1WTNT44 KNHC 132043 2TCDAT4 3 4Tropical Depression Nine Discussion Number 5 5NWS National Hurricane Center Miami FL AL092019 6500 PM EDT Fri Sep 13 2019 7 8An Air Force plane extensively investigated the disturbance near the 9Bahamas during the past several hours, and in the last portion of 10the mission, the crew was able to locate a center of circulation, 11although weak, near the convection. The center was a little bit 12to the east of the previous estimates. Satellite images also 13indicate that the cloud pattern has become a little better organized 14and Dvorak estimates are T2.0 and 1.5 from TAFB and SAB, 15respectively. On this basis, the disturbance has been classified as 16a tropical depression with 25 kt winds. 17 18Conditions are not ideal for strengthening since the depression 19is still embedded within a moderate shear environment, but 20this parameter is not expected to be strong enough to halt 21additional development. The NHC forecast still calls for this system 22to become a tropical storm on Saturday with gradual intensification 23thereafter. Global models insist on further development, and the 24reliable guidance suggests that the cyclone could even reach 25hurricane intensity in about 3 days, and so does the NHC forecast. 26By then, the system is expected to be over the Atlantic waters well 27southeast of the coast of the Carolinas. 28 29Due to the reformation of the apparent center, the initial motion is 30highly uncertain. The best estimate is toward the northwest or 305 31degrees at 7 kt. A weakness in the ridge over the western Atlantic 32is forecast to develop, and this pattern should steer the system 33slowly toward the northwest and then northward. In about 3 days, an 34eastward moving mid-latitude trough will force the system to recurve 35away from the coast toward the Atlantic. The track guidance has 36shifted to the east again, and this shift is larger due to the 37eastward formation of the center. Consequently, the NHC track 38forecast was adjusted in that direction, but it remains on the 39western edge of the guidance envelope. 40 41Key Messages: 42 431. The depression is forecast to become a tropical storm within 44the next 24 hours and will likely bring tropical-storm-force winds 45and heavy rainfall to portions of the northwestern Bahamas later 46today and Saturday. Significant storm surge is not expected in the 47northwest Bahamas from this system. Residents there should follow 48any advice given by local officials. 49 502. The system could still bring tropical storm conditions to 51portions of the Florida east coast. Residents there should monitor 52the progress of this system and follow any advice given by local 53officials. 54 553. Heavy rainfall and scattered flash flooding is possible this 56weekend in coastal sections of eastern Florida, Georgia, and South 57Carolina. The chance of heavy rainfall affecting coastal North 58Carolina early next week continues to diminish. 59 60 61FORECAST POSITIONS AND MAX WINDS 62 63INIT 13/2100Z 25.6N 75.0W 25 KT 30 MPH 64 12H 14/0600Z 26.2N 76.0W 30 KT 35 MPH 65 24H 14/1800Z 27.4N 77.6W 35 KT 40 MPH 66 36H 15/0600Z 28.8N 78.5W 45 KT 50 MPH 67 48H 15/1800Z 30.0N 78.8W 55 KT 65 MPH 68 72H 16/1800Z 31.5N 76.5W 65 KT 75 MPH 69 96H 17/1800Z 32.0N 73.0W 70 KT 80 MPH 70120H 18/1800Z 32.5N 68.0W 75 KT 85 MPH 71 72$$ 73Forecaster Avila 74 75 76 77------------=_1568407405-121860-1280 78Content-Type: text/plain; charset="US-ASCII" 79Content-Disposition: inline 80Content-Transfer-Encoding: 7BIT 81 82= = = == = = 83