This would not work.
Tomahawk would require the enemy battle fleet to be stationary to achieve any chance of a serious kill from a long range.
Tomahawk is slow, numbers matter but given the ability of the fleet to move at speeds of 24+ knots your Tomahawks are going to have to be fired in a dispersal pattern. Meaning that coupled with being slow they can be engaged in waves, avoided and generally managed.
Tomahawk can also be engaged by most modern fighters with look down shoot down capability. Give the speed of fighters and the slow speed of Tomahawk this could prove to be bad for the Tomahawk. Hell I suspect on a flat sea with the Tomahawk flying in a straight line a fighter might be able to engage with guns... though maybe not.
IF and this is a big IF the Battlegroup wasn't stationary. You have to keep a constant update on the battlegroup. That means you have to be able to pinpoint their location exactly to give Tomahawk the GPS location. This also means you will probably have to be running on active scanners.... You will be seen, you will be found and you will be engaged by the enemy... not good.
Finally you have the option of getting close... in which case if you get close enough to hit with a slow tomahawk and launch all 150 of before the ASW elements of a battlegroup kill you dead you deserve to hit them
The above is one of the reasons I'm just not sure about Tomahawk, Harpoon, NSM etc. They are slow missiles. Stealthy yes but I guess I just get nervous about that wait. Theres nothing like a missile that lets you fire, bug out and while your bugging out the enemy HAS to deal with a missile coming towards you at MACH 2.5- MACH 3