El Niño and California rain: The complex relationship and how the current storm fits the overarching narrative

One-sentence summary

With a powerful storm hammering California today, we take a look at why California is targeted so often during El Niño winters and a quick look at what’s to come after this week.

California Streaming

One of the biggest storms in years is impacting portions of California. Rain totals are expected to be in the double digits in a few places, with upwards of 5 more inches of water coming to LA and 1 to 4 inches or more up and down the coast from the Bay Area through San Diego.

Additional rainfall as forecast by the National Weather Service in the southern half of California over the next 2 days. (Pivotal Weather)

This has led to two days worth of high risks from the Weather Prediction Center for excessive rainfall. High risks are uncommon, and they are historically very well correlated to flood damage. Over 80 percent of flood-related damage and nearly 40 percent of flood-related fatalities occur on high risk days.

Click to enlarge maps of Weather Prediction Center excessive rainfall outlooks today and tomorrow. High risks are posted for California, level 4 out of 4, indicating a significant risk of life-threatening and/or damaging flooding. This includes the Los Angeles metro area. (NOAA)

Seeing back to back high risks in California is certainly impressive. Translation: Take all warnings seriously.

In addition, powerful winds are impacting the Central Coast, Bay Area, portions of SoCal, and in the mountains. Wind gusts are expected to top 60 mph, and in fact the NWS actually issued a hurricane-force wind warning offshore of California for the first time in this region. The wind should begin to ease up a bit heading into tomorrow.

Wind gusts will be powerful today and tonight on the coast of California and inland as well. (Pivotal Weather)

Lest we forget, the winter weather impacts from this storm will also be big. The Sierra will see upwards of 1 to 3 feet of snow, wind, and risk of avalanches.

A late Sunday morning view of I-80 at Donner Summit. (CalTrans)

Additional moisture will continue to move through California and the West into midweek, but it should be a less impactful than what is currently ongoing.

Why California?

When you think of El Niño, many of you will think of Chris Farley or weak hurricane seasons or warm Pacific Ocean water. All three, while nuanced are correct thoughts to have. You may also think of rain in California. If you’re a student of the 90s (raises hand), you may remember the 1997-98 El Niño, which at that time was one of the strongest on record. So why does California tend to be stormy during stronger El Niño events, such as the one we have ongoing in 2024?

If you look at a comparison of the 30-year average of jet stream zonal winds side by side with just El Niño years from December through March in the higher end El Niño events since the 1960s, you get a few interesting things that stick out.

A comparison of jet stream level winds between December and March in a “normal” year (left) and a strong El Niño year (right). (NOAA)

In the area I’ve labeled “A,” you can see that the map on the right has stronger winds farther east than in the map on the left. What does this mean? We usually see a stronger jet stream extended across the Pacific during El Niño winters, which points it more often at the southern half of California or northern Mexico. For the area labeled “B,” you can see that in the map on the left, the peak of that portion of the jet stream is centered more over the Mid-Atlantic. The map on the right shows that more over Florida or the Southeast. Basically, the jet stream aims south more often. And historically, you’ve ended up with a wetter southern tier of the United States from California to Texas to Florida.

Rainfall patterns during a typical El Niño event around the world. (Columbia University IRI)

Essentially what happens is that as the water of the Pacific Ocean warms in the Equatorial region, you force typical features to displace relative to normal. This shakes up the landscape, including that shift and intensification of the jet stream. Not every El Niño is created equal, even the strong ones. The 2015-16 El Niño was a bust in SoCal in terms of rainfall, but the following year was pretty wild, especially in NorCal.

You can see a pretty good positive correlation between rainfall in Southern California and “maximum ONI,” which is the Oceanic Nino Index: As El Niño peaks stronger, precipitation tends to increase. Or so it was through the 2000s. (NWS Los Angeles)

But in general, the relationship does hold up historically. A strong El Niño usually produces a wetter SoCal. Things are a little more muddled in the northern part of California. And notably, when you consider flood damage, things get more confusing, with only four of the top 13 most damaging winters in terms of flooding in all of California occurring during El Niño years according to Jan Null of Golden Gate Weather Services.

So all in all, while this storm is particularly intense, it basically fits the overarching narrative of an El Niño winter in California.

The storm train should calm down some in California after this week, with the jet stream aiming a bit farther south more into Mexico and deep south Texas and Florida.

The 8 to 14 day outlook shows that California rain may ease up some after this week, but wetter than normal conditions are still favored broadly across the southern tier of the U.S. (NOAA CPC)

It’s not unheard of for a rebound of storminess to occur in California into March or even April in years like this, so I doubt we’re done yet. But it will be good to hopefully have some time to dry out a bit between storms there.

