 Photo: Projected Wind Chills for the Continental United States for Wednesday, January 30 at 12z from the NAM model. (Courtesy of PivotalWeather.com) In the North Pole, the polar vortex is usually found as a strong upper-level low pressure that is confined to that area. Under the current circumstances, warm air has made its way into that area which weakens the vortex, causing a split into multiple vortices that can travel away from its natural location. Due to this phenomenon, the polar vortex is slated to move into the United States overnight and into the morning of Wednesday, January 30th. There are many discussions explaining the extreme cold temperatures with comparisons to previous events. A similar cold air outbreak occurred in the region on January 5, 2014 which set records for cities over Illinois, Wisconsin and Minnesota. The current event is being referred to as a “generation spanning event” by local news stations, likely because of the comparisons from the previous generation that experienced an event like this in 1985. Specifically, the coldest temperature ever recorded in Chicago at the O’hare International Airport station was -27℉ back on January 20, 1985 (from NWS Chicago). Other stations in the Northern Illinois region that day may have actually been colder than that! Along with the discussion of historic cold temperatures, must be a talk about equally historic wind chill values. The next graphic from the Golden Gate Weather Services (https://www.ggweather.com/windchill.htm) demonstrates the difference of wind chill calculations from past and present.   Photo: (1) “New” Wind Chill Chart (2001-Present), (2) “Old” Wind-Chill Chart (Past-2001) (Courtesy of Golden Gate Weather Services) Popular social media outlets are comparing the severe wind chill event from 1985 in Chicago being record-breaking with wind chills in the 70 to 80 degree below-zero range, to the event that is occurring tomorrow, the 30th of January. What makes this interesting is that in November 2001, National Weather Service determined a more elaborate formula to calculate wind chill that is deemed more accurate, and may better reflect reality. Using the above graphics with an example, prior to 2001, a -20 degree Fahrenheit temperature reading with 35 mph wind speed was suggested to feel like -82℉. Today, with the new calculation and the same variables, that would feel like -55℉. Regardless of comparison, it will certainly be dangerously and historically cold tomorrow (1/30) and the proper precautions are necessary to remain safe.  Photo: A comparison of the new wind chill formula vs. the old Formula. (Courtesy of 1728.org) To learn more about other interesting winter weather topics from around the world, click here! © 2019 Meteorologist Jason Maska
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 A weakening polar vortex has unleashed extremely cold air that is beginning to propagate southward into the Central U.S. Multiple cities will experience record breaking cold that most of us haven't seen in quite some time. The arctic air, together with brisk winds, will lead not only to dangerously cold wind chill values but extremely dangerous weather conditions. It is important during this type of event to take any warning seriously and to take as many safety precautions as possible to ensure the highest rate of safety for yourself and others.  In preparation for this record cold air mass, National Weather Service (NWS) Offices stretching from Montana all the way to Pennsylvania have issued Wind Chill advisories (light blue) and Wind Chill Warnings (light steel blue). Now both should be taken seriously and it is important to know the difference between an advisory and a warning. Here are the definitions provided by the NWS:
Wind Chill Warnings will begin to go into effect tonight and will last through the day on Wednesday & Thursday. Wind chills during this time frame will be extremely dangerous and range from -35° to -55°. Morning low temperatures on both Wednesday & Thursday look to be between -20° and -35° across portions of the central U.S. This is very dangerous cold air that we are going to be dealing with throughout the next 48 hours. Below is a chart provided by the NWS on how fast frostbite can occur in certain extreme cold conditions.  With how extremely cold this arctic air mass is, it is important to follow these safety procedures to not only ensure your safety, but the safety of everyone around you. To make sure you and your family are safe from the cold, make sure to dress up in multiple layers and cover any exposed skin. Frostbite can occur within 5 to 10 minutes of being outside in this type of extremely cold weather. So it is important to limit your time outdoors and stay indoors as much as possible. Same thing goes for your pets. Remember, your pets are family too so they should be given same amount of love and safety as you. Bring any outdoor pets inside and limit their time outdoors. When you take them outside, cover their paws. Then once you are back inside, check their paws to see if any symptoms of frostbite are present. Also, make sure that they have plenty of food and water before the cold hits. It will not be a good idea to go get pet supplies during the extreme cold event because you are putting not only your pet at risk, but you as well. Cold temperatures will also have an effect on your cars engine as well. When it is this cold outside, the engine fuel becomes thicker causing it to not flow through the engine as smoothly as it should. The extremely cold air also causes car batteries to drain quicker than when it is hot outside. And if there is any moisture in the fuel lines of the engine, it will freeze up causing a blockage which will allow the engine to not start properly. To make sure that your car starts up properly, put it in somewhere where it is warmer like a parking garage, a shelter, or in your own garage. This is to ensure that if you have to travel somewhere, your car won't have any problem starting up. But if by chance you have to travel, make sure that your gas tank is a least half full. To fully prepare for traveling in the extreme cold, it would be wise to fill up your gas tank before the record cold air moves in. Another important thing to check is your coolant. Make sure that you fill your coolant fluid so that the car warms up quicker and doesn't have any trouble performing while traveling. Always make sure someone in your family knows that you are traveling so that if you have any problems on the road, someone will be there to help!  Once the arctic blast has fully moved out of your area, here are few things to keep in check. The top priority is to check to see that your family, and neighbors are okay after the cold blast. Power outages can occur during the extreme cold and can expose a person to not only frostbite but to hypothermia as well. Area of the human body that are most prone to frostbite are uncovered skin and the extremities, such as hands and feet.
