTED TO HOLD OFF JUST ENOUGH SO THAT T.S.
BONNIE MAY REACH THE LEVEL OF A CATEGORY ONE HURRICANE BEFORE
LANDFALL.  NUMEROUS STRONG CONVECTION IS FROM 26N-29N BETWEEN
86W-88W.

HURRICANE CHARLEY IS CENTERED NEAR 18.0N 79.2W...OR ABOUT 165
MILES/265 KM EAST SOUTHEAST OF GRAND CAYMAN...AT 12/0600 UTC. IT
IS MOVING WEST-NORTHWEST 15 KT. MAXIMUM SUSTAIN WIND SPEED IS 65
KT GUSTS 80 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 989 MB. SEE
LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. CHARLEY CONTINUES TO
AFFECT JAMAICA 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 17N-20N
BETWEEN 76W-81W.

...TROPICAL WAVES...

CENTRAL ATLANTIC TROPICAL WAVE IS ALONG 46W/47W SOUTH OF 17N
MOVING WEST ABOUT 15 KT. SCATTERED MODERATE CONVECTION IS ALONG
THE ITCZ FROM 12N-14N BETWEEN 47W-48W.

TROPICAL WAVE IS OVER CENTRAL AMERICA...MOVING THROUGH SOUTHERN
MEXICO...ALONG 92W/93W SOUTH OF 18N MOVING WEST 15-20 KT.  NO
SIGNIFICANT CONVECTION IS NOTED.

...ITCZ...

ITCZ AXIS IS ALONG 16N1W 10N15W 12N45W 9N80W. NUMEROUS STRONG
CONVECTION IS ALONG THE COAST OF AFRICA FROM 9N-11N BETWEEN
13W-17W.  SCATTERED MODERATE CONVECTION IS FURTHER S FROM 6N-8N
BETWEEN 11-16W.  SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS FROM 5N-11N 29W-33W.  ISOLATED MODERATE CONVECTION
IS FROM 10N-12N BETWEEN 37W-40W.

...DISCUSSION...

THE GULF OF MEXICO...
SEE TROPICAL STORM BONNIE ABOVE.  IN ADDITION A WEAK 1013 MB
HIGH IS OVER THE W GULF OF MEXICO NEAR 22N95W.  IN THE UPPER
LEVELS...A LONG WAVE TROUGH IS DIPPING INTO THE NW GULF OF
MEXICO N OF 26N AND W OF 88W MOVING E.  A SMALL ANTICYCLONIC
CIRCULATION IS OVER BONNIE FROM 25N-32N BETWEEN 80W-88W.
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 WITH TIME.

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 70W-82W.  A CYCLONIC CIRCULATION IS OVER
THE NW CARIBBEAN...W OF CHARLEY WITH CENTER NEAR 20N85W.
CYCLONIC FLOW AND SUBSIDENCE IS FROM 17W-24W BETWEEN 82W-88W.
THE TWO UPPER LEVEL SYSTEMS ARE MOVING W IN TANDEM.

THE SUBTROPICAL ATLANTIC OCEAN...
1020 MB HIGH IS OVER THE W ATLANTIC NEAR 26N66W.  A 1018 MB LOW
IS OVER THE CENTRAL ATLANTIC NEAR 34N48W.  A TROUGH EXTENDS SW
FROM THIS LOW TO 27N53W 24N58W.  A 1025 MB HIGH IS OVER THE E
ATLANTIC NEAR 34N29W.  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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