The coldest air of the winter is draining into the United States, and holy crap it's cold. Temperatures in much of the north are struggling to climb into the single digits today, while Boston and the NYC suburbs will flirt with lows near zero on Thursday morning. Here's what you need to know to survive the deep freeze.

How cold will it get?

That depends on where you live. We have to break this down into two shots of cold air; the first is going on right now, with the second one swinging through on Wednesday and Thursday.

First Shot

The upper Midwest, Great Lakes, and interior sections of the Northeast are catching the brunt of today's cold snap, where temperatures are struggling to climb above zero even during the "heat" of the day. The temperature in Minneapolis as I wrote this sentence was -5°F. Tonight will be even colder, with lows of -15°F to -25°F possible, especially across the border states.

Second Shot

This is the one that will cause the most problems. It will arrive on Wednesday night and stick around through the day on Thursday. Low temperatures on Thursday morning will drop into the single digits as far south as Alabama, with teens likely as far south as the Gulf of Mexico. This is cold—almost as cold as the Great Polar Vortex Panic of 2014™—but surprisingly it won't break records in as many spots as you would think.

Here are forecast lows for Thursday morning compared to record lows for January 8. Only Chicago and Mobile come within one degree of breaking their record lows—every other city has at least a four-degree cushion between the forecast and record for the date.

  • Chicago — Forecast: -11°F | Record: -10°F
  • Minneapolis — Forecast: -10°F | Record: -23°F
  • NYC (Central Park) — Forecast: 8°F | Record: 2°F
  • Boston — Forecast 0°F | Record: -4°F
  • Washington (DCA) — Forecast: 15°F | Record: 7°F
  • Greensboro NC — Forecast: 10°F | Record: 6°F
  • Mobile AL — Forecast: 18°F | Record: 19°F
  • Huntsville AL — Forecast: 9°F | Record: 2°F
  • Nashville TN — Forecast: 4°F | Record: -9°F
  • Tallahassee FL — Forecast: 23°F | Record: 14°F
  • Houston TX — Forecast: 28°F | Record: 21°F

This doesn't even take into account wind chills. Even a light wind is dangerous to exposed skin in areas that experience bitterly cold temperatures. Wind chills close to -50°F are possible in the coldest spots this week. Frostbite will develop in just a few minutes with this combination of cold and wind.

Duh. It's January. It's supposed to get cold. Thanks for the scoop.

God, statements like this are insufferable. There's a difference between cold and cold. Run-of-the-mill cold that hovers around average is normal (in every sense of the term), but when you start dipping 20 or more degrees below normal, it's extreme. This kind of cold weather is dangerous to people walking from the bus stop to their work, let alone homeless people and those who have to work outside.

Look at areas like Huntsville, Alabama, where it's going to dip into the single digits on Thursday morning. Huntsville's normal low on January 8 is 32°F. Their forecast is 9°F. It's not quite record cold, but it's still really freakin' cold. Such a deep freeze dipping into the southern United States isn't rare (just look at last year), but you have to remember that not everybody has access to heat or even the proper clothing to protect them from such bitterly cold temperatures.

And then there's Minneapolis. The city's average low at the beginning of January is below zero. Residents know how to deal with it. However, wind chills that are something like -40°F are extreme even for winter-hardy residents of Minnesota. There's a reason the National Weather Service keeps issuing wind chill warnings for areas of the Plains and upper Midwest—it's dangerously cold!

Going outside without the proper clothing will subject you to hypothermia and frostbite. Frostbite can develop in just a couple of minutes when the wind blows with temperatures at or below zero. Go to Google and look up pictures of frostbite and then tell me if that's supposed to happen, you awful weather snob.

Well then. Why is this happening? Is it the polar vortex?

Sort of! This extreme cold is thanks to a glancing blow from the polar vortex instead of a full attack like we saw last year. Here's what I said about the polar vortex on Friday:

The polar vortex is a persistent, large-scale counterclockwise circulation around the Arctic that acts like a moat keeping bitterly cold air confined to the far north. The vortex often looks like a smooth belt, but every once and a while the circulation will become wavy, allowing cold air to flow south out of the Arctic. Last year, the vortex broke into several upper-level lows, one of which rotated over Ontario and the Great Lakes, causing a prolonged period of extremely cold weather in the United States.

This time around, the main circulation will stay safely up by Greenland, but a trough extending off of the upper-level low will swing down through the Great Lakes and Northeastern United States, facilitating low temperatures at or below zero for a large portion of the Midwest and Northeast for a few days next week.

The forecasts didn't really change over the weekend, signaling that the models are extremely confident that it will get very cold. Here's a look at the 500 millibar forecast from the GFS model, showing the atmosphere between 16,000 and 18,000 above sea level. Colder colors show lower heights (roughly lower pressure), and warmer colors show higher heights.

Just as the models showed last week, the polar vortex is spinning above Quebec and Nunavut, nowhere near the United States like it was this time last year. A deep trough in the upper-level low will swing over southern Canada and the eastern half of the United States this week, allowing very cold Arctic air to spill south and freeze us to death in about 36 hours.

The great thing is that the trough is a fast mover, so the cold blast in most spots won't last very long. Outside of the frozen tundra that is the Midwest, temperatures will rebound to the 30s and 40s in most places after Friday, but the cold, wintry pattern will persist for at least another week or two.

What did The Weather Channel name this storm?

Hell if I know. Gargle? Ganglion? Skittlebip? It doesn't matter, because it's just a social media advertising campaign.

What else should I know?

  • Bring your pets inside. If you leave your dog or cat outside during this cold, they will die and you are responsible for Fido's negligent homicide.
  • Donate unused clothes like coats or sweatshirts. They're just sitting in your closet anyway. People who need them more than you will really need them this week.
  • If you have frost or ice on your windshield, don't throw hot water on it unless you don't want a windshield anymore.
  • Check on your elderly friends, relatives, and neighbors, even if they have heat. If not to see if they're doing okay, it's just a nice thing to do.
  • For most places that experience single-digit (or colder) temperatures, it will only take about 30 minutes or less for frostbite to set in. The frostbite event horizon is closer to ten minutes if the wind chill is -35°F or colder.

Stay warm, and there are only 74 days until spring.

[Images: AP, NWS, WeatherBELL]

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