But it looks like the run may be over, as prices saw their largest one-day drop in six years. 

It happened after meteorologists predicted this week's "Polar Vortex" hit could be winter's last gasp.

"A midday update to the National Weather Service’s Global Forecast System model showed higher temperatures than previously forecast in the Midwest from March 6 to March 10," Bloomberg's Christine Buurma reported, noting tomorrow is the last trading day for March natgas options