Matt Lanza

The pendulum swings back to high water on the Mississippi River

Headlines

  • The southern half of Mississippi River will experience moderate to major flooding in the days ahead, albeit well under levels seen in other flood events in recent years.
  • But the addition of potentially significant rainfall in portions of the Mid-South this weekend (Oklahoma, Missouri, Arkansas) could add to Lower Mississippi flooding risks.

Flood situation on the Mississippi

About a year and a half ago, dire concerns were raised about salt water intrusion into the water supply of the Mississippi River because water levels had gotten so low. Thankfully that threat passed, and for the most part, things have been rather ho-hum in the Mississippi. We’re beginning to see signs of change now, however, as all the water from the multi-day rainstorm earlier this month dumps into the Mississippi River.

River gauges along the Mississippi and nearby tributaries that are expected to be in moderate or major flood stage over the upcoming days. (NOAA National Water Prediction Service)

None of the rises on the Mississippi look to be anything outlandish. For example, at Hickman, Kentucky, just downstream of where the Ohio empties into the Mississippi, there is major flooding expected, but still about 9 feet shy of the record from 2011.

The Mississippi at Hickman, KY will remain stable in major flood through the weekend. (NOAA)

Farther downstream at Osceola, Arkansas (just north of Memphis), the river is slated to be at a level of about 37.5 feet, which multiple floods have topped in the last 15 years.

The Mississippi at Osceola, AR will stay stable in major flood but well shy of levels seen in 2011, 2016, 2018, and 2019. (NOAA)

The story repeats down past Memphis into Mississippi, where the river will rise to moderate or major levels but nothing too absurd.

Down in Baton Rouge, the river will continue rising this week, eventually projected to crest around next Wednesday at levels similar to what had been seen in May of 2017 (and lower than levels reached in 2011, 2016, 2018, 2019, and 2020).

The Mississippi in Baton Rouge will crest sometime next week just over the mark into major flooding but lower than levels seen in 2018-2020. (NOAA)

Back to the rains in the Mid-South

One interesting element about the river forecasts is that they only contain rainfall forecasts in the next 24 to 36 hours or so. So, we assume 0 rain falls after, say this Wednesday. Which brings me to an interesting possible storyline that could develop in the Mississippi. Over the upcoming holiday weekend, a cold front is going to push into the Ohio Valley and Mid-South again. There will likely be some degree of severe weather with this, though exactly how widespread or significant remains to be seen.

Forecast surface weather map for Saturday morning, showing a cold front pushing into the Mid-South and some disturbances gathering across the Southwest. (NOAA WPC)

One thing I did notice this morning while going over my forecasting is that the ridge of high pressure setting up over the Southeast is expected to flex again this weekend. In fact, on Saturday morning, the European ensemble has about an 80 percent probability of the upper-level high pressure being in 99.5th percentile for this time of year. In simple language: It will be strong. Similar (but far less alarming at this point) than what we saw a couple weeks ago.

The probability is high that the ridge of high pressure over the Southeast will be quite strong this weekend, likely slowing or stalling the Mid-South cold front. (Polarwx.com)

So the combination of a cold front slowing or stalling as it runs into a southeast ridge would likely lead to an increasing risk of heavy rainfall. Unlike last time, where the bullseye was extremely widespread but focused on Kentucky, at least the initial odds this time favor Missouri and Arkansas. About 40 to 50 percent of the 51 European ensemble members show 3 inches or more of rainfall over northwest Arkansas through early next week, with 20 to 30 percent showing 4 inches or more.

Another round of possibly significant rain shows increasing odds this weekend from southern Missouri through Oklahoma. (Polarwx.com)

What does this all mean? For one, it means that the upcoming weather story will perhaps focus once more on the Mid-South or southern Plains. Secondly, it could mean that the forecasts for the Mississippi River, particularly those down into Louisiana have some risk of increasing in the days ahead. Or, perhaps the river will just stay high for longer, an entirely feasible outcome. Whatever the case, after a quiet week last week, the weather is beginning to look interesting again.

