 While the term "lake effect snow" may have little meaning for people who live a good distance away from the Great Lakes, people who live near the Great Lakes are very familiar with the extreme impacts it has on daily routines. The formation of lake effect snow first starts when cold air, that normally originates from Canada, drifts across the relatively warm waters of the Great Lakes. As the cold air travels across the lakes, warm moist air will begin rise into the lowest section of the atmosphere. This warm moist air will then cool and condense into lake effect clouds. These clouds will then congeal into these narrow bands of heavy snow or also known as "streamers" that could produce intense snowfall rates of 2 to 3 inches per hour. And depending on how cold the air is at the surface, the snowfall rates could be even higher. The graphic below is a brief description by the National Weather Service (NWS) showing how lake-effect snow forms.  Wind direction plays a key role in not only the formation of lake-effect snow, but what areas receive the most snow from a lake-effect event. For example, after a low pressure system moves through the Great Lakes region, flow will be mostly dominate from the Northwest. Wherever that northwest flow is the strongest is where you will find lake-effect streamers with the most intense snowfall rates. Underneath these streamers, it may be snowing heavily or whiteout conditions could be present. And just a few miles down the road, the sun could be shining with no snow accumulation on the ground. This goes to show how narrow a lake-effect streamer may be. Though streamers are very narrow, they could stretch for more than 100 miles from their original starting point. Sometimes, they could stretch as far east as the Appalachian mountains.  Another key element that aid in the formation of lake-effect snow is the amount of instability or energy there is in the atmosphere. For lake-effect clouds to form, there needs to be a temperature difference of at least 13 degrees Celsius or 26 degrees Fahrenheit between the temperature of the lake and the temperature about 5,000 feet up in the atmosphere. This temperature difference provides the necessary ingredients for instability to build over the lakes which will allow the warm moist air to rise vertically. Sometimes, the amount of energy that forms from the instability could be enough to produce another fascinating and somewhat rare weather phenomenon called thundersnow. In other words, lightning that accompanies an intense snow band. And depending on your location, you may even be able to observe the actual lightning bolt. Other key factors for lake-effect snow include wind shear (change in wind speed and direction with height), fetch, the amount of moisture, synoptic forcing, and topography. But one factor that definitely takes a toll on the duration of lake-effect events is the percentage of ice cover over the lakes. As we head further into the winter season, the air will get colder and the lakes will gradually begin to freeze over. The more ice there is covering the lakes, the chances for a lake-effect event become very slim. And the lake doesn't need to be completely frozen to stop the formation of lake-effect precipitation. That is why late fall and early winter is the time of the year where lake-effect events make there appearance the most. One of the most known historical lake-effect events happened near Buffalo, NY just prior to Thanksgiving in 2014. This was a multi-day event that pummeled the Buffalo area with an astonishing 88 inches of lake-effect snow. Provided below are some of the mind-blowing snowfall totals and radar imagery by the NWS office in Buffalo from that multi-day event. - Cowlesville: 88 inches - Orchard Park: 71 inches - Lancaster: 74 inches - Wales Center: 69.3 inches - West Seneca: 52.5 inches - Buffalo Int'l Airport: 16.9 inches - Tonawanda: 7.9 inches To learn more about other interesting and/or high-impact winter weather events occurring around the world, be sure to click here!
© 2018 Meteorologist Joseph Marino
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DISCUSSION: As many people living across southern and western Alaska look to the skies tonight, things are likely pretty typical across most of Alaska. However, in southern Alaska (i.e., not too far from the city of Juneau), there was an interesting and complex situation on the regional radar screens as of earlier Tuesday evening. This interesting site came in the form of a reasonably well-wrapped low-pressure system which was moving to the northwest and was on a collision course with the coastline of western Alaska. More specifically, this low-pressure system was taking aim close to the city of Sitka, Alaska.
What was somewhat peculiar about this low-pressure system is the fact that it tremendously resembled a tropical cyclone even though it is a system which is occurring in mid-November here in 2018. The reason for the mention of this specific tropical cyclone similarity is the fact that this low-pressure system had features which included the following: spiral rain-bands, deeper convection near the center of the low-pressure circulation, the almost perfectly symmetric rotation throughout the periphery of the low-pressure system, and a feature which closely resembles the eye and broken eye-wall of a typical tropical cyclone. What is even more interesting is the fact that such an event is occurring at this unusually far northern latitudinal position and is occurring in colder waters during November which is unfavorable for an event with such uniquely dynamic characteristics to occur in both regards. As noted in the Tweet attached above (courtesy of the National Weather Service office in Juneau, Alaska), this system will have more than likely delivered sustained winds in excess of 50 to 60 knots by earlier on Tuesday evening. Thus, despite not quite being a true tropical cyclone in all facets of the typical tropical cyclone scenario, this is still going to be regarded as an interesting event which more than likely will deliver substantial impacts to the western parts of southern Alaska. This situation just goes to prove that interesting and compelling weather events can occur at any time of the year and without much notice even with the best numerical forecast models at the ready. To learn more about other interesting and/or high-impact winter weather events occurring around the world, be sure to click here! © 2018 Meteorologist Jordan Rabinowitz How To Correctly Prepare Yourself for Winter Weather. (Credit: National Weather Service, FEMA)11/5/2018  DISCUSSION: As we get closer and closer to the Winter season of 2018-2019, it is critical to remember that preparation is everything when it comes to being ready for whatever may come your way. For example, one such way of getting ready for the heart of a cold, snowy Winter season, is to get a safety and emergency preparedness kit for your automotive vehicle which contains all the critical essential components for you and anyone you live with to be ready when the time comes.
