[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 050244
TCDAT5
TROPICAL STORM JOSEPHINE DISCUSSION NUMBER  12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL102008
1100 PM EDT THU SEP 04 2008

JOSEPHINE HAS BEEN MOVING IN A STAIR STEPPED FASHION DURING THE LAST
SEVERAL HOURS BUT A 12 HR AVERAGE YIELDS 290/09.  THIS GENERAL
MOTION IS FORECAST TO CONTINUE FOR THE NEXT DAY OR SO AS THE
CYCLONE IS STEERED BY A LARGE SUBTROPICAL RIDGE TO THE NORTH. AFTER
THAT...A WEAKNESS IS FORECAST TO DEVELOP IN THE RIDGE...WHICH
SHOULD ALLOW A TURN TOWARD THE NORTHWEST.  THERE IS STILL SOME
SPREAD IN THE TRACK GUIDANCE WITH THE NOGAPS...GFDL...AND HWRF
MODELS FORECASTING A MORE POLEWARD TRACK WHILE THE UKMET...
GFS...MODELS KEEP JOSEPHINE MOVING WEST-NORTHWEST.  SINCE TRACK
GUIDANCE HAS BEEN TRENDING NORTHWARD...THE NEW OFFICIAL FORECAST IS
SHIFTED A LITTLE TO THE NORTH BUT STILL LIES ALONG THE SOUTHERN
SIDE OF THE GUIDANCE ENVELOPE.

JOSEPHINE IS CURRENTLY EXPERIENCING SOUTHERLY VERTICAL SHEAR
ASSOCIATED WITH A LARGE UPPER-LEVEL LOW TO ITS WEST WHICH IS
INHIBITING DEVELOPMENT.  WITH THE SHEAR EXPECTED TO REMAIN STRONG
FOR ANOTHER COUPLE OF DAYS AND THE SSTS FALL ALONG THE FORECAST
TRACK... SIGNIFICANT DEVELOPMENT IS NOT EXPECTED.  HOWEVER...IF
JOSEPHINE CAN SURVIVE THE NEXT COUPLE OF DAYS...THE ENVIRONMENT
COULD BECOME MORE  FAVORABLE FOR STRENGTHENING.  IN FACT...SOME OF
THE GLOBAL MODELS DEVELOP AN UPPER-LEVEL ANTICYCLONE OVER JOSEPHINE
AND THE SSTS RISE ALONG THE FORECAST.  STILL...NONE OF THE
AVAILABLE GUIDANCE FORECAST SIGNIFICANT STRENGTHENING AND THE GFDL
AND HWRF MODELS ACTUALLY SHOW THE CYCLONE ESSENTIALLY DISSIPATING.
THE OFFICIAL FORECAST ASSUMES JOSEPHINE WILL SURVIVE LONG ENOUGH TO
REACH THE MORE FAVORABLE ENVIRONMENT AND SHOWS A LITTLE
RESTRENGTHENING AT DAYS 3-5.

FORECAST POSITIONS AND MAX WINDS

INITIAL      05/0300Z 15.1N  33.8W    40 KT
 12HR VT     05/1200Z 15.4N  34.9W    40 KT
 24HR VT     06/0000Z 15.8N  36.3W    35 KT
 36HR VT     06/1200Z 16.5N  37.9W    35 KT
 48HR VT     07/0000Z 17.5N  39.8W    35 KT
 72HR VT     08/0000Z 19.5N  44.0W    40 KT
 96HR VT     09/0000Z 21.5N  48.0W    40 KT
120HR VT     10/0000Z 23.5N  51.0W    45 KT

$$
FORECASTER RHOME



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