Let’s talk about the Western U.S. and their water situation in 2025

As a meteorologist, weather in general fascinates me. I worked two years in California about 15 years ago, and when I took that job, everyone teased me, saying the weather was “so easy” to forecast. And, yes, about 80 percent of the year, conditions are pretty stable overall. There is nuance to that. Most people may not realize a minor difference in temperature from day to day, but it’s something that can be reflected in power usage. Same goes for wind or solar output in terms of forecast weather for wind farms or solar facilities. But what always kind of fascinated me about the West was water.

So far, 2025 has been a mixed year in the Western U.S. On the one hand, California snowpack is doing great.

Sierra snowpack is running about 120 percent of normal in the north and 85 percent of normal in the south. (California DWR)

It’s been a late season bonanza up north, with snowpack levels sitting at 120 percent of average north of Lake Tahoe. The central Sierra are a little less well-off but still close to normal. The southern Sierra have not had their best winter ever, but even still snow water equivalent is around 85 percent of normal. There have certainly been worse years in California.

It’s when you get into the interior West that the problems start. Take Colorado. Their peak snowpack is likely to be the lowest since 2018. The northern part of the state has done well with near average snowfall this year.

Colorado’s snowpack as of April 8th as a percent of the 30 year median. (USDA)

The Colorado River headwaters are also running near average, but southern Colorado, particularly the San Juan and Upper Rio Grande basins are in bad shape. Snow water equivalents are running about 60 percent of the median right now, or well, well below average.

The story improves some in Utah, where the basins are a little noisier, but in general not in bad shape outside of southern Utah. Similar story in Wyoming and Idaho. Not great, not terrible. Oregon? Fantastic winter. Washington? Less so. But for Arizona and New Mexico, it was a dreadful winter.

Snow-water equivalents compared to the median are running way above normal in Oregon and way below normal in Arizona and New Mexico. (USDA)

Flagstaff, Arizona has seen 51 inches of snow this winter, compared to a normal of 86 inches typically. In Albuquerque, they’ve had 1.68 inches of rain since October 1st, compared to 3.38 inches on average. It’s turning out to be pretty bad. Snowpack is particularly important because as the seasons change, that snow melts and it feeds the rivers of the West and subsequently the reservoirs, farms, and hydroelectric power that is scattered about. The relationship is not 1-to-1, where 100 percent of snowpack means streamflow of 100 percent. Even though the upper Colorado Basin saw decent snow, with nearly 100 percent of normal, the forecast streamflow from CLIMAS is only 84 percent of normal.

New Mexico reservoirs are in very poor condition. (CLIMAS via Laura Paskus)

For the Rio Grande it’s even worse, with the CLIMAS streamflow forecast being only 52 percent of normal! Laura Paskus, who writes an excellent blog focused on New Mexico recently shared the image above from the CLIMAS March report showing reservoir levels in New Mexico. They are not good. At all.

Suffice to say, there have been glimmers of hope in recent years from some strong winters — but the underlying problems are not going anywhere in the West. There is still a shortage of water, and there is high risk that this will only get worse in future years. Absolutely reckless and illogical decisions like releasing water in California earlier this year may not seem like a huge deal on the surface, but every single drop is precious in the West. As it is, the situation regarding water is already tense. The states that utilize the Colorado River are up against a clock to come to an agreement on a joint management proposal by May. A quasi-handshake agreement that had been in place with Mexico for a shift in water delivery to Tijuana from the Colorado was rejected for the first time in 80 years this year because of complaints that Mexico is not supplying enough treaty-mandated water to Texas from the Rio Grande.

All this underscores the very, very tenuous situation in the West. I hope to include some additional coverage or words on this topic in the future here because this problem is not going to go away anytime soon, and if anything, it’s going to continue to worsen. Water doesn’t recognize borders of states or countries, which makes it an especially challenging and precious commodity to wrangle.

Could the 2025 Atlantic hurricane season have some tricks up its sleeve? Breaking down the CSU Outlook

Late last week, the team at Colorado State University issued their always hotly anticipated seasonal hurricane outlook for the Atlantic Basin. To clear this up at the beginning, their forecast calls for:

  • 17 named storms (normal 14)
  • 9 hurricanes (normal 7)
  • 4 major hurricanes (normal 3)
  • Accumulated cyclone energy: 155 (normal 123)

Nothing about this forecast on the surface is especially notable or alarming or fascinating. It’s simply a slightly above average forecast.

