By Jim Stefkovich, Meteorologist, Alabama Emergency Management Agency
CLANTON – The National Oceanic and Atmospheric Administration (NOAA) has come out with their predictions for this winter (December – February). As you can see from the graphics below, there is a good chance (40%-50%) that temperatures will “average” above normal and precipitation will “average” below normal (33%-50% chance).
What does this really mean? Let’s look at an example. For Huntsville from December – February, high temperatures average in the 40s. Are there days when the actual high temperatures will be both higher and below the average temperature? You bet! If one day the high temperature reaches 60 degrees, and the next day it only reaches 30 degrees, 60+30=90, divide 90 by 2 (for two days). That equals 45, and the average temperature for those two days is 45 degrees, even though one day was much higher and the next day was much lower.
The average high temperature for a month is to take all the high temperatures for each day and divide that by the number of days in the month. Then, NOAA figures out what occurred for each month over the past 30 years, and that is where the “average” is finally determined. The same applies with low temperatures and precipitation.
All this to say, this is NOAA’s climate forecast based on expected weather patterns across the US this winter. The higher the probability percentage, the greater the confidence in the forecast. But, this is NOT a day to day forecast for this winter. Could there be days that are extremely cold with one or more winter storms across Alabama? ABSOLUTELY! Don’t let your guard down this winter based solely on these climate forecasts.
Finally, before we get too far into winter, remember we are about to enter our secondary severe weather season across the state, with high winds, flooding and tornadoes. I’ll write more about that in the next blog.