The Department of Labor's Unemployment Insurance Weekly Claims Report was released this morning for last week.
In the week ending Dec. 11, the advance figure for seasonally adjusted initial claims was 420,000, a decrease of 3,000 from the previous week's revised figure of 423,000. The 4-week moving average was 422,750, a decrease of 5,250 from the previous week's revised average of 428,000.
The advance seasonally adjusted insured unemployment rate was 3.3 percent for the week ending Dec. 4, unchanged from the prior week's revised rate of 3.3 percent.
As we can see, there's a good bit of volatility in this indicator, which is why the 4-week moving average (shown in the callouts) is a more useful number than the weekly data.
Occasionally I see articles critical of seasonal adjustment, especially when the non-adjusted number better suits the author's bias. But a comparison of these two charts clearly shows extreme volatility of the non-adjusted data, and the 4-week MA gives an indication of the recurring pattern of seasonal change in the second chart (note, for example, those regular January spikes).
The Bureau of Labor Statistics provides an overview on seasonal adjustment here (scroll down about half way down). For more specific insight into the adjustment method, check out the BLS Seasonal Adjustment Files and Documentation.