Tornado season is already here. There is a high threat for tornadoes between March and May in the southern region of the United States. This is not to say that tornadoes cannot happen at any other time of the year, rather, these months are the highest threat. A southward dip in the jet stream accompanied with warm, moist air flowing into the South from the Gulf of Mexico will cause instability in the atmosphere. The jet stream will provide the winds rotating at different levels of the atmosphere, or wind shear. Strong low-level winds, or winds near the surface, will be the key ingredient of supercell development.
Now that you know when and how tornadoes form, do you know what to do during a tornado outbreak? When a tornado warning is issued, that means a tornado is imminent; that a tornado has been spotted or rotation has been detected on radar. You only have between 10 and 15 minutes to get to safety. What is your plan? When a warning is issued or you hear the sirens you should only be taking action, not thinking about what to do next.
If you are inside your house, go to the lower-level, and find an interior room. An interior room is a room that does not have any exterior walls. Stay away from the windows and do not try to see the tornado or it might be too late once it’s in sight. There have been instances where a wooden post was thrown through a concrete sidewalk. Anything in a tornado’s path can become a projectile and you need to be sure you stay away from windows. If you do not have a lower-level, or an interior room, then go to the bathroom and put a mattress overtop of you to shield you from any flying debris. If you have a storm shelter, get in it and stay there until the threat no longer exists. If you are caught outside, get inside immediately. If you are in your car, then you need to pull over and seek shelter. Vehicles are easily tossed around by a tornado, and as such, you should get out of the vehicle and lie flat on a low-lying part of the ground such as a ditch away from vehicles. You should not seek shelter under an overpass due to the wind increasing speed when tunneling under the overpass.
You must take action as soon as you know you are in danger. The more time you spend planning, the less time you will spend in the danger zone. Ensure your family also knows the plan so everyone knows what to do and where to go. You should also stay updated on the latest forecasts especially if you live or work in a high threat area. Stay close to a radio or a local news station to get the latest watches and warnings.
Helpful websites include:
Storm Prediction Center – www.spc.noaa.gov
National Weather Center – www.weather.gov
Global Weather and Climate Center – www.globalweatherclimatecenter.com/severe
ⓒ 2017 Meteorologist Brandie Cantrell
DISCUSSION: In light of several nor’easters battering the Midwest and northeast of the United States in the past few weeks, it is interesting to view the factors that determine whether or not a storm has the right recipe for a snow day to be issued. Some states, particularly in the South (think Florida, parts of Texas, etc.), may close schools even though the projected forecast may call for only up to one inch over 24 hours. Other states, like those in the north central plains and Rocky Mountains, normally require much higher snow amounts to close schools. The following is a list of factors that determine calling a snow day with a quick description and/or example for each:
Timing – When the snow will fall, i.e. during the day, overnight, intermittent, when it will start and end
Snowfall intensity – 2 inches of snow in 12 hours vs. 2 inches of snow in 1 hour (the latter occurred recently in winter storm Quinn in the northeast). Snowplows have difficulty keeping up with high snowfall rates.
Ice accumulation – Causes hazardous driving conditions, even a thin layer can be dangerous
Ground temperature – Can be warm enough for falling snow to melt, may melt snow but refreeze overnight, can determine if traction is possible for tires when traveling, important on overpasses and bridges
Wind chill – protect the safety of students and staff
Power outages – current outage or extremely likely chance of losing power, some schools look at power outages in immediate surrounding area even if the school itself still has power
Non-weather factors - resources to remove snow, available snow days left, state testing make-up dates
Ultimately the decision to close school and issue a snow day is for the safety of students and everyone involved. Some of these factors are more relevant than others depending on where one lives. For example, wind chill is more prevalent in the Midwest while snowfall intensity and power outages can be a deciding factor in the Northeast. Those living in the South may not see much snow but can sometimes be the recipients of an abundance of ice.
Check out this link to read the full article and view an intriguing snow map.
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©2018 Meteorologist Nicholas Quaglieri