The weather pattern that dominates the U.S. for much of January has become extremely violent this week. Nearly all of the 48 contiguous states were unusually cold, although this was a pale imitation of the massive, nationwide Arctic invasion of decades earlier. Cold outbreaks like those of the 20th century may become increasingly difficult to deal with in a warming climate.
However, winter still brings dangers, and people along the Gulf Coast and in California are discovering this in two very different ways. Historic, city-wide snowfall — in some cases, potentially the heaviest in more than a century — spread to coastal communities from Texas to Florida on Tuesday. Areas expected to receive snow include Galveston, Texas; New Orleans, Louisiana; Mobile, Alabama; and Pensacola, Florida.
Meanwhile, high winds, bone-dry air and parched vegetation continue to plague coastal Southern California just weeks after the region suffered one of the most catastrophic fire events in modern U.S. history.
How wonderful! Snow and Jazz in New Orleans❄️💃❄️pic.twitter.com/in3z4EerZO
— Volcaholic 🌋 (@volcaholic1) January 21, 2025
Rare winter snowfall on Gulf Coast
Those along the Gulf Coast will experience the occasional mix of snowflakes with cold rain, sometimes even an inch or two of fast-melting snow. This week brings something different — snow more familiar to Midwesterners than Gulf Coast residents. A sharp wave is skirting the base of a huge upper low that stretches from eastern Canada to the eastern United States, which will produce a band of snow from west to east along and near the coast Tuesday into Wednesday.
Ironically, one of the things that makes the Gulf Coast exceptionally good for snow is dry air. About a mile above sea level, the driest air on record is flowing across the south toward the Gulf of Mexico. When the atmosphere is forced to rise in a storm system, temperatures drop until the air is saturated (i.e., the relative humidity reaches 100%). Along the Gulf Coast, ample moisture supplies from the Gulf of Mexico often create saturation conditions at above-freezing temperatures that are enough to prevent snowfall.
Dry air aloft was just below freezing on Tuesday, resulting in a rare all-snow temperature profile (see Figure 1 below), including in some locations more accustomed to sleet, freezing rain, or sleet. occur. The National Oceanic and Atmospheric Administration (NOAA) website shows how the structure of the atmosphere changes for each condition.
Here's a sample of Gulf Coast cities that could see their heaviest snowfall in decades, along with the official National Weather Service forecast as of Tuesday morning, January 21. The jaw-dropping storm of February 1895 (see Space City Weather and wunderground.com for an overview). Note that changes in official observing locations (particularly in the Houston area) may affect such records, as small areas near the coast are prone to large-scale snowfall changes. Totals are also measured more frequently during modern snowstorms than the previous standard of once a day, which may result in higher totals than those recorded long ago.
Houston, Texas
20.0” February 14-15, 1895
3.0” February 12, 1960
3.0” January 22, 1940
2.6” January 30, 1949
2.5” December 21-22, 1929
2.0” January 11, 1973
Forecast as of Tuesday morning, January 21st: 3”-5”
Galveston, Texas
15.4” February 14-15, 1895
6.0” January 12, 1886
4.0” December 24-25, 2004
2.5” January 11, 1973
2.2” February 12-13, 1960
Forecast as of Tuesday morning, January 21st: 3”-5”
new orleans louisiana
8.2” February 14, 1895
4.0” January 27, 1897
3.0” February 12, 1899
2.7” December 31, 1963
2.0” February 12, 1958
Forecast as of Tuesday morning, January 21st: 4”-8”
Baton Rouge, Louisiana
12.5” February 14-15, 1895
6.0” February 25, 1914
3.5” December 8, 2017
3.5” January 23, 1940
3.2” February 5, 1988
Forecast as of Tuesday morning, January 21st:3”-7”
Mobile, Alabama
6.0” February 14-15, 1895
5.0” January 24, 1881
3.6” February 9, 197
3.5” January 23, 1955
3.0” December 31, 1963
Forecast as of Tuesday morning, January 21st:2-4”
pensacola florida
3.0” February 14-15, 1895
2.3” March 6, 1954
2.1” February 12, 1899
1.9” February 9-10, 1973
1.5” January 31, 1977
Forecast as of Tuesday morning, January 21st:2”-4”
Tallahassee, Florida
2.8” February 12-13, 1958
1.0” December 22-23, 1989
0.4” February 10, 1973
0.4” March 28, 1955
0.2” February 2, 1951
Forecast as of Tuesday morning, January 21st: 2” (includes snow, freezing rain and/or sleet)
In addition to these impressive numbers, which could have significant local impacts, enough cold will linger for a day or two to help protect the snowpack – which itself could send temperatures plunging to record lows once skies clear level.