But what is somewhat notable about their forecast is some of the under the hood items they address. First, we are likely to be coming out of a La Niña event, something we discussed last back in February. But as the CSU team notes, we don’t know for sure if we’re headed for El Niño or ENSO neutral (La Nada) conditions. ENSO neutral summers combined with warm water temperatures “typically provides a more conducive dynamic and thermodynamic environment for hurricane formation and intensification.” In other words, hurricanes like those background conditions.

We do not yet have a “plume” from the C3S suite for April, but the March plume skewed slightly toward El Niño development.

Multi-system ensemble of various forecast models predicting a trend toward positive sea-surface temperature anomalies this summer, possibly giving a slight edge to a developing El Niño event. (Copernicus)

If we get to El Niño conditions by late summer or fall, that does not guarantee that conditions will shift to become more hostile to hurricane development. But that may take the edge off a bit. However, if we “hang” near the neutral line or even in weak La Niña territory, any hostile conditions may be apt to stay away, ensuring a busier season than usual.

In addition to the forecast for named storms and such, the CSU team also does try to convert that seasonal outlook to a prediction of U.S. landfall risk. Indeed, with a more active season expected, the odds of a U.S. landfall are also higher. They have a 51 percent chance of a major hurricane landfall on the U.S. coast, compared to a historical average of 43 percent. The odds on the East Coast are 26 percent, compared to 21 percent typically. And in the Gulf of Mexico, the landfall odds between the Florida Panhandle and Brownsville are 33 percent versus a 27 percent average.

According to the CSU team, all model guidance is pointing to an above-normal season. Water temperatures remain well above long-term averages across the Atlantic. As we noted earlier this year, however, this is not last year’s Atlantic sea-surface temperature profile. But it’s still quite warm.

March 2025 minus March 2024 sea-surface temperatures, showing year over year warming in the Caribbean, Gulf, and mid-latitudes, but not in the tropical Atlantic. (NOAA PSL)

From the map above, you’ll notice that the eastern Atlantic has cooled markedly since last year, however the Gulf, Caribbean, and northern Atlantic Ocean are all warmer. The fire that was burning all last summer in the eastern Atlantic is still smoldering, but it has been somewhat extinguished. The Gulf and Caribbean are another matter. The Gulf is warmer than 2024 by a good bit but still lags 2023. While the Caribbean was warmer than 2024 in March, it has since cooled some in April, taking it back under 2024 levels. Water temperature conditions can change quickly, but the bottom line is that the Atlantic, with the exception of the eastern basin are in the upper echelon of warm years at this point. The warmer overall waters in March in the eastern North Atlantic (north of the tropics), along with the warm Caribbean do correlate to active hurricane seasons.

The bottom line is that the underlying data support the idea of an active hurricane season — but not to the levels feared last year. But there aren’t very many red flags at this time arguing against that outcome. At least last year, we had the expectation of a developing La Niña to help grease the wheels a bit, and a slow development could have slowed the hurricane season a bit. This year? There’s no real glaring red flag that says the season will bust. But hurricane seasons always have surprises. Hopefully this year’s involves calm.

Colorado State’s seasonal hurricane forecast is just that, a seasonal forecast. Should you plan your life based on this? No. But they generally have good skill. And their skill in the last 10 years or so has been great. You still have a few weeks, but it’s time to start thinking about, refreshing, and planning for the season ahead. There’s a lot of uncertainty this year in terms of FEMA and federal response to storms, so it probably behooves you to plan that kit even a bit more than usual. We have tips on our preparedness page, which we will go through and adjust any broken links when we have some time in the coming weeks.

A quieter week after an incredible rainfall forecast, as huge footprint of major flooding continues

Headlines

  • Weather forecasts verified exceptionally well with the ongoing Mid-South flooding.
  • Numerous rivers are experiencing or soon will experience major flooding as all this feeds into the larger Ohio/Mississippi Basin.
  • A much quieter week is expected this week.
  • Next week may be a good bit stormier, however.

