Extreme Temperature Diary- Thursday October 1st, 2026/Main Topic: Fall Flooding for U.S. As a Consequence of Climate Change

Green News Report

Episode: 10/1/2026 — More info…

Hurricane remnents + Gulf inflow are slamming the I-35 corridor from E Neb to SW TX. Lincoln NE had its wettest day in 139 years of recordkeeping on Wed. The soggy scoop from @irenesans.bsky.social, @drjeffmasters.bsky.social and myself:yaleclimateconnections.org/2026/10/trop…

— Bob Henson (@bhensonweather.bsky.social) 2026-10-01T18:18:49.204Z

Tropical moisture, stalled front fueling flood threat across the Central Plains » Yale Climate Connections

Tropical moisture, stalled front fueling flood threat across the Central Plains

A pipeline of tropical moisture is feeding a slow-moving storm system, unleashing repeated downpours from Texas to the Central Plains.

A womanBob HensonJeff Masters

by Irene Sans, Bob Henson and Jeff Masters

Water floods Highway 370 and 25th Street in Bellevue, Nebraska, early Thursday morning, October 1, 2026. (Image credit: Nebraska Department of Transportation, via Nebraska Public Media)

Amoisture-loaded weather pattern is producing rounds of heavy rain and an increasing flood threat across the central United States. Tropical moisture from former Hurricane Polo, additional Pacific moisture from Hurricane Rachel, and humid air flowing north from the Gulf of Mexico are interacting with a slow-moving frontal boundary across the Plains.

The result is an environment capable of producing repeated thunderstorms and torrential rainfall from Texas and Oklahoma northward into Kansas, Missouri, and portions of the Midwest. These features produced several water rescues across Arizona and New Mexico earlier this week after roads flooded and river levels rose. The combination of these multiple atmospheric features, along with their slow movement, is allowing thunderstorms to repeatedly cross some of the same areas. Meteorologists call this “training” because thunderstorms behave like train cars following the same track.

Figure 1. Surface analysis of the United States depicting moisture surge extending from South Texas through the Midwest. A slow-moving front will continue to bring rounds of heavy rains over Texas through Friday. (Image credit: National Weather Service)

Tropical moisture goes well beyond a storm’s name

After moving inland from the eastern Pacific and weakening over Mexico, Hurricane Polo lost its organized tropical circulation. However, a considerable amount of tropical moisture remained and was pulled northeastward into the southern and central Plains.

Notably, at least three eastern Pacific hurricanes contributed to torrential rains across the Southwest in September: Marie, Odalys, and Polo. Now, a bit of Hurricane Rachel’s moisture can be added to the mix. How much of Rachel’s moisture is contributing to the heavy rains in the Central Plains? Depends on which level of the atmosphere we analyze and how deep we dig into air-parcel trajectories.

Hurricanes lose their organization, including their maximum sustained winds, after making landfall, but their moisture can remain prolific. That moisture can become absorbed into a larger weather system, travel hundreds of miles from the original cyclone, and contribute to flooding far inland. This is why residents are always reminded that a system, or its remnants, can still bring catastrophic impacts even if the system no longer has a name.

As Polo’s remnant moisture reached the Plains, it encountered a developing low-pressure system and frontal boundary. The front has focused showers and thunderstorms, helping convert deep tropical moisture into widespread heavy rainfall. Warm, moisture-rich air flowing northward encounters the front and is forced upward. As the air rises and cools, its abundant water vapor condenses into clouds, thunderstorms, and heavy rain.

A slow-moving front creates a train of storms

Normally, a progressive cold front might produce a line of thunderstorms before quickly moving east. But in the current case, the frontal boundary is moving much more slowly. That creates the possibility of thunderstorms repeatedly developing along the same corridor. Storms can also move parallel to the boundary, causing several thunderstorms to cross the same communities.

Training can produce enormous differences in rainfall over relatively short distances. One community might receive an inch of rain, while another nearby location receives several inches because repeated thunderstorms pass overhead.