Even with Arctic temperatures plunging this week, much of the rest of the U.S. won't be experiencing record-breaking cold. Although January temperatures were below average across much of the continental United States, the cold was more noteworthy for its persistence and widespread nature than for sheer coldness. In fact, as of Monday, January 20, there have been far more record daily highs than record lows across the country so far this month (thanks in large part to Florida and parts of Alaska area's relatively mild temperatures). This is a far cry from truly historic cold snap outbreaks, such as those in December 1983, February 1989 and December 1990, all of which destroyed hundreds of daily records across the central and eastern United States.
So, does climate change have an impact on the polar vortex event that has become so publicized in recent years? This has been a topic of research and debate for more than a decade, especially in the context of overall warming U.S. winters with catastrophic events like the 2021 Texas cold snap, and research continues to evolve. We will revisit this topic in depth in an upcoming article.
High winds, unprecedented winter dryness have Southern California on edge
Another round of powerful Santa Ana winds is blowing through the coastal mountains of Southern California Monday night into Tuesday. Winds are becoming warmer and drier as they blow off the slopes toward the coast, driving relative humidity well below 10 percent and pushing fire weather conditions once again into the highest end of the “extreme hazard” category. Peak wind gusts of 88 mph were observed on the Magic Mountain Truck Trail (about 20 miles north of Los Angeles) during the event at 9:50 a.m. PST on January 20. miles) on January 20 at 1:51 pm, sustained winds of 48 mph, gusts to 74 mph, and relative humidity of 11%. Communication infrastructure.
Strong winds fueled a number of fires overnight, but firefighters acted quickly to extinguish the blazes before serious impact occurred. The largest new fire, the Lilac Fire, is an 80-acre fire in San Diego County and was 10% contained as of 10 a.m. ET on January 21, according to Cal Fire. Evacuation orders were issued due to the fire, but there were no reports of extensive structure damage.
Breaking down… Bonsal, California (north of San Diego). As of 6 a.m. PST, #lilacfire Has grown to 80 acres, is spreading at a moderate rate, and has achieved 10% control. most local television stations #sandiego There is live coverage in the area. Evacuation map: pic.twitter.com/LdTzWLPcU5
— Warren Fedeli – Stormchaser (@Stormchaser) January 21, 2025
Strong Santa Ana winds are a normal part of the region's winter climate. Winds have been unusually frequent this month and are sometimes exacerbated by mountain wave effect. This occurs when strong winds blow nearly perpendicular to a mountain range and connect through the temperature structure, trapping energy in shallow layers and then being forced to the surface downstream. The winds that caused the catastrophic Eaton and Palisades fires near Los Angeles on January 7 and 8 had a strong mountain wave component and tracked more north to south than usual, which helped push the fires unusually southward Residential areas have not been burned in modern times.
It's not just wind that causes fires. Additionally, the winds coincided with dry conditions more typical of late summer and exceeded anything recorded in late January, when the winter rainy season is typically near its peak. As the climate warms and the rainy season shortens, these intersections between the dry end of the warm season and the front of the cold monsoon are becoming increasingly threatening, and this trend is expected to continue.
As of Tuesday, Jan. 21, only 0.16 inches of rain had fallen since July 1 in downtown Los Angeles (data since 1878) and San Diego (data since 1851). Unprecedented, the next driest period in the region was 0.35 inches in 1962-63. In Los Angeles, drought levels are now as severe as in 1962-63, but an additional 0.40 inches of rain fell before the end of January 1963. .
Rain is expected to finally hit Los Angeles and San Diego this weekend as the jet stream across the country is expected to leave a trail along the Pacific Coast before spiraling eastward. European ensemble models suggest half an inch of rain could fall near San Diego, an inch or more in nearby mountains and smaller amounts near Los Angeles. The GFS team was less enthusiastic, projecting less than half an inch almost everywhere. With just the slightest change in jet trajectory, the pattern becomes windy and dry instead of wet.
Regardless, it will take far more rain than expected to bring the region close to normal levels for the rainy season, which typically begins to wind down in late March.
Only 28% of U.S. residents regularly hear about climate change in the media, but 77% want to hear it. By 2025, you can show Americans more climate news.
Republish our articles for free online or in print under a Creative Commons license.
