[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 120010 AAA
TWDAT

TROPICAL WEATHER DISCUSSION...AMENDED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED 11 AUG 2004

AMENDED TO INCLUDE THE 12/0000 POSITION FOR T.S. BONNIE

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...

TROPICAL STORM BONNIE CENTER 27.1N 88.7W...OR ABOUT 140 MILES
SOUTH OF THE MOUTH OF THE MISSISSIPPI RIVER. THIS IS ALSO ABOUT
295 MILES SOUTHWEST OF APALACHICOLA FLORIDA...AT 12/0000 UTC.
IT IS MOVING NORTHEAST 10 KT. MAXIMUM SUSTAINED WIND SPEED 55 KT
GUSTS 65 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 1001 MB. SEE
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. NUMEROUS STRONG SHOWERS
AND THUNDERSTORMS FROM 25.5N TO 27.5N BETWEEN 87W AND 89W. OTHER
SHOWERS STRETCH FROM 27.5N TOWARD 30N BETWEEN 87W AND 90W. AN
UPPER LEVEL RIDGE STILL IS ON TOP OF T.S. BONNIE. AN UPPER LEVEL
TROUGH IS REACHING THE NORTHWEST GULF OF MEXICO...APPROACHING
T.S. BONNIE. THIS TROUGH IS SET TO STEER T.S. BONNIE TO THE
NORTHEAST. 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.

HURRICANE CHARLEY CENTER 17.2N 78.2W...OR ABOUT 250 MILES/400 KM
SOUTHEAST OF GRAND CAYMAN...OR ABOUT 140 MILES/220 KM
WEST-SOUTHWEST OF KINGSTON JAMAICA. IT IS MOVING WEST-NORTHWEST
15 KT. MAXIMUM SUSTAIN WIND SPEED 65 KT GUSTS 80 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE 993 MB. SEE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE
DETAILS. THERE IS AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IN
THE NORTHWESTERN CARIBBEAN SEA...AND THE CYCLONIC FLOW AROUND
THIS CENTER PROBABLY HAS BEEN LIMITING THE UPPER LEVEL
ANTICYCLONIC OUTFLOW TO THE SOUTHWEST OF HURRICANE CHARLEY. THIS
OUTFLOW NOW REACHES AS FAR NORTH AS THE BAHAMAS NEAR
25N78W...CURVING TOWARD THE EASTERN DOMINICAN REPUBLIC...AND
REACHING THE SHORES OF COLOMBIA. NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS FROM 17N TO 19N BETWEEN 76W AND 78W. SIMILAR
SHOWERS/THUNDERSTORMS ARE APPROACHING AND REACHING THE
SOUTHEASTERN COAST OF CUBA NEAR 20N77W. NUMEROUS STRONG SHOWERS
AND THUNDERSTORMS ALSO ARE ALONG THE CUBA COAST FROM 21N TO 23N
BETWEEN 77W AND 79W.

...TROPICAL WAVES...

CENTRAL ATLANTIC TROPICAL WAVE ALONG 45W/46W SOUTH OF 17N MOVING
WEST ABOUT 15 KT. ISOLATED MODERATE SHOWERS AND LOCALLY STRONG
THUNDERSTORMS IN THE ITCZ FROM 11N TO 13N BETWEEN 43W AND 48W.

TROPICAL WAVE OVER CENTRAL AMERICA...MOVING THROUGH WESTERN
GUATEMALA...ALONG 91W SOUTH OF 18N MOVING WEST 15 TO 20 KT.
MIDDLE TO UPPER LEVEL DRY AIR COVERS THE NORTHERN HALF OF
GUATEMALA. SHOWERS AND THUNDERSTORMS STRETCH FROM SOUTHWESTERN
GUATEMALA TO THE ISTHMUS OF TEHUANTEPEC OF MEXICO TO THE NORTH
OF A WEAK MIDDLE TO UPPER LEVEL TROUGH ALONG 93W/94W...MOSTLY
IN THE EASTERN PACIFIC OCEAN SOUTH OF MEXICO.

...ITCZ...

ITCZ 10N10W 10N30W 12N70W 13N45W 6N60W 9N80W. NUMEROUS STRONG
SHOWERS AND THUNDERSTORMS ALONG AFRICA COAST FROM 8N TO 10N
BETWEEN 12W AND 16W...PROBABLY WITH THE NEXT AFRICAN EASTERLY
WAVE. SCATTERED STRONG SHOWERS AND THUNDERSTORMS WITHIN 30 TO
40 NM ON EITHER SIDE OF 10N26W 8N28W 6N29W. ISOLATED MODERATE
SHOWERS AND LOCALLY STRONG THUNDERSTORMS FROM 6N TO 14N BETWEEN
30W AND 40W. ISOLATED MODERATE SHOWERS...SOME DISSIPATING WITH
TIME...FROM 9N TO 12N BETWEEN 50W AND 60W.

...DISCUSSION...

