How do they forcast something this detailed?
Link.
How detailed do you think it really is?
How many people are calibrated enough to tell the difference between 20 deg F and 21 deg F.
If it is that cold and I go outside, I say “Dang it is cold outside.”
Indeed, Grandmother Plant once remarked that “Once it gets below 20, it’s just COLD.” and I’m not going to take a thermometer out and check their forecast every hour, but I presume they aren’t just making this shit up. 
I’m not very familiar with many aspects of numerical weather prediction (NWP), so I’m not positive what I write here is correct.
However, what may be happening is that TWC runs their own mesoscale (fine scale) model over the continental US (which isn’t that hard to do, plenty of entities and even individuals can do this). Basically the models will ingest various data and spit out a forecast. Basically you can get any variable you wish (pressure, humidity, temperatures, wind speeds, rainfall amounts, etc.) at any time-scale you wish.
One hard part can be generating the initial conditions (at zero hour, the “start” time of the forecast model), as the distance resolution of the model (a data point generated every few kilometers for example) is much much less than most of our hard data (rawinsondes are launched twice a day generally and can be several hundred miles apart). Granted, there is a ton of remote sensing data that is input into forecast models (satellite data, etc), however the initial conditions of this TWC mesoscale model can be highly dependent on other larger-scale forecast models (such as models developed/used by the U.S. National Weather Service, and other World Meteorological Organization members)
Hope this helps. Again, I’m just guessing on how it actually may work.
I know lots of people that think this way, but I can tell you as a person that walks most everywhere it ain’t so.
Once you get below zero my eyes will hurt as the moisture in them starts to freeze.
Once you get below 10 degrees you’re fingers will almost instantly freeze up. This evening it was -10ºF (-23º) and I took my gloves off and the keys dropped. By the time I picked them up my forefinger and thumb were so frozen I couldn’t feel the key anymore and had to turn it with my other hand.
Word on this. There’s a difference between 20º and 0º. There’s a difference between 0º and -20º, and there’s a difference between -20º and -40º. People in cold weather climates understand the different nuances and levels of cold, and this information actually is of use to us.
And 20º isn’t cold. Cold doesn’t start until you at least get to the donut.
never mind