Jeff Masters Hurricane Blog

Real winter finally roars into the United States » Yale Climate Connections

Like a diva who keeps the audience waiting for a grand entrance, the winter of 2023-24 hasn’t been in any hurry to enter full force across most of the United States. Over the next few days, though, things should look and feel much stormier and a lot more seasonable across many parts of the country.

During the next couple of weeks, a rapid-fire sequence of major midlatitude cyclones will sweep across the central and eastern United States, bringing a cornucopia of wild weather from tornadoes to blizzard conditions. The snow and cold may fall well short of record territory but will still be a dramatic change, given the eerie warmth and snowlessness that ruled the holiday period over some of the most reliably wintry parts of the nation. (We’ll have more on December’s impressive heat records in our monthly U.S. roundup post on Tuesday, January 9.)

To get a quick sense of what’s going on, consider the National Weather Service’s all-hazards map issued at midday Monday (Figure 1). It includes a startlingly widespread and diverse set of threats that collectively will touch nearly every U.S. state over the next several days. Here’s a sampling:

  • Blizzard warning (dark red): New Mexico, Texas, Oklahoma, Kansas, Colorado, Nebraska, Oregon, Idaho, Washington
  • Winter storm warning (pink): Nebraska, Kansas, South Dakota, Minnesota, Iowa, Missouri, Wisconsin, Illinois
  • Winter storm watch (blue): California, Nevada, Idaho, Utah, Wyoming, New Hampshire, Maine, Michigan
  • Flood watches (dark green): Hawaii, Virginia, Maryland, Delaware, Pennsylvania, New Jersey, New York, Connecticut, Rhode Island, Massachusetts, New Hampshire, Maine
  • High wind warning (golden): Montana, Wyoming, Colorado, New Mexico, Texas, Oklahoma, Arkansas, Georgia, Tennessee, North Carolina, West Virginia, New York, Vermont
  • Wind advisories (beige): Washington, Oregon, New Mexico, Texas, Oklahoma, Missouri, Arkansas, Louisiana, Mississippi, Alabama, Tennessee, Kentucky, Georgia, South Carolina, North Carolina, Virginia, West Virginia, Maryland, Pennsylvania, New York

On top of all this, tornado and/or severe thunderstorm watches are expected from Monday afternoon into Tuesday over parts of the the South.

A map showing weather hazards for 1/8/24. Much of the U.S. is in some kind of watch, warning or advisory.
Figure 1. All-hazards map from the National Weather Service issued at 11:40 a.m. EST Monday, January 8, 2024. (Image credit: NWS)

Severe weather to erupt in the Southeast

Powering the next few days of storms will be an unusually energetic and progressive polar jet stream, laced with disturbances and frontal systems propagating through it. The largest dips in the jet stream, called long-wave troughs, will tend to set up shop across the eastern two-thirds of the country and off the Pacific Northwest coast, and that’s where we can expect the highest-impact weather. This is a slight variation on what’s most common during strong El Niño events like the one now underway. During strong El Niño conditions, the jet stream tends to favor the southern tier of states, often bringing heavy rain and mountain snow across the Southwest and severe weather to the Gulf Coast and Florida.

If the Southwest hasn’t yet gotten its share of moisture (more on that in a minute), the Southeast is falling closer to the El Niño template. A severe weather outbreak with the risk of strong tornadoes is on tap from Monday afternoon in east Texas and Louisiana, shifting rapidly eastward overnight and toward Florida and Georgia by Tuesday. On Monday morning, the NOAA/NWS Storm Prediction Center issued enhanced-risk outlooks (level 3 of 5) for both Monday and Tuesday.

If enough surface warming occurs, there’s a distinct threat of strong supercell-type tornadoes with any discrete storms that form ahead of a raging squall line, which itself may itself produce shorter-lived but still dangerous twisters during the overnight hours Monday night. Flooding rains will also be a threat, including urban areas along and near the Gulf Coast.

Numerous pockets of damaging wind on the order of 60-80 mph are possible anywhere along the squall line or within supercells, as the fast flow aloft mixes to the surface.

