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SUBTROPICAL STORM TWO DISCUSSION NUMBER   2
NATIONAL WEATHER SERVICE MIAMI FL
11 PM AST SAT NOV 24 2001
 
SUBTROPICAL STORM TWO PRESENTS A CLASSICAL HYBRID APPEARANCE
THIS EVENING.  ON THE LARGER SCALE...THE SYSTEM SHOWS EXTRATROPICAL
CHARACTERISTICS...WITH WHAT APPEARS TO BE AN OCCLUDED FRONT TO
THE NORTH OF THE CENTER BRANCHING OUT INTO A WARM FROM AND COLD
FROM NORTHEAST AND EAST OF THE CENTER.  COLD-AIR STRATUS IS PRESENT
TO THE NORTH OF THE OCCLUDED AND WARM FRONTS BUT IS NOT CURRENTLY
WRAPPING INTO THE CENTER.  ON THE SMALLER SCALE...THE SYSTEM LOOKS
MORE TROPICAL...WITH INCREASING CONVECTIVE BANDING AND EVIDENCE
OF ANTICYCLONIC OUTFLOW AT UPPER LEVELS.  THE MAXIMUM INTENSITY
WILL REMAIN 50 KT FOR THIS PACKAGE BASED ON CURRENT SATELLITE
INTENSITY ESTIMATES AND PREVIOUS SHIP REPORTS.
 
THE INITIAL MOTION IS A LITTLE TRICKY...AS THE CENTER MAY BE
PERFORMING A LOOP INSIDE THE LARGE-SCALE CIRCULATION.  THE BEST
ESTIMATE OF THE INITIAL MOTION IS 320/9.  LARGE-SCALE GUIDANCE
INDICATES THE STORM SHOULD MOVE GENERALLY WESTWARD FOR THE NEXT
THREE DAYS AS THE SYSTEM CUTS OFF FROM THE WESTERLIES AND DEEP-
LAYER RIDGING DEVELOPS TO THE NORTH...AND WATER VAPOR IMAGERY
INDICATES THAT THE RIDGE IS ALREADY STARTING TO BUILD.  NHC
HURRICANE GUIDANCE INDICATES A MORE NORTHWESTWARD OR WEST-
NORTHWESTWARD MOTION...POSSIBLY IN RESPONSE TO THE INPUT INITIAL
MOTION.  BASED ON THE CURRENT POSITION AND MOTION...THE FORECAST
TRACK IS SHIFTED CONSIDERABLY TO THE SOUTHWEST OF THE PREVIOUS
TRACK.  IF THE CURRENT MOTION IS PART OF A LOOP...THE FORECAST
TRACK MAY HAVE TO BE SHIFTED EVEN FURTHER TO THE WEST IN SUBSEQUENT
PACKAGES.
 
THE INTENSITY FORECAST IS QUITE TRICKY.  LARGE-SCALE MODELS SEEM
TO HAVE A GOOD HANDLE ON THE OUTER ENVELOPE OF THE STORM...AND
THEY SUGGEST THE SYSTEM WILL CHANGE LITTLE IN INTENSITY DURING
THE NEXT 2-3 DAYS.  THUS...THE STORM IS LIKELY TO MAINTAIN SOMETHING
CLOSE TO ITS CURRENT INTENSITY EVEN IF THE CENTRAL CONVECTION
FIZZLES AND THE CYCLONE AGAIN BECOMES EXTRATROPICAL.  THIS SCENARIO
IS THE ONE REFLECTED IN THE OFFICIAL FORECAST.  HOWEVER...IF THE
CONVECTIVE INNER CORE REMAINS ISOLATED FROM COLD AIR AND VERTICAL
SHEAR...AS SUGGESTED BY THE LARGE-SCALE AND SHIPS MODELS...THEN IT
COULD INTENSIFY INDEPENDENTLY OF THE REST OF THE CYCLONE AND MIGHT
EVEN COMPLETE THE TRANSFORMATION INTO A TROPICAL STORM OR HURRICANE.
THIS SCENARIO WILL NOT BE INCLUDED IN THE INTENSITY FORECAST AT
THIS TIME...BUT THE STORM WILL BE CLOSELY MONITORED FOR ADDITIONAL
SIGNS OF TROPICAL TRANSITION.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     25/0300Z 31.5N  50.6W    50 KTS
12HR VT     25/1200Z 32.0N  51.5W    50 KTS
24HR VT     26/0000Z 32.5N  52.9W    50 KTS
36HR VT     26/1200Z 32.8N  54.2W    50 KTS
48HR VT     27/0000Z 33.0N  55.5W    50 KTS
72HR VT     28/0000Z 33.0N  57.0W    50 KTS
 
 
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