[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 052039
TCDAT5

TROPICAL STORM ERNESTO DISCUSSION NUMBER  17
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052012
500 PM EDT SUN AUG 05 2012

ASIDE FROM A SMALL BURST OF THUNDERSTORMS JUST EAST AND SOUTHEAST
OF THE LOW-LEVEL CENTER...MOST OF THE DEEP CONVECTION IS IN
DISORGANIZED PATCHES WELL TO THE EAST-NORTHEAST OF THE CENTER.
DRY AIR IN THE LOW- TO MID-LEVELS HAS BEEN DISRUPTING THE
STORM...ALONG WITH SOME SOUTH-SOUTHWESTERLY VERTICAL SHEAR.
HOWEVER...THE SHEAR APPEARS TO BE ABATING RECENTLY AND...ASSUMING
THAT ERNESTO WILL BE ABLE TO OVERCOME THE UNFAVORABLE
THERMODYNAMICS...SOME STRENGTHENING SHOULD COMMENCE WITHIN A DAY
OR SO. ONCE AGAIN...THE STATISTICAL-DYNAMICAL LGEM/SHIPS GUIDANCE
SHOWS SIGNIFICANT STRENGTHENING WITHIN THE NEXT 48 HOURS. GIVEN THE
CURRENT ORGANIZATION AND APPEARANCE OF THE STORM...THIS SEEMS
DUBIOUS. THE OFFICIAL INTENSITY FORECAST IS CLOSE TO THE LATEST
HFIP INTENSITY MODEL CONSENSUS.

THE ANTICIPATED DECELERATION IS FINALLY OCCURRING AND THE INITIAL
MOTION ESTIMATE IS 280/17. THERE IS LITTLE CHANGE IN THE TRACK
FORECAST REASONING FROM THE PREVIOUS ADVISORY PACKAGE. A
MID-TROPOSPHERIC SUBTROPICAL RIDGE TO THE NORTH OF ERNESTO IS
PREDICTED TO WEAKEN SOMEWHAT AS A TROUGH DIPS OVER THE EASTERN
UNITED STATES DURING THE NEXT FEW DAYS. AS A RESULT...THE TROPICAL
CYCLONE SHOULD TURN TOWARD THE WEST-NORTHWEST WITH A FURTHER
REDUCTION IN FORWARD SPEED OVER THE NEXT DAY OR SO. MOST OF THE
MODELS ARE IN AGREEMENT THAT THE RIDGE WILL NOT WEAKEN ENOUGH TO
RESULT IN ERNESTO TURNING TOWARD THE NORTHWEST GULF COAST IN THE
LATTER PART OF THE FORECAST PERIOD. IN FACT...THE GFS AND ITS
ENSEMBLE MEAN...AS WELL AS THE LATEST ECMWF...ARE SOUTH OF THIS
OFFICIAL TRACK FORECAST.

FORECAST POSITIONS AND MAX WINDS

INIT  05/2100Z 15.3N  78.6W   45 KT  50 MPH
 12H  06/0600Z 15.5N  80.8W   45 KT  50 MPH
 24H  06/1800Z 16.0N  82.8W   50 KT  60 MPH
 36H  07/0600Z 16.7N  84.7W   55 KT  65 MPH
 48H  07/1800Z 17.5N  86.6W   60 KT  70 MPH
 72H  08/1800Z 19.0N  90.5W   40 KT  45 MPH...INLAND
 96H  09/1800Z 20.5N  94.5W   55 KT  65 MPH
120H  10/1800Z 21.5N  97.5W   70 KT  80 MPH

$$
FORECASTER PASCH/ROBERTS



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