[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 071456
TCDAT5

TROPICAL STORM ERNESTO DISCUSSION NUMBER  24
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052012
1100 AM EDT TUE AUG 07 2012

AN AIR FORCE HURRICANE HUNTER AIRCRAFT INVESTIGATING ERNESTO THIS
MORNING FOUND THAT THE CENTRAL PRESSURE HAS DROPPED TO 989 MB...BUT
SO FAR THE SFMR-OBSERVED SURFACE WINDS DO NOT SUPPORT ANYTHING
HIGHER THAN 55 KT FOR THE CURRENT INTENSITY.  THE AIRCRAFT DATA
SUGGEST SOME EXPANSION OF THE INNER WIND FIELD...WHICH MAY
PARTIALLY EXPLAIN THE LACK OF STRENGTHENING THIS MORNING.  CIRRUS
MOTIONS SHOW A FAIRLY WELL-ESTABLISHED ANTICYCLONIC OUTFLOW PATTERN
OVER THE STORM.  SINCE THE TROPICAL CYCLONE SHOULD REMAIN IN A
FAVORABLE ATMOSPHERIC AND OCEANIC ENVIRONMENT UP TO LANDFALL...THE
OFFICIAL FORECAST CONTINUES TO SHOW ERNESTO BECOMING A HURRICANE
PRIOR TO REACHING THE YUCATAN PENINSULA.  THE NHC WIND SPEED
FORECAST IS NEAR THE HIGH END OF THE VARIOUS INTENSITY MODEL
PREDICTIONS.

CENTER FIXES FROM THE AIRCRAFT SHOW THAT THE MOTION CONTINUES
WEST-NORTHWESTWARD...OR 290/12.  NO IMPORTANT CHANGES TO THE TRACK
FORECAST ARE REQUIRED.  ERNESTO IS EXPECTED TO GRADUALLY TURN
WESTWARD AS IT MOVES ALONG THE SOUTH SIDE OF A NARROW
MID-TROPOSPHERIC RIDGE OVER THE GULF OF MEXICO.  THE NHC TRACK
FORECAST IS VERY CLOSE TO THE PREVIOUS ONE AND ALSO VERY CLOSE TO
THE MODEL CONSENSUS.  THE GFS SHOWS A MORE SOUTHERLY TRACK IN THE
LATTER PART OF THE FORECAST PERIOD...AND EVEN MOVES THE CYCLONE INTO
THE EASTERN PACIFIC IN 4-5 DAYS.

FORECAST POSITIONS AND MAX WINDS

INIT  07/1500Z 18.1N  85.0W   55 KT  65 MPH
 12H  08/0000Z 18.6N  86.8W   65 KT  75 MPH
 24H  08/1200Z 19.0N  89.1W   50 KT  60 MPH...INLAND
 36H  09/0000Z 19.4N  91.3W   45 KT  50 MPH...OVER WATER
 48H  09/1200Z 19.4N  93.4W   65 KT  75 MPH...OVER WATER
 72H  10/1200Z 19.2N  96.6W   60 KT  70 MPH...INLAND
 96H  11/1200Z 19.0N 100.0W   20 KT  25 MPH...INLAND
120H  12/1200Z...DISSIPATED

$$
FORECASTER PASCH


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