ZCZC MIATCDAT2 ALL TTAA00 KNHC DDHHMM TROPICAL STORM OLGA DISCUSSION NUMBER 20 NATIONAL WEATHER SERVICE MIAMI FL 11 AM AST THU NOV 29 2001 OLGA IS SHOWING SIGNS OF SHEARING THIS MORNING...WITH THE LOW- LEVEL CENTER PARTLY EXPOSED AT THE NORTHERN EDGE OF THE DEEP CONVECTION. SATELLITE INTENSITY ESTIMATES ARE 65 KT FROM SAB AND 55 KT FROM TAFB AND AFWA. THE INITIAL INTENSITY REMAINS 55 KT FOR THIS PACKAGE. THE INITIAL MOTION IS NOW 230/15. SATELLITE IMAGERY INDICATES DEEP-LAYER RIDGING TO THE NORTH AND WEST OF OLGA...AND LARGE-SCALE MODELS INDICATE THIS SYSTEM SHOULD PERSIST FOR 24-48 HR BEFORE WEAKENING AS A TROUGH MOVES TO THE U. S. EAST COAST. THIS PATTERN SHOULD KEEP OLGA ON A GENERAL SOUTHWESTWARD HEADING FOR 24 HR OR SO...FOLLOWED BY A GRADUAL TURN TOWARD THE WEST AND DECELERATION. ALL GUIDANCE IS IN AGREEMENT WITH THIS SCENARIO...INCLUDING THE AVN...WHICH HAS BACKED OFF OF THE NORTHWESTWARD TURN FORECAST EARLIER. THE OFFICIAL FORECAST IS SIMILAR TO BUT FASTER THAN THE PREVIOUS FORECAST. WHILE OLGA IS CURRENTLY GENERATING STRONGER CONVECTION THAN AT ANY OTHER TIME IN ITS LIFE...IT IS EXPERIENCING 20-30 KT OF SHEAR ACCORDING TO ANALYSES BY CIMSS AT THE UNIVERSITY OF WISCONSIN. LARGE-SCALE MODELS INDICATE THIS CONDITION SHOULD PERSIST FOR AT LEAST 36 HR...AND OLGA SHOULD WEAKEN STEADILY DURING THIS TIME. THE MODELS SUGGESTS THE SHEAR COULD DECREASE SOMEWHAT AFTER 36 HR...AND SHOULD THIS HAPPEN THE WEAKENING COULD BE INTERRUPTED OR AT LEAST SLOWED AS INDICATED BY THE SHIPS MODEL. THE INTENSITY FORECAST WILL CALL FOR SLOW WEAKENING DURING THE 36-72 HR PERIOD. FORECASTER BEVEN FORECAST POSITIONS AND MAX WINDS INITIAL 29/1500Z 28.1N 60.7W 60 KTS 12HR VT 30/0000Z 27.0N 62.7W 55 KTS 24HR VT 30/1200Z 26.1N 65.2W 50 KTS 36HR VT 01/0000Z 25.6N 67.6W 45 KTS 48HR VT 01/1200Z 25.5N 69.4W 40 KTS 72HR VT 02/1200Z 25.5N 71.5W 35 KTS NNNN