Be sure to check your pipes because they may be frozen. Especially the water pipes located on outside walls and in places that are subject to the cold, like in your basement or underneath your kitchen cabinets, will freeze during a cold blast. When water freezes up, it cause the pipes to also expand and burst. A good way to warm the pipes back up is to first turn on the faucet and let water drip. If you want a quicker way to heat the pipes, try using a space heater, electric hair dryer, or hot water on a cloth. Continue these processes until water pressure returns to normal. For more winter weather topics, click here. © 2019 Meteorologist Joseph Marino 
DISCUSSION: After a relatively warm start to the winter across much of the United States, winter has decided to show its face. Forecasters in the National Weather Service (NWS) are becoming more confident that as the month of January draws to a close, extreme cold will progress southward from the pole. The brutal cold will move into the Northern Plains, the Midwest and the Great Lakes, with the dangerously cold temperatures starting to move into these areas Monday, Jan 28 2019, with the coldest temperatures around mid-week. The Northeast and the Mid-Atlantic will also feel the chill from this article blast, but the cold temperatures will likely not be as extreme in these regions. The forecasted severe cold is the result of a portion of the polar vortex splitting from its center near the north pole, moving southward; for more information on the Polar Vortex please click here. Portions of the Northern Midwest are already feeling the effects of the arctic blast. Overnight, temperatures in northern Minnesota dropped below -30˚F in some locations. When the wind chill was factored in, it felt like -50 ˚F in portions of the region. As the poral vortex moves southward, places as far south as Nashville could see their temperatures 20-40 ˚F below average for this time year. To make matters worse, it is expected to be windy, resulting in dangerously cold wind chill temperatures. Overall, the general thinking is that most of the Northern Plains, the Midwest and the Great Lakes will see lows between -20˚F and -30 ˚F. The areas closest to the core of the vortex will see lows below -40 ˚F. Many NWS offices across the Northern Plains, the Midwest and the Great Lakes are preparing for the brutal cold by creating graphics for the public, such as the one below done by NWS Detroit, which includes not only the forecasted chilly temperatures but also safety tips. For more safety tips about extreme cold please click here.  In addition to the severe cold, heavy snow is also likely across the Upper Midwest and the Great Lakes. A clipper system is forecasted to move into North Dakota late tonight. By Monday it is expected to be somewhere over the eastern Iowa and western Wisconsin region. This system is forecasted to bring heavy snowfall to the Upper Great Lakes region on Monday, with a possibility of snowfall amounts greater than a foot. It will continue eastward, bringing snow into the lower Great Lakes Monday night into Tuesday.
For more winter weather topics, click here. © 2019 Meteorologist Sarah Trojniak, Ph.D.  Photo: 24-Hour Accumulated snowfall map showing lake effect snows bringing accumulation to lake adjacent areas. Map generated from pivotalweather.com on December 28, 2017. As December has come and gone and we are knee deep in Meteorological Winter, the discussion of winter weather in the Midwest usually starts with strong cyclones passing through the continental United States bringing anything from blizzards to the north and strong thunderstorms to the south. We can steer our focus into something on a smaller scale (or mesoscale) and focus on the Great Lakes region, specifically on lake effect snow. The importance of understanding lake effect snow lies in the fact that it is convectively induced (similar to thunderstorms in the summer), thus is often very intense compared to other systems. The snow-to-liquid ratio for lake effect snow can range from 15 to up to 30 inches of snow per one inch of liquid, compared to 10:1 for other systems as a general ratio. Bands of lake effect snow can fall at intense rates of 2-3 inches in the matter of one hour and can be very localized in nature based on the size of the snow band. Snowfall forecasts can often be misleading if we are unaware of the ratio during a given system. The general rule of thumb with these snows is when cold air passes over a generally warmer lake, the temperature differential causes rising motions over the lake producing a cloud and eventual strong snow. When forecasting lake effect snow, there are multiple aspects to consider besides cold air over a warm lake:
Lake effect snow bands are different from most other snows that there are usually more intense snowfalls in a short time period. These storms can also occur during large scale high pressure, which can be deceiving for a storm to pass in a moment’s notice, only to have the sun reappear. Observing temperatures at 850mb is a common forecast tool because the convective cloud tops for these systems usually is between 700 and 850mb. Convection refers to the ability of motion in warmer air to rise and cooler air to sink which in the atmosphere can create varied forms of severe weather. Warm waters in contact with cold air allow for CAPE (Convective Available Potential Energy) to be generated (usually around 300-400 J/KG) in a shorter layer called the boundary layer (roughly a mile above the surface) that allows for quick rising motions to create these systems. This can be compared to summertime convection which can reach and exceed 200mb (6-7 miles) into the atmosphere where CAPE values have values in the thousands and allow for higher and faster updrafts (rising motion).  Photo: 850mb Temperature, Height and Wind map showing cold air over the Great Lakes Region ideal for producing lake effect snows. Image generated from pivotalweather.com on December 29, 2017. Based on the forecasting factors, travelers will need to be aware of changing conditions based on their proximity to lakes. Short term forecasts and nowcasting is crucial to understanding where these bands could hit and who can be affected. Snows like these can mean significant accumulation to nothing in as little as 40 miles distance. Ultimately, preparation will be important as these storms can be deceiving since they can occur during high pressure systems, meaning that a strong winter storm can pass by with high pressure behind it, but still bring more accumulation near a lake. Awareness of the situation is important along with staying up to date with changes throughout the day. To learn more about other interesting winter weather topics from around the world, click here! © 2019 Meteorologist Jason Maska |
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