Figure 2. Rainfall totals between Thursday and Friday across North Texas. Dangerous, possibly life-threatening flooding persists. (Image credit: NWS-Fort Worth)

Gulf of Mexico moisture adds to an already bad combination in the Plains

Texas is being impacted on a large scale in part because of its location. Humid air from the Gulf of Mexico is flowing northward into Texas and the Plains. Meanwhile, moisture from the eastern Pacific is streaming northeastward across Mexico.

Hurricane Rachel is another part of that broader Pacific moisture supply. Satellite imagery shows Rachel’s moisture streaming northward over Mexico, where stronger winds higher in the atmosphere catch it and transport it toward the southern United States.

The Plains are therefore dealing with several moisture sources simultaneously: Polo’s remnants, the Gulf of Mexico, and additional eastern Pacific moisture associated with the broader environment around Rachel.

Flood watches extend hundreds of miles

Central Texas is especially sensitive to intense rainfall. The Hill Country contains numerous creeks, rivers, and low-water crossings that can respond rapidly when torrential rain falls over a short period. Urban areas face a different problem. Intense rainfall can overwhelm storm drains and quickly flood roads, intersections, and underpasses.

Recent dry conditions across parts of the region do not necessarily eliminate that threat. Extremely dry or compacted soil may initially struggle to absorb sudden heavy rainfall. If rain falls faster than the ground can absorb it, water runs across the surface and collects in low-lying areas.

Flood watches extend from the Texas-Mexico border near Langtry through South Texas and northward to the Dallas-Fort Worth Metroplex, reaching areas just south of Oklahoma City.

Figure 3. Rainfall totals between Thursday and Friday across the I-35 corridor between Georgetown and San Antonio. Heaviest rains are forecast near I-35 Thursday afternoon and will move east of I-35 slowly by Friday morning. Dangerous flooding, possibly life-threatening, persists. (Image credit: NWS-Austin/San Antonio)

By Thursday morning, a few flash flood warnings had already been issued. These warnings indicate that flash flooding is occurring, imminent, or expected and that rapidly rising water could pose a life-threatening danger.

The threat does not end in Texas and Oklahoma. Polo’s remnant moisture and the larger storm system are also supporting rain and thunderstorms farther north into Kansas, Missouri, and portions of the Midwest. Again, the greatest concern will be in locations where thunderstorms repeatedly track over the same watersheds. Heavy rain may also hurt agriculture by saturating fields and interrupting harvest operations.

Rainfall recorded and record rainfall

Exactly where the highest rainfall totals occur will depend on where the front stalls and where bands of training thunderstorms become established. Across the central and southern Plains, plenty of moisture is available. The biggest question is exactly where — and how quickly — the atmosphere unloads it.

Much of the heavy rain came in a burst of training showers and thunderstorms Wednesday night, with lines of torrential rain moving northeast across the same areas as the larger complex moved only slowly eastward.

The rainfall was fueled by the arrival of the remnant circulation and moisture from former Hurricane Polo. The thunderstorms evolved into a mesoscale convective system (MCS) over eastern Nebraska on Wednesday evening before progressing into Iowa overnight.

Des Moines fell just short of breaking its September precipitation record of 14.81 inches, established in 1914. Monthly precipitation reached 14.50 inches, still making it the third-wettest month in Des Moines history.

🚨 Flood Warning issued October 1 at 12:58AM CDT until October 3 at 8:00PM CDT by NWS Omaha/Valley NE 🚨Additional Details Here.

— Alerts from NWS Omaha/Valley NE (UNOFFICIAL) (@oax.nws-bot.us) 2026-10-01T06:00:10+00:00

Rainfall of 4.74 inches in Omaha, Nebraska, marked its ninth wettest day on record (period of record: Jan. 1, 1871, to Sept. 29, 2026).

