202008 - Tropical Cyclone - Isaias

Status: Finalised Material from: Linu, Esti, Sharan

1. Impact

Tropical cyclone Isaias affected the Caribbean and the U.S east-coast in the beginning of August. Isaias killed at least 8 people as it whipped up the East Coast on Tuesday, including several people whose deaths are being blamed on falling trees. There have been preliminary reports of more than 30 tornadoes along the East Coast. As I mentioned yesterday, what made Isaias particularly dangerous was how quickly was travelling. By Tuesday evening. the storm was heading north-northeast at 40 mph (65 km/h). I added here a photo of the sand from Topsail Beach, North Caroline, covering cars like it's snow.

2. Description of the event

3. Predictability

3.1 Data assimilation

3.2 HRES

3.3 ENS

The plots below show tracks from HRES (red), ensemble control (blue) and ensemble member (grey) and intensity and positions on 4 August 12UTC (symbols). The BestTrack positions and intensities are in circles for every 6th hour, which an hourglass marking 4 August 12UTC. The forecasts shown are from 4 August 00UTC (first plot) back to 25 July 00UTC (last plot), issued every 24 hour. Note that the cyclone had a slow bias in predicting the position on 4 August 12UTC.