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TROPICAL STORM BERTHA DISCUSSION NUMBER   3
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT SUN AUG 04 2002
 
THE LAST RECON PENETRATION AT 05/0058Z FOUND AN EXTRAPOLATED CENTRAL 
PRESSURE OF 1007 MB...WHICH EQUATES TO ROUGHLY 1008 MB WHEN 
CORRECTED. WHILE TOPS HAVE WARMED OVERALL IN INFRARED SATELLITE 
IMAGERY...A FEW STRONGER CELLS HAVE REDEVELOPED NEAR AND NORTHEAST 
OF THE CENTER. IN ADDITION...THE SLIDELL DOPPLER RADAR HAS BEEN 
INDICATING 35 TO 50 KT WINDS BETWEEN 3000 AND 7000 FT AND THE SOUTH 
BILOXI BUOY HAS RECENTLY REPORTED 10-MINUTE AVERAGE WINDS OF 32 
KNOTS WITH GUSTS TO 35 KT. THEREFORE...THE INITIAL INTENSITY WILL 
REMAIN AT 35 KT FOR THIS ADVISORY. AS SUCH...THE TROPICAL STORM 
WARNING FROM PASCAGOULA TO THE MOUTH OF THE MISSISSIPPI RIVER 
REMAINS IN EFFECT.
 
THE INITIAL MOTION ESTIMATE IS 310/07. RECON AND RADAR FIXES 
INDICATE THERE HAS BEEN SOME ERRATIC MOTION DURING THE PAST 6 HOURS 
AS THE CENTER HAS WEAKENED AND REFORMED FARTHER WEST A COUPLE OF 
TIMES. HOWEVER...THE GENERAL MOTION HAS BEEN TO THE NORTHWEST AND 
BERTHA MAY BE STARTING TO TURN MORE TOWARD THE WEST-NORTHWEST AS 
INDICATED BY THE AVN/GFS MODEL AND OTHER NHC DYNAMICAL GUIDANCE. THE 
OFFICIAL TRACK IS JUST A TAD SOUTH OF THE PREVIOUS SPECIAL ADVISORY 
TRACK AND NORTH OF THE AVN TRACK. THE 18Z AVN MODEL INITIALIZED 
BERTHA ABOUT 120 NM TOO FAR TO THE SOUTHWEST...HENCE THE REASON FOR 
THE MORE NORTHWARD TRACK ADJUSTMENT.
 
THE UPPER-LEVEL OUTFLOW PATTERN REMAINS CONDUCIVE FOR A LITTLE MORE 
STRENGTHENING TO OCCUR...IF DEEP CONVECTION CAN REDEVELOP AROUND THE 
LOW-LEVEL CENTER. THE TEMPERATURES OF THE COASTAL WATERS AND LAKE 
PONTCHARTRAIN ARE AROUND 30C TO 32C...SO THERE IS PLENTY OF FUEL. AS 
BERTHA MOVES CLOSER TO LAND...AN INCREASE IN THE FRICTIONAL 
CONVERGENCE MAY  HELP TO TIGHTEN UP THE LOW-LEVEL WIND FIELD A 
LITTLE BIT AND ALSO ACT TO TRIGGER SOME MORE CONVECTION BY EARLY 
MONDAY MORNING WHEN THE SYSTEM IS JUST SOUTH OF NEW ORLEANS AND LAKE 
PONTCHARTRAIN. AFTER 12 HOURS...RAPID WEAKENING IS EXPECTED AND 
BERTHA SHOULD DISSIPATE INLAND OVER EAST TEXAS...IF NOT SOONER. 
HOWEVER...THE THREAT OF LOCALLY HEAVY RAINFALL WILL CONTINUE 
THROUGHOUT THE FORECAST PERIOD.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     05/0300Z 29.6N  89.4W    35 KTS
12HR VT     05/1200Z 30.1N  90.5W    40 KTS...INLAND
24HR VT     06/0000Z 30.6N  91.9W    25 KTS...INLAND AND DISSIPATING
36HR VT     06/1200Z 31.1N  93.6W    20 KTS...INLAND AND DISSIPATING
48HR VT     07/0000Z...INLAND AND DISSIPATED
 
 
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