According to a report in the 'Financial Times', a former senior official at the US Department of Defense explained that Israel has a significant ammunition problem and that if there is a combined attack by Iran and its proxies, Israel's defense systems will reach their limits.
According to the Financial Times, "with more than 20,000 rockets and missiles fired at Israel over the past year from Gaza and Lebanon alone, according to official Israeli figures, analysts say defense planners and Israel’s artificial intelligence-powered air defenses are having to choose which areas to protect over others."
Regarding the expected Iranian attack, the director general of the Israeli Aerospace Industries responsible for the production of the "Arrow" missiles told the newspaper, "We work around the clock, literally 24 hours, and operate triple shifts, to meet our commitment [but] it is no secret that we have to replenish our stock – producing such missiles takes more than just a few days.
In an unprecedented move, and possibly because Netanyahu promised to stay away from Iran's oil fields and nukes in his counter-attack, America is sending its THAAD missile battery and 100 US soldiers to Israel in an attempt to close the gaps in Israel's air defenses.