[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 121850 CCA
TWDAT

TROPICAL WEATHER DISCUSSION...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU 12 AUG 2004

...CORRECTED FOR ADVISORY TIMES...

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
1740 UTC.

...SPECIAL FEATURES...

TROPICAL STORM BONNIE IS CENTERED NEAR 30.0N 84.0W...OR ABOUT 30
MILES SOUTHEAST OF TALLAHASSEE FLORIDA...AT 12/1800 UTC. BONNIE
IS NOW MOVING NORTHEAST 24 KT. MAXIMUM SUSTAINED WIND SPEED IS
35 KT GUSTS TO 45 KT AND THE ESTIMATED MINIMUM CENTRAL PRESSURE
IS 1005 MB. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. AFTER MAKING
LANDFALL OVER THE FLORIDA PANHANDLE NEAR APALACHICOLA EARLIER
TODAY...SATELLITE IMAGERY SUGGEST THAT BONNIE IS BECOMING LESS
ORGANIZED WITH AN INCREASINGLY SW/NE ELONGATED CLOUD STRUCTURE.
THIS PATTERN INDICATES THAT BONNIE IS LOSING TROPICAL
CHARACTERISTICS AND BEGINNING EXTRATROPICAL TRANSITION.  BONNIE
IS EXPECTED TO MERGE WITH A MID-LATITUDE FRONTAL BOUNDARY OVER
THE SE UNITED STATES AS SHE ACCELERATES NEWD. HOWEVER...ABUNDANT
TROPICAL MOISTURE  SURGING NWD CONTINUES TO GENERATE SCATTERED
TO LOCALLY NUMEROUS SHOWERS/THUNDERSTORMS OVER THE SE UNITED
STATES FROM THE CAROLINAS SWD TO N FLORIDA.  ADDITIONALLY...A
LOW LEVEL TROUGH TRAILING SW INTO THE CENTRAL GLFMEX IS
SUPPORTING WIDELY SCATTERED SHOWERS/THUNDERSTORMS WITHIN 100 NM
EITHER SIDE OF A LINE FROM 30N83W TO 26N93W.

HURRICANE CHARLEY IS CENTERED NEAR 20.4N 81.5W AT 1800 UTC OR
ABOUT 190 MILES SOUTH-SOUTHEAST OF HAVANA CUBA. CHARLEY
CONTINUES TO MOVE NORTHWEST AT 15 KT. MAXIMUM SUSTAIN WIND SPEED
HAVE INCREASED TO 90 KT WITH GUSTS 105 KT AND THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 980 MB. SEE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE
DETAILS. LATEST VISIBLE SATELLITE IMAGERY DEPICTS AN
INTENSIFYING CYCLONE WITH AN EYE FEATURE NOW APPARENT AND UPPER
LEVEL OUTFLOW EXPANDING WESTWARD. THE MID/UPPER LEVEL LOW WHICH
WAS RESTRICTING OUTFLOW TO THE WEST IS RETREATING WSW TOWARD THE
YUCATAN PENINSULA AND UW-CIMSS SATELLITE DERIVED WINDS NOW SHOW
A WELL DEVELOPED RIDGE OVER CHARLEY EXTENDING FROM E CUBA SWD TO
COLOMBIA.  THIS IS TYPICALLY A FAVORABLE REGIME FOR
INTENSIFICATION AND CHARLEY IS CURRENTLY MOVING OVER VERY WARM
WATER. THE NHC FORECAST CALLS FOR FURTHER INTENSIFICATION AS
CHARLEY APPROACHES W CUBA.  ASSOCIATED CONVECTION IS NOW QUICKLY
DEPARTING THE CAYMAN ISLAND AND SPREADING RAPIDLY NWD OVER W
CUBA FROM 20N-23N BETWEEN 79W-83W.  LOCALLY HEAVY RAINFALL AND
SQUALLY CONDITIONS WILL LIKELY AFFECT THIS REGION TODAY AS THE
CYCLONE APPROACHES.

...TROPICAL WAVES...

TROPICAL WAVE EMERGING OFF THE WEST COAST OF AFRICA ALONG 17W
SOUTH OF 18N MOVING WEST ABOUT 15 KT.  A 1010 MB LOW IS ANALYZED
WITH THE WAVE NEAR 15N.  THIS SYSTEM DISPLAYS A RATHER
IMPRESSIVE SATELLITE SIGNATURE WITH A MID-LEVEL CIRCULATION NEAR
12N AND   SCATTERED MODERATE TO STRONG CONVECTION FROM 9N-13N
BETWEEN 14W-21W.

TROPICAL WAVE OVER THE CENTRAL ATLC ALONG 34W SOUTH OF 16N
MOVING WEST ABOUT 20 KT. A DISORGANIZED AREA OF SCATTERED
MODERATE CONVECTION LIES W OF THE WAVE AXIS FROM 6N-12N BETWEEN
34W-42W. THERE ARE NO IMMEDIATE SIGNS OF DEVELOPMENT.

TROPICAL WAVE APPROXIMATELY 600 NM E OF BARBADOS ALONG 50W SOUTH
OF 17N MOVING WEST ABOUT 15 KT. THE WAVE IS NOT WELL DEFINED IN
SATELLITE IMAGERY WITH ONLY ISOLATED SHOWERS/THUNDERSTORMS.

TROPICAL WAVE OVER S MEXICO NEAR THE ISTHMUS OF TEHUANTEPEC
ALONG 95W SOUTH OF 18N MOVING WEST 15 KT. NO ASSOCIATED
CLOUDS/CONVECTION.

