[Tropical] Tropical Cyclone Discussion
EMWIN Server
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Wed Sep 3 15:38:46 CDT 2008
WTNT45 KNHC 032037
TCDAT5
TROPICAL STORM JOSEPHINE DISCUSSION NUMBER 7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL102008
500 PM EDT WED SEP 03 2008
STRONG VERTICAL SHEAR AND DRY AIR HAVE REALLY WORKED A NUMBER ON
JOSEPHINE DURING THE LAST SEVERAL HOURS. AFTER LOOKING RATHER
IMPRESSIVE EARLY THIS MORNING...THE SATELLITE PRESENTATION HAS
SINCE RAPIDLY DEGRADED. CLOUD TOPS HAVE WARMED AND THERE IS NOW A
NOTICEABLE LACK OF ORGANIZATION. THE INITIAL INTENSITY IS LOWERED
TO 50 KT BASED ON A BLEND OF THE VARIOUS SATELLITE ESTIMATES BUT
THIS COULD BE A BIT GENEROUS GIVEN JOSEPHINE'S CURRENT APPEARANCE.
IN TERMS OF THE INTENSITY FORECAST...THE ENVIRONMENT GETS MORE
HOSTILE FROM HERE. MOST OF THE GLOBAL MODELS INDICATE THAT
JOSEPHINE WILL CONTINUE TO ENCOUNTER STRONG VERTICAL SHEAR AND SOME
MODELS EVEN SUGGEST THE SHEAR WILL INCREASE. ADDITIONALLY...SSTS
ALONG THE FORECAST TRACK GRADUALLY DECREASE THROUGH ABOUT 3 DAYS.
THE ENVIRONMENT DOES BECOME A LITTLE MORE CONDUCIVE FOR
STRENGTHENING AT DAYS 4 AND 5. HOWEVER...IT IS UNCLEAR WHAT WILL
BE LEFT OF JOSEPHINE BY THAT TIME. THE NEW OFFICIAL INTENSITY
FORECAST IS A LITTLE LOWER THAN THE PREVIOUS ADVISORY AND CALLS FOR
GRADUAL WEAKENING.
WITH JOSEPHINE'S FUTURE VERTICAL DEPTH NOW IN QUESTION...THE
STEERING IS A LITTLE LESS CERTAIN. IF THE CYCLONE CANNOT GENERATE
NEW CONVECTION...IT COULD BE STEERED MORE BY THE SHALLOW CURRENTS
AND MOVE WESTWARD OR WEST-NORTHWESTWARD AS SHOWN BY THE GFS.
CONVERSELY...IF THE CYCLONE CAN REGENERATE CONVECTION AND REMAIN A
DEEP SYSTEM...IT WOULD TEND TO MOVE NORTHWESTWARD AS SHOWN BY THE
NOGAPS AND GFDL MODELS. IT IS ALSO POSSIBLE THAT THE CYCLONE COULD
HAVE INTERMITTENT BURSTS OF CONVECTION RESULTING IN A STAIR-STEPPED
TRACK. GIVEN THE CURRENT LACK OF ORGANIZATION AND ANTICIPATED
STRONG SHEAR...THE OFFICIAL FORECAST LEANS TOWARD THE GFS RESULTING
IN A SOUTHWARD SHIFT AND SLOWER FORWARD SPEED.
FORECAST POSITIONS AND MAX WINDS
INITIAL 03/2100Z 13.8N 29.9W 50 KT
12HR VT 04/0600Z 14.0N 31.8W 50 KT
24HR VT 04/1800Z 14.6N 34.1W 50 KT
36HR VT 05/0600Z 15.2N 36.5W 45 KT
48HR VT 05/1800Z 15.9N 38.8W 40 KT
72HR VT 06/1800Z 17.5N 43.5W 35 KT
96HR VT 07/1800Z 19.0N 48.0W 30 KT
120HR VT 08/1800Z 21.5N 52.5W 30 KT
$$
FORECASTER RHOME
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