Military movements from the NATO side against Syria strongly suggest preparation for a coordinated air attack. President Trump's early morning Tweet stated clearly that missiles are coming. He did not say they might be coming but that they are coming.
Military movements on the Syria, Russia, Iran side indicate defensive measures and movements being undertaken. For example, Syrian aircraft and Russian aircraft landing at Iranian bases. Evacuation of Syrian military sites and so on.
Russia has clearly stated that it will shoot down missiles and also neutralize their launch systems. The missiles can be launched by air and by sea so the implication is that these Western assets would be targeted.
NATO can open other fronts against Russia such as Ukraine.
The China factor is in the background. China is an ally of Russia loosely speaking and it has interests in Syria and the Middle East. China is also friendly with Iran. So this must be considered.
If the US is tied up in the Middle East with Russia, this might be a good opportunity to use force against Taiwan to reunite it with the mainland. Or, China could render some assistance to Iran and Russia and Syria in the event of war.
It is unlikely that the approaching war can be limited to just Syria. Lebanon and Iran can become quickly involved. Also, there could be an international dimension at the global rather than regional level depending on conflict management.
There is high risk for the United States despite its clear military advantage.