West Coast Storm Pattern Sets Up East Floods

A powerful atmospheric river—a moisture‑laden plume of tropical air typically blamed for West Coast deluges—was the hidden engine behind the deadly, historic floods that slammed the U.S. South and Midwest in early April. Now, another atmospheric river is poised to unleash heavy rain from the southern Plains into the Midwest this weekend, raising fresh concerns for regions less accustomed to such torrents.

• Phenomenon: Atmospheric rivers—“rivers in the sky”—transport vast moisture from the tropics.

• Historic floods: Early April storms claimed at least 23 lives, fueled by AR‑driven rainfall.

• Epicenter: Kentucky, Tennessee, Arkansas, Missouri, Alabama, and beyond saw record crests, power outages, and mass evacuations.

• Science: ARs account for up to 50% of West Coast precipitation, but can trigger “biblical” East‑of‑the‑Rockies floods 

• Next storm: A new atmospheric river will drop heavy rain from the southern Plains into the Midwest this weekend.

• Definition: Long, narrow bands of water vapor—sometimes 250–375 miles wide—that stream from the tropics to higher latitudes.

• Water content: Strong ARs can carry 10–20 times the daily flow of the Mississippi River.

• Common names: The West Coast’s most famous AR is the “Pineapple Express,” drawing moisture from near Hawaii.

• Impact: While beneficial for replenishing water supplies, they also cause 30–50% of annual West Coast rainfall, and can trigger catastrophic flooding when they strike the wrong place at the wrong time.

On April 2–7, 2025, a stationary frontal boundary combined with an energetic Pacific flow to produce unprecedented rainfall across the central and southern U.S.:

• Kentucky: The Kentucky River crested at 48.27 ft in Frankfort—17 ft above flood stage—submerging neighborhoods and shutting down over 500 roads.

• Tennessee & Arkansas: Flash flood emergencies were issued as rivers overflowed; 10 deaths were confirmed in Tennessee alone.

• Missouri, Alabama: Record rainfall totals—6.51 in at Mobile Regional Airport—and widespread evacuations in low‑lying areas.

• Fatalities & damage: Across five states, at least 23 people died, thousands were evacuated, and tens of thousands were left without power or safe water.

Unlike West Coast ARs that unload in mountains and foothills, this event’s slow‑moving convection allowed moisture‑laden air to drift farther east, dumping rain on steep terrain and urban centers unprepared for such volumes.

• Moisture transport

  • ARs form when subtropical jets tap oceanic moisture and funnel it poleward.

  • As these plumes cross the Rockies, they’re forced upward, triggering precipitation even well inland.

• Climate amplification

  • Yale researchers found ARs can also deliver significant heat, increasing atmospheric capacity for moisture—and thus flood potential.

  • Warmer oceans feed stronger ARs; studies show a trend toward more intense AR events under climate change.

• Regional vulnerability

  • East‑of‑the‑Rockies states lack the infrastructure and early warning systems honed in the West.

  • Urban drainage systems, floodplains, and emergency response plans were overwhelmed by unprecedented rainfall rates.

According to CNN meteorologists, a new atmospheric river is set to:

• Strike the southern Plains (Texas, Oklahoma) by Saturday, then

• Move into the Midwest (Missouri, Illinois, Indiana) by Sunday

• Rainfall totals: Models forecast 2–4 inches in many places; higher amounts in uplands 

  • Heed Warnings

    • Monitor NOAA Weather Radio or local alerts for flash flood warnings.

  • Avoid Floodwaters

    • “Turn around, don’t drown”—even shallow water can sweep vehicles off roads.

  • Secure Property

    • Clear storm drains, elevate valuables, and reinforce doors/windows if possible.

  • Emergency Kit

    • Keep a go‑bag with water, snacks, a flashlight, and first‑aid supplies.

  • Community Support

    • Check on vulnerable neighbors, share evacuation routes, and coordinate plans.

This next pulse, though less potent than early April’s “exceptional” AR, still poses flash‑flood risks for communities reeling from the last disaster.

• Road closures: Over 500 roadways shuttered in Kentucky; major highways in Tennessee and Arkansas also flooded.

• Power outages: Tens of thousands left without electricity; mobile networks were intermittently down.

• Business losses: Local economies dependent on tourism and agriculture face multi‑million‑dollar setbacks.

• Insurance claims: Flood insurance uptake in the Midwest remains low—many will rely on federal disaster aid.

• FloodRelief trended as communities shared local shelter and donation info.

• Residents posted dashcam videos of street‑turned‑rivers, urging caution on social platforms.

• Citizen weather observers on social apps captured rising creeks and overflowing gutters, aiding real‑time situational awareness.

Atmospheric rivers are no longer a West Coast story. As this week’s incoming AR demonstrates, the power of “rivers in the sky” can reshape weather patterns and risk far from the Pacific. Preparedness, awareness, and updated infrastructure will be critical as these storms grow in frequency and intensity.

Stay connected to our live updates for the latest forecasts, safety advisories, and expert insights on atmospheric rivers—and learn how you can protect your community when the next storm arrives.