FROM THE NATIONAL WEATHER SERVICE - PADUCAH
Tornados can occur during any month of the year here in the Lower Ohio Valley. This chart below shows the number of tornadoes by month from 1996 to 2011. Although there is a peak in the spring and fall, the most important point is that we have had tornadoes every month. You need to be aware of this fact.
Plus a lot of our tornadoes that occur in the winter happen at night.
This is also evident by looking at tornadoes by the time of day.
Yes, most tornadoes happen in the late afternoon and evening, but notice that we have had almost 40 tornadoes between midnight and 6AM when most people are asleep.
Tornadoes in the winter act a bit differently than they do in the spring. One of the most important features of tornadoes in the winter is that they move extremely fast and develop extremely fast. It is not uncommon for tornadoes in the winter to move at speeds of 60 to 70 mph! That means that your time to react and to get to safety is shorter than during other parts of the year. Make sure you have plans for home, at work, and at your place of worship.
We issue warnings for tornadoes based upon three things:
1) The environment: Tornadoes are most likely in the winter when the winds are very strong throughout the atmosphere and when there is a very small amount of instability (warm, moist air near the ground). This information can help you too. Whenever you notice it is unusually warm and humid outside, you need to be on alert. More than likely thunderstorms, and possibly severe weather, will be in the area within 48 hours. One of the ways you can keep ahead of this is by looking at our Outlooks page. That page will show you what we expect to happen for the next few days.
2) Spotter Reports: Each year we train hundreds of volunteers to contact us when they see certain cloud formations or experience strong, damaging winds, hail, or if they see a funnel cloud or tornado. Storm spotting in the winter can be very difficult as the storms are moving and developing rapidly, and often it is dark, so it is difficult to see the cloud formations. We now also use Facebook (https://www.facebook.com/US.NationalWeatherService.Paducah.gov) and Twitter to gather reports. We send tweets as #NWSPaducah and we monitor the following streams: #nwspah and #tristatewx for weather reports.
3) Radar: Doppler radar cannot see the actual tornado. However, the circulation associated with tornadoes extend well into the cloud in most cases. We look for this larger circulation, and once we see the circulation intensify, a tornado warning is issued. Almost all storms have some rotation, but the strength of the rotation is one of the things we look for on radar. When we go back and research past cool season tornadoes, some of them go from little or no rotation in the cloud to producing a tornado on the ground in just 10 minutes! There is still a lot of research to be done on these tornadoes to better understand them.
In an ideal world, we would like to have all 3 of the above items available to us before we issue warnings, but that is not always possible. Sometimes there are no spotter reports, and sometimes the atmosphere is marginally favorable for tornadoes to form. So, we often have 2 out of the 3 and we then issue warnings based upon the information we have. We, as meteorologists, know that there is still much to learn about the atmosphere and how it works, but we make decisions based upon the information we have.
If you think about it, this is very similar to how a doctor might think when you go into an emergency room. They do not have all the information, but they look for symptoms, listen to you, and then make decisions based upon that information.
Safety is key and part of being safe is having a plan. If a tornado moves through your neighborhood at 2 AM, how are you going to know? If we issue a tornado warning at 2AM, will you know about it? How are you going to know about tornado warnings when you are asleep.
There are several ways to make sure you are awake.
1) Purchase and program a NOAA Weather Radio. We can help you program them.
2) Appoint a family member to stay up and watch the weather, then have them call some friends and relatives before the storms move into your neighborhood and make sure people are awake.
3) Subscribe to receive warnings via your cell phone. Several local media outlets provide this service for free or a nominal fee. In addition, tornado and flash flood warnings are received for free on smart phones with WEA technology.
In addition, have a plan to know where to go. Again, there is little time to react during the winter when severe weather arrives. You have to have a safe location in your home, office, place of worship, before severe weather starts. If you have a basement or a storm shelter, great, that is likely the safest location. If not, try to find a room or a hallway that is near the center of the building on the lowest floor. Try to put as many walls as possible between you and the outside of the building. Schools have tornado drills, you need to make sure everyone in your home or business knows where to go when severe weather strikes. It is not if severe weather will occur, it is when.