Initial conditions

I think your suggestion of intializing the model with a more uniform flow field, rather than a MABL which becomes increasingly steep and fast offshore, is good.

A "typical" profile of the change in MABL depth would be a steep slope near the coast but a more gradual slope offshore.  I have put Neiburger et al.'s 1961 climatology of mbl height here to show this, and the plan view here. Since the model's steady state solution resemble the intial flow field, we should probably start out with something closer to the slope we'd expect.  From the June 12 data, I have estimated that the MABL slopes about 2.4 m/km along the upstream line at Cape Mendocino.  Without data out to 400 km offshore (the offstream extent of the model domain at y=0) we might want to use this slope across the whole domain, since the change in slope in the climatology doesn't happen until about 600 km offshore.

For the distribution of speed across the coast, we'd expect from observations that there would be a zone of stronger winds near the coast with weaker winds offshore. In the climatology of wind stress from Nelson 1977 which I have put here,  the stress peaks at around the Rossby radius (150 km) off of Cape Mendocino, then decreases further off shore.  In the June 12 wind layer-averaged speeds which I have gridded here, the wind dies down to about 13.5 m/s by about 222 km offshore along 40.1N.  We may want to use a cross-shore wind profile which peaks at 18 m/s at -125.2W and then decreases offshore to 13.5 m/s at -126.4W.

Model physics

It is occurring to me that we can learn a lot about how trancritical flow with rotation & friction adjusts to coastal bends from the model.  Because the change in coastline orientation, friction, and rotation combine to give the flow solution, we might want to look at these things separately (I apologize in advance for my lack of knowledge about how much work it is to do a model run!).
I don't have a grasp of:

1)      How the separate coastline bends affect the flow.

To identify the 7 coastline bends, I have labelled them A,B,C...G going down the coast, which you can see here.  Similarly I have put the bend locations on the along-coast steady solution here.  This let me notice that:

To clarify how the flow changes at bends, we might want to do a coastline with a single inward bend, then one with an outward bend, to see how flow that was initially sub or supercritical was affected.

2)      How friction affects the flow

It seems like the sub-to-supercritical transition doesn't happen right at bend B.  In "Hydraulic Control of Sill Flow with Bottom Friction," JPO 16, Nov 1986, p 1670-1980, Larry Pratt finds that the addition of friction causes the point of control to move downstream from a sill.  Is that happening here?  Also in "Supercritical Flow along a Smoothly Varying Coastline," Roger found that friction changed the shape of supercritical flow features, causing a fan to become bulge shaped and weakening a hydraulic jump.  Does this happen for us?  What about in the subcritical parts of the flow?  Comparing the single-bend solutions in with and without friction would be really interesting.

3)      What changes when you include rotation

Again I'd like to sharpen my intution on this.  In Roger's paper the addition of rotation to supercritical flow made expansion fans more extreme and jumps weaker because it forced flow offshore.  How would our transcritical solution change without rotation?