data=TimeSeries[FinancialData["SBUX","Close",{{2013,1,1},{2013,12,1},"Week"},Method->"WDF"],TemporalRegularity->True]

DateListPlot[data,FrameLabel->Automatic,Filling->Axis]

eproc=EstimatedProcess[data,ARIMAProcess[2,1,1],ProcessEstimator->"MaximumConditionalLikelihood"]

forecast=TimeSeriesForecast[eproc,data,{26}];

DateListPlot[{data,forecast},Filling->Axis]