The rest of the state was placed under a Winter Storm Warning, a Wind Chill Warning, and a Hard Freeze Warning. This day was the turning point where the front became a historic winter event. The Arctic cold front made its way to southeast Texas on February 14. Throughout central Texas, including Austin and Waco, six to nine consecutive days of freezing temperatures broke records for the longest freezing streak in the state’s recorded history. On Saturday, February 13, a Winter Storm Warning went into effect for Houston from that day to the following Tuesday. The first Winter Weather Advisory was issued on Thursday, February 11 in northwest Texas, where isolated freezing rain was occurring. The first day of the cold air outbreak occurred on February 10, with precipitation beginning on the following day as sleet and freezing rain fell across Texas’s northwestern counties. When the vortex weakens or is disrupted, the jet stream often becomes extremely wavy, allowing warm air to flood into the Arctic and polar air to sink down into the mid-latitudes.Ĭourtesy of NOAA, adapted from original by. When the polar vortex is strong and stable, the polar jet stream shifts northward, causing the cold air to remain in the Arctic. A polar vortex is an extensive coverage of low pressure and cold air surrounding Earth's poles.

With a negative AO, a weaker jet can dip further south, enabling outbreaks of Arctic air into the mid-latitude regions.Īnother element at play in the cold air outbreak was the polar vortex. A strongly positive AO can influence the powerful mid-latitude jet stream to move storms northward, reducing cold air blasts in the mid-latitude regions. The AO influences weather and climate in North America, Europe, and Asia, making the most impact during the winter season. One notable factor was the strongly negative Arctic Oscillation (AO), a back-and-forth shifting of atmospheric pressure between the Arctic and the mid-latitudes of the north Pacific and north Atlantic. A multitude of factors contributed to the brutal and enduring cold that enveloped the entire state of Texas.