Significant freezing rain has occurred already this week across portions of the Upper Midwest through central Oklahoma, and more is on the way for some of the same areas. This was the view from Purcell, Oklahoma Tuesday morning, where all of the tree branches were encased in a thick ice due to hours of freezing rain.
— Kristina Bunn (@kbunn2013) February 20, 2018
We’re going to be tracking a strong cold front with a super tight temperature gradient moving slowly to the east on Wednesday. Precipitation will linger behind this front and that is where we’ll have freezing rain. With freezing rain, you need a thick layer of warm air aloft and a thin layer of freezing temperatures at the surface. This allows for snowflakes to melt into raindrops as they fall from the clouds. Then once they hit the ground, those raindrops will freeze on contact, coating all surfaces in ice. So Wednesday morning, a light to moderate freezing rain is possible from southeastern Michigan through portions of western Ohio into central Indiana, portions of southern Illinois, Missouri, northwestern Arkansas, eastern Oklahoma, and extreme-north-central Texas. Again, this is where freezing rain is possible. Not all of these places will experience freezing rain, but there is a moderate to high chance of icing to occur. As we get into the afternoon, the freezing rain should diminish in the Ohio Valley before it breaks out again Wednesday night. It’s from southern Illinois into southern Missouri where there’s the best chance for icy conditions during the afternoon. Meanwhile in the Southern Plains, a new storm system will move in from the West, beginning our next shot for freezing rain to similar areas. Therefore on Wednesday afternoon, freezing rain and sleet is possible from central Texas through central and western Oklahoma and into central Kansas.
Then overnight Wednesday, freezing rain may redevelop in portions of the Ohio Valley from central/northern Ohio through central/northern Illinois. We cannot reiterate this enough on how hard freezing rain is forecast. The temperature profile of the atmosphere has to be perfect in order to produce freezing rain. If the temperature is off by just one degree, it can screw the forecast, so understand you may only deal with rain instead. To the west, freezing rain is also possible Wednesday night in portions of Missouri–again–into eastern and central Kansas and Oklahoma and maybe as far north as southern Iowa. Also widely scattered, light, freezing rain showers are possible in central Texas.
On Thursday, the ice risk will continue for yet another day as the new disturbance tracks toward the Great Lakes. Pockets of freezing rain are still possible from northern Indiana through Ohio and maybe even into portions of northern Pennsylvania and western New York. Then back to the Midwest and Southern Plains, freezing rain is in the forecast across central Texas and Oklahoma, northeastern Kansas, southeastern Nebraska, northern Missouri, portions of Iowa, northern Illinois, and southern Wisconsin. Some of this freezing rain may be associated with convection, so some thunder and lightning is possible due to instability aloft.
As our storm lifts into Canada Thursday night, much of the activity will move out of the Midwest, although freezing rain is possible from portions of Wisconsin into northern Lower Michigan. Also a pocket of ice in parts of the interior Northeast cannot be ruled out.
Speaking of the Northeast, the ice threat may move into to this region by the weekend. Freezing rain is possible across Upstate New York into northern New England Friday night. By Saturday, we’re hopeful the risk for freezing rain will come to an end across the country.