ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM TROPICAL STORM MADELINE DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP142016 800 PM PDT SAT AUG 27 2016 The cloud pattern has changed little in organization during the past several hours and convection is not as deep as earlier today. However, the pattern still consists of a cyclonically curved convective band around the center. Dvorak estimates continue to support an initial intensity of 50 kt. The cyclone is expected to be moving within an environment of light shear for the next 2 to 3 days and over warm waters. This should encourage some intensification. After that time however, the shear is expected to increase to above 20 kt, and the environment will be less humid, resulting in gradual weakening. The NHC forecast is very similar to its predecessor, and is very close to the intensity consensus IVCN. Satellite fixes indicate that Madeline is moving toward the west- northwest or 285 degrees at 7 kt. The cyclone is located on the southwestern edge of the subtropical ridge and is approaching a large mid-latitude trough to its northwest. This pattern should steer Madeline on a more west-northwest course during the next day or two. The trough is forecast to lift out quickly and be replaced by a strong ridge in about 3 days. This pattern should force Madeline to turn toward the west or even south of due west by the end of the forecast period. Track guidance has been very consistent with this solution, and the NHC forecast is in a narrow gap between the previous NHC prediction and the multi-model consensus. Given the small southward shift of the consensus at day 5, the NHC forecast position was adjusted southward accordingly. The confidence in the track foreast late in the period is lower than usual and it is too early to determine what impacts Madeline could have on the Hawaiian Islands late in the forecast period. It is important to remind users that the average day 4 and 5 track forecast errors for eastern Pacific tropical cyclones are around 145 and 170 miles, respectively. Given that Madeline has moved into the Central Pacific basin, future information on this system will be issued by the Central Pacific Hurricane Center. FORECAST POSITIONS AND MAX WINDS INIT 28/0300Z 15.7N 140.1W 50 KT 60 MPH 12H 28/1200Z 16.5N 141.0W 55 KT 65 MPH 24H 29/0000Z 17.4N 142.4W 65 KT 75 MPH 36H 29/1200Z 18.4N 143.8W 70 KT 80 MPH 48H 30/0000Z 19.2N 145.5W 70 KT 80 MPH 72H 31/0000Z 20.0N 149.5W 60 KT 70 MPH 96H 01/0000Z 19.5N 153.8W 55 KT 65 MPH 120H 02/0000Z 19.0N 158.5W 45 KT 50 MPH $$ Forecaster Avila NNNN