The most common variant of the Out of Africa Model is this: Homo sapiens emerge in Africa approximately 200,000 years ago (based on the Omo remains found in modern-day Ethiopia, which date to 195,000 years ago) and emerge from Africa approximately 100,000 years ago (1).
Under this model, Homo sapiens would be required to stay in Africa for 100,000 years, from 200,000 to 100,000 years ago, and then emerge from Africa 100,000 years ago and reach Arctic Siberia by 45,000 years ago (2).
This would require that for 100,000 years, advanced Homo would expand their range northward no more than 25 meters per year, and then would suddenly expand to Siberia between 100,000 and 45,000 years ago. This is at a time when the Sahara was at times a grassland and not the desert that it has been for the last eight thousand years and most of the last 70,000 years. Needless to say, this problematic scenario of complete stasis in the range of early Homo sapiens is almost never discussed by proponents of the Recent Out of Africa Model.
Even more curious is the sudden mobility of Homo sapiens 100,000 years ago. Suddenly, from 100,000 years ago, to 45,000 years ago, Homo sapiens, under this model, expands at a rate of 250 meters per year, ten times their former dispersal rate, and reaches, as well as adapts to, Arctic Siberia 45,000 years ago.
Some argue that the reason for this is that prior to approximately 100,000 years ago, Eurasia was occupied by other hominins and therefore, that the possibility of range expansion for Homo sapiens was blocked. It is possible that this is true, but many other scenarios, almost never explored or even considered, are plausible.