Thank you all for the replies. Ok this does make sense. I actually did measure the bulb hot in a second test, but I only found about 5 more ohms. Obviously I wasnt fast enough. Clearly the rise in temperatture really ramps up resistance. Thanks for the insight on traffic lights!
In Canada in the colder provinces, municipalities are having trouble because some cities have changed traffic signal lights to led lamps to save energy, but now face the problem of the lights being covered with snow and no one can see them. They dont get as warm anymore and melt the snow. Someone didnt think that one through in the relentless quest to terminate incandescence.
