It is only a matter of time. Aleppo, once Syria's largest city, will fall to the Syrian Army, reclaiming it from the Free Syrian Army (FSA) which has held it for almost four years. The Syrian Army is not capable of doing this alone - if they were, they would have done it long ago.
It is only with the indiscriminate bombing by the Russian Air Force and support on the ground by Iranian Islamic Revolutionary Guard Corps (IRGC) Qods Force fighters that the Syrians are in a position to reclaim Aleppo. There are reports of Hizballah and Iraqi Shi'a militias working with the Iranians, as well as unconfirmed reports of Russian combat forces on the ground in the area.
After years of ineffective operations and embarrassing setbacks at the hands of the FSA, Jabhat al-Nusrah (the al-Qa'idah affiliate in Syria), other rebel groups and occasionally the Islamic State in Iraq and Syria (ISIS), the Syrian Army has been able to make rather quick advances in Idlib and Aleppo provinces, as well as in the areas south of Damascus.
However, it is the push towards Aleppo in Idlib province, southwest of the city, and in the mountains northeast of the port of Latakia that the Syrian Army has had the most success. Idlib province had almost completely been taken by the rebels in 2015, forcing the Syrian regime forces to withdraw to the south. Note also that the Russian Air Force is operating out of Humaymim Air Base just south of Latakia.
What has changed in the last few months that has allowed the Syrians to be effective? Easy answer - Russian Air Force strikes and the increased deployment of Iranian fighters. Unlike the US-led coalition, the Russians do not exercise restraint when conducting air strikes - minimizing collateral damage (military-speak for civilian casualties) does not seem to be in the Russian lexicon. Hundreds, if not thousands, of Syrian civilians have been killed needlessly.
In addition to the Russian airpower and Iranian forces, the Syrians seem to be doing things in a more professional military manner - I have to assume the Russians are not only providing air support, but military advice and intelligence as well. The Russians have deployed their newest state-of-the-art TU-214R intelligence, surveillance and reconnaissance aircraft (photo) to the Syrian theater.
As I said, I believe Aleppo will fall - given the recent change in Syrian Army momentum thanks to the Russians and Iranians, it is inconceivable to me that the rebels will be able to prevent the regime from gaining the upper hand. It does not help when the various rebel factions fight with each other rather than maintaining an alliance against the regime.
The big question - what happens after the Syrian Army takes Aleppo? Here are my thoughts, what I suspect the Russians will advise the Syrian leadership to do.
If I were the Russians, I would advise operations on two axes, indicated by the blue and black arrows. Ideally, these could be done simultaneously, but if that is too difficult for the regime and its Russian and Iranian backers, I would recommend they focus on the black arrow. This indicates an offensive to regain control of the main Damascus-Aleppo highway, often called the International Highway. It is an excellent four-lane, limited access route - crucial to consolidating control of the northern part of the country. It also splits the rebel-controlled area.
Currently, the Syrian Army is using the route indicated in green as their main supply route from Hamah to Aleppo via Khanasir and al-Safirah. This indirect route uses a mediocre two-lane desert road that has areas of vulnerability to being cut by rebel attacks. The Syrians need to re-open the main highway to allow sufficient logistics to maintain control over Aleppo once the regime has taken it.
As for the axis indicated by the blue areas, this would re-open the Aleppo-Latakia highway, again splitting the rebel forces. The Syrian Army has been able to steadily push the rebels out of the mountains east of Latakia and edge closer to the Aleppo pocket. After the rebels have been split, the Syrian Army - with ample Russian air support - will likely be able to re-establish control over most of Idlib province.
Unless the situation changes, the Syrians have an excellent chance of regaining control of a major portion of the north central part of the country. I have no reason to believe that the situation will change - in fact, given the penchant for the US Administration to make concessions to the Russians, there may be an increase in the tempo of Russian air operations and a resultant increase in Syrian Army efficiency.
The tide of battle is shifting in favor of the Syrian regime of President Bashar al-Asad. The Russian and Iranian support has proven to be decisive.
All that said, none of this changes the confusing situation involving the Turks, the Syrian Kurds and ISIS, not to mention the US-led coalition.