A look at the omega blocking pattern that will lead to flooding concerns

“Plenty of moisture will be underneath those lows. It's a slow-moving pattern that will kind of keep us locked in place with rain," said FOX Weather meteorologist Jane Minar.

A rather unusual weather pattern for early May is setting up across the United States, one that meteorologists warn will lead to a stagnant pattern with prolonged periods of warmth in some areas and steady rain in others.

The pattern, known as the "omega block," is named after the Greek letter omega and disrupts the usual zonal flow of weather systems.

As a result, two distinct regions of precipitation are expected to dominate the workweek: one stretching from the Southern Plains to the Gulf Coast, and another affecting the Northeast.

"Plenty of moisture will be underneath those lows. It's a slow-moving pattern that will kind of keep us locked in place with rain," said FOX Weather meteorologist Jane Minar.

WHAT IS AN OMEGA BLOCK?

Forecast models indicate a widespread 3 to 6 inches of rainfall across the South, with isolated areas possibly receiving even more. 

The rain may also be accompanied by strong thunderstorms, some of which could reach severe levels.

Cities such as New Orleans, Jackson, Mississippi, and Alexandria, Louisiana are either in or near the bullseye for where the heaviest rain is expected to fall through the week.

Some communities in the region are especially vulnerable, as many have already experienced torrential rainfall in recent weeks.

The FOX Forecast Center warns that saturated ground and elevated river levels will increase the risk of flooding, especially in low-lying or poorly drained areas.

The highest flood risk is expected from Tuesday evening through early Wednesday, when over 50 million people across the southern U.S. will be under Level 1 to Level 3 flash flood risks, according to NOAA’s Weather Prediction Center.

In contrast, the Northeast stands to benefit from the incoming precipitation. Forecast models predict 1 to 3 inches of rain across the I-95 corridor, with locally higher amounts possible.

The rainfall could provide welcome relief to regions experiencing moderate to severe drought along the eastern seaboard.

This type of pattern is not known to produce extensive severe weather outbreaks, as the dynamics aren’t in place, but localized bouts with hail and gusty winds are possible.

SOMETHING A BIT UNUSUAL IS HAPPENING IN THE TROPICS WITH LESS THAN A MONTH TO GO BEFORE HURRICANE SEASON

Meanwhile, regions outside the influence of the low-pressure systems will experience drier air and temperatures that will vary significantly. 

The Northern Plains are expected to see highs climb into the 70s and 80s, while parts of the Southwest, including cities like Las Vegas and Los Angeles, may struggle to reach seasonal norms.

"It’ll feel more like Christmas in Los Angeles and the Fourth of July in Fargo," Minar noted.

Looking ahead, forecasters anticipate that the jet stream will begin to shift by the upcoming weekend, allowing a return to a more typical springtime weather pattern across a large section of the country.

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