000 WTNT44 KNHC 220838 TCDAT4 HURRICANE DANNY DISCUSSION NUMBER 16 NWS NATIONAL HURRICANE CENTER MIAMI FL AL042015 500 AM AST SAT AUG 22 2015 Danny's cloud pattern consists of a central dense overcast with the low-level center estimated to be on the southwestern side of that feature due to southwesterly shear. Some fragmented curved bands exist on the north side of the circulation as well. The initial wind speed is lowered to 85 kt, but this could be generous as it is slightly above the Dvorak CI-numbers. NOAA and Air Force Reserve Unit reconnaissance aircraft are scheduled to investigate Danny this afternoon and should provide a better estimate of its intensity. The hurricane is moving west-northwestward at about 9 kt. A turn to the west with an increase in forward speed is expected to begin later today when the subtropical ridge to the north of the cyclone builds westward and strengthens. This general motion is expected to persist for the next several days taking Danny across the Leeward Islands in 2 to 3 days, and near Puerto Rico and Hispaniola in 3 to 4 days. The track model guidance remains in good agreement, and the only change made to the previous forecast was a slight northward adjustment at the latter forecast points. Strong southwesterly winds aloft and a stable air mass are expected to cause Danny to continue losing strength during the next several days. In addition, the potential land interaction with the Greater Antilles could contribute to the weakening. Although the guidance agrees on the overall trend, there remains a significant discrepancy between the dynamical and statistical model solutions on the weakening rate. The GFS, ECMWF, and HWRF models show Danny weakening quickly and opening up into a trough over the eastern Caribbean. Conversely, the SHIPS and LGEM models show a slower decay. The NHC intensity forecast is between these scenarios and is in best agreement with the intensity model consensus. Based on the current forecast, tropical storm watches will likely be required later today for portions of the Leeward Islands and the Virgin Islands. FORECAST POSITIONS AND MAX WINDS INIT 22/0900Z 15.2N 50.8W 85 KT 100 MPH 12H 22/1800Z 15.4N 52.6W 75 KT 85 MPH 24H 23/0600Z 15.8N 55.0W 65 KT 75 MPH 36H 23/1800Z 16.3N 57.6W 60 KT 70 MPH 48H 24/0600Z 16.8N 60.1W 55 KT 65 MPH 72H 25/0600Z 18.1N 64.9W 50 KT 60 MPH 96H 26/0600Z 19.7N 69.5W 40 KT 45 MPH 120H 27/0600Z 21.0N 74.0W 30 KT 35 MPH $$ Forecaster Cangialosi