The Top Weather Stories of the Coming Week
Forecast Discussion: July 20 – 26, 2025
The week of July 20–26, 2025, will feature a dynamic weather pattern across the United States, driven by a combination of a strengthening mid-level ridge, tropical moisture influences, and shortwave perturbations. The top weather stories include a return of excessive heat across the central and southeastern U.S., severe weather threats in the northern Plains and Midwest, ongoing flooding risks along the Gulf Coast, and potential tropical development in the Atlantic and Gulf. Below, we discuss each of these phenomena and the atmospheric dynamics driving them.
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1. Excessive Heat Returning to Central and Southeastern U.S.
A significant heat wave is expected to intensify across the central U.S. and Southeast starting this weekend and continuing through much of the week. High temperatures are forecast to climb into the mid-90s to low 100s (°F) across the central Plains, Midwest, and Southeast, with heat indices potentially exceeding 105–110°F due to high humidity. The most intense heat is expected mid-to-late week (July 23–26), particularly in the Southeast, where dangerous heat stress is possible.
Atmospheric Dynamics
The heat wave is driven by a strengthening mid-level ridge centered over the Ohio and Tennessee Valleys by mid-week. This ridge, characterized by a 500-hPa high-pressure system, will promote subsidence, clear skies, and prolonged surface heating. The ridge’s northward expansion into the Upper Midwest and Great Lakes will amplify the heat, while high moisture content from the Gulf will elevate dew points, exacerbating the heat index. A persistent southerly flow at the surface, coupled with a lack of significant frontal passages, will trap warm, humid air across the region, preventing nighttime cooling and increasing heat stress risks.
Impacts
Health Risks: Prolonged exposure to heat indices above 105°F poses risks of heat exhaustion and heat stroke, particularly for vulnerable populations.
Energy Demand: Increased air conditioning use may strain power grids, especially in urban areas like Atlanta, Dallas, and Memphis.
Mitigation: Residents should stay hydrated, avoid outdoor activities during peak heat, and check on at-risk individuals.
2. Severe Weather Threats
Severe weather is expected across portions of the northern Plains, Upper Midwest, and Mid-Atlantic through the weekend and into early next week, with potential for scattered severe thunderstorms continuing through mid-week (July 20–23). The primary threats include:
Northern Plains (July 20–21): Scattered large to very large hail (1–2 inches) and severe wind gusts (60–80 mph) are possible, particularly along a lee trough from eastern Montana to the Wyoming/Nebraska border. Low-probability tornadoes may also occur.
Midwest and Mid-Atlantic (July 20–22): Scattered damaging winds and isolated tornadoes are forecast, with the greatest risk in parts of Iowa, Illinois, and the Lower Mid-Atlantic states.
Tennessee Valley to Southern Atlantic Seaboard (July 21–22): Strong thunderstorms may produce severe wind gusts and hail.
Atmospheric Dynamics
The severe weather is driven by a combination of a modestly amplified westerly flow and shortwave perturbations moving through the northern mid-latitudes. A mid-level low digging southeast from the Canadian Arctic will enhance west-northwesterly flow across Ontario and the U.S. Upper Midwest, increasing wind shear conducive to organized thunderstorms. A lee trough in the northern Plains will provide low-level convergence, while high CAPE (Convective Available Potential Energy) values (2000–3000 J/kg) and steep lapse rates will fuel supercell development. In the Midwest and Mid-Atlantic, a warm, moist airmass ahead of a weak cold front, combined with subtle perturbations rotating around the northern periphery of the mid-level ridge, will support severe thunderstorm development.
Impacts
Northern Plains: Large hail and severe winds could damage crops, vehicles, and infrastructure in rural areas like eastern Montana and western North Dakota.
Midwest/Mid-Atlantic: Damaging winds may cause power outages and tree damage in urban areas like Des Moines and Baltimore.
Mitigation: Residents should monitor NOAA Weather Radio for watches and warnings and seek shelter during severe thunderstorms.