RankRainfallDate
16.46″Aug. 7, 1999
26.30″Aug. 12, 1932
36.24″Sept. 7, 1965
46.17″Aug. 20, 2018
55.74″Sept. 23, 2015
65.69″Sept. 28, 1923
75.30″June 3, 2014
85.02″June 17, 1875
94.74”Sept. 30, 2026
104.64″Aug. 26, 1903

Well, it rained last night. 5.47” at our house, to be precise. We are fine, and the neighborhood is mostly good (a few wet basements). But wow, there was a lot of flash flooding around the Omaha metro last night!

— Dr. Barb Mayes Boustead (@windbarb.bsky.social) 2026-10-01T14:49:29.228Z

Rainfall of 6.15 inches at Lincoln, Nebraska marked it the wettest calendar day in 139 years of recordkeeping — and by a considerable margin. The previous record was 5.45 inches, set on Aug. 29, 1910.

RankRainfallDate
15.45″Aug. 29, 1910
25.42″July 25, 1990
34.86″July 1, 1957
44.70″Sept. 28, 1923
54.68″Sept. 8, 1989
64.59″June 24, 1963
74.29″July 1, 2024
84.27″Aug. 16, 1900
94.24″June 23, 1985
104.22″Sept. 9, 1914

Figure 4. A wide view of the Central and Eastern Pacific on Thursday at 11 a.m. EDT. (Image credit: NHC)

Meanwhile, in the tropics…

The Atlantic has returned to sleep mode. According to the National Hurricane Center, no tropical activity is forecast during the next seven days.

In the Pacific, Nolo remains a tropical storm as it moves farther away from Hawaii, but is still forecast to regain hurricane status through the weekend. The extreme western Hawaiian Islands are under a Hurricane Warning as Polo moves south, and rainbands and wind will radiate over the region through Friday night.

Figure 5. The official track of Polo, issued Thursday at 11 a.m. EDT on October 1, 2026, shows Polo regaining hurricane status over the weekend. (Image credit: NHC)

Rachel is a Category 2 hurricane moving westward, away from Mexico. It is forecast to intensify into a major hurricane, continuing to add to the season’s Accumulated Cyclone Energy (ACE), but it is not currently threatening land. A new system, Tropical Depression 19-E, is also over the open waters of the eastern Pacific and well away from land. It is forecast to dissipate by Thursday evening.

Figure 6. The official track for Rachel issued Thursday at 8 a.m. MDT on October 1, 2026. Rachel is forecast to reach 120 mph maximum sustained winds on Friday, Oct. 2, 2026, then gradually come down in strength throughout the weekend (Image credit: NHC)

Looking ahead to next week, another system could form by mid- to late-week south of southern Mexico. As of Thursday morning, the National Hurricane Center gives the disturbance a 70% chance of developing into a tropical cyclone. The next name on the eastern Pacific list is Simon.

Was Fay actually the Atlantic’s first hurricane of 2026?

For the first time since reliable satellite and hurricane-hunter data began in 1945, the Atlantic hurricane season ended September without a single hurricane. It was also the first time in more than 30 years, since 1994, that no hurricane was recorded during September.

Figure 7. Wind profiler estimates from the Canadian Space Agency’s Synthetic Aperture Radar during a pass over Fay around 4:30 p.m. EDT Sep. 20, 2026. The satellite-derived wind profile shows wind estimates on the storm’s northwest side that suggest peak winds as high as 73 knots or 84 mph about 15 miles from its center. SAR wind estimates have historically run hot, but the information will be considered by NHC in its post-season assessment to determine whether Fay ultimately reached hurricane strength last week. (Credit: NOAA Center for Satellite Applications and Research, via Michael Lowry)

September did produce four named storms: Edouard, Fay, Gonzalo, and Hanna. Fay lasted longer than any of the others, peaking on Sept. 21 with winds of 70 mph (115 km/h), just shy of the 74-mph threshold for a hurricane.

However, the National Hurricane Center could upgrade Fay to a hurricane during its post-season analysis. A surface wind measurement from high-resolution Synthetic Aperture Radar (SAR) aboard a Canadian Space Agency satellite estimated winds on Fay’s northwest side at around 84 mph (135 km/h) at approximately 4:30 p.m. EDT on Sept. 20.

