Strategypage assesses Syria much as I have, putting limits on Assad's so-called winning streak of late.
Read it all.
Syria needs lots of Iranian cash.
Assad's army is broken in spirit although it still has firepower.
Hezbollah's expeditionary force is small and can't afford to fight too many more battles.
Assad's air force is worn out and not contributing that much to the fight.
Iran is unlikely to send gunmen, contrary to rumors.
Rebel morale is up on news of foreign arms aid coming.
Arab and Western special forces and similar civilians are in or near Syria training and advising rebels.
But on the bright side for Assad, rebel fragmentation allows Assad to focus efforts on parts of the rebels without a lot of worry that the other fragments will take advantage of the narrow focus on another part of the fight.
Those are the basics. There's more, too.
I don't see Assad with a winning hand. At best he can abandon Damascus and Aleppo to hold a coastal enclave where most of his Alawite supporters are, out to the main north-south highway for some depth.
If Assad could get a Russian paratrooper regiment and a battalion of naval infantry on the ground in that rump Assad-land, he might survive. But Assad isn't going to hold Syria or pretend to by hanging on to the capital. I just don't think he has the numbers. And now that we will arm rebels (and get out of the way of others doing the same, I assume), the rebels will be able to add more shooters to the field.
Or Secretary Kerry might figure out a way to salvage Assad's regime by pretending to broker a grand diplomatic "solution."