I have no hot water pressure in the entire house... all sinks tubs and showers...

We have city water so there is no pump involved. We have a 40gal tank, the top pipes are appropriately cold and hot to the touch.

Upon turning on the hot water faucet just a trickle comes out then stops...

Best time of year to have this happen isn't it:(

Try opening the boiler drain valve at the bottom of the tank. There should be about 40 psi of pressure in the tank, if not check your supply line to the tank. If the tank does have good pressure then the blockage is after the tank but possibly right at the connection where the water leaves the tank. If you plan to open the connection at the top of the tank shut off the fuel source and open the drain to blow off pressure. Come back with your results and we'll go further if needed.

Is it an electric water heater? It sounds like it could be a few things. First check areators for white plastic stuff. If so, you have a dip tube problem. Then check if valve for heater is open all the way. Lastly, it could be a simply blockage on the hot port at the water heater. If so, simply cut pipe about 3" above water heater on hot side and poke out blockage with long screwdriver and reconnect pipe.