Goto UI->DeveloperTools->States and scroll down to your weather.NWSCODE_daynight, and you should see an attribute: forecast with a list and each item in the list that contains detailed_description.
I think what you are saying is that there use to be a sensor that also contained the detailed description. That could be, I’m not sure. But back around release [2023.9], the NWS forecast integration was “modernized”. The HA Architecture team decided that forecast attribute (which contained the detailed description) did not belong with weather entities so they deprecated it and so I think around April 2024, the forecast attribute will disappear altogether. The NWS modernization change is also planning to remove the forecast as a weather entity attribute. This nodernization may have been where you lost that sensor attribute.
There is possibly a work around, and here is one of many threads (I would start at the end of this thread and work backwards) on this subject