...ITCZ...

ITCZ AXIS IS ALONG 13N1W 9N20W 8N40W 12N50W 10N70W. SEE TROPICAL
WAVE DISCUSSION ABOVE.

...DISCUSSION...

GULF OF MEXICO...
UNUSUALLY HIGH AMPLITUDE PATTERN CONTINUES TO UNFOLD OVER THE
GLFMEX AS A STRONG MID-LATITUDE TROUGH DIGS SWD OVER THE CENTRAL
UNITED STATES INTO THE NW GULF.  ABUNDANT TROPICAL MOISTURE
ASSOCIATED WITH T.S. BONNIE IS NOW SURGING RAPIDLY NWD OVER THE
SE UNITED STATES AHEAD OF THE TROUGH SUPPORTING AN IMPRESSIVE
AREA OF SHOWERS/THUNDERSTORMS EXTENDING FROM THE CAROLINAS SWD
TO THE FLORIDA PANHANDLE.  ADDITIONALLY...SCATTERED SHOWERS/
THUNDERSTORMS HAVE FORMED AHEAD OF AN UNSEASONABLY STRONG COLD
FRONT EXTENDING ACROSS THE NW GLFMEX FROM MOBILE BAY TO S TEXAS
NEAR BROWNSVILLE.  THE AMPLIFYING UPPER TROUGH WILL DRIVE THIS
FRONT WELL INTO THE GLFMEX EXTENDING FROM FLORIDA PANHANDLE TO
THE BAY OF CAMPECHE BY TOMORROW AFTERNOON.  MOST OF THE UPPER
LIFT AND DYNAMICS WITH THE UPPER TROUGH WILL REMAIN WELL N OF
THE AREA BUT SUFFICIENT LOW LEVEL MOISTURE POOLING COUPLED WITH
THE RAPIDLY APPROACHING HURRICANE CHARLEY WILL PRODUCE A VERY
UNSETTLED/STORMY PATTERN OVER THE SE GLFMEX AND MUCH OF FLORIDA
TOMORROW.

CARIBBEAN SEA...
THE MAIN WEATHER FEATURE CONTINUES TO BE CHARLEY WHICH IS NOW
AMPLIFYING AS IT LEAVES JAMAICA AND HEADS FOR W CUBA...SEE
SPECIAL FEATURES ABOVE.  MID/UPPER LEVEL LOW OVER THE NW
CARIBBEAN IS RETREATING QUICKLY WESTWARD TOWARD THE YUCATAN
PENINSULA WITH ASSOCIATED SUBSIDENCE AND DRY AIR NOW CONFINED TO
A SMALL AREA W OF 84W N OF HONDURAS.  FURTHER E...A WELL-DEFINED
MID/UPPER LEVEL RIDGE HAS FORMED OVER CHARLEY EXTENDING FROM
CENTRAL CUBA SWD TO NW COLOMBIA.  MOISTURE REMAINS LIMITED OVER
MUCH OF THE CARIBBEAN E OF 75W COURTESY OF STRONG SUBSIDENCE
WITH AN AMPLIFYING TROUGH OVER THE CENTRAL ATLC.

SUBTROPICAL ATLANTIC...
SIMILAR TO THE GLFMEX...AN AMPLIFYING PATTERN IS UNFOLDING OVER
THE ATLC AS A LARGE MID/UPPER LEVEL RIDGE BUILDS W OF 55W AHEAD
OF THE CENTRAL UNITED STATES TROUGH.  THE RIDGE IS ANCHORED BY A
ANTICYCLONE 400-500 NM NE OF THE BAHAMAS NEAR 25N70W. WHILE
THERE IS AMPLE UPSTREAM MOISTURE OVER THE E GLFMEX AND SE UNITED
STATES...NEARLY OF OF IT IS RIDING UP AND OVER THE RIDGE LEAVING
A GOOD CHUNK OF THE W ATLC UNDER SUBSIDENCE AND DRY AIR. FURTHER
E...A SHORTWAVE TROUGH MOVING AROUND THE N PERIPHERY OF THE
RIDGE N OF 33N ALONG 50W IS PRODUCING A FEW ISOLATED
SHOWERS/THUNDERSTORMS RIGHT ALONG THE N PORTION OF THE AREA...N
OF 27N BETWEEN 50W-70W. OVER THE CENTRAL ATLC MID-OCEANIC TROUGH
EXTENDS FROM A COLD CORE UPPER LOW NEAR 25N51W SWD TO
TRINIDAD/TOBAGO.  THERE IS LIMITED ACTIVITY WITH THE UPPER
TROUGH OWING TO LACK OF MOISTURE.  ELSEWHERE OVER THE E
ATLC...WELL-DEFINED E/W ORIENTED RIDGE EXTENDS ALONG 20N/21N E
OF 40W WITH STRONG SUBSIDENCE AND VERY DRY AIR.

TROPICAL ATLANTIC...
WELL-DEFINED MIDDLE TO UPPER LEVEL RIDGE STRETCHES ACROSS THE
EASTERN HALF OF THE TROPICAL ATLC ALONG 20N/21N WITH DEEP
EASTERLY FLOW NOTED E OF 45W. W OF 50W...MIDDLE TO UPPER LEVEL
TROUGH OVER THE CENTRAL ATLANTIC OCEAN DISRUPTS THE WESTERN
EXTENT OF THE RIDGE IN THE VICINITY OF THE LESSER ANTILLES
PRODUCING SW SHEAR BETWEEN 45W-60W.

$$
RHOME





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