Winter prepares to take a break, so we’ll talk about crawfish, recent research, and the 2024 Atlantic hurricane season

One-sentence summary

Today’s post will discuss the return of mild weather, Louisiana crawfish, rain in California, some recent hurricane research, and some too early thoughts on the 2024 hurricane season.

Winter hiatus

After a week where we’ll see heavy rain in the south and wintry precipitation scattered across remnant cold air to the north, the bigger weather story may be what’s coming next week.

Significant expected rainfall is both welcome and concerning, as Flood Watches are posted from north of Houston into northern Alabama. (Pivotal Weather)

First, we have some flooding concerns in spots in the South to get through, although in some areas, like Texas and Louisiana and Mississippi, this rain is quite welcome. Some of those areas remain in extreme drought. While this is good news in general, it may be too late for crawfish season in Louisiana. Between high costs, the recent cold, and the long-term drought plaguing the region, it’s going to be a tough harvest this year. Mark Shirley of the LSU AgCenter shared thoughts on this season recently, and they were not positive. Not great news for those who bank on this season.

Rains should wind down later this week, setting up a drier week in the South next week. In terms of temperatures, where won’t it be cold for this time of year? Virtually everywhere.

If you like winter weather, the 8 to 14 day outlook is a tough one to look at. (NOAA)

The most recent 8 to 14 day outlook from NOAA’s Climate Prediction Center looks bleak for winter lovers. Weather model data strongly backs this up, and it appears that winter will go on hold for a time as we close January and open February. Though this map stops at the border, it’s expected that warm air is going to flood most of Canada as well, particularly central Canada. The Maritimes and West Coast will be much more moderate than this.

If there is some good news, it comes in California and the West, which is expected to see above average precipitation continuing into next week as well.

California looks to be targeted by a pretty wet stretch of weather next week. This should hopefully also help the snowpack some in the Rockies. (NOAA)

The combination of warm temperatures and wet weather is not always the greatest duo to see out West in winter, but hopefully this can at least continue the snow building process in the higher terrain. Whatever the case, there is high confidence in a fairly wet pattern in that region.

Recent hurricane research: More storms with more rainfall

Shifting gears now, as we advertise ourselves as primarily a hurricane-focused site! I wanted to highlight a couple batches of recent hurricane research that came out in late 2023. Last June, we published an article that summarized a bunch of research on the Gulf of Mexico and rapid intensification. We want to try to continue to keep you informed on general interest research on the tropics, particularly as it relates to the Atlantic Basin and North America.

A preprint being reviewed for publication in Nature Portfolio authored by a group from both the Pacific Northwest National Laboratory and Lawrence Berkeley National Laboratory was posted in early November discussing climate change, flooding, and social inequality from Hurricane Ida back in 2021. The general gist of the paper is like this: We know that climate change will tend to exacerbate social inequality. Disasters tend to hit more vulnerable populations both worse and more often. The paper finds that the climate change impact on flooding is non-linear, which is to say that as the planet warms, flooding should worsen at a faster rate. So as social vulnerability increases, the risk of suffering from deep flooding also increases. “In other words, for deep flood exposure, both past and future warming increase social inequality in the direction that exacerbates relative flood risk for more vulnerable people.”

The study essentially confirms that the flood impacts from Ida’s remnants were worsened by increasing precipitation due to climate change and the most vulnerable segment of the population saw a worse outcome than they otherwise would have because of this. You can see the paper to learn more about their methods and some of the specific numbers they used, which are in line with prior studies done after Hurricane Harvey. While the rainfall element of hurricanes has always been a bad one, we’ve seen several recent examples where it seems as though it’s getting worse, and research in recent years continues to basically confirm that feeling.

Another interesting paper published in November in the European Geophysical Union’s Journal of Atmospheric Chemistry and Physics touches on how aerosols from anthropogenic (human) sources impact the destructiveness of hurricanes. What stood out about this article was their finding that an increasing concentration of aerosols near the immediate coast (say, as storms approach the petrochemical complexes of the Gulf Coast) can lead to a weaker but larger storm with an 11 to 22 percent increase in precipitation within 100km of the center. The study used Hurricane Katrina as a model storm, and they worked to utilize very sophisticated modeling to solve for this.

“For the first time, a 3-D atmosphere–ocean fully coupled regional model (WRF–ROMS) at the cloud-resolving scale was used to simulate Hurricane Katrina in order to investigate the aerosol–TC system with the inclusion of air–sea interaction,” the authors write.

What I think our readers should take away from this research is that it adds to the growing body of evidence that suggests hurricanes are becoming more moisture-laden as they approach land, which is resulting in more rain, more flooding, more damage, and more impacts to more people.

2024 hurricane season early vibes check

There have been some items published in recent weeks about the upcoming hurricane season. I’ve seen everything from people expecting an active season to a very active season to the “hurricane season from hell.” Hyperbole aside, what does the very early data actually show about the hurricane season that begins in just over 4 months?

The first question we’d ask is whether El Niño will continue into this summer. The answer to that question is still an uncertain one. Modeling is aggressively weakening the El Niño event by late spring, as is often typically the case with strong events like this one. The European model below, for example, has us close to “ENSO Neutral,” or “La Nada” by mid-summer, with extrapolation pushing us toward weak La Niña perhaps by the peak of hurricane season.

The ECMWF long range forecast suggests an aggressive weakening of El Niño this summer, but still some question as to whether or not we end up in La Niña. (ECMWF)

Why does this matter? La Niña events are much more favorable for active hurricane seasons than El Niño events. So if we were to hypothetically tip back into La Niña this summer, it would likely aid an active hurricane season.

Historically, since 1950 in hurricane seasons immediately following a higher-end El Niño, we average 6 hurricanes (with as many as 10 in 1998). A normal hurricane season has about 7 hurricanes, so one could argue that the season proceeding after stronger El Niños may not necessarily skew dramatically higher. From that end, I don’t know that we can currently read too much into El Niño vs. La Niña chances this summer and how they may influence the season.

That being said, one thing we can absolutely read into are sea-surface temperatures (SSTs). The globe’s oceans are undergoing a heat wave of sorts. In fact, water temperatures in the main development region of the Atlantic basin are currently in line with what you would normally expect to see in July. That’s not a typo.

So I do not think it’s a stretch to say that we would expect SSTs to be warmer, if not much warmer than normal again this summer across much of the Atlantic basin. A look at one model in particular, the NMME, which is an ensemble of several different climate models shows an extremely warm look to the Gulf, Caribbean, and Atlantic this summer.

The NMME model forecast for SSTs this summer is ugly looking in the Atlantic with warm water everywhere again. (NOAA)

Now, what I might caution about here is that the NMME also has a dramatic La Niña signature in the Pacific that might be a little (or a lot) overdone. Just because these maps are scary looking does not mean that they will verify as shown. But, there’s more than enough evidence right now to suggest that SSTs will skew warm this hurricane season.

So sitting here on January 23rd, I would be willing to say this right now: The combination of warm water and a weakening El Niño probably suggests an active hurricane season ahead in 2024, but there is a very long way to go yet. No reason to worry about the sky falling right now, but I would not be surprised to see some fairly aggressive seasonal forecasts in the months ahead.

The next storm up brings more of the same across the country, while we eye some serious cold heading into next week

One-sentence summary

An active stretch of weather continues with a major storm developing today and tomorrow, followed by a serious blast of Arctic air across much of the country next week and the potential for an East Coast storm.

The next storm up: More flooding, more Midwest snow, more strong wind

The next storm in our parade is gathering in the Rockies today. This one will track south into the Texas Panhandle and then hook back northeast across the mid-Mississippi Valley into Michigan, Ontario and Quebec into the weekend. At its peak, this storm will likely test some January low pressure records in the Midwest, including in places that just set them earlier this week.

So, yes, it’s active.

There will be some tweaks compared to the storm earlier this week, but in general, the story is similar in some ways. Let’s run through the impacts.

Heavy rain & flooding: The Northeast and parts of the Mid-Atlantic will again be ground zero for flooding risks from this storm. Another inch and change of rain is expected here into portions of Atlantic Canada, on top of saturated ground and ongoing flooding in spots. While these totals are lower than the previous storm this week, the ground is more saturated now than it was then, so less rain can cause issues.

While rain totals don’t look quite as high as we saw with the storm earlier this week, another inch or so across parts of the Mid-Atlantic and southern New England will further stress already stressed and saturated grounds. (Pivotal Weather)

The Weather Prediction Center has the area outlined for the upper end of a slight risk (level 2 of 4) for excessive rainfall, close to a moderate risk.

A slight risk of excessive rainfall (level 2/4) is up from near Harrisburg, PA through southern New England on Friday (Pivotal Weather)

Flood Watches are already posted in parts of southern New England.

