The Ukrainian offensive isn't going well and it may be clear to the US and NATO that the equipment they have won't be enough to re-take lost territory and win the war.
So the US is upping the ante.
The WSJ reports the US is close to approving the transfer of the Army Tactical Missile System, or ATACMS, has a range of about 250 km, or four times the longest range HIMARS system currently in Ukraine's arsenal. They use the sane launcher system so the roll-out could be relatively quick and there would surely be targets in Crimea.
The US had previously opposed the systems because of fears they could be used to strike inside Russia but the reports says the White House may have relented.