The weather pattern that’s dominated the United States for most of January jumped into overdrive this week. Nearly all of the 48 contiguous states are unusually cold, though it’s a pale imitation of the colossal, nationwide Arctic intrusions of decades past. In our warming climate, such 20th-century cold outbreaks may become increasingly tougher to match.
Yet winter can still pack a dangerous punch, as folks on the Gulf Coast and in California are finding in two very different ways. Historic, city-snarling snowfall – in some cases, possibly the heaviest in more than a century – was spreading on Tuesday into coastal communities from Texas toward Florida. Locations expecting snow include Galveston, Texas; New Orleans, Louisiana; Mobile, Alabama; and Pensacola, Florida.
Meanwhile, high winds, bone-dry air, and tinder-dry vegetation continue to plague coastal Southern California, just weeks after the area was hit by one of the most catastrophic fire events in modern U.S. history.
Officially skiing and sledding in Houston off Allen Parkway. #snow #houwx pic.twitter.com/3GJckAECyT
— Sally MacDonald (@SallyMacFox26) January 21, 2025
How wonderful! Snow and jazz music in New Orleans ❄️💃❄️pic.twitter.com/in3z4EerZO
— Volcaholic 🌋 (@volcaholic1) January 21, 2025
A rare taste of winter snowfall along the Gulf Coast
People along the immediate Gulf Coast occasionally get snowflakes mixed with cold rain, and sometimes even an inch or two of quick-melting snowfall. This week is bringing something different – the kind of snow more familiar to Midwesterners than Gulf Coast denizens. A sharp wave is rounding the bottom of a massive upper low extending from eastern Canada across the eastern U.S., and that will spawn a band of snow extending along and near the coast from west to east from Tuesday into Wednesday.
Ironically, one thing that’s helping to make the Gulf Coast setup so unusually snow-favorable is dry air. About a mile above sea level, some of the driest air on record was flowing across the South toward the Gulf of Mexico. When the atmosphere is forced upward in a storm system, temperatures drop until the air is saturated (i.e., relative humidity hits 100 percent). Along the Gulf Coast, the ample moisture supply from the Gulf of Mexico often yields saturation at temps above freezing – enough to put the brakes on snow formation.
On Tuesday, the air aloft was saturating at temps just below freezing, allowing for a rare all-snow temperature profile (see Fig. 1 below), including at some places more accustomed to sleet, freezing rain, or snow mixed with rain when winter weather does occur. A NOAA website shows how the atmospheric structure can vary for each of these.
Below is a sampling of Gulf Coast cities that could end up with their heaviest snowfall in decades, along with the official National Weather Service forecasts as of Tuesday morning, January 21. As the numbers show, the event to beat is the jaw-dropping storm of February 1895 (see the recaps from Space City Weather and wunderground.com). Note that changes in the official observing sites (especially in the Houston area) can affect such records since the near-coastal region is prone to wide snow variations across small areas. Totals are also measured more often during modern snowstorms than the former once-a-day standard, and this can lead to higher totals than would have been recorded long ago.
Houston, TX
20.0” Feb 14-15, 1895
3.0” Feb 12, 1960
3.0” Jan 22, 1940
2.6” Jan 30, 1949
2.5” Dec 21-22, 1929
2.0” Jan 11, 1973
Forecast as of Tuesday morning, Jan 21: 3”-5”
Galveston, TX
15.4” Feb 14-15, 1895
6.0” Jan 12, 1886
4.0” Dec 24-25, 2004
2.5” Jan 11, 1973
2.2” Feb 12-13, 1960
Forecast as of Tuesday morning, Jan 21: 3”-5”
New Orleans, LA
8.2” Feb 14, 1895
4.0” Jan 27, 1897
3.0” Feb 12, 1899
2.7” Dec 31, 1963
2.0” Feb 12, 1958
Forecast as of Tuesday morning, Jan 21: 4”-8”
Baton Rouge, LA
12.5” Feb 14-15, 1895
6.0” Feb 25, 1914
3.5” Dec 8, 2017
3.5” Jan 23, 1940
3.2” Feb 5, 1988
Forecast as of Tuesday morning, Jan 21: 3”-7”
Mobile, AL
6.0” Feb 14-15, 1895
5.0” Jan 24, 1881
3.6” Feb 9, 197
3.5” Jan 23, 1955
3.0” Dec 31, 1963
Forecast as of Tuesday morning, Jan 21: 2-4”
Pensacola, FL
3.0” Feb 14-15, 1895
2.3” Mar 6, 1954
2.1” Feb 12, 1899
1.9” Feb 9-10, 1973
1.5” Jan 31, 1977
Forecast as of Tuesday morning, Jan 21: 2”-4”
Tallahassee, FL
2.8” Feb 12-13, 1958
1.0” Dec 22-23, 1989
0.4” Feb 10, 1973
0.4” Mar 28, 1955
0.2” Feb 2, 1951
Forecast as of Tuesday morning, Jan 21: 2” (including snow, freezing rain, and/or sleet)
On top of these impressive amounts, which could have major local impacts, enough cold will stick around for a day or two to help preserve the snowpack – and the snow itself may help temperatures to plummet to record lows once the skies clear.
Most of the rest of the United States won’t see much if any record cold, even with this week’s Arctic plunge. Although January has been colder than average for most parts of the contiguous U.S., the chill is noteworthy more for its persistence and expansiveness than its sheer bite. In fact, as of Monday, January 20, the nation had seen many more record daily highs than record daily lows for the month thus far (thanks in large part to relatively balmy temperatures in parts of Florida and Alaska). This is a far cry from truly historic cold outbreaks such as those in December 1983, February 1989, and December 1990, all of which pulverized many hundreds of daily records across the central and eastern United States.
So is climate change having any influence on the much-publicized polar vortex episodes of recent years? That’s been a topic of research and debate for more than a decade, especially with disastrous episodes like the 2021 Texas cold wave interspersed amid an overall warming of U.S. winters, and the research continues to evolve. We’ll take a fresh dive into the topic in a forthcoming post.
Fierce winds and unprecedented winter dryness keeps Southern California on edge
Yet another round of powerful Santa Ana winds was cascading through the coastal mountains of Southern California from late Monday into Tuesday. The winds warmed and dried as they flowed downslope toward the coast, sending relative humidity well below 10 percent and pushing fire weather into the top-end “extremely critical” category once again. The peak wind gust observed so far during the event was 88 mph at Magic Mountain Truck Trail (located about 20 miles north of Los Angeles) at 9:50 am PST Jan. 20. Sandberg, California (located about 65 mi NW of Los Angeles) had sustained winds of 48 mph, gusting to 74 mph, with a relative humidity of 11%, at 1:51 pm Jan. 20. The station stopped sending data thereafter, likely because the high winds damaged the station or its communications infrastructure.
The strong winds fanned multiple fires overnight, but quick action by firefighters served to squelch them before serious impacts occurred. The largest new fire, called the
