Dye Release Advisory for 18 Aug 1300Z to 19 Aug 2000Z, Issued on 18 Aug 2017, 8am

The following figures show the MSEAS PE forecasts of horizontal velocities snapshots in a region covered by the HF-radar, every hour, extracted out of the 200m simulation (with implicit 2-way nesting in a 600 m simulation). Also shown are the FTLE but in the full 200 m simulation domain.

As a reminder, 12:00Z = 08:00 EDT, i.e., local time is 4 hours behind Zulu time.

The predictions below should be useful for selecting possible location for the dye release, with ocean forecasts for the HF-radar region and FTLE fields for mid-day today.

In the ocean current forecasts, you can see the effect of the increasing winds, starting around 18Z. This may also help you plan for avoiding dye advection to the coastlines.
In the FTLE forecasts, during 10am to 8pm, the FTLE ridges are weaker than in the past just south of MV. This is in part due to the tidal cycle we are in and later due to uniform winds. This may favor a more "turbulent diffusion" goal, but you could also select some of the region with stronger shear and FTLE ridges over 3h or 6hr (stronger than 3hr ridges). For example, one could release the dye far enough on the opposite side of the repelling ridge, i.e. sufficiently east of no man’s land. You can then show it does not reach the coastline. Note that currents there are to the nonetheless to the west, so be careful (check trajectories forecast here)

The MSEAS PE forecasts of horizontal velocities snapshots (velocity vectors overlaid on velocity magnitude) are shown every hour in a region covered by the HF-radar.

Hz200mN001/pe_vtot_20170818_1300Z_hfradar_axis.png

Hz200mN001/pe_vtot_20170818_1400Z_hfradar_axis.png

Hz200mN001/pe_vtot_20170818_1500Z_hfradar_axis.png

Hz200mN001/pe_vtot_20170818_1600Z_hfradar_axis.png

Hz200mN001/pe_vtot_20170818_1700Z_hfradar_axis.png

Hz200mN001/pe_vtot_20170818_1800Z_hfradar_axis.png

Hz200mN001/pe_vtot_20170818_1900Z_hfradar_axis.png

Hz200mN001/pe_vtot_20170818_2000Z_hfradar_axis.png

The FTLE computations are for a time window of 1, 3, or 6 hours for the forecast of 18 August 2017 to 19 August 2017. The window center shifts in 1 hour intervals. The flow maps were calculated using a PDE based approach by using 5th order spatial and 3rd order temporal schemes, and a novel composition based approach. As a reminder, 12:00Z = 08:00 EDT, i.e., local time is 4 hours behind Zulu time.