Bush's speech is at 3 AM Israel time. We'll do the sealed room (mostly) before then even though the official instructions won't come down until after the speech.

According to this article, the IDF's assessment is still that there are "probably" no scud laaunchers in western Iraq, but that the population should be prepared anyway.

Ynet, quoting "security sources", puts it a little differently: there is very little chance that Israel will be attacked in the first days of the war. This is because Saddam does not/did not want to reveal his long-range missile capability, which could have been used as justification for attacking him.