[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 070851
TCDAT5

TROPICAL STORM ERNESTO DISCUSSION NUMBER  23
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052012
500 AM EDT TUE AUG 07 2012

THE DEEP CONVECTION THAT DEVELOPED NEAR THE CENTER OF ERNESTO AROUND
THE TIME OF THE PREVIOUS ADVISORY HAS EXPANDED SOMEWHAT DURING THE
PAST SEVERAL HOURS.  THE AIR FORCE AIRCRAFT THAT DEPARTED THE
CYCLONE A COUPLE OF HOURS AGO REPORTED PEAK 850-MB FLIGHT-LEVEL
WINDS OF 63 KT AND SFMR SURFACE WINDS OF AROUND 55 KT.  THESE DATA
SUPPORT MAINTAINING AN INITIAL WIND SPEED OF 55 KT.  ALTHOUGH
ERNESTO STILL APPEARS TO BE HAVING SOME ISSUES WITH DRY AIR...THE
CYCLONE IS EXPECTED TO BE IN AN OTHERWISE FAVORABLE ENVIRONMENT OF
LOW VERTICAL WIND SHEAR AND SSTS OF AROUND 29 DEGREES CELSIUS.
THEREFORE...THE OFFICIAL FORECAST CALLS FOR STRENGTHENING AND
BRINGS ERNESTO TO HURRICANE STATUS BEFORE THE CYCLONE REACHES THE
EAST COAST OF THE YUCATAN PENINSULA TONIGHT.  THIS IS IN GOOD
AGREEMENT WITH THE SHIPS...GFDL...AND HWRF MODELS.  WEAKENING
IS EXPECTED AS THE CYCLONE TRAVERSES THE YUCATAN PENINSULA.
CONDITIONS APPEAR CONDUCIVE FOR SOME RESTRENGTHENING WHEN THE
CYCLONE MOVES OVER THE BAY OF CAMPECHE...ALTHOUGH THIS PORTION OF
THE INTENSITY FORECAST IS OF LOWER CONFIDENCE SINCE IT WILL DEPEND
ON HOW MUCH OF THE CIRCULATION IS OVER LAND.

THE INITIAL MOTION ESTIMATE IS 295/11.  ERNESTO IS FORECAST TO
CONTINUE WEST-NORTHWESTWARD TODAY...THEN TURN WESTWARD TO THE
SOUTH OF A NARROW MID-LEVEL RIDGE OVER THE GULF OF MEXICO.  THE
TRACK GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO.  THE
GUIDANCE IS SLIGHTLY FASTER THAN BEFORE AND HAS ALSO SHIFTED A
LITTLE SOUTHWARD AFTER 72 HOURS.  AS A RESULT...THE OFFICIAL
FORECAST INDICATES A SLIGHTLY FASTER FORWARD MOTION AND HAS BEEN
NUDGED SOUTHWARD AT DAY 3 AND BEYOND.  THE NHC FORECAST IS NEAR THE
MIDDLE OF THE GUIDANCE ENVELOPE.

FORECAST POSITIONS AND MAX WINDS

INIT  07/0900Z 17.5N  83.9W   55 KT  65 MPH
 12H  07/1800Z 18.2N  85.8W   65 KT  75 MPH
 24H  08/0600Z 18.8N  88.0W   70 KT  80 MPH...INLAND
 36H  08/1800Z 19.3N  90.4W   40 KT  45 MPH...INLAND
 48H  09/0600Z 19.4N  92.5W   50 KT  60 MPH...OVER WATER
 72H  10/0600Z 19.3N  96.0W   60 KT  70 MPH
 96H  11/0600Z 19.0N  99.0W   25 KT  30 MPH...INLAND
120H  12/0600Z...DISSIPATED

$$
FORECASTER BROWN


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