[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 111803
TWDAT

TROPICAL WEATHER DISCUSSION...AMENDED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED 11 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
1715 UTC.

...SPECIAL FEATURES...

TROPICAL STORM BONNIE IS CENTERED NEAR 26.2N 89.5W..AT 11/1800
UTC...OR ABOUT 205 MILES SOUTH OF THE MOUTH OF THE MISSISSIPPI
RIVER.  BONNIE IS MOVING NNE 10 KT. MAXIMUM SUSTAINED WIND SPEED
IS 55 KT WITH GUSTS TO 65 KT AND THE ESTIMATED MINIMUM CENTRAL
PRESSURE 1000 MB.  SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/
WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. AFTER
DISPLAYING A RATHER POOR SATELLITE SIGNATURE OVER THE LAST FEW
DAYS...A BURST OF DEEP CONVECTION OCCURRED NEAR THE CENTER THIS
MORNING WITH NUMEROUS MODERATE ACTIVITY CURRENTLY FROM 25N-27N
BETWEEN 88W-91W.  WHILE CLOUD TOPS ASSOCIATED WITH THIS ACTIVITY
HAVE BEEN WARMING DURING THE LAST FEW HOURS...VISIBLE SATELLITE
IMAGERY DOES SHOW IMPROVEMENT IN STRUCTURE. UPPER-LEVEL OUTFLOW
ALSO APPEARS TO BE IMPROVING OVER THE SE SEMI-CIRCLE BUT REMAINS
SOMEWHAT RESTRICTED OVER THE W SEMI-CIRCLE. MOTION-WISE...BONNIE
NOW APPEARS TO BE FEELING THE EFFECTS OF THE AMPLIFYING
MID-LATITUDE SHORTWAVE TROUGH OVER THE CENTRAL AND E UNITED
STATES.  THE TROUGH IS IMPARTING A MORE NWD MOTION AND BONNIE IS
NOW ACCELERATING. IN ADDITION TO CONVECTION NEAR THE CENTER OF
BONNIE...SHOWERS/THUNDERSTORMS ARE DEVELOPING AHEAD OF THE
SYSTEM ALONG THE N GULF COAST FROM SE LOUISIANA TO THE FLORIDA
BIG BEND AREA.

TROPICAL STORM CHARLEY HAS BEEN UPGRADED TO A HURRICANE AT 1800
UTC CENTERED NEAR 16.5N 76.1W...OR ABOUT 110 MILES
EAST-SOUTHEAST OF KINGSTON JAMAICA. THE FORWARD MOTION HAS
DECREASED DURING THE LAST FEW HOURS WITH CHARLEY NOW MOVING
WEST-NORTHWEST AT 16 KT. MAXIMUM SUSTAIN WIND SPEED IS 65 KT
WITH GUSTS TO 80 KT AND THE ESTIMATED MINIMUM CENTRAL PRESSURE
993 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. LATEST VISIBLE SATELLITE
IMAGERY REVEALS AN IMPROVING STRUCTURE WITH INDICATION OF A
BANDING EYE FEATURE FORMING. THE STORM IS FAVORABLY SITUATED E
OF A MID/UPPER LEVEL LOW OVER THE NW CARIBBEAN WHICH IS MOVING
WESTWARD IN TANDEM WITH CHARLEY.  AS A RESULT...THE UPPER LEVEL
PATTERN REMAINS FAVORABLE FOR INTENSIFICATION WITH GOOD OUTFLOW
AND LOW SHEAR. ASSOCIATED CONVECTION IS NOW RAPIDLY
OVERSPREADING JAMAICA WITH NUMEROUS STRONG ACTIVITY LOCATED FROM
15.5N-19N BETWEEN 74W-78W.  WHILE THE CENTER OF CHARLEY IS
EXPECTED TO PASS JUST S OF JAMAICA...HEAVY RAINS AND GUSTY
WINDS WILL AFFECT MUCH OF THE ISLAND TODAY AND TONIGHT.

...TROPICAL WAVES...

CENTRAL ATLANTIC TROPICAL WAVE ALONG 45W SOUTH OF 16N MOVING
WEST NEAR 15 KT. NO SIGNIFICANT CONVECTION IS NOTED WITH THIS
WAVE.

TROPICAL WAVE OVER CENTRAL AMERICA NEAR GUATEMALA ALONG 90W
SOUTH OF 20N MOVING WEST 15 TO 20 KT. THIS WAVE IS WITHIN AN
AREA OF MIDDLE TO UPPER LEVEL SUBSIDENCE AND DRY AIR.  NO
SIGNIFICANT CONVECTION IS NOTED.

...ITCZ...

ITCZ AXIS EMERGES OFF THE COAST AFRICA NEAR 10N10W TO 10N30W
12N70W 13N45W 6N60W 9N80W. AREA OF SCATTERED STRONG CONVECTION
MOVING OFF THE W COAST OF AFRICA FROM 7N-11N BETWEEN 8W-15W.
SCATTERED MODERATE CONVECTION FROM 6N-9N BETWEEN 23W-29W. WIDELY
SCATTERED MODERATE CONVECTION FROM 6N-12N BETWEEN 30W-38W.

...DISCUSSION...

