Purdy inaccurate in Niners start.

I am watching the Niners-Seahawks wild card playoff game. Purdy was inaccurate on every pass on the first drive. But they managed to get a field goal out of it. I do not understand the problem. It is raining, but in one case, the receiver went right and the pass went left where there were only Seahawks.
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Second possession, they did more running and his passes were more accurate. Fast TD.
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At halftime, Seahawks winning. What a bummer!