What exactly does the Day 3 Excessive Rainfall Outlook entail?

The Day 3 Excessive Rainfall Outlook is a national storm forecast released by the National Weather Service. It provides a 24-hour forecast from September 30, 2026, to October 1, 2026, detailing the risk of excessive rainfall and potential flash flooding across the United States. The forecast includes varying levels of severity, from Marginal (MRGL) to High (HIGH).

How does the National Weather Service determine the risk levels for excessive rainfall?

The National Weather Service uses flash flood guidance to translate complex data into understandable risk levels. The risk levels range from Marginal (MRGL) to High (HIGH), indicating the probability of rainfall exceeding critical thresholds within a 25-mile radius. The levels are based on the chance of flash flooding, with HIGH being the most dangerous and MRGL being the least.

What does the Marginal (MRGL) risk level mean in the Day 3 Excessive Rainfall Outlook?

A Marginal (MRGL) risk level indicates a 5% or greater chance of rainfall exceeding flash flood guidance over a 24-hour period. This means small streams or urban areas might overflow, but widespread or significant flooding isn’t expected. However, it’s important to stay aware of weather updates and be prepared to act if conditions change.

Why is the Day 3 Excessive Rainfall Outlook important in the context of climate change?

The Day 3 Excessive Rainfall Outlook is crucial because it helps quantify the risk of excessive rainfall and flash flooding in a changing climate. Patterns of rain and drought are shifting, and what was once considered excessive rainfall a decade ago is no longer the case. This outlook provides a way to plan and prepare for severe weather events that are becoming increasingly unpredictable.

How does the National Weather Service communicate the risk of flash flooding to the public?

The National Weather Service communicates the risk of flash flooding through its Day 3 Excessive Rainfall Outlook, which includes different risk levels from Marginal (MRGL) to High (HIGH). These levels are based on the probability of rainfall exceeding flash flood guidance within a 25-mile radius. The public can understand these risk levels to stay informed and prepared for potential flash flooding.

What should I do if my area is under a High (HIGH) risk level for excessive rainfall?

If your area is under a High (HIGH) risk level, it indicates a 70% or greater chance that rainfall will exceed the critical flash flood guidance for that area. This means there is a high risk of severe flash flooding. You should stay informed through weather updates, follow the advice of local authorities, and be prepared to evacuate if necessary.

United States Excessive Rainfall Forecast September 2026

What is the Excessive Rainfall Outlook?

The National Weather Service uses the term Day 3 Excessive Rainfall Outlook to describe a national storm forecast. It projects the risk of excessive rainfall and potential flash flooding across the United States, with varying levels of severity from Marginal (MRGL) to High (HIGH). The Day 3 forecast covers a 24-hour period from Wednesday, September 30, 2026, to Thursday, October 1, 2026. TechTimes broadcasted this map to help population and authorities understand the forecast period, issuance time, and the forecaster's identity. The NOAA/NWS also lists the critical thresholds for rainfall, even naming them like "HIGH" or "HIGH".

Where We Stand: The Challenge of Rainfall in a Changing Climate

The outlook for this Day 3 forecast reflects the increasing unpredictability of weather pattern around the United States. Patterns of rain and drought are shifting — and the amount of rain once considered excessive isn’t what it was even a decade ago. Water levels near flash flood guidance within 25 miles often change — but NOAA/National Weather Service has a 5% to 70% MRGL, MDT, SLGT, to HIGH chart that helps authorities and population along with the TechTimes brand. This outlook presents a way to quantify the risk and plan accordingly. The latest forecast shows that excessive rainfall can be deadly, and flash floods are harder than ever to predict. That makes the Day 3 Excessive Rainfall Outlook indispensable.

The Three Days of Severