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Tropical Storm Epsilon Forecast Discussion Number 6
2020-10-20 17:00:20| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Tue Oct 20 2020 000 WTNT42 KNHC 201500 TCDAT2 Tropical Storm Epsilon Discussion Number 6 NWS National Hurricane Center Miami FL AL272020 1100 AM AST Tue Oct 20 2020 A curved band of deep convection persists near and over the center of Epsilon this morning. The cyclone is experiencing southwesterly vertical wind shear as it interacts with an upper-level trough to its southwest, and the storm still has a hybrid-like appearance in satellite imagery with a band of convection well to the east and northeast of the center. Water vapor imagery indicates that some dry mid-level air is impinging on the south and west sides of the circulation. A very recent ASCAT-A overpass shows several 45-kt vectors in the southeast quadrant, and it is certainly possible that the intensity could be near 50 kt based on the known undersampling issues. The initial intensity is raised to 45 kt with this advisory, which is consistent with a T3.0 Dvorak classification from SAB. Epsilon remains a large cyclone with tropical-storm-force winds extending outward more than 250 n mi in the northern semicircle. Although Epsilon was drifting northeastward earlier this morning, recent visible satellite imagery suggest Epsilon is beginning to turn north-northwestward or northwestward with a faster forward speed as a mid-level ridge builds to its north and east. This general motion is expected to continue for the next several days. Beyond 72 h, a deep-layer trough moving eastward into the western Atlantic should cause Epsilon to turn northward and then accelerate northeastward near the end of the forecast period. The track guidance remains in good agreement, and only minor adjustments were made to the previous track in line with the consensus aids (excluding the outlying HWRF solution at this time). Epsilon is still forecast to make its closest approach to Bermuda on Friday. The intensity forecast remains tricky since moderate south-southwesterly shear is expected to persist for another 12-18 h as Epsilon continues to interact with a nearby upper-level trough. By the time the deep-layer shear abates, Epsilon will be gaining latitude and moving over waters with lower oceanic heat content. Additionally, intrusions of environmental dry air could inhibit or at least slow the development process. Regardless, the global models show fairly significant deepening of the cyclone in the coming days, and the intensity guidance consensus still supports at least gradual strengthening. Therefore, little change was made to the official NHC intensity forecast, which still shows Epsilon becoming a hurricane late this week. Key Message: 1. Epsilon is forecast to be at or near hurricane strength when it makes its closest approach to Bermuda late this week. While it is too soon to determine the exact details of Epsilon's track and intensity near the island, there is a risk of direct impacts from wind, rainfall, and storm surge on Bermuda. A Tropical Storm Watch is in effect for the island. FORECAST POSITIONS AND MAX WINDS INIT 20/1500Z 26.5N 55.0W 45 KT 50 MPH 12H 21/0000Z 27.4N 56.1W 50 KT 60 MPH 24H 21/1200Z 28.2N 58.1W 55 KT 65 MPH 36H 22/0000Z 28.9N 59.4W 55 KT 65 MPH 48H 22/1200Z 30.0N 60.0W 60 KT 70 MPH 60H 23/0000Z 31.4N 60.7W 65 KT 75 MPH 72H 23/1200Z 32.4N 61.0W 70 KT 80 MPH 96H 24/1200Z 34.5N 61.0W 70 KT 80 MPH 120H 25/1200Z 39.5N 55.0W 70 KT 80 MPH $$ Forecaster Reinhart/Brown
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