December 2016 was a good month for the Syrian army. It finally expelled rebel forces from eastern Aleppo thus taking full control of Syria's most populous city. But it was not without drawbacks.

So many of best Syrian units were in Aleppo that defense of Palmyra was left to easily-spooked second string formations. ISIS took advantage of that, launched a shock offensive of its own and quickly took the town, as well as chased the defenders a further 60 kilometers -- all the way back to the T4 airbase.

At this point the Syrian government controlled less of central Syria than ever since the start of Russian military intervention in September 2015. On a map it looked like this:
syria map control 2015

After successive Russian-backed offensives the map now instead looks like this:
syria map control 2017
Syrian government forces have gone from having almost no presence in central Syria to taking some 5,000 square kilometers in just four months since the offensive to retake Palmyra was launched in early February.

The Syrian army is now just 30 kilometers from Suknah. The effort to reach and take Suknah is expected to be slow because the terrain is difficult and easy to defend for ISIS (the road to Suknah is dominated by highlands to its north). However after Suknah it is all open and flat desert all the way to Deir ez-Zor.