First off, when it comes to travelling during the Winter, you should always be sure to have items such as automotive vehicle jumper cables, a spare tire, emergency flares, a full tank of fuel, sand or kitty litter, tow rope, a snow shovel, water and snacks, a flashlight, and a cell phone charger. Thus, it is important to always be ready for any situations during a given winter storm or winter weather event you run across in which you happen to run off the road or get into an automotive accident. Moreover, it is critical to always have enough power in your cell phone so that if you do run into trouble, you will have a means of communicating to friends, family, and/or emergency services. Thus, whenever you start to get ready for Winter, always be sure to have these items on hand well before you must travel out and about around the time at which winter weather is predicted to hit. This information is all courtesy of the National Weather Service and the Federal Emergency Management Agency. To learn more about how you can prepare and be ready in many other aspects for what winter weather can bring, be sure to click here! To learn more about other winter weather topics and/or issues from around the world, be sure to click here! © 2018 Meteorologist Jordan Rabinowitz What Is Changing this Winter Regarding Winter Weather Warning Issuance? (Imagery credit: NWS)11/5/2018  DISCUSSION: Although millions of people both across the United States and around the world may feel like they just enjoyed following and are only starting to get used to the month of November, there are already definitive signs that winter is quickly bearing down on us already. With a storm system expected to deliver the first legitimate round of winter weather impacts later this week, it goes without saying that there are preparations that all people need to make both physically and mentally as we get closer and closer to the 2018-2019 Winter season.
One such preparation from a mental perspective that everyone needs to make is to understand the array of winter weather advisories that may get issue during this or any future Winter-time seasons. Many of us are accustomed to bearing witness to the issuance of the more conventional winter weather statements which include (but are certainly not limited to) winter weather advisories, ice storm watches, ice storm warnings, lake effect snow watches, lake effect snow warnings winter storm watches, winter storm warnings, blizzard watches, and blizzard warnings just to name some of the many. Having said that, year in and year out the National Weather Service network always strives to improve the ways in which weather dangers and weather hazards are communicated from season to season. In that light, the National Weather Service has a new winter weather statement which will be issued (as needed) during the 2018-2019 Winter season. This new winter weather statement is going to be known as a snow squall warning. This is a new but important change to the winter weather forecast process due to the unique nature of what snow squalls physically are and represent in the context of winter weather hazards. Snow squalls are best defined as short-lived bursts of heavy snowfall that result in the rapid onset of near-zero visibilities and are often accompanied by gusty winds per the definition from the National Weather Service headquarters office. Moreover, the criteria for the issuance of such warnings will a combination of two individual factors. The first criterion is visibilities drop down to ¼ mile or less with falling snow as well as gusty winds combined with sub-freezing road temperatures. The second criterion is the threshold for situations in which temperatures drop behind a cold front and produce gusty winds that blow snow off the ground. Another essential component to being able to effectively and timely issues such warnings from various National Weather Service offices is the advent of high-resolution satellite imagery products from satellite imagers such as the GOES-East satellite imager. Attached here is an article courtesy of the NOAA NESDIS Research Division office which provides more information on how this works in an operational setting. Thus, when you head for various plans and trips this coming Winter season, always be aware of the upcoming forecast and be sure to remain prepared for anything which may come your way. To learn more about other high-impact weather events and/or topics from around the world, be sure to click here! © 2018 Meteorologist Jordan Rabinowitz  DISCUSSION: As we head deeper into Fall and towards the beginning of Winter 2018-2019, there are several curious things which people wonder about day-to-day weather on even the calmest of days. More specifically, om days when there is little to no active weather occurring in a given region, there are still many curious things which will often occur even on the clearest of days. One such example of an unusual phenomena to the minds of most average people is when there is a random, light breeze on a calm, clear day with no clouds or precipitation in sight. However, there happens to be a clear and concise explanation for why such breezes occur on the calmest of days.
First off, it is important to understand that when infrared radiation enters the Earth’s atmosphere and reaches all the way to the surface of the Earth, this process acts to heat the immediate surface and surface layer. Thus, this incoming infrared radiation which reaches the surface of the Earth acts to increase the Earth’s skin temperature and gradually will partially be re-emitted back from the immediate surface and surface-based layer of the Earth in the form of weak low-level thermals. Thermals are effectively small-scale perturbations (i.e., smaller-scale changes) which transfer infrared radiation-based heat energy just above the surface. As a result of this infrared radiation being re-emitted from the surface of the Earth, these low-level thermals act to induce very small-scale pressure changes. These very small-scale pressure changes ultimately lead to light breezes which will occasionally reach the surface of the Earth. Therefore, the next time that you go outside on a calm Fall or Winter day, you can now understand how and why you will sometimes experience an occasional light breeze even on the calmest of days. Of course, it is worth noting that such light breezes occur even more often on Summer days since there is even more intense infrared radiation reaching the surface of the Earth due to a higher Sun angle during the Summer-time months. To learn more about other winter weather topics from around the world, be sure to click here! © 2018 Meteorologist Jordan Rabinowitz |
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