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
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