Storms Head Across the U.S. This Week

Scott Olson/Getty Images
Scott Olson/Getty Images

We just lived through one of the warmest winters in recent memory. The warmth and relative lack of storminess was odd compared to a normal year, but the weather was downright quiet compared to what we've seen over the last couple of years. Unfortunately, our luck is running out as the Sun creeps into the Northern Hemisphere and the atmosphere slowly warms up. The clash of the seasons will cause a steady train of storms to glide across the country through the end of March, bringing along with them noticeably rapid changes in weather from day to day, including the risk for severe thunderstorms and some beneficial heavy rainfall.

The forecast position of the jet stream from the GFS weather model on the evening of Monday, March 27, 2017, showing three troughs (southward dips) in the jet stream as they cross the United States. Image Credit: Tropical Tidbits

 
Current weather models suggest that a series of upper-level troughs—elongated areas of lower air pressure—will come ashore on the West Coast every couple of days for the next two weeks, each wave taking about three days to traverse the length of the United States before retreating over the Atlantic Ocean. Each trough will be sandwiched between ridges of high pressure, which are associated with warmer air and calmer skies. This trough-ridge combination will allow warm, unstable air to flow north from the Gulf of Mexico before the trough arrives to take advantage of the favorable atmosphere ahead of it. The end result will be heavy rain and thunderstorms, some of which could turn severe.

The greatest risk for severe thunderstorms with each wave will lie across the southern Plains and interior sections of the Gulf Coast states, exactly where you'd expect dangerous weather to develop at the end of March. The extent of the severe weather depends on how much instability, moisture, and wind shear are present when the storms bubble up. If the right mix of ingredients doesn't come together at the right time, the weather won't be much more than an inconvenience. If storms are able to take advantage of the right conditions, though, all types of severe weather—damaging winds, large hail, and tornadoes—will be possible with each outbreak of severe thunderstorms.

It shouldn't come as too much of a surprise that severe weather is ramping up as we get closer to April. We're rapidly approaching prime season for severe thunderstorms and tornadoes. The average number of tornadoes that touch down each day climbs rapidly between the end of March and the beginning of summer, with each day of spring becoming historically more favorable for nasty severe weather outbreaks.

The Weather Prediction Center's precipitation forecast (in inches) between March 24 and March 31, 2017. Image Credit: NOAA/WPC

 
The silver lining to the cycles between calm and stormy is that it will bring much-needed rain to just about everyone east of the Rockies who are currently experiencing drought conditions. The same weather pattern that allowed California to climb out of its drought in just a couple of months also dried the eastern half of the country to the point of drought. Moderate to severe drought conditions covered nearly 16 percent of the contiguous United States on the U.S. Drought Monitor's analysis for March 21, with the worst drought covering the central Plains and much of the East Coast.

Rain from the upcoming train of storm systems will drop several inches of rain over a widespread area, helping to put a small dent in the drought. It won't be enough to cure the parched earth in many places, but as Californians will tell you, any amount of rain can help.

What Is a Bomb Cyclone?

Maddie Meyer/Getty Images
Maddie Meyer/Getty Images

The phrase bomb cyclone has re-entered the news this week as parts of the central U.S. face severe weather. Mountain and Midwestern states, including Colorado, Nebraska, Wyoming, and South Dakota, all fall in the path of a winter storm expected to deliver tornadoes, hail, heavy snow, flooding, and hurricane-force winds on Wednesday, March 13 into Thursday. It seems appropriate for a storm that strong to have bomb in its name, but the word actually refers to a meteorological phenomenon and not the cyclone's explosive intensity.

According to The Denver Post, the bomb in bomb cyclone stands for bombogenesis. Bombogenesis occurs when a non-tropical storm experiences at least a 24 millibar (the unit used to measure barometric pressure) drop within 24 hours. Low pressure makes for intense storms, so a bomb cyclone is a system that's built up a significant amount strength in a short length of time.

This type of storm usually depends on the ocean or another large body of water for its power. During the winter, the relatively warm air coming off the ocean and the cold air above land can collide to create a sharp drop in atmospheric pressure. Also known as a winter hurricane, this effect has produced some of the worst snowstorms to ever hit the U.S.

The fact that this latest bomb cyclone has formed nowhere near the coast makes it even more remarkable. Rather, a warm, subtropical air mass and a cold, Arctic air mass crossed paths, creating the perfect conditions for a rare bombogenesis over the Rockies and Great Plains states.

Central U.S. residents in the bomb cyclone's path have taken great precautions ahead of the storm. Over 1000 flights have been canceled for Wednesday and schools throughout Colorado have closed.

[h/t The Denver Post]

Watch a Rare ‘Ice Tsunami’ Slam Lake Erie

Clean Lakes Alliance, Flickr // CC BY 2.0
Clean Lakes Alliance, Flickr // CC BY 2.0

A combination of freezing cold temperatures and high winds is creating an unusual phenomenon along Lake Erie. As KDKA reports, ice tsunamis are toppling onto lake shores, and many locals have been asked to stay inside and even evacuate their homes.

On February 24, 2019, the National Weather Service in Buffalo, New York issued a warning about dangerous wind gusts in the Lake Erie area. The service urged citizens to seek shelter indoors and avoid traveling if possible. Winds peaked at 74 mph earlier this week, the level of a Category 1 hurricane, and tore down trees and power lines throughout the region.

People who got close to Lake Erie during the windstorm witnessed a rare event known as an ice tsunami. When wind pushed ice on the lake's surface toward the retaining wall, the sheet broke apart and dumped massive ice chunks on the shore. The video below captures the phenomenon.

In some areas, the ice piles grew so large that roadways had to be closed. Residents of Hamburg, New York's Hoover Beach area were asked to voluntarily evacuate due to the encroaching ice.

Ice tsunamis, or ice shoves, are rare, but in some cases they can be life-threatening. In 2013, waves of ice shards from a Minnesota lake destroyed people's homes.

[h/t KDKA]

SECTIONS

arrow
LIVE SMARTER