NEW ORLEANS (AP) — Powerful storms with a threat of tornadoes are expected to punch through Louisiana and other parts of the South on Tuesday just as huge parades and costumed revelers are set to celebrate Mardi Gras in New Orleans and other southern cities.

The alarming forecast will be one of the first big tests for the National Weather Service after hundreds of its forecasters were fired last week under President Donald Trump’s moves to slash the size of the federal government. Former employees say the firing of meteorologists who make crucial local forecasts across the U.S. could put lives at risk.

Multiple weather threats loom this week for the U.S., starting with dust storms that brought near-zero visibility to parts of New Mexico and west Texas, prompting the National Weather Service to issue Dust Storm Warnings, the agency said. “Widespread blowing dust,” was expected Tuesday, said the weather service office covering Midland and Odessa, Texas.

A strong weather system this week will bring “a threat of blizzard conditions, high winds, flash flooding, severe weather, dust storms, and critical to extreme fire weather conditions to the nation’s heartland,” the weather service said in an update Monday.

On Tuesday, twisters, damaging winds and large hail are all possible as a strong storm system moves across the nation’s midsection into Arkansas, Louisiana and Mississippi, the federal Storm Prediction Center warns.

The bullseye is a zone designated at an enhanced risk of severe weather — an area stretching from east Texas to Alabama that’s home to more than 7 million people. The area under threat includes Baton Rouge and Shreveport in Louisiana; Jackson, Mississippi; and Mobile, Alabama.

The New Orleans area is also bracing for strong storms, though Fat Tuesday’s traditionally raucous annual rite of parades of floats and costumed merrymakers remain scheduled to hit the streets, with some changes still being worked out by authorities and leaders of “krewes” — social clubs that organize parades.

“We’re going to start off with an earlier start time,” said Elroy James, president of the Zulu Social Aid and Pleasure Club. “All krewes have been willing to lean in and make whatever adjustments necessary.”

Yet just outside New Orleans in neighboring Jefferson Parish, officials canceled planned Mardi Gras Day parades due to anticipated high winds and thunderstorms Tuesday.

Mardi Gras floats “could become unstable” and heavy winds could “blow down trees and power lines,” The National Weather Service warned. Wind gusts of up to 60 mph (97 kph) are expected Tuesday afternoon, the agency said.

“This is disappointing, but our top priority is ensuring the well-being of everyone in our community, and we must always prioritize safety above all else,” Jefferson Parish President Cynthia Lee Sheng said in a statement.

In Pointe Coupee Parish, which is near Louisiana’s capital city of Baton Rouge and boasts having one of the oldest Mardi Gras celebrations in the state, the incoming weather forced drastic changes to Mardi Gras festivities. The parade there is scheduled to roll without any bands, marching teams or dance groups — a staple of Carnival Season parades.

In addition, the parade start time was moved up, and officials urged residents to remove all tents and trash after the parade ends “due to the dangers they can present during weather.”

Elsewhere, large crowds were expected Tuesday for Mardi Gras celebrations in Mobile, Alabama. Police there said they were continuing to monitor the forecast and would let the public know if plans for the celebration change.

Other cities hosting large Mardi Gras events included Biloxi, Mississippi, where an annual Mardi Gras parade was scheduled to start at 1 p.m. Tuesday.

In downtown Pensacola in the Florida Panhandle, organizers are planning a Big Easy-style Mardi Gras festival that includes food trucks, dancing, live entertainment and a low country seafood boil.