When meteorologist educators teach students of all levels, one of the first things we do is to distinguish the difference between weather and climate. Technically speaking, weather is the day-to-day conditions that describe the state of the atmosphere, while climate is an average of weather conditions at a particular place, generally averaged over a 30 year time period. In my classes, I always say that the best way to remember this distinction is that ‘weather impacts your daily life’. Many disruptions to people’s lives were caused as a result of a very dynamic spring weather pattern which has been present over the continental United States for the last few weeks.
A strong low pressure system located along the Mississippi River on the morning of April 14, 2019 was responsible for dramatic weather conditions in many locations east of the Rockies. There was accumulating snow across parts of the Midwest, from Missouri into Illinois and Michigan. Some locations received double-digit snowfalls. At the Chicago O’Hare International Airport, a record 5.4 inches of snow fell, breaking the old record for that date set in 1980 and tying the record for all-time largest April snowfalls set in 1961.
On the east side of the storm, a strong jet stream, very warm surface temperatures, and plentiful low-level moisture allowed for severe thunderstorms to develop along and east of the Appalachian mountains.
Surface temperature contrasts were very large across the eastern half of the United States. While the temperatures in the Midwest stayed in the 30s, in the mid-Atlantic and along the Eastern Seaboard temperatures on April 14 soared into the upper 70s. The surface map below shows temperatures at approximately 3:00 PM EDT (the red numbers represent the temperature). Notice that across the (relatively small) state of Indiana, the temperatures at this time ranged from 37 to 70 degrees!
The Storm Prediction Center issued a series of tornado watches during the afternoon and evening hours of April 14 which covered parts of Florida up through the Northeast. Numerous severe thunderstorm and tornado warnings were issued as the evening progressed, and there were many reports of damage as lines of severe and tornadic thunderstorms marched eastward.
So, back to the ‘weather vs. climate’ discussion: how did this weather system impact people’s daily life? In addition to widespread reports of structural damage and downed trees, air travel was disrupted all across the United States as a result of the storm. Flights in the Midwest were delayed due to periods of moderate snow, low ceilings and low visibility. Airports all up and down the East Coast struggled to land (often delayed) flights in poor conditions which included heavy rain, strong surface winds, and strong wind shear (changing wind speed and/or direction) in the low levels of the atmosphere. There were many pilot reports of moderate to severe turbulence.
So did the weather impact my daily life? The image below shows a particular flight which landed, over five hours late, at the Albany International Airport very early in the morning on April 15.
Notice that there are thunderstorms in the vicinity, and that the flight descent into Albany involved numerous twists, turns, and one aborted landing due to strong crosswinds. One of my family members whom I was picking up at the Airport that night ranked this landing as the second most turbulent he has experienced (maybe the weather conditions which occurred on the one which holds first place should be the topic of a future blog post!). Thus, the adage that ‘weather impacts your daily life’ was certainly true for the author on April 14-15, 2019!