Polar Vortex Will Park Frigid Temps Over Maryland

MARYLAND — The polar vortex — that punishing blast of cold air that dives straight down from the Arctic — has fractured, and it’s going to make for hideously cold temperatures in much of the United States, including Maryland.

In our state, the National Weather Service says the coldest air arrives ahead of the Martin Luther King Jr. Day weekend. Overnight low temperatures will plunge to only 13 on Sunday, Jan 20, and drop to 17 degrees on Monday, Jan 21. There's also a chance of rain or snow every day through Sunday; see the forecast below, which starts with a mix of rain and sleet Thursday night.

Some forecast models call for temperatures 25 degrees or colder than normal by the end of the weekend in the central and eastern U.S. The blast of Arctic air should arrive in the Midwest just in time for Sunday night’s AFC Championship Game between the Kansas City Chiefs and New England Patriots. The National Weather Service predicts temperatures of 6 degrees at kickoff time in Kansas City, with a wind chill of about 3 below zero.

The Washington Post's Capital Weather Gang — not one to hype snowstorms — tweeted Tuesday: "GET READY.... The end of this month and especially February may be WILD for winter weather in eastern U.S."

And a USA Today report noted: "Any hopes we had for a mild end to January appear to be over."

If you recall the sudden burst of snowstorms we got in the early spring last year after a mild winter, that was also a result of the polar vortex splitting a few weeks prior. This one looks likely to have a more powerful effect, and it's taking place right in the dead of winter.

Don’t think you can pack up your parkas, face masks and other gear and be done with bone-chilling temperatures. Forecast models suggest the brutal, Arctic cold could hang around well into February, bringing an end to what has been a mild winter so far in many parts of the United States.

The polar vortex, a whirlpool of dense, frigid air over the Arctic that looks like a large tornado, is always around in the winter, but in some years it remains parked in the stratosphere where it belongs through the winter months and then dissipates in the spring. But in other years, warm air makes its way north and heat things up in what’s called “sudden stratospheric warming” — temperatures in this part of the atmosphere can increase by as much as 90 degrees in a matter of a few days.

When that happens, the vortex either moves south or it splits, as it did this winter when the stratosphere over Siberia suddenly warmed in early December. The three-way split, or fracture, suggests “severe and punishing” weather and “heightened storminess,” according to a weather model forecasts cited by The Washington Post.

The Weather Channel said the polar vortex has split into three distinct circulation areas — hurling frigid air south toward Russia, Europe, Canada and the United States. Other meteorologists suggested it’s a two-way split.

Either way, predicting what a fractured polar vortex means for a specific area is complicated and such events always come with big expectations, Amy Butler, an atmospheric scientist at the Boulder, Colorado-based Cooperative Institute for Research in Environmental Sciences, told Popular Science.

“People will always be like OK, it’s happened, I want to know when it’s going to get cold in New York,” she said. “We can say your chances of it being cold in this region have now increased … But we don’t know for sure when it’s going to snow.”

“A big factor is just random variability,” William Seviour, an atmospheric scientist at the University of Bristol in the United Kingdom, told the magazine.“The atmosphere is chaotic, which means there’s a limit to how much you can predict.”

Butler does expect the eastern two-thirds of the United States to begin feeling the effects of the polar vortex by the end of January, and it could last as long as six weeks, she said.

Weather observer Eric Webb, a University of North Carolina-Charlotte graduate who studies climate phenomena, has been watching polar vortex models. He tweeted temperatures that could hover around the 10-degree mark in central North Carolina, but “what’s coming at the tail end of January into February will be a lot more impressive.”

“This is about the coldest planetary-scale pattern you could ask for,” he said.

And Michael Ventrice, a meteorological scientist for The Weather Company, noted that forecasting models for the United States and Europe are in agreement in their 14-day outlooks. “Wow,” Ventrice tweeted. “This is going to be a wild, wild wintry ride for the eastern U.S. and Europe during the end of January.”

The National Weather Service notes that the Arctic air typically shoves further south during the winter, so it's a good time to make sure your car and home are ready.

Maryland Weather Forecast

Thursday: A chance of snow after 5pm. Increasing clouds, with a high near 34. North wind around 6 mph becoming southeast in the afternoon. Chance of precipitation is 30%.

Thursday Night: Snow before 2am, then rain, snow, and sleet. Low around 31. Southeast wind around 6 mph. Chance of precipitation is 90%. New snow and sleet accumulation of 1 to 2 inches possible.

Friday: Rain, snow, and sleet before 8am, then a slight chance of rain and snow between 8am and 1pm. High near 45. Calm wind becoming west 5 to 7 mph in the morning. Chance of precipitation is 80%. New snow and sleet accumulation of less than a half inch possible.

Friday Night: Partly cloudy, with a low around 29. Northwest wind around 6 mph becoming calm after midnight.

Saturday: A slight chance of rain and snow between 8am and 2pm, then a chance of rain. Partly sunny, with a high near 40. Chance of precipitation is 50%.

Saturday Night: Rain, mainly after 8pm. Low around 35. Chance of precipitation is 100%.

Sunday: Rain before 3pm, then a chance of rain and snow. High near 46. Chance of precipitation is 100%.

Sunday Night: A chance of rain and snow showers before 8pm. Mostly cloudy, with a low around 13. Chance of precipitation is 50%.

Prepare for Cold Weather

The way to avoid frostbite and hypothermia is to plan for extreme cold before it arrives. Don't get caught unprepared.

• Protect Your Pets, Livestock and other Property: If you have pets or farm animals, make sure they have plenty of food and water, and are not overly exposed to extreme cold. Take precautions to ensure your water pipes do not freeze. Know the temperature thresholds of your plants and crops.
• Fill up the tank: Make sure your car or vehicle has at least a half a tank of gas during extreme cold situations so that you can stay warm if you become stranded.
• Update Your Winter Car Survival Kit: Make sure your car survival kit has the following:
  • Jumper cables: flares or reflective triangle are great extras
  • Flashlights: Replace the batteries before the winter season starts and pack some extras
  • First Aid Kit: Also check your purse of bag for essential medications
  • Baby, special needs gear: If you have a baby or family member with special needs, pack diapers and any special formula or food
  • Food: Stock non-perishable food such as canned food and a can opener, dry cereal and protein rich foods like nuts and energy bars
  • Water: Have at least 1 gallon of water per person a day for at least 3 days
  • Basic toolkit: Pliers, wrench, screwdriver
  • Pet supplies: Food and water
  • Radio: Battery or hand cranked
  • Cat litter or sand: For better tire traction
  • Shovel: To dig out snow
  • Ice scraper: Even is you usually park in a garage, have one in the car.
  • Clothes: Make sure you dress for the weather in warm clothes, gloves, hat, sturdy boots, jacket and an extra change of clothes for the cold
  • Warmers: Pack extra for body, hand, feet
  • Blankets or sleeping bags: If you get stranded in traffic on a lonely road, you'll be glad to have it.
  • Charged Cell Phone: Keep a spare charger in your car as well

Patch Editor Dan Taylor contributed to this story.

Photo: Nicholas Rizzi/Patch