3. Ongoing Flooding Risks
Heavy rainfall and flash flooding risks will persist along the north-central Gulf Coast, particularly from the Florida Panhandle to southeastern Louisiana, through mid-to-late week (July 20–24). Rainfall totals of 3–7 inches are expected, with isolated areas potentially seeing 8–10 inches, especially in Louisiana. A Level 2–3 (of 4) excessive rainfall threat is in place for southeastern Louisiana, including New Orleans and Baton Rouge, on July 23–24. Flash flooding is the primary concern due to slow-moving rain bands.
Atmospheric Dynamics
The flooding threat is tied to a disorganized tropical disturbance (Invest 93L) moving westward across the northeastern Gulf. High atmospheric moisture content (precipitable water values of 2–2.5 inches) and warm sea surface temperatures (83–87°F) in the Gulf are fueling heavy rainfall. A weak upper-level trough and a quasi-stationary surface low enhance lift and convergence, promoting persistent rain bands. The system’s slow movement, driven by weak steering currents around a high-pressure ridge to the north, increases the risk of prolonged rainfall over the same areas.
Impacts
Flash Flooding: Low-lying and urban areas, particularly in New Orleans and Baton Rouge, face significant flood risks. Sandbag distribution has begun in some areas.
Infrastructure: Flooded roads and potential mudslides could disrupt travel and damage property.
Mitigation: Residents should avoid flooded roads, monitor flood watches, and prepare emergency supplies.
4. Tropical Threats in the Atlantic and Gulf
Two areas of interest are being monitored for potential tropical development:
Gulf (Invest 93L): A tropical disturbance moving across the Florida Panhandle has a 40% chance of becoming a tropical depression by mid-week (July 22–23) as it moves over the northeastern Gulf. If it strengthens further, it could become Tropical Storm Dexter. The system is expected to track westward toward Louisiana, bringing heavy rainfall regardless of development.
Central Tropical Atlantic: A tropical wave 900 miles west-southwest of the Cabo Verde Islands has a 20% chance of development over the next 7 days. It is moving westward at 10 mph, but environmental conditions are expected to become unfavorable by mid-week, limiting further development.
Atmospheric Dynamics
Gulf: Warm sea surface temperatures (83–87°F) and high moisture content provide favorable conditions for tropical development. However, proximity to land and moderate wind shear from northerly mid-level winds may limit organization, keeping the system weak and disorganized. A weak upper-level trough enhances lift, supporting heavy rainfall.
Central Atlantic: The tropical wave is interacting with a broad low-pressure area, but marginal environmental conditions (moderate wind shear and dry air intrusion) will likely hinder significant development. By mid-week, increasing wind shear from the strengthening west-northwesterly flow will further suppress cyclogenesis.
Impacts
Gulf Coast: Heavy rainfall from Invest 93L could exacerbate flooding in Louisiana, Alabama, and Mississippi. Rough surf and rip currents are also expected along Gulf Coast beaches.
Atlantic: No immediate land impacts are expected from the Central Atlantic disturbance, but mariners should monitor for potential rough seas.
Mitigation: Gulf Coast residents should prepare for flooding and monitor National Hurricane Center updates. Coastal areas should heed rip current warnings.
In Summary
The week of July 20–26, 2025, will bring a potent combination of excessive heat, severe weather, flooding, and potential tropical activity. A strengthening mid-level ridge will drive dangerous heat across the central and southeastern U.S., while shortwave perturbations and a lee trough spark severe thunderstorms in the northern Plains and Midwest. A slow-moving tropical disturbance in the Gulf will fuel heavy rainfall and flooding risks, with a moderate chance of becoming Tropical Storm Dexter. In the Central Atlantic, a tropical wave is unlikely to develop significantly. Atmospheric dynamics, including a prominent ridge, high moisture content, and weak steering currents, are key drivers of these threats. Residents should stay informed via NOAA Weather Radio, local NWS offices, and the National Hurricane Center for real-time updates.