GULF OF MEXICO...
THE BIGGEST WEATHER MAKER IS TROPICAL STORM BONNIE IN THE
CENTRAL GULF OF MEXICO.  BONNIE IS SHOWING SIGNS OF INTENSIFYING
AS IT INTERACTS WITH A SHORTWAVE TROUGH DIGGING SEWD OVER THE
CENTRAL UNITED STATES. THE SHORTWAVE TROUGH IS EXPECTED TO CAUSE
BONNIE TO ACCELERATE NEWD TOWARD THE FLORIDA PANHANDLE DURING
THE NEXT 12-24 HOURS.  FURTHER S...A SHARP MID/UPPER LEVEL RIDGE
EXTENDS FROM CENTRAL MEXICO SEWD OVER THE CENTRAL GLFMEX ALONG
24N. MID/UPPER LEVEL SUBSIDENCE AND DRY AIR S OF THE RIDGE IS
CAPPING SIGNIFICANT CONVECTIVE ACTIVITY.  AT THE SURFACE...WEAK
LOW LEVEL TROUGH EXTENDS ACROSS THE N GLFMEX FROM THE FLORIDA
PANHANDLE SW TO THE S TIP OF TEXAS. SCATTERED SHOWERS/
THUNDERSTORMS ARE DEVELOPING ALONG THE TROUGH...ESPECIALLY FROM
THE SE TIP OF LOUISIANA EWD TO THE FLORIDA BIG BEND...AS
TROPICAL MOISTURE SURGES NWD WITH BONNIE. STRONG SHOWERS/
THUNDERSTORMS AND LOCALLY HEAVY RAINFALL WILL LIKELY BECOME MORE
NUMEROUS WITHIN THIS REGION TODAY AND TONIGHT AS BONNIE
APPROACHES.  AN UNSEASONABLY STRONG COLD FRONT CURRENTLY
POSITIONED OVER TEXAS WILL BE SWEPT QUICKLY SEWD INTO THE NW
GLFMEX TOMORROW AS BONNIE ACCELERATES NEWD.

CARIBBEAN SEA...
HURRICANE CHARLEY CONTINUES TO STRENGTHEN OVER THE CENTRAL
CARIBBEAN AS IT MOVES IN TANDEM WITH A MID/UPPER LEVEL LOW
ROUGHLY HALFWAY IN BETWEEN JAMAICA THE THE YUCATAN PENINSULA
NEAR 19N84W.  WHILE SUBSIDENCE AND DRY AIR ASSOCIATED WITH THE
UPPER LOW IS CURRENTLY PRODUCING FAIR WEATHER OVER THE NW
CARIBBEAN...THE CAYMAN ISLANDS...AND W CUBA...THIS WILL QUICKLY
GIVE WAY TO HURRICANE CHARLEY IS IT MOVES RAPIDLY WESTWARD.  E
OF CHARLEY...MID/UPPER LEVEL RIDGE IS BUILDING FROM THE SE
CARIBBEAN TO W HISPANIOLA. MOISTURE IS LIMITED E OF 70W WITH
VERY LITTLE IN WAY OF SIGNIFICANT CLOUDS/CONVECTION.  WATER
VAPOR IMAGERY INDICATES A DIGGING TROUGH OVER THE CENTRAL ATLC
WITH ASSOCIATED SUBSIDENCE NOW ENTERING THE EXTREME NE
CARIBBEAN. THIS SHOULD FURTHER CAP TYPICAL CONVECTION OVER THE
AREA.

SUBTROPICAL ATLANTIC...
THE SUBTROPICAL ATLC FEATURES A MID TO UPPER LEVEL
RIDGE-TROUGH-RIDGE PATTERN WITH AN E/W ORIENTED RIDGE OVER THE W
ATLC FROM THE BAHAMAS TO 20N60W...MID-OCEANIC TROUGH EXTENDING
FROM 32N42W SW TO THE LESSER ANTILLES...AND BROAD RIDGE OVER THE
E ATLC ALONG 21N/22N. MID/UPPER LEVEL MOISTURE IS PRIMARILY
RIDING UP AND OVER THE W ATLC RIDGE LEAVING A GOOD PORTION OF
THE AREA W OF 60W UNDER SUBSIDENCE AND DRY/TRANQUIL CONDITIONS.
OVER THE CENTRAL ATLC...INSTABILITY ASSOCIATED WITH A COLD CORE
LOW NEAR 24N50W IS SPARKING A FEW SHOWERS/THUNDERSTORMS ALONG A
REMNANT FRONTAL TROUGH STRETCHING FROM 30N50W TO 25N60W.  OVER
THE E ATLC...STRONG SUBSIDENCE E OF THE MID-OCEANIC TROUGH
DOMINATES THE ENTIRE AREA LIMITING SIGNIFICANT
CLOUDS/CONVECTION. AT THE SURFACE...SUBTROPICAL RIDGE EXTENDS
FROM A 1025 MB HIGH NEAR 33N30W SW TO 26N50W. RIDGE BECOMES
DISRUPTED BY A REMNANT FRONTAL TROUGH ALONG 30N50W-25N60W THEN
BECOME RE-ESTABLISHED OVER THE W ATLC ALONG 26N WESTWARD OVER
CENTRAL FLORIDA.

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

$$
RHOME





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