A potent blast of cold air, like a knife, is cutting through the central U.S. Bitter, record-setting arctic air now grips the Rockies and northern Plains in its wake. And as this razor sharp cold boundary collides with warm, moist air at its southern reaches, a serious ice storm is in the making from Dallas to Nashville.
Let’s just say the cold Thursday morning was brutal in the northern Rockies and northern Plains. Wind chills of 30-40 below were common in Montana, the Dakotas and Wyoming.
These temperatures were some 40 to 50 degrees below normal.
Temps in Montana 40 to 50°F below normal — huge area of 30 below normal filling behind Arctic front. Houston soon pic.twitter.com/6lfeMnVZSi
— Ryan Maue (@RyanMaue) December 5, 2013
Denver plunged to -15 F, tying a record low for the date (from 1972). The air temperature across the entire state of Wyoming was below zero and the entirety of 15 states was below freezing.
All of the stations in CO, IA, ID, KS, MN, MT, ND, NE, NV, OR, SD, UT, WA, WI, and WY are sub freezing right now
— TerpWeather (@TerpWeather) December 5, 2013
The frigid air today has carved through Texas during the day, with amazing temperature contrasts between the northwest and southern parts of the state.
— Travis Herzog (@HerzogWeather) December 5, 2013
Ice storm threat
At the intersection of the arctic boundary and moist air oozing north out of the Gulf of Mexico, a swath of heavy ice has already developed and will expand northeastward overnight into tomorrow. Winter storm and ice storm warnings span a large region from Texas to eastern Ohio.
Some of the worst icing is expected in northeast Arkansas, where over one inch may accumulate. There, the Sperry-Piltz Ice Accumulation Index (SPIA), predicts category 3 ice storm conditions on a 0-5 scale. This means “excessive” tree limb damage is possible and power outages lasting 1-5 days.
“If the expected accruals verify, with a buildup of ice on power lines, power outages could becomes widespread and prolonged,” writes the National Weather Service in Little Rock.
Tennessee has issued a State of Emergency given the anticipated ice storm conditions.
Dallas, Texas, which soared to 80 degrees on Wednesday is now 33 (as of 3 p.m. CT), is also bracing for significant icing on the storm’s southwest flank.
“If you are in or near the watch area, begin making preparations now for possible power outages, icy roads, and the likelihood of having to remain at home for several days,” cautions the National Weather Service office serving Dallas and Ft. Worth.
— Shawn Reynolds (@WCL_Shawn) December 5, 2013
The worst of this ice storm should exit the region during the afternoon and evening Friday. But a second ice storm may target the Mid-Atlantic Sunday and Sunday night.