Severe weather: Another round of severe storms is likely from northeast Texas into the Lower Mississippi Valley later today, and an enhanced (level 3/5) risk is in place for parts of Arkansas and extreme northeast Texas, and northwest Louisiana.

An enhanced (level 3/5) risk of severe storms is in place for later today south of Little Rock through Shreveport. (NOAA SPC)

That will expand into the Southeast on Friday, where another enhanced risk is already established from Alabama through the Carolinas. This map may be updated after publication.

An enhanced risk of severe storms is also in place for Friday across parts of the Southeast, with strong winds and tornadoes possible. This map may be updated after publication. (NOAA SPC)

Tornadoes and damaging winds will be a possibility in these areas on Friday.

Heavy snow: The storm earlier this week brought heavy snow in a corridor from Kansas through Nebraska, northern Missouri, Iowa, northwest Illinois and southern Wisconsin into Michigan. Tomorrow’s storm will bring the heaviest snow from Nebraska into Iowa, Wisconsin, northern Illinois (including Chicago), and Michigan into Ontario.

Snow totals for this storm will peak from Iowa (again) through Wisconsin and Michigan. Chicago may see more snow with storm than the prior one. (Pivotal Weather)

An additional area of heavy snow will be possible in Upstate New York and interior New England, particularly in the mountains. That will extend into Canada with heavy snow across Quebec (outside of Montreal) and in Newfoundland and Labrador.

Snow totals in the Northeast will be highest in portions of the White Mountains and possibly the Adirondacks in New York, as well as in Quebec and parts of Newfoundland. (Weathernerds.org)

More travel headaches are expected in those areas.

Meanwhile, as that storm exits east, another storm, the one that will really help drag in the Arctic blast for early next week, will dump snow in the Western U.S.

Snowfall through Sunday morning in the Western U.S. will be ample in spots. (Weather Bell)

We’ve been in a bit of a snow drought nationally this winter, so this is helping to make up some ground.

Strong winds: In addition to the heavy rain and flooding, heavy snow, and severe weather, widespread strong winds will once again tax trees and power lines across the country. A huge chunk of the nation will see 35 to 50 mph wind gusts in the coming days, with the worst coming in parts of the Rockies, Texas, Appalachia, the Great Lakes, and on the Northeast and Mid-Atlantic coasts into Atlantic Canada.

A large swath of the country will be seeing wind gusts in excess of 35 mph (green) and 45 mph (gold/yellow), with the strongest winds impacting parts of the Rockies and Texas, the Mississippi and Ohio Valleys, Great Lakes, and East Coast. (Weather Bell)

This has been a pretty remarkable week for wind across the Lower 48. I know we have a subset of readership in portions of Atlantic Canada, so I just want to note the wind gusts there as well. They may not be as strong as explicitly shown on the map below (especially east of Nova Scotia), but I just want to highlight that the wind doesn’t magically stop in Maine.

Strong wind gusts of 40 to 60 mph (65-95 km/hr) are likely in parts of Atlantic Canada with this next storm as well. (Weather Bell)

Really an impressive stretch lately.

Arctic blast next week impacts much of the country

As alluded to above, the cold coming next week looks impressive. Nationally, it may be the coldest outbreak since just before Christmas in 2022. Numerous locations are already forecast to reach record lows on Monday and Tuesday next week.

Locations currently forecast near record lows on Tuesday morning (NOAA)

This won’t be as long lasting or potent as what was seen in February 2021 in Texas, but it marks yet another in a series of winters with some sort of cold air shenanigans in that part of the world. The core of the coldest air relative to normal will likely pass over the northern Rockies Sunday and Monday, the central Plains and Mid-Continent Monday and Tuesday, and into the Ohio Valley and Southeast on Tuesday and Wednesday.

For folks in Texas, this will be a prepare for impacts type of cold: Protect plants, pipes, pets, and people. The shorter duration of this event compared to February 2021 should hopefully take some of the more catastrophic problems off the table (like grid failure), but cold of this magnitude in this part of the world can always spring surprises on folks. So please take it seriously and prepare accordingly.

A second push of cold may arrive again next weekend, but that’s TBD at this point.

East Coast storm chances next week?

The rumor mill is cranking on the potential for an East Coast winter storm next week. As the Arctic air slides east, a secondary storm is expected to develop in the Southeast and track off the East Coast. Exactly where it tracks will determine what, if anything is seen in parts of the Southeast, Mid-Atlantic, or Northeast. We’re still a good 5 to 6 days or so away from this, so there’s plenty of uncertainty.

