Big storms, severe weather, snow and floods hit the US

The storm’s final stop will be in New England in midweek, where some areas could be hit by the typically late-season heavy snowstorms.

Spring is known as one of the most volatile and disruptive times of the year in North America. Collision of air masses resulting from seasonal warmth and prolonged winter cold can produce powerful weather systems like this early storm.

California was hit by heavy rain, hail and mountain snow.

The storm began Saturday and pushed an atmospheric river into the West Coast. Rain continued to fall Sunday, and flood watches were in effect across Southern California, including San Diego and Los Angeles.

In San Diego, 1.30 inches fell on Saturday; Record set on March 30th. High water flooded several streets.

Two to three inches of rain had fallen in the Los Angeles area by Sunday morning, and the National Weather Service warned that up to 0.75 inches of rain could fall per hour if the downpour continued.

Santa Barbara had received 3.93 inches of rain by Sunday morning, with up to 6.5 inches falling in the mountains just north of Santa Barbara. Floodwaters submerged five vehicles and closed southbound Route 101 at San Ysidro Road in Santa Barbara County Saturday night.

Heavy snow blanketed the mountains of Central and Southern California. A winter storm warning blanketed the Sierra Nevada, with up to several feet of snow possible, and extended into the mountains east of Los Angeles, where up to 8 inches of snow could fall into Sunday night. On Saturday evening, 14 inches of snow was reported at Big Bear Mountain Resort in San Bernardino County.

Severe thunderstorms expected to continue for several days

The same storm system impacting California is forecast to form a new low-pressure belt east of the Rocky Mountains late Sunday, causing a severe multi-day threat of severe thunderstorms.

Ahead of this new low-pressure system, a stagnant band of warm, moist air in the eastern United States could swirl from the Gulf of Mexico into the central states, providing fuel for severe storms.

Meanwhile, a drop in the jet stream pushes into warmer, moister air masses. There will be storms for several days. The addition of high-altitude winds associated with the jet stream causes shear, or changes in wind speed and direction with altitude. This can cause rotation in some storms, creating a tornado risk.

There may not be as many storms on Sunday, but a few could intensify along the northern edge of the high pressure system and its associated warm air mass from Missouri to southwest Virginia. The storms will likely be most prevalent in northeastern Missouri, central Illinois, and western Indiana. There, the Japan Meteorological Bureau’s Storm Prediction Center has given it a level 2 out of 5 danger zone.

The main concerns are locally damaging winds and hailstones that are about a quarter the size of the storm. The risk of isolated tornadoes is minimal.

The threat of severe weather will become more pronounced Monday as a storm system becomes more organized over the central states. The area with a 3 out of 5 enhanced risk for severe storms stretches from the Oklahoma City metropolitan area to southwestern Indiana and includes Tulsa and the Missouri cities of Springfield, Joplin and St. Louis. .

Three zones in particular should be monitored:

• A warm front from central Missouri to Indiana. A warm front could increase spin and increase the chance of tornadoes by early afternoon.
• Along the “triple junction” of the storm in Oklahoma. A triple point is where dry air, moist air, and cold air all meet near the center of a low pressure system. This will strengthen low-level easterly winds, increasing the risk of tornadoes and potentially producing large, destructive hailstones the size of baseballs.
• Squall line in the southern plains. Most of Oklahoma, Texas, and Arkansas will be affected by a confluence of storms that could form a windy squall line. Embedded fast-acting tornadoes can form within the spin twists surrounded by the entire squall line. It will last until night.

Areas from Kentucky to western West Virginia are at a Level 3 out of 5 risk for severe weather as the storm heads east Tuesday. This zone includes Cincinnati, Louisville, and Charleston, West Virginia. Level 2 danger extends from northern Mississippi and Alabama to the mid-Atlantic.

“The greatest tornado threat is predicted from eastern Kentucky to West Virginia,” the Storm Prediction Center wrote.

Thunderstorms are possible across the Mid-Atlantic by Tuesday evening, reducing the risk of tornadoes, but wind damage remains possible. The Washington-Baltimore area is in the Level 2 danger zone, but a wedge of cold air could limit the chance of severe storms there.

Midweek snowstorm possible in interior New England

The final act of a storm system can occur in the form of a late-season snowstorm.

On Tuesday, the same jet stream drop associated with severe thunderstorms in the central states will be absorbed by an even stronger upper-level disturbance over the Great Lakes. The disruption will pull colder air south, potentially turning rain to snow and reaching as far as Chicago and southern Michigan by Tuesday night.

Coastal storms are possible east of Long Island as the Great Lakes disruption impacts the Northeast into Wednesday. Rain is most likely in coastal areas, but heavy snow is possible in interior New England on Wednesday and Thursday. It’s too early to predict amounts, but some areas, especially at higher elevations, could easily see at least 6 to 12 inches of rain.