000 WTNT41 KNHC 231438 TCDAT1 TROPICAL STORM DANIELLE DISCUSSION NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010 1100 AM AST MON AUG 23 2010 AT 1028 UTC...AN SSMIS MICROWAVE PASS INDICATED THAT DANIELLE WAS STILL UNDER THE INFLUENCE OF EAST-NORTHEASTERLY SHEAR WITH THE LOW-LEVEL CENTER LOCATED ON THE EASTERN EDGE OF THE DEEP CONVECTION. HOWEVER...THE SHEAR APPEARS TO BE SLOWLY DECREASING... AND CURVED BANDING HAS BECOME MORE PROMINENT OVER THE PAST FEW HOURS. THE INITIAL INTENSITY IS RAISED TO 55 KT BASED ON DVORAK FINAL T-NUMBERS OF 3.5 FROM TAFB AND SAB. A FEW RECENT MICROWAVE IMAGES INDICATE THAT THE LOW-LEVEL CENTER IS A LITTLE SOUTH OF PREVIOUS ESTIMATES...THE THE INITIAL MOTION IS NOW 290/14. THE LONGWAVE PATTERN OVER THE ATLANTIC IS EXPECTED TO CHANGE LITTLE OVER THE NEXT FEW DAYS...AND A BREAK IN THE SUBTROPICAL RIDGE NEAR 45W SHOULD ALLOW THE CYCLONE TO TURN TOWARD THE NORTHWEST WITHIN THE NEXT 36-48 HOURS. ONCE THIS HAPPENS...THE RIDGE OVER THE WESTERN ATLANTIC IS EXPECTED TO BLOCK THE WESTWARD MOVEMENT OF DANIELLE AND FORCE IT TO TURN NORTH-NORTHWESTWARD BY DAY 5. THE MODEL GUIDANCE IS TIGHTLY CLUSTERED THROUGH DAY 5...AND LITTLE CHANGE FROM THE PREVIOUS FORECAST WAS NEEDED. IT SHOULD BE NOTED THAT THE TIGHT CLUSTERING OF THE MODEL GUIDANCE INDICATES THAT CONFIDENCE IN THIS TRACK FORECAST IS HIGHER THAN NORMAL. THE INTENSITY GUIDANCE CONTINUES TO SHOW STEADY STRENGTHENING OVER THE NEXT 36 TO 48 HOURS WITH THE HELP OF LOW VERTICAL SHEAR AND WARM OCEAN WATERS. AS COMPARED TO YESTERDAY...HOWEVER...THE SHIPS AND LGEM STATISTICAL MODELS NOW SHOW MORE INTENSIFICATION THAN THE GFDL AND HWRF DYNAMICAL MODELS. THE OFFICIAL FORECAST IS CLOSE TO THE SHIPS AND LGEM MODELS FOR THE FIRST 72 HOURS BUT THEN VERY CLOSE TO THE CONSENSUS AND PREVIOUS FORECAST THEREAFTER. THE RAPID INTENSIFICATION INDEX IS CURRENTLY NEAR 40 PERCENT...SO THERE IS SOME CHANCE THAT DANIELLE COULD STRENGTHEN A LITTLE FASTER DURING THE NEXT 24 HOURS THAN INDICATED IN THE FORECAST. BY DAYS 3 THROUGH 5...VERTICAL SHEAR COULD INCREASE AS DANIELLE APPROACHES A LONGWAVE TROUGH OVER THE WESTERN ATLANTIC... SO FOR NOW THE INTENSITY IS HELD NEAR THE LOWER END OF CATEGORY 2 STRENGTH. THERE IS NOW A 1 IN 4 CHANCE...HIGHER THAN YESTERDAY...THAT DANIELLE COULD BECOME A MAJOR HURRICANE DURING THE NEXT 5 DAYS BASED ON HISTORICAL NHC INTENSITY ERRORS. FORECAST POSITIONS AND MAX WINDS INITIAL 23/1500Z 15.1N 39.4W 55 KT 12HR VT 24/0000Z 16.0N 41.5W 65 KT 24HR VT 24/1200Z 17.3N 44.5W 75 KT 36HR VT 25/0000Z 18.9N 47.2W 80 KT 48HR VT 25/1200Z 20.8N 49.5W 85 KT 72HR VT 26/1200Z 24.5N 53.5W 90 KT 96HR VT 27/1200Z 27.0N 55.5W 90 KT 120HR VT 28/1200Z 29.5N 57.0W 90 KT $$ FORECASTER BERG