ZCZC MIATCDAT2 ALL TTAA00 KNHC DDHHMM HURRICANE OLGA DISCUSSION NUMBER 11 NATIONAL WEATHER SERVICE MIAMI FL 4 AM EST TUE NOV 27 2001 OLGA HAS BEEN MAINTAINING A WELL-DEFINED EYE OVER THE PAST SEVERAL HOURS...ALTHOUGH THE EYEWALL CONVECTION IS NOT QUITE AS SYMMETRIC AS IT WAS A FEW HOURS AGO. DVORAK T-NUMBERS FROM TAFB AND SAB CORRESPOND TO AN INTENSITY OF ABOUT 75 KT...AND THAT REMAINS THE OFFICIAL INTENSITY FOR THIS ADVISORY. IT IS POSSIBLE THAT WITH THE COOLISH WATER TEMPERATURES AND A PRESUMABLY STABLE BOUNDARY LAYER THESE DVORAK ESTIMATES ARE A LITTLE HIGH. THERE IS A CONSIDERABLY-IMPROVED OUTFLOW PATTERN NOW COMPARED TO THIS TIME YESTERDAY...WHEN THE UPPER WIND STRUCTURE WAS DECIDEDLY SUBTROPICAL. OLGA HAS BEEN MEANDERING AND IS CURRENTLY EXECUTING A CYCLONIC LOOP WITH A SEPARATE UPPER-LEVEL VORTICITY MAXIMUM CURRENTLY TO ITS SOUTHEAST. AS THESE TWO FEATURES INTERACT I EXPECT A SHORT-TERM MOTION TO THE SOUTHWEST OR SOUTH FOR THE NEXT SEVERAL HOURS. BEYOND THAT...NEARLY ALL THE GUIDANCE SUGGESTS A SLOW NET EASTWARD DRIFT OVER THE NEXT DAY OR TWO...BUT I AM NOT SOLD ON THE INITIALIZATION OF THE GUIDANCE. NEITHER THE AVN NOR THE UKMET SEEMS TO BE CAPTURING THE FULL EXTENT OF THE OUTFLOW ON THE WEST SIDE OF THE CYCLONE VISIBLE IN THE WATER-VAPOR IMAGERY. THE OFFICIAL FORECAST THEREFORE IS SOMEWHAT WEST OF THE GUIDANCE DURING THE FIRST HALF OF THE FORECAST PERIOD...AND CALLS FOR LITTLE NET MOTION DURING THE NEXT 36 HOURS. BEYOND THAT...A SOUTHWESTWARD TRACK IS EXPECTED AS HEIGHTS RISE NORTHWEST OF OLGA IN RESPONSE TO AN APPROACHING TROUGH OVER THE CENTRAL U.S. THE SSTS WOULD ARGUE THAT THERE SHOULD NOT BE MUCH MORE UPSIDE TO THE INTENSITY OF OLGA...ALTHOUGH SOME MODEST ADDITIONAL STRENGTHENING IS STILL POSSIBLE. LATE IN THE PERIOD...WHEN OLGA IS EXPECTED TO MOVE SOUTHWESTWARD...INCREASING SHEAR SHOULD MITIGATE AGAINST INCREASING SSTS. CLIMATOLOGICALLY..SOUTHWARD-MOVING TROPICAL CYCLONES USUALLY WEAKEN. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 27/0900Z 32.5N 57.5W 75 KTS 12HR VT 27/1800Z 32.5N 57.5W 80 KTS 24HR VT 28/0600Z 32.5N 57.5W 80 KTS 36HR VT 28/1800Z 32.5N 57.5W 80 KTS 48HR VT 29/0600Z 31.5N 58.0W 75 KTS 72HR VT 30/0600Z 29.5N 59.5W 65 KTS NNNN