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| #931799 (Received by flhurricane at: 4:42 PM 06.Jul.2018) TCDAT3 Tropical Depression Three Discussion Number 1 NWS National Hurricane Center Miami FL AL032018 500 PM EDT Fri Jul 06 2018 The area of low pressure located a few hundred miles southeast of the North Carolina coast has developed enough deep convection with a well-defined circulation to be classified as a tropical depression. This is supported by a Dvorak T-number of 2.0 from TAFB, and an earlier ASCAT pass with 25-kt winds, which is the initial intensity assigned to the depression. Given that the system is moving over warm waters and in a low-shear environment, gradual strengthening is indicated, and the NHC forecast shows the depression becoming a tropical storm on Saturday. Additional intensification could occur by the end of the forecast period when the cyclone moves northeastward away from the U.S coast and interacts with a mid-level trough. The intensity forecast is very close to the SHIPS model and the Corrected Consensus HCCA. The depression is moving toward the north-northwest or 335 degrees at about 4 knots. The tropical cyclone is currently located on the southwestern edge of the subtropical ridge, and this weak flow pattern should keep the depression on the same slow track for the next 24 hours or so. After that time, the steering currents are expected to collapse, and the cyclone should begin to meander for a couple of days well off the coast of North Carolina. Then a mid-level trough is expected to approach from the west and force the system on a northeastward track. Most of the guidance suggests that the tropical-storm-force winds associated with the cyclone will occur in the eastern quadrant well away from the U.S. coast. On this basis, no watches or warnings are required for the U.S coast at this time, however, interests along the North Carolina coast should monitor the progress of this system. Due to a technical issue, the wind speed probability values at land locations in the wind speed probability text product are too high and do not reflect reduced probabilities that are expected over land. The wind speed probability values provided in the graphics on the NHC website at hurricanes.gov, and in the publicly disseminated grid files do correctly reflect the reduced probabilities over land. As a result, users should refer to the NHC website graphics and gridded products instead of the text product for the most accurate wind speed probability values until this problem is resolved. FORECAST POSITIONS AND MAX WINDS INIT 06/2100Z 32.2N 73.8W 25 KT 30 MPH 12H 07/0600Z 32.9N 74.3W 30 KT 35 MPH 24H 07/1800Z 33.7N 74.5W 35 KT 40 MPH 36H 08/0600Z 34.0N 74.3W 40 KT 45 MPH 48H 08/1800Z 34.0N 74.0W 45 KT 50 MPH 72H 09/1800Z 33.5N 73.7W 50 KT 60 MPH 96H 10/1800Z 33.5N 73.7W 65 KT 75 MPH 120H 11/1800Z 36.5N 69.5W 70 KT 80 MPH $$ Forecaster Avila |