SAR measurements are known to have a high bias in their wind estimates, so this measurement alone does not establish that Fay became a hurricane. However, the National Hurricane Center can consider these data, along with other observations, during its post-season review to determine whether Fay briefly reached hurricane strength.

A woman

Irene Sans

Irene Sans is an Emmy-winning double-certified meteorologist by the American Meteorological Society (AMS, CBM, CDM) with almost 20 years of experience covering severe weather and climate stories across… More by Irene Sans

Bob Henson

Bob Henson

Bob Henson is a meteorologist and journalist based in Boulder, Colorado. He has written on weather and climate for the National Center for Atmospheric Research, Weather Underground, and many freelance… More by Bob Henson

Jeff Masters

Jeff Masters, Ph.D., worked as a hurricane scientist with the NOAA Hurricane Hunters from 1986-1990. After a near-fatal flight into category 5 Hurricane Hugo, he left the Hurricane Hunters to pursue a… More by Jeff Masters

Jeff Masters

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Jeff Master’s and Bob Henson’s “Tropical moisture, stalled front fueling flood threat across the Central Plains” was first published on Yale Climate Connections, a program of the Yale School of the Environment, available at: http://yaleclimateconnections.org. This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 2.5 license (CC BY-NC-ND 2.5).

Dems have serious power coming our way on 11/3 if we're smart enough to use it. "Now or never" threats from GOP, Big Oil, etc. are absurd. API & others will still want permitting reform in 3 mos. Ever-bluffing TACO Trump saying "this or nothing" is weak sauce. We can do better than pre-caving here.

— Rep. Jared Huffman (@realjaredhuffman.bsky.social) 2026-10-01T19:49:18.915Z

" El Niño could put Washington’s coastal towns in hot water" by @heyjohnryan.bsky.social for @kuow.org Public Radio: www.kuow.org/environment/…

— Michael E. Mann (@michaelemann.bsky.social) 2026-10-01T13:28:24.231Z

Wading into the "relative versus absolute" El Niño intensity debate: I genuinely think both are important–and I think we lose important information if we focus solely on one vs another. And both, as of late Sep, have now reached or exceeded record levels! [Thread]

— Daniel Swain (@weatherwest.bsky.social) 2026-09-30T20:05:44.000Z

nice thread Daniel, but I'm not sure I get your point here. If we're interested in global influence on ocean heat & evaporation, we wouldn't look to the Nino3.4 region anyway, we'd look further west where absolute SSTs are still the highest:

— Michael E. Mann (@michaelemann.bsky.social) 2026-09-30T23:45:56.189Z

This despite record global temperatures & extreme weather events.It didn't happen by accident. It's a predictable consequence of Trump/GOP assault on the media coupled w/ plutocratic capture of media outfits and platforms.

— Michael E. Mann (@michaelemann.bsky.social) 2026-10-01T14:53:57.486Z

#climate impact on #nuclear oh oh – San Onofre nuclear station in California holds significant radioactive waste …www.theguardian.com/us-news/2026…

— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2026-10-01T09:07:40.940Z

We surveyed 210 of the most active climate communicators across the US and Canada.Only one pair reported both collaborating with each other AND sharing information with each other.Key results below. Read the full report here: talkingclimate.com/landscape-as…

— Katharine Hayhoe (@katharinehayhoe.com) 2026-10-01T14:17:39.379Z

Today we'll share why we're building @tccollab.bsky.social — to connect, resource and support climate communicators. We'll unpack the data: some what you'd expect, some surprising! And we'll introduce what we've already built — including our Start a Conversation flash cards — and what's coming next.

— Katharine Hayhoe (@katharinehayhoe.com) 2026-10-01T14:18:53.839Z

Imagine a room full of brilliant jazz musicians, all playing solos, none of them listening to each other.That's climate communication right now–and we have the data to prove it.Join @fisherdanar.bsky.social, @bernwoodsplacky.bsky.social & I on our @tccollab.bsky.social webinar today, 3pm ET!

