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Tropical Depression Fifteen Forecast Discussion Number 5
2019-10-15 22:51:43| National Hurricane Center (Atlantic)
Issued at 500 PM AST Tue Oct 15 2019 000 WTNT45 KNHC 152051 TCDAT5 Tropical Depression Fifteen Discussion Number 5 NWS National Hurricane Center Miami FL AL152019 500 PM AST Tue Oct 15 2019 The multiple circulations mentioned in the previous advisory discussion now appear to have consolidated into a tight low-level center that has recently passed over or near Sal island in the northeastern Cabo Verde archipelago. Deep convection has increased slightly and now consists of an elongated band confined to the eastern semicircle due to modest southwesterly vertical wind shear, leaving the low-level center exposed to the west. A late-arriving 1128Z ASCAT-C scatterometer pass indicated several 28-29 kt surface wind vectors within the band of convection, which supports maintaining an intensity of 30 kt. The initial motion remains northwestward, or 315/09 kt. There is no significant change to the previous forecast track or rationale. The latest NHC model guidance remains in very good agreement that the large cyclone will move generally northwestward during the next 48 hours or so, followed by a turn to the west-northwest when the expected shallow system will become embedded in the brisk low-level easterly trade wind flow. The new official track forecast is similar to the previous advisory track, and lies just to the left of the HCCA and TVCN consensus models. The environmental conditions are expected to only be marginal, so little, if any, strengthening is anticipated during the next 12 hours. By 24 hours and beyond, the combination of strong southwesterly vertical wind shear, drier and more stable air, and SSTs less than 26C should cause steady to rapid weakening, resulting in the cyclone degenerating into a remnant low by 36 hours and dissipating shortly after 72 hours, if not sooner. Regardless of whether or not the depression becomes a tropical storm as it passes near the Cabo Verde Islands, the primary threat from this system is the potential for locally heavy rainfall and flash flooding in those islands. FORECAST POSITIONS AND MAX WINDS INIT 15/2100Z 16.8N 22.9W 30 KT 35 MPH 12H 16/0600Z 17.8N 23.7W 30 KT 35 MPH 24H 16/1800Z 19.0N 24.8W 25 KT 30 MPH 36H 17/0600Z 19.9N 26.3W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 17/1800Z 21.2N 28.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 18/1800Z 23.0N 32.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 19/1800Z...DISSIPATED $$ Forecaster Stewart
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