Weather Gadget Dubbed 'Rain Machine' Affects Southern U.S. Over Mother's Day Weekend
Mother's Day Weather Woes: Deep South Stuck in a Rainstorm Rut
Expect a splash while you're out Mother's Day dinners in the Southeast, as the region is locked into a damp pattern all weekend long, with rainfall extending into the early part of next week. Here's a simple breakdown of the weather phenomenon behind this wet weather binge in Mother's Day weekend.
The National Oceanic and Atmospheric Administration's (NOAA) Weather Prediction Center (WPC) noted, "A lazy storm system along the Gulf Coast will churn out heavy rain and thunderstorms this weekend and into the initial half of next week." The villain here is an upper-level low meandering over the Deep South, according to WPC. Meteorologically, Gulf moisture and a stationary front offer a "lift" that could trigger daily thunderstorms. WPC also FLAGGED an expansive Marginal Risk (threat level 1/4) for Excessive Rainfall from the Lower Mississippi River Valley to as far east as the Southeast coast each day this weekend. Parts of Florida Panhandle, Alabama, Georgia, and South Carolina have received a Slight Risk (threat level 2/4).
By Sunday, the upper low won't have moved much at all and will remain resolutely over Louisiana. This stationary setup provides a "moisture pump" into the Southeast, guaranteeing a wet Mother's Day for many. Let'
's delve deeper into this weather scenario.
What's the Deal with a Cutoff Low?
The "rain machine" in question is not a conspiracy theory, but a common weather occurrence. University of South Alabama meteorologist Jordan McLeod referred to it as a "classic cutoff low pattern in a transition season." So, what exactly is a cutoff low? According to the National Weather Service, it is an upper-level low-pressure system that has become detached from the surrounding flow and moves independently.
Meteorologically, the circulation around a low is counterclockwise in the Northern Hemisphere. In this scenario, the low over Louisiana draws moisture from the Gulf region. Historically, such weather patterns have led to events like the major flooding Atlanta experienced in 2009 when a cutoff low settled to the west of Georgia. A 2025 study published in the journal Nature suggested these atmospheric quirks may become more frequent.
Atmospheric River in the South?
Although the term "atmospheric river" is more commonly associated with the West Coast, the southeast is susceptible to similar setups. Ben Noll described this weekend's atmospheric river scenario in the Washington Post. Though less common, eastern atmospheric rivers can bring substantial precipitation to the region. Researchers at the University of Georgia published a 2017 study documenting these atmospheric river events impacting the southeastern U.S from 1979 to 2015. So, remember to carry your umbrella for those Mother's Day celebrations this weekend.
[1] https://www.nws.noaa.gov/om/geo/atmospheric_rivers.pdf[2] https://www.nature.com/articles/nature15440
- The National Weather Service (NWS) explains that a cutoff low is an upper-level low-pressure system that moves independently, such as the one currently over Louisiana, contributing to the excessive rainfall in the Lower Mississippi River Valley and beyond.
- In environmental-science terms, the atmospheric river in question is the movement of water vapor from the Gulf region into the Southeast, bringing rainstorms and flooding risks for areas including Georgia, Alabama, Florida, and Louisiana.
- As documented in a 2017 study by researchers at the University of Georgia, eastern atmospheric rivers, like the one this weekend, can bring substantial precipitation to the southeastern U.S, as seen in the Mother's Day 2009 flooding in Atlanta.
- According to a 2025 study published in the journal Nature, atmospheric quirks like cutoff lows may become more frequent, potentially leading to increased flood risks in the future.
- In weather forecasting, the National Weather Service (NWS) has flagged a Marginal Risk (threat level 1/4) for excessive rainfall from the Lower Mississippi River Valley to the Southeast coast this weekend, with parts of Florida Panhandle, Alabama, Georgia, and South Carolina on Slight Risk (threat level 2/4).
