LAREDO, Tex. (KGNS) – A cold airmass that originated in Canada has reached far south, well beyond Texas into eastern Mexico. With clear skies, very dry air and light winds, heat will radiate away from the earth’s surface, allowing temperatures at the bottom of the atmosphere (where we are!) to lower to around the freezing point, prompting a Freeze Warning at the end of tonight to early Tuesday morning. Moist air flowing north, above our cold north winds will bring a cloud cover by Tuesday night, and a cold rain will develop, especially during Thursday…