Weather Whiplash: Blizzard Conditions, Record Heat and Flood Threats Strike the U.S. at Once

On a recent afternoon in downtown Los Angeles, construction workers ducked into slivers of shade and passed around bottles of water as thermometers pushed into the low 90s—a level of heat more typical of July than mid-March. Two thousand miles away on Minnesota’s North Shore, snowplow crews fueled up in a biting wind, bracing for whiteout conditions and drifts that could rise past the hoods of their trucks.

The scenes bookend an extraordinary stretch of “weather whiplash” across the United States, as a contorted jet stream and a weakened polar vortex combine to deliver blizzard conditions, record heat, flooding rain and sudden temperature crashes—often within the span of a day.

Forecasters at the National Weather Service say that through at least early next week, a deep trough of low pressure and an associated Arctic air mass will plunge into the central and eastern United States, while a strong ridge of high pressure—effectively a heat dome—parks over the Southwest. At the same time, a Pacific storm system is channeling an atmospheric river into the Pacific Northwest, and a powerful Kona storm is dumping heavy rain on Hawaii.

“Pretty much everybody in the country is going to see a change—either from cold to warm, or from warm to cold to warm again,” said Marc Chenard, a meteorologist at the Weather Prediction Center in College Park, Maryland. Former National Oceanic and Atmospheric Administration chief scientist Ryan Maue described the setup as capable of producing “extreme weather in all 50 states” over the course of the event.

A contorted jet stream

The pattern taking shape in mid-March is the product of a highly amplified jet stream, the fast-moving river of air high above the surface that steers storms.

A strong upper-level ridge over the Southwest and parts of California is locking in unusually hot, dry conditions there. To the east, a sharp dip in the jet—a deep trough—is opening a pathway for Arctic air to surge south over the Plains, Midwest and eventually the East Coast.

Over the Pacific, a separate storm system is drawing a plume of subtropical moisture toward the Pacific Northwest, forming what scientists call an atmospheric river, capable of producing inches of rain in a short time and feet of snow at higher elevations. West of Hawaii, a Kona low—a slow-moving, deep area of low pressure that forms to the leeward side of the islands—is spinning bands of heavy rain over the state.

The World Meteorological Organization has noted that a stratospheric warming earlier in the winter helped weaken and displace the polar vortex, the pool of frigid air normally trapped over the Arctic. Such disruptions can increase the likelihood of late-season cold air intrusions into North America, even as background temperatures trend warmer.

Winter hangs on in the Upper Midwest

In the Upper Midwest and Great Lakes, the clash of Arctic air and a strengthening surface low is setting the stage for a significant late-season snowstorm.

The Weather Prediction Center expects moderate to heavy snow from the northern Plains into the Upper Midwest and Great Lakes, with more than a foot of accumulation possible in parts of Wisconsin and Michigan. A Blizzard Warning has been posted for Minnesota’s North Shore, including southern Lake and southern Cook counties, where forecasters warn of an “extraordinary threat to life or property” from blowing snow and winds strong enough to produce whiteout conditions.

Behind the storm, temperatures are forecast to plunge, with wind chills dipping well below zero in portions of the northern Plains and upper Great Lakes that had seen milder weather earlier in the month.

The combination of heavy, wet snow and gusty winds raises the risk of downed trees and power lines, potentially knocking out electricity to thousands of customers. Interstate highways, including I‑35 and I‑94, could see closures or long delays, and airports in Minneapolis, Duluth, Green Bay and Detroit are preparing for possible disruptions.

Online, residents of Minnesota and Wisconsin circulated National Weather Service snowfall probability maps showing low-probability “worst case” totals near 2 feet around the Twin Cities, a range that prompted both nervous comparisons to the notorious 1991 Halloween blizzard and questions about how to interpret uncertain forecasts.

Spring, then winter, in the Northeast

The central and eastern United States have already had a taste of how violent this transition can feel.

On Wednesday, Washington, D.C., hit 86 degrees, breaking a March temperature record as joggers filled park trails in shorts and T‑shirts. By Thursday morning, wet snowflakes were swirling around the Washington Monument as a strong cold front swept through, pulling down much colder air.

Similar swings are expected across the Mid-Atlantic and Northeast as the weekend storm system moves from the Plains into the Great Lakes and then toward eastern Canada. Ahead of the front, temperatures will spike into the 60s and 70s, with even some 80s to the south. As the Arctic air follows, readings are projected to tumble 20 to 30 degrees, with rain changing to a mix of snow, sleet and freezing rain in interior New England and upstate New York.

Along the Interstate 95 corridor from Washington to Boston, forecasters expect periods of heavy rain and gusty winds, followed by a rapid temperature drop and the potential for slick spots. Behind the storm, lake-effect snow bands could flare downwind of the Great Lakes.

The quick reversal is likely to complicate commutes and force some school districts in snow-prone areas to delay opening or shift to remote learning at least temporarily. Utilities are also preparing for another swing back to heating demand, after a brief period of early air-conditioning use during the warmth.

Summer in March for the Southwest

While winter reasserts itself in the north and east, much of the Southwest is facing conditions more typical of mid-summer.

Forecasters say a strong ridge of high pressure is driving an early-season heat wave across Southern California, Nevada and Arizona. Downtown Los Angeles is projected to reach the low to mid‑90s, roughly 20 degrees above normal for this time of year, while parts of the Coachella Valley and lower Colorado River valley could top 100 degrees on multiple days.

The National Weather Service has issued a Heat Advisory for large portions of Los Angeles County through at least Friday, covering the Santa Clarita Valley, Malibu coast, beach communities, inland valleys and the Santa Monica Mountains. Los Angeles County’s Department of Public Health urged residents to avoid prolonged outdoor activity during the hottest parts of the day, stay hydrated and check on older adults, young children and people without access to air conditioning.

“This kind of heat can be dangerous even in summer, and it’s especially risky when it arrives this early in the year and catches people off guard,” the department said in a statement announcing the advisory and the opening of cooling centers.

Local meteorologists have described the event as “extremely rare” for March and warned that it could break several all-time March temperature records in Southern California. National centers tracking daily records say hundreds of record highs are at risk across the West over the next several days.

The heat is also expected to accelerate snowmelt in mountain watersheds feeding Southern California and parts of the Colorado River system, potentially undermining snowpack that water managers rely on to stretch supplies into the dry season.

Atmospheric river batters the Pacific Northwest

Farther north, an atmospheric river aimed at Washington and Oregon is producing heavy coastal rain and substantial mountain snow.

The Weather Prediction Center has outlined a marginal risk of excessive rainfall along the coast and in the Cascades, with 72‑hour rainfall totals of 3 to 10 inches possible on windward slopes and coastal ranges. In higher elevations, forecasters have issued Winter Storm Warnings and, in some passes, Blizzard Warnings for 1 to 4 feet of snow and wind gusts up to 50 mph.

Transportation officials in Washington have warned travelers to expect chain requirements and possible closures on major passes such as Snoqualmie and Stevens, and to be alert for falling rock and tree limbs in saturated areas. Heavy rain on steep, previously burned slopes raises the risk of small landslides and debris flows, especially near highways and in narrow valleys.

While the precipitation will boost snowpack and reservoir levels after a lean start to winter in some basins, it also could force dam operators to manage high inflows and rapid swings in river levels.

Hawaii drenched by a Kona storm

In the central Pacific, the Weather Prediction Center is warning of a “prolonged and potentially life-threatening” Kona storm northwest of Hawaii, with a broad cyclonic circulation and strong upper-level support for widespread heavy rain.

The system has already brought days of downpours to parts of the islands, prompting flood advisories and raising concerns about flash flooding in normally dry gulches and along small streams. Forecasters expect the risk of excessive rainfall to linger into early next week as the storm moves slowly.

A stress test for systems built for another climate

The nationwide burst of extremes comes after a winter that has already featured a major January cold wave and a series of disruptive snow and ice storms tied to earlier polar vortex disturbances.

Scientists caution against attributing any single weather event solely to climate change, but say the broader backdrop of a warming planet is increasing the odds of certain kinds of extremes and reshaping when they occur. Hot spells are arriving earlier and lasting longer. A warmer atmosphere can hold more moisture, fueling heavier downpours when storms line up, as with atmospheric rivers. At the same time, research is ongoing into how Arctic warming and changes in snow and sea ice may be influencing the jet stream and the behavior of the polar vortex.

For communities, utilities and emergency managers on the ground, the immediate focus is less on the abstract mechanics and more on practical strain.

Power grid operators are preparing for a rare combination of intense heating demand in the Midwest and East and surging air-conditioning load in the Southwest, alongside the possibility of weather-related outages. Road crews and aviation officials are juggling blizzard conditions in the Great Lakes, avalanche risks in the Cascades and turbulent, thunderstorm-prone air along the East Coast. Public health agencies are pushing out messages about both heat stroke and hypothermia.

For many residents, the week will be remembered less for the meteorological details than for the disorienting feeling of it all: snow following a day in the 80s, sweating through a “winter” heat wave, or watching rivers climb toward flood stage even as nearby mountains disappear behind fresh snow.

On calendars and almanacs, it is still technically late winter. On the ground, from Los Angeles to Duluth to Honolulu, it feels like something else entirely.