To follow up on my annual meteorological images of the year article, here is a monthly edition with highlights from January 2017, and an opportunity to show some of the ingredients and processes in the atmosphere that create stormy weather.
The good news from last month is that we started receiving the first products via NOAA & NASA from the next generation of weather satellite, GOES-16 (known as GOES-R at the time of launch), like the picture above. Currently in this part of the world we only get images with such high resolution a couple times each day, but once this satellite is fully operational we’ll be receiving them every few minutes, even as frequently as 30 seconds when in “rapid scan” mode, and which in turn can be made into loops. I can’t wait!
Other good news was that California, after years of extreme drought, received lots of beneficial precipitation.
The bad news is that in January the weather was very destructive and deadly. That included tornado outbreaks near the Gulf Coast, a major ice storm in the central states, and a severe nor’easter; and the Cali precip was a double-edge sword as it also produced extensive flooding (including in SoCal, and without El Niño being present, further debunking that misperception).
The massive ice storm occurred due to an unusually large area with a warm layer aloft on top of below-freezing temperatures at the surface.
In the alternating maps below, the one with yellow & green shades was an analysis of temps a few thousand feet up, with those colors representing warm air, well above freezing, in which snowflakes from above melted into raindrops. The one with colder shades showed temperatures at the surface of the Earth, with blues being 32° or lower; as the rain fell onto the cold surfaces, it froze and turned into ice on roads, trees and power lines.
Most of the tornadoes last month weren’t the “Wizard of Oz” type that form during the daytime from discrete supercells. Many were at night, a particularly dangerous time, and were associated with lines of thunderstorms, which can seem like ordinarily squall lines with straight-line winds but then all of a sudden twisters spin up.
The year got off to a bad start on the 2nd as people lost their lives in Rehobeth, Alabama. Red shades on the left side graphic depict heavy rain and represented thunderstorms. An amorphous cluster ahead of a line of storms merged with the line. In the process, a strong circulation developed. Red/green colors on the right half of the graphic indicate winds blowing in opposite directions, and where they intensified tightly adjacent to each other near the red dot, which is the location of Rehobeth, that was indicative of the tornado.
Later in the month was the second largest January tornado outbreak on record. Many of the tornadoes were produced by this line of thunderstorms, within which were irregularities and circulations.
That was all part of a wicked coast-to-coast storm system, and as it headed up the East Coast it evolved into a enormous circulation. As this model forecast of low-level wind speeds accurately predicted five days in advance and enabled us to alert people ahead of time, that included a strong onshore flow in Delaware and New Jersey into New England, with wind damage and coastal flooding the result. At the surface the wind direction was from the northeast, from which the term nor’easter comes.
Finally, as the month ended, another big swirl, this one over the Pacific and about to lead to more storminess across the U.S. as we head into February…