Let’s look quickly at the Euro ensemble “spread” in options for this storm. The IQR values for sea-level pressure shown on the map below from Tomer Burg are high, which tells us that there is considerable spread within model guidance for potential outcomes. The European ensemble runs the European model 51 different times with different tweaks each time. When you see this sort of variability within the ensemble, it lends to lower confidence in the forecast track of the storm. Obviously that will have huge implications on what sort of precip falls and where.

A map showing the European ensemble’s interquartile range for next Wednesday morning suggests a very, very high amount of uncertainty regarding placement and intensity of low pressure off the East Coast. It’s far too soon to say which areas will be likely to see snow, rain, or something in between. (Tomer Burg)

So it’s much too soon to say with any confidence who will see snow and how much next week. Suffice to say, however, there is a storm system likely that will cause impacts on the East Coast, continuing our active weather pattern. Milder weather may be on the horizon for later in January.

Updated look at what to expect into Tuesday with the major Eastern U.S. winter storm

One sentence summary

This evening’s post offers an update on what to expect with a major Eastern U.S. storm into Tuesday, as well as some comments on more storms to come.

Major Eastern U.S. storm hitting through Tuesday

Back on Saturday we talked about the flooding risk specific to New Jersey due to snowmelt, saturated ground, and 2-3 inches of additional rain tomorrow. That risk has been refined today to include eastern Pennsylvania, DC, Maryland, northern Virginia, and portions of southern New York and Connecticut.

A moderate risk (level 3/4) for excessive rainfall and flooding is posted for Tuesday in the Northeast and Mid-Atlantic. (NOAA)

Total rainfall will be on the order of 1 to 3 inches in this region, which is plenty of water to produce flash and river flooding. Flood Watches are up from southern New England into Virginia, and tomorrow should be a very active day.

Rainfall tomorrow will be on the order of 1 to 3 inches over a broad area from the Southeast into New England, with the greatest flooding risk from Virginia into southern New England. (Pivotal Weather)

There are a ton of other elements to this storm. Let’s walk through them.

Severe weather: Tonight looks to be a very active severe weather night in the Deep South and along the Gulf Coast east of Texas. An enhanced risk is in effect for this region (level 3/5), and tornadoes are a distinct possibility. That severe risk will continue into the southeast tomorrow with an enhanced risk from north Florida into southern Georgia, and eastern South & North Carolina.

An overview of the severe weather expected tonight into Tuesday across the South. (NOAA SPC)

Again, strong winds and tornadoes are possible in these areas.

Wind gusts: Widespread wind gusts in excess of 40-50 mph are possible, if not likely across the Plains, Midwest, Southeast, and East tonight into tomorrow. Coastal New England, Long Island, and the Mid-Atlantic could see 60+ mph winds. This will be an exceptionally potent and widespread wind storm across the eastern half of the country, and there will likely be numerous power outages.

The NWS forecast for wind gusts shows 50 mph or stronger for parts of the Gulf Coast and South, as well as up the East Coast into coastal New England and in Upstate New York. This type of wind will cause numerous scattered power outages in parts of the Eastern U.S., so prepare for some disruption on Tuesday. (Weather Bell)

Snow: A major snowstorm will occur on the northwest flank on this storm, with anywhere from 6 to 12 inches or even more across northern Missouri, Iowa, northern Illinois, and southern Wisconsin.

Heavy snow will fall in the Midwest, with Iowa, extreme northern Missouri, and parts of Wisconsin seeing the heaviest snow. Slightly less snow will fall south and east of there for Chicago and Detroit. (Pivotal Weather)

The combination of snow and wind will produce blizzard conditions from northeast New Mexico into Kansas, with near-blizzard conditions at times northeast of there.

The NWS Winter Storm Severity Index shows major impacts from northern Missouri into Wisconsin, as well as moderate impacts for some areas from New Mexico into Maine.

But wait, there’s more!

At least two more major storms are queued up in the pipeline. The next one will take a track similar to slightly farther east than the current storm. Expect more wind, more snow, more flooding rain, and more severe weather risk on Friday into Saturday.

The European model forecasting a parade of winter storms across the Midwest and Eastern U.S. over the next 10 days.

The subsequent storm will arrive Monday or Tuesday next week, and this one may take a farther east track, meaning we’ll watch for snow chances to creep eastward. But it could also produce more flooding and more wind in the East. Additional total liquid of 2 to 4 inchers more is almost certainly going to exacerbate flooding concerns in the Mid-Atlantic and Northeast. More to come on these.