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Potential Tropical Cyclone Six Forecast Discussion Number 3
2018-08-31 04:40:31| National Hurricane Center (Atlantic)
Issued at 1100 PM AST Thu Aug 30 2018 870 WTNT41 KNHC 310240 TCDAT1 Potential Tropical Cyclone Six Discussion Number 3 NWS National Hurricane Center Miami FL AL062018 1100 PM AST Thu Aug 30 2018 Satellite imagery indicates that the disturbance is gradually becoming better organized. However, the convection is not yet well enough organized to call the system a tropical cyclone, and recent scatterometer data show that the system still lacks a well-defined center of circulation. The scatterometer did indicate winds of 25-30 kt, so the initial intensity is nudged upward to 30 kt. The system should be in an environment of light to moderate easterly vertical shear for the next three to four days. Sea surface temperatures decrease along the forecast track during this time, though, reaching 26C by 72-96 h. The intensity guidance suggests that the system should at least slowly develop despite the falling SSTs, and based on this the new intensity forecast calls for it to become a tropical depression in about 12 h, a tropical storm in 12-24 h, and a hurricane near the 96-h point. While the system is expected to reach warmer SSTs near the end of the forecast period, it is also expected to encounter westerly shear at that time, which should limit additional intensification. The initial motion is a somewhat uncertain 280/11. The trade winds on the south side of the subtropical ridge should steer the system west-northwestward with an increase in forward speed during the next 3-4 days, passing near or over the southern Cabo Verde Islands Friday or Friday night. Near the end of the forecast period, a turn toward the northwest is forecast as the system approaches a weakness in the ridge. The new track forecast is again little changed from the previous forecast and lies near the various consensus models. It should be noted that some adjustments to the early parts of the forecast track may occur until the center becomes better defined. FORECAST POSITIONS AND MAX WINDS INIT 31/0300Z 13.2N 20.9W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 12H 31/1200Z 13.7N 22.3W 30 KT 35 MPH...TROPICAL DEPRESSION 24H 01/0000Z 14.5N 24.9W 40 KT 45 MPH 36H 01/1200Z 15.3N 27.7W 45 KT 50 MPH 48H 02/0000Z 16.0N 30.4W 50 KT 60 MPH 72H 03/0000Z 17.5N 35.5W 60 KT 70 MPH 96H 04/0000Z 19.0N 40.0W 65 KT 75 MPH 120H 05/0000Z 21.5N 44.0W 65 KT 75 MPH $$ Forecaster Beven
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