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Tropical Storm ZETA


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TROPICAL STORM ZETA DISCUSSION NUMBER  16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
4 AM EST TUE JAN 03 2006
 
AT THE CIRRUS LEVEL...ZETA IS NOW EXHIBITING OUTFLOW IN EVERY
QUADRANT WHILE IT MAINTAINS CONVECTION WITH TOPS NEAR -70C. 
HOWEVER...THE CENTER IS STILL NEAR THE SOUTHWEST EDGE OF THE DEEP
CONVECTION AS SOME SOUTHWESTERLY FLOW UNDERCUTS THE DEVELOPING
OUTFLOW.  DVORAK CI NUMBERS FROM TAFB AND SAB ARE T3.5...OR 55
KT...AND AS NOTED IN THE PREVIOUS DISCUSSION THE QUIKSCAT PASS FROM
2039Z LAST EVENING SUPPORTED WINDS THIS STRONG AS WELL. 
CONSEQUENTLY THE ADVISORY INTENSITY IS INCREASED TO 55 KT.  WATER
VAPOR IMAGERY SHOWS A MID- TO UPPER-LEVEL TROUGH APPROACHING ZETA
FROM THE WEST...BUT THE GLOBAL MODELS ARE QUITE CONSISTENT IN
FORECASTING THIS TROUGH TO SPLIT AND DROP SOUTH OF ZETA.  IF THIS
OCCURS...THE WESTERLY SHEAR OVER ZETA COULD LESSEN SUBSTANTIALLY
OVER THE NEXT 12-24 HOURS AND THE GFDL'S FORECAST OF A HURRICANE
DOESN'T LOOK SO UNREASONABLE ANY MORE.  NO KNOWN HURRICANE HAS EVER
FORMED DURING THE MONTH OF JANUARY.  I WON'T GO THAT FAR WITH THE
OFFICIAL FORECAST...BUT WILL HOLD THE INTENSITY STEADY FOR THE NEXT
DAY OR SO.  AFTER THE UPPER TROUGH MOVES THROUGH I EXPECT THE SHEAR
TO INCREASE AGAIN...AND EVEN THE GFDL WEAKENS ZETA SUBSTANTIALLY BY
DAY 4.  

THE INITIAL MOTION IS 245/2.  ZETA REMAINS SOUTH OF A WEAK MID- TO
LOWER-LEVEL RIDGE...AND THIS RIDGE SHOULD REMAIN IN PLACE FOR THE
NEXT COUPLE OF DAYS.  AFTER THAT...MUCH OF THE MODEL GUIDANCE
SUGGESTS THAT ZETA MAY LIFT NORTHWARD AHEAD OF THE LARGE LOW
CURRENTLY OVER THE EASTERN UNITED STATES...BUT ONCE AGAIN THIS
TROUGH IS FORECAST TO SPLIT AND HENCE MAY LEAVE ZETA...OR ITS
REMNANTS...BEHIND.  THE OFFICIAL FORECAST IS SHIFTED A LITTLE TO
THE RIGHT OF THE PREVIOUS TRACK TO BE IN BETTER AGREEMENT WITH THE
GFDL.
 
FORECASTER FRANKLIN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      03/0900Z 23.3N  41.3W    55 KT
 12HR VT     03/1800Z 23.3N  41.7W    55 KT
 24HR VT     04/0600Z 23.3N  42.9W    55 KT
 36HR VT     04/1800Z 23.5N  43.9W    45 KT
 48HR VT     05/0600Z 24.3N  44.8W    40 KT
 72HR VT     06/0600Z 27.0N  45.5W    30 KT
 96HR VT     07/0600Z 27.5N  45.5W    25 KT...REMNANT LOW
120HR VT     08/0600Z...DISSIPATED
 
 
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