000 WTPZ41 KNHC 300841 TCDEP1 TROPICAL DEPRESSION TWENTY-ONE-E DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL EP212014 200 AM PDT THU OCT 30 2014 Deep convection associated with the low pressure area south of Acapulco, Mexico, has become more concentrated overnight, and recent microwave and conventional satellite imagery suggest that the low-level center has become better defined. Therefore, the system is being designated as a tropical depression. The satellite data indicate that the center is located near the southern edge of the main convective mass. Subjective Dvorak T-numbers from TAFB and SAB are 2.5 and 1.5, respectively. A blend of these estimates support an initial wind speed of 30 kt. The depression is over warm water and expected to remain in a low shear environment during the next several days. The main limiting factor will be some drier air in the low to mid-levels. As a result, gradual strengthening is predicted during much of the forecast period. The NHC forecast is a little above the intensity guidance through the first couple of days. After 72 hours, the NHC forecast is in good agreement with the HWRF which brings the cyclone to hurricane strength in about 4 days. Increasing south-southwesterly shear could halt any additional strengthening after that time. The depression is moving west-northwestward at about 5 kt. The depression is forecast to turn west-southwestward later today as a mid-level ridge builds to the north and northwest of the cyclone. The ridge is forecast to shift eastward during the next few days, which should cause the cyclone to turn west-northwestward, then northwestward in 48 to 72 hours. After that time, the tropical cyclone is forecast to turn northward while a mid-latitude trough approaches the Baja California peninsula. The track guidance is in good agreement on this scenario and the NHC track is near the middle of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 30/0900Z 11.0N 100.2W 30 KT 35 MPH 12H 30/1800Z 11.1N 100.8W 35 KT 40 MPH 24H 31/0600Z 10.8N 101.8W 40 KT 45 MPH 36H 31/1800Z 10.3N 102.9W 45 KT 50 MPH 48H 01/0600Z 10.1N 104.2W 50 KT 60 MPH 72H 02/0600Z 10.9N 107.7W 60 KT 70 MPH 96H 03/0600Z 14.0N 110.0W 70 KT 80 MPH 120H 04/0600Z 18.0N 109.0W 70 KT 80 MPH $$ Forecaster Brown