— Katharine Hayhoe (@katharinehayhoe.com) 2026-10-01T14:15:26.585Z

Hope you can join us! If you’re a scientist or ally to science, please share with your networks.

— Dr. Kristin Hook for Congress (@kristinhook.bsky.social) 2026-09-27T19:51:23.864Z

Second of two events I'll be doing in the U.K. during the week of Oct 12 | I will be in conversation at the #OxfordUnion in Oxford, 5pm Thurs Oct 15: issuu.com/oxfordunion/…

— Michael E. Mann (@michaelemann.bsky.social) 2026-10-01T18:26:36.999Z

Global model ensembles are in strong agreement that a prolonged &anomalous nearly West-wide autumn heatwave will develop this week & persist for 10+ days. While some daytime records may be set, this event will be more notable for its persistence & breadth. [Thread]

— Daniel Swain (@weatherwest.bsky.social) 2026-10-01T00:50:29.000Z

A powerful El Niño is already influencing extreme weather around the planet. During the last strong El Niño, federal agencies ramped up research in the hope of improving weather forecasts. This year, they won't be matching that effort. trib.al/dkJLZ2X

— NPR (@npr.org) 2026-10-01T12:37:05.533367Z

In other words: This meme is a surprisingly accurate scaled depiction of the magnitude of the 2026 El Niño event vs the 1997 event *if using the absolute index.* But if using the relative index, Danny DeVito is currently the same height as Arnold Schwarzenegger. And either pairing is striking… 👀

— Daniel Swain (@weatherwest.bsky.social) 2026-09-30T20:25:57.508Z

International Energy Agency report on 'Electrification' can be traced back to 2009, when Mark Jacobson wrote an article for Scientific American presciently arguing that we could power 100 % of the planet with #renewables. www.onlygoodnewsdaily.com/post/the-arg…

— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2026-10-01T08:14:11.943Z

An electrified economy powered by abundant, homegrown #renewables would get us off gas and diesel, passing the cost savings of clean power on to consumers. More drilling in the North Sea will not lower bills. www.greenpeace.org.uk/press-centre/

— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2026-10-01T08:04:57.372Z

UK avoided gas imports worth £5.9bn since the start of the Hormuz crisis due to record power generation from #wind and #solar #renewables www.carbonbrief.org/analysis-win…

— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2026-10-01T08:45:55.490Z

Large-scale storage #batteries are the fastest-growing power technology today, according to International Energy Agency.Cost of #battery packs used in grid-scale storage systems fell by 45 % last year alone.www.ft.com/content/b847…

— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2026-10-01T08:31:10.119Z

Zero-bills home: how one family is beating the energy price hikes. The home acts like a mini-power station after retrofitting #solar panels, a #battery and a #heatpump. The house behaves like a mini-power station that feeds excess energy back to the grid.www.theguardian.com/environment/…

— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2026-10-01T08:23:39.041Z

Free #solar panels and #battery storage can cut energy bills for vulnerable households by 62%, saving an average of £681 a year.www.energylivenews.com/2026/09/30/f…

— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2026-10-01T08:19:41.199Z

#Nuclear power’s quarter-century of stagnation has no end in sight, and has been overtaken by #solar PVreneweconomy.com.au/nuclear-powe…

— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2026-10-01T07:44:52.428Z

More than two million people in England are unaware their properties are at risk of flooding, as the UK braces for a wet and stormy start to the winter, according to the Environment Agency. www.theguardian.com/environment/…

— Dr Paul Dorfman (@drpauldorfman.bsky.social) 2026-10-01T08:37:19.453Z

First of two events I'll be doing in the U.K. during the week of Oct 12 | "Insight lecture" on #ScienceUnderSiege at the #CrickInstitute in London, 4pm Wed Oct 14: michaelmann.net/events/scien…

— Michael E. Mann (@michaelemann.bsky.social) 2026-10-01T18:22:41.872Z

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