Day 19: Riding the Wave Train
After last week was relatively quiet, albeit cold in places, this week is promising to be very active in terms of low pressures, upper-level lows, and precipitation. Just look at the 5-day precipitation forecasts from the Hydrometeorological Prediction Center posted from a few days ago! One reason for the wet, stormy weather pattern is the number of storm systems (an organized collection of low pressure/height throughout the atmosphere) that are identifiable on water vapor.
In the image below, five upper-level lows are circled – two in yellow and three in red. I’ve used two colors to distinguish between upper-level lows that have aided in the recent west coast deluge (red) and those that haven’t (yellow). (Author’s note: It is possible to identify additional upper-level lows, vorticity maximums, and/or short-wave troughs; however, I only circled those “easily identifiable” on a single image – not a loop.) When analyzed on weather maps, upper-level lows often look like waves with crests (ridges) and troughs (troughs). When several of these waves line up one after another, similar to box-cars on a train, meteorologists call it a wave train. Hence the name of this post.
The eastern (rightmost) upper-low circled in red is currently aiding the development of showers and thunderstorms across the southern plains and will affect a large portion of the central United States on Wednesday. In fact, Ice Storm Warnings are in effect for a good portion of Iowa and a chance of severe weather is possible across a large portion of the north central Gulf Coast states.
The middle of the upper-lows circled in red moved onshore in southern California this afternoon and resulted in at least three tornado reports along the California coast. The western (leftmost) upper-low circled in red also came ashore earlier today with a myriad of severe weather associated with it. I’m uncertainly, but one of these two upper-lows was responsible for a wind gust of 93 mph recorded at Newport Beach Pier.
The parent long-wave trough (giant upper-low) responsible for these short-wave troughs (smaller upper-lows) will remain off the west coast for the next several days. When this long-wave trough begins to move eastward, a decent severe thunderstorm threat will be possible across a large portion of the southern United States.