THE GULF OF MEXICO...
TROPICAL STORM BONNIE IS IN THE NORTH CENTRAL GULF OF MEXICO.
AN UPPER LEVEL RIDGE IS IN PLACE OVER BONNIE. A SHORTWAVE
TROUGH IS MOVING INTO THE NORTHWESTERN GULF OF MEXICO AT THIS
TIME...FORECAST TO MOVE T.S. BONNIE NORTHEASTWARD WITH TIME.
THE UPPER LEVEL TROUGH WHICH WILL PLAY A ROLE IN THE FUTURE
MOVEMENT OF T.S. BONNIE IS SUPPORTING A SURFACE COLD FRONT...
NOW MOVING INTO SOUTH CENTRAL TEXAS. NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS ARE OCCURRING IN NORTHEASTERN MEXICO JUST SOUTH OF
THE LOWER RIO GRANDE VALLEY OF TEXAS...IN AN AREA OF UPPER LEVEL
DIFFLUENT FLOW...FROM 23N TO 26N BETWEEN 97W AND 100W. A SURFACE
TROUGH RUNS FROM SOUTHEASTERN GEORGIA...TO THE NORTHEASTERN GULF
OF MEXICO WATERS NEAR 29N86W...TO 27N91W. BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND MODERATE SHOWERS ARE NORTH OF 28N EAST
OF 90W. SHOWERS AND THUNDERSTORMS ARE IN SOUTH FLORIDA...SOUTH
OF 27N...AND MOVING OFFSHORE IN NORTHEASTERN FLORIDA...FROM
29N TO 30N BETWEEN 80W AND 81W.

THE CARIBBEAN SEA...
JAMAICA NOW IS COVERED BY NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS FROM HURRICANE CHARLEY. AN AREA OF SHOWERS IS
APPROACHING CUBA FROM THE SOUTH...WHILE CUBA ON THE ATLANTIC
OCEAN SIDE BETWEEN 77W AND 80W ALREADY IS EXPERIENCING NUMEROUS
STRONG SHOWERS AND THUNDERSTORMS. AN UPPER LEVEL CYCLONIC
CIRCULATION CENTER IS IN THE NORTHWESTERN CORNER OF THE AREA...
WITH A TROUGH EXTENDING FROM THE CENTER NEAR 20N84W TOWARD THE
GULF OF HONDURAS. WARMING CLOUD TOP TEMPERATURES AND DISSIPATING
SHOWER ACTIVITY IS OFF THE WESTERN TIP OF CUBA. MIDDLE TO UPPER
LEVEL DRY AIR REMAINS IN THE NORTHWESTERN CARIBBEAN SEA IN THE
AREA OF THE CYCLONIC CENTER AND TROUGH. A COMPARATIVELY
SMALLER-IN-SIZE AND WEAKER-IN-CIRCULATION CYCLONIC CENTER IS
ON TOP OF EL SALVADOR. SCATTERED TO NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS ARE IN HONDURAS AND NICARAGUA FROM 13N TO 16N
BETWEEN 83W AND 87W. COLD CLOUD TOP TEMPERATURES OF -77C WITH
TOPS NEAR 48000 FEET AND STRONG SHOWERS AND THUNDERSTORMS ARE
ON TOP OF LAKE MARACAIBO IN NORTHWESTERN VENEZUELA...POSSIBLY
WITH LATE AFTERNOON HEATING AND POSSIBLY WITH THE ITCZ. ISOLATED
MODERATE TO LOCALLY STRONG SHOWERS IN THE SOUTHWESTERN CORNER
OVER PANAMA...FROM 8N TO 10N BETWEEN 78W AND 82W...WITH THE ITCZ.

THE SUBTROPICAL ATLANTIC OCEAN...
BROAD UPPER LEVEL ANTICYCLONIC FLOW IS IN THE ATLANTIC NORTH OF
20N BETWEEN 55W AND 80W. MIDDLE TO UPPER LEVEL DRY AIR WITHIN
400 NM EAST OF THE LINE FROM GRENADA...IN THE SOUTHEASTERN
CARIBBEAN SEA...TO THE NORTHERN BAHAMAS. 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. SURFACE 1013 MB LOW PRESSURE CENTER NEAR 34N70W.
COLD FRONT FROM THIS LOW CENTER TO 31N68W. STATIONARY FRONT
31N68W TO 30N76W. ISOLATED MODERATE SHOWERS WERE SEEN FROM 29N
TO 31N BETWEEN 65W AND 75W. BROAD UPPER LEVEL ANTICYCLONIC FLOW
AND MIDDLE TO UPPER LEVEL DRY AIR COVER THE REST OF THE
SUBTROPICAL ATLANTIC OCEAN. SURFACE TROUGH...FROM AN 1016 MB
LOW PRESSURE CENTER NEAR 33N49W...TO 27N53W TO 24N60W. THIS
TROUGH IS IN THE MIDDLE OF BROAD SURFACE ANTICYCLONIC FLOW.

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.

$$
MT



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