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Tropical Storm NADINE (Text)

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM
 
TROPICAL STORM NADINE DISCUSSION NUMBER  28
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142012
500 AM AST TUE SEP 18 2012
 
MOST OF THE DEEP CONVECTION NEAR THE CENTER OF NADINE HAS
DIMINISHED...AND THE STRONGEST ACTIVITY IS LOCATED WITHIN A BAND TO
THE WEST AND NORTHWEST OF THE CENTER.  THIS COULD SUGGEST THAT
NADINE IS BEGINNING TO LOSE SOME TROPICAL CHARACTERISTICS.  THE
INTENSITY REMAINS 50 KT BASED ON DVORAK ESTIMATES OF T3.0 FROM SAB
AND T3.5 FROM TAFB.

JUST ABOUT EVERY ASPECT OF THE FORECAST IS COMPLICATED.  THERE IS
RELATIVELY HIGH CONFIDENCE IN THE TRACK FORECAST FOR THE FIRST 2
DAYS...WITH ALL OF THE MODELS SHOWING A SLOW NORTHEASTWARD TO
NORTHWARD MOTION AS NADINE MOVES ALONG THE WESTERN SIDE OF A
MID-LEVEL ANTICYCLONE.  THE DISAGREEMENT AMONG THE MODELS INCREASES
SUBSTANTIALLY BEYOND 3 DAYS.  THE MAJORITY OF THE GUIDANCE SHOWS
NADINE INTERACTING WITH A DEVELOPING CUT-OFF LOW TO ITS NORTH AND
EITHER MOVING EASTWARD AS ITS OWN ENTITY...OR IN THE CASE OF THE
00Z GFS...MOVING EASTWARD AND BECOMING ABSORBED BY THE CUT-OFF LOW. 
ON THE OTHER HAND...THE ECMWF SHOWS THE CUT-OFF LOW BYPASSING
NADINE AND BEING REPLACED BY AN ANTICYCLONE...WHICH PUSHES NADINE
BACK TO THE SOUTH AND WEST.  DUE TO THE IMMENSE UNCERTAINTY...THE
OFFICIAL FORECAST INDICATES VERY LITTLE MOTION AT THE END OF THE
FORECAST PERIOD.  AT THIS POINT...THE STEERING PATTERN IS TOO
COMPLEX TO KNOW EXACTLY WHICH SCENARIO WILL VERIFY.

ALTHOUGH NADINE WILL BE MOVING OVER PROGRESSIVELY COOLER SSTS DURING
THE NEXT FEW DAYS...BAROCLINIC PROCESSES ARE LIKELY TO OFFSET ANY
WEAKENING THAT THE COLDER WATERS WOULD INDUCE.  THE GUIDANCE AS A
WHOLE AGREES THAT NADINE SHOULD CHANGE VERY LITTLE IN INTENSITY
DURING THE FORECAST PERIOD...WHICH IS REFLECTED IN THE OFFICIAL
FORECAST.

ONLY SOME OF THE GLOBAL MODELS HAVE NADINE BECOMING FULLY INVOLVED
WITH A FRONT...MAKING IT EXTRATROPICAL IN 3 TO 4 DAYS.  THE OTHER
MODELS...INCLUDING THE ECMWF...SHOW NADINE STAYING AWAY FROM THE
STRONGEST TEMPERATURE GRADIENT AND MOVING BACK TO THE SOUTH AS A
NON-FRONTAL CYCLONE.  EVEN IF THE ECMWF SOLUTION VERIFIES...NADINE
IS STILL LIKELY TO BECOME POST-TROPICAL DUE TO A LACK OF DEEP
CONVECTION OVER COLD WATERS.  THE OFFICIAL FORECAST SHOWS NADINE
BECOMING POST-TROPICAL IN 3 DAYS...WITHOUT SPECIFYING WHETHER OR
NOT THE CYCLONE WILL BE FRONTAL.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/0900Z 34.3N  33.6W   50 KT  60 MPH
 12H  18/1800Z 35.1N  32.9W   50 KT  60 MPH
 24H  19/0600Z 36.2N  32.7W   50 KT  60 MPH
 36H  19/1800Z 36.9N  32.6W   50 KT  60 MPH
 48H  20/0600Z 36.8N  31.9W   50 KT  60 MPH
 72H  21/0600Z 35.5N  28.5W   50 KT  60 MPH...POST-TROPICAL
 96H  22/0600Z 35.0N  26.0W   50 KT  60 MPH...POST-TROPICAL
120H  23/0600Z 35.0N  26.0W   50 KT  60 MPH...POST-TROPICAL
 
$$
FORECASTER BERG
 
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