Exceptional flooding, exceptional forecasting

Now that it’s over, we can say that last week and weekend’s rainstorm sadly lived up to the expectations set days before. Take a look at the map comparison below. Use the slider to toggle between the rainfall forecast issued on Monday and the observed rainfall based on MRMS analysis.

A comparison of the rainfall forecast issued Monday and the observed rainfall late last week and weekend. Additional rain was expected south and east. (Pivotal Weather)

Is this a perfect rainfall forecast? No, but my goodness it’s pretty darn close. The Weather Prediction Center, which is an arm of NOAA issues these larger scale precipitation forecasts daily. I reference these forecasts regular in my day job and for our readers both in Houston and elsewhere. They’re valuable. But they have exceptional utility ahead of major events such as this flood in the Mid-South. The folks at the WPC, much like those at other national centers under NOAA’s umbrella are the absolute best of the best in our field when it comes to marrying forecasts with historical analysis and numerical prediction models. As a public service, I’ll remind you that the budget cuts currently being proposed to NOAA will cost more in both lives and property in the long run than they’ll save in the short run.

All that said, this forecast was exceptional, but so were the impacts. Here is a look at the wide swath of double-digit rainfall totals seen through this event.

A non-comprehensive look at rainfall totals in excess of 10 inches across the lower Ohio Valley and Mid-South. (NOAA)

Many rivers in western Kentucky, southwest Indiana, or southern Illinois will be at their highest levels since 2018; in some cases on the White River in Indiana, it will likely be their highest levels since 2005 or 2008 floods. A few spots on the Kentucky River will actually set new records from this event.

The Kentucky River is setting new records in places. (NOAA)

In Frankfort, the state capital, a record from 1978 is threatened from the Kentucky.

Those recurrence intervals are pretty amazing from southwest Tennessee through central Kentucky. For Memphis, this was the 2nd wettest four-day stretch on record, just falling about an inch shy of a June 1877 flood event there. Six flash flood emergencies were issued for the event across Arkansas, Texas, Mississippi, Tennessee, Kentucky, and Missouri.

Rivers that are forecast to be in moderate (red) or major (purple) flooding encompass a huge swath of the Mid-South and Ohio Valley. (NOAA National Water Prediction Service)

Dozens of river gauge locations are expected to experience major flooding. All this water is going to flow into the Mississippi River eventually, and depending on where you are on the river, the forecast crests right now are the highest since somewhere between 2011 and 2020.

All this water is flowing into the Mississippi, which is expected to reach major flood as far south as Baton Rouge by next week. (NOAA)

This one will go down in the record books with some of the bigger Mid-South floods.

Quiet week for the most part

Fortunately, the forecast this week there looks fairly calm with some rain later in the week, likely at manageable levels. Elsewhere across the country, we get to still discuss winter. Cooler temps will allow for some locally heavy snowfall from Ontario, across southern Quebec and into interior northern Maine, where as much as 4 to 8 inches could fall tomorrow.

Winter is not quite over just yet. (NWS Caribou)

Otherwise, the late week storm system mentioned above may allow for a return to some fire weather conditions in the southern Plains. Unlike in March, however, quite a few areas have seen some decent precipitation recently. So hopefully that puts a bit of a lid on severe fire weather concerns for the Plains.

Back at it next week?

I think the next significant weather item to watch will be a chance for multiple days of severe weather next week in the southern Plains. Exactly what that looks like or how it unfolds is TBD, but there are definitely signs in the models that after a quiet-ish week this week, we pick up the pace again next week.

I’m going to aim for a couple more posts this week. One will discuss the hurricane outlook issued by Colorado State. I may try to get another one later in the week on water issues and low snowpack in the interior West. We’ll see how this week goes!

Going, going, gone?

I want to leave you with a couple fun links today. As baseball season ramps, up, there are two new ballparks in play this year with the A’s in Sacramento and the Rays playing at Steinbrenner Field in Tampa. Over at Fangraphs, Michael Rosen did a two-part look at the weather effects in the new ballparks. Both have interesting quirks. Sacramento’s field will have some of the lowest humidity of any ballpark in the league. Tampa will have some fascinating winds which may make Rays games pretty fun to watch. Anecdotally, I did watch parts of some Rays games during Opening Week, and there were some interesting dynamics in play on fly balls. I encourage you to check those links out!