Chipping away at an unprecedented snow drought

The Northeast’s first noteworthy snow of the season dropped heavy amounts from the inland mid-Atlantic to New England — including 18 inches at Milton, New York, and 17 inches in Salem, New Hampshire. However, the storm was a big disappointment to snow lovers along the Washington-to-New-York urban corridor, which is still waiting for its first calendar-day inch of snow since early 2022 (a record-long “snow drought” in city observations that go back more than 120 years).

The nation’s next snowstorm will unfold from Monday into Wednesday from the Plains to the Upper Midwest, on the cold side of this week’s severe-weather-producing cyclone. Blizzard conditions are expected across the central High Plains by late Monday, with some parts of eastern Colorado and western Kansas in line for six to 12 inches of snow and winds gusting up to 70 mph. Less-fierce but still dangerous winds will generate snowdrifts across cities farther east, including Omaha, Nebraska; Des Moines, Iowa; and Madison, Wisconsin.

In the Chicago area, several inches of snow are possible, but rain mixing in could put a dent in accumulations. Mostly lighter snows are expected in Minnesota, which just wrapped up its warmest December on record.

Winter flooding is possible in parts of the mid-Atlantic

Farther to the east, the strong surface low will put the East Coast firmly in the warm sector — which means heavy rain along with the prospect of flash-melting of large amounts of snowfall dropped just a couple of days earlier.

A powerful low-level jet stream blowing at hurricane strength (sustained winds of 75-80 mph) just a mile or so above ground level will push rich tropical moisture northward, creating an unusually potent rainmaking setup for midwinter. To make matters worse, the runoff from heavy rain and snowmelt will encounter storm surge pushing upstream against bays and inlets, leading to what the NOAA/NWS Weather Prediction Center called a “dire situation from a river flood perspective.” The center has issued a moderate risk of excessive rainfall and potential flooding for Tuesday along and northwest of the Interstate 95 corridor from northern Virginia to western Connecticut.

River runoff combined with onshore winds are expected to create widespread moderate coastal flooding in Chesapeake Bay (Figure 2), with a few areas of major flooding. Minor coastal flooding is predicted along much of the East Coast from North Carolina to Massachusetts.

A map of flood risk along the coast of the northern mid-Atlantic and Southern New England the second week of January 2024. Moderate to major flooding is expected in Maryland, New Jersey, New York, Connecticut and Rhode Island.
Figure 2. Maximum flood category predicted across the mid-Atlantic and southern New England for the week of January 8-14, 2024. (Image credit: NOAA/USG)

Pacific Northwest braces for potential blizzard conditions

Rather than plowing into California, as is often the case during an El Niño January, the Pacific jet stream will slam into the Pacific Northwest early this week. The result will be unusual blizzard conditions over mountain areas and heavy rains at lower elevations. Most elevations above 2,000 feet can expect two to five feet of snow amid winds gusting to 60 mph — more wind and more snow than is typical for such winter events there.

Meanwhile, the Southwest is getting off to an underwhelming start for critical winter moisture. Memories are still fresh of the powerhouse 2015-16 El Niño, which ended up drier than a typical year in and near California while the Pacific Northwest was unusually wet. We’re still not even to the halfway point of western winter in terms of precipitation, so it’s too soon to know whether the 2023-24 El Niño will end up as another contrarian event a la 2015-16.

Arctic outbreak setting up for next week

Long-range models are increasingly pointing toward an intrusion of Arctic air next week from the northwestern U.S. into the Plains and eastward, in association with a southward displacement of the stratospheric polar vortex. Exactly when the cold air will arrive, and just how cold it will get, remain highly uncertain, with major disagreements remaining among models and within model ensembles. One weather watcher on Twitter/X bemoaned the contrast in high-temperature forecasts for Denver next Sunday, January 21 (see below). The app-based outlooks, each of which hinge on a different model or model mix, varied from 47 to negative 3 degrees Fahrenheit. It’s a telling sign of how difficult it is to nail down daily forecasts a week in advance during such an active weather pattern.

Jeff Masters contributed to this post. Website visitors can comment on “Eye on the Storm” posts (see comments policy below). Sign up to receive notices of new postings here.

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