je.st
news
Potential Tropical Cyclone Sixteen Forecast Discussion Number 4
2019-10-18 10:33:56| National Hurricane Center (Atlantic)
Issued at 400 AM CDT Fri Oct 18 2019 000 WTNT41 KNHC 180833 TCDAT1 Potential Tropical Cyclone Sixteen Discussion Number 4 NWS National Hurricane Center Miami FL AL162019 400 AM CDT Fri Oct 18 2019 Although the convection associated with the disturbance has increased during the past few hours, there is no evidence that a well-defined center has formed yet. One can observe several swirls of low clouds rotating within a larger gyre. Most of the global models forecast that the system will become better organized later today, and given the current trend, NHC forecasts that a tropical or most likely a subtropical cyclone will form later this morning. A reconnaissance plane will investigate the disturbance in a few hours. The disturbance is located to the east of an upper trough which is digging along the western Gulf of Mexico, and the upper-level diffluence caused by the trough should induce some strengthening during the next 24 hours or so before the system moves inland. However, the simulated convection by the GFS and the ECMWF models resembles a comma-shape pattern which is characteristic of a subtropical cyclone. After landfall, the cyclone is expected to become extratropical and gradually weaken while it moves northeastward near the southeast U.S. coast. By day 5, the low is forecast to be absorbed by a front over the western Atlantic. Since the center is not well defined, the initial motion is highly uncertain. The best estimate is toward the northeast or 045 degrees at 12 kt. The system should accelerate later today and continue toward the northeast embedded within the flow ahead of the trough. Track models are in remarkably good agreement, and the NHC forecast is in the middle of the tight guidance envelope. Regardless of the exact evolution of the system, portions of the northern coast of the Gulf of Mexico will experience strong winds, locally heavy rains, and storm surge Friday and Saturday. Similar impacts are expected across portions of the Atlantic coast of the southeastern United States Saturday and Sunday. Key Messages: 1. There is a danger of life-threatening storm surge inundation of up to 5 feet above ground level beginning today along the Florida Gulf Coast from Indian Pass to Clearwater, where a Storm Surge Warning is in effect. Residents in these areas should follow advice given by local officials. 2. Tropical storm force winds are likely by later today along portions of the central and eastern Gulf Coast, where tropical storm warnings are in effect. Regardless of the exact track and intensity of the system, these winds will cover a large area, especially east of the center. 3. Isolated flash flooding is possible along the central and eastern Gulf Coast and southeastern United States coast from today through Saturday night. Since soils across the southeast are dry, the risk of flash flooding will be confined to the immediate coast where heavier rainfall is possible. 4. Wind and coastal flooding hazards along the U.S. East Coast will be covered by non-tropical watches and warnings issued by local NWS offices, since the system is expected to lose any tropical characteristics after it moves inland along the Gulf Coast. FORECAST POSITIONS AND MAX WINDS INIT 18/0900Z 24.3N 92.5W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 12H 18/1800Z 26.8N 89.8W 40 KT 45 MPH...TROPICAL STORM 24H 19/0600Z 29.0N 87.0W 45 KT 50 MPH 36H 19/1800Z 31.5N 84.5W 35 KT 40 MPH...INLAND 48H 20/0600Z 33.5N 80.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 72H 21/0600Z 37.0N 72.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 96H 22/0600Z 37.5N 69.5W 30 KT 35 MPH...POST-TROP/EXTRATROP 120H 23/0600Z...DISSIPATED $$ Forecaster Avila
Tags: number
discussion
potential
tropical
Category:Transportation and Logistics