Proc ESM just repeats numbers

[pjy1006]

I am forecasting 3 months weekly data based on 48 weeks of data. One year has roughly 52 weeks of data. So 48 weeks of data is less than a year. When using proc esm, some models (addwinter, seasonal) just use the same numbers from historical week n to predict future week n. For ex, if my historical week 1 is of 163 , historical week 2 is 115, historical week 3 is 97... . My forecast week 1 also has 163, forecast week 2 has 115, forecast week3 has 97...Is this caused by lack of sufficient data? 

[Ksharp]

Plz post it at Forecast Forum since PROC ESM is under SAS/ETS module.

https://communities.sas.com/t5/SAS-Forecasting-and-Econometrics/bd-p/forecasting_econometrics