ZCZC MIATCDAT2 ALL TTAA00 KNHC DDHHMM TROPICAL STORM OLGA DISCUSSION NUMBER 30 NATIONAL WEATHER SERVICE MIAMI FL 10 PM EST SAT DEC 01 2001 DURING THE PAST 6 HOURS...DEEP CONVECTION HAS RE-DEVELOPED NEAR THE CENTER AND OVER MUCH OF THE EASTERN SEMICIRCLE OF OLGA. DVORAK SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE BOTH 35 KT... T2.5...WITH DATA-T NUMBERS OF T3.0...OR 45 KT. AS SUCH...OLGA HAS RE-STRENGTHENED BACK TO TROPICAL STORM STATUS. OUTFLOW IS FAIR TO GOOD IN THE EASTERN SEMICIRCLE AND RESTRICTED TO THE WEST DUE TO MODERATE UPPER-LEVEL SOUTHWESTERLY SHEAR. THE INITIAL MOTION ESTIMATE IS 320/05. OLGA HAS ACTUALLY MOVED LITTLE DURING THE PAST 12 HOURS OR SO. A MID- TO UPPER-LEVEL VORTICITY CENTER CAN BEEN SEEN IN WATER VAPOR IMAGERY DROPPING SOUTHWARD JUST TO THE WEST OF OLGA. THIS APPEARS TO BE INDUCING SOME BINARY INTERACTION MOTION ONCE AGAIN...AND CAUSING THE CYCLONE TO MOVE NORTHWARD AND NOW NORTHWESTWARD. AS THE VORTICITY MAXIMUM DROPS FARTHER SOUTH...OLGA SHOULD TURN BACK MORE TOWARD THE WEST-NORTHWEST...POSSIBLY EVEN WESTWARD...IN 24 TO 36 HOURS. THE AVN MODEL QUICKLY MOVES A SHORTWAVE TROUGH OFF THE CAROLINAS IN 24 TO 48 HOURS...WHICH CREATES A WEAKNESS IN THE STRONG SUBTROPICAL RIDGE CURRENTLY LOCATED TO THE NORTH OF OLGA. THIS ALLOWS THE CYCLONE TO MOVE SLOWLY NORTHWARD BEFORE THE SHORTWAVE LIFTS OUT AND THE RIDGE BUILDS BACK IN...PUSHING OLGA BACK TO THE WEST OR EVEN TO THE SOUTHWEST. THE UKMET AND NOGAPS MODELS ARE LESS AGGRESSIVE WITH THE AMPLITUDE OF THE SHORTWAVE TROUGH AND KEEP THE RIDGE TO THE NORTH INTACT THROUGHOUT THE FORECAST PERIOD. THE OFFICIAL FORECAST TRACK IS A LITTLE TO THE RIGHT OF THE PREVIOUS TRACK AND CLOSE TO THE AVN-UKMET-NOGAPS MODEL CONSENSUS. AS THE AFOREMENTIONED VORTICITY CENTER DROPS SOUTHWARD...THE UPPER-LEVEL SHEAR MAY DECREASE ENOUGH TO ALLOW FOR SOME ADDITIONAL SLIGHT STRENGTHENING TONIGHT. HOWEVER...ALL OF THE GLOBAL MODELS AGREE THAT STRONG UPPER-LEVEL WESTERLY SHEAR WILL OVERSPREAD THE BAHAMAS AND AFFECT OLGA IN 24 TO 36 HOURS...WHICH SHOULD BRING ABOUT SIGNIFICANT WEAKENING IN THE LATTER FORECAST PERIODS. HOWEVER...IF OLGA TRACKS A LITTLE FARTHER NORTH OR NORTHWESTWARD THAN THE OFFICIAL FORECAST IS INDICATING...THEN THE CYCLONE COULD MOVE UNDER A 200 MB ANTICYCLONE EAST OF FLORIDA LIKE THE NEW 18Z AVN RUN IS FORECASTING. THIS WOULD CREATE A MORE FAVORABLE ENVIRONMENT FOR STRENGTHENING...AND ALSO PROLONG THE ALREADY VERY LONG 2001 ATLANTIC HURRICANE SEASON. 12-FT SEAS RADII WERE INCREASED IN ALL QUADRANTS BASED ON 13-FT SEA HEIGHTS REPORTED IN 21Z AND 00Z SHIP AND BUOY OBSERVATIONS. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 02/0300Z 23.6N 69.1W 35 KTS 12HR VT 02/1200Z 24.1N 69.6W 35 KTS 24HR VT 03/0000Z 24.7N 70.2W 35 KTS 36HR VT 03/1200Z 25.3N 70.8W 30 KTS 48HR VT 04/0000Z 26.0N 71.5W 25 KTS...DISSIPATING 72HR VT 05/0000Z 26.5N 73.0W 20 KTS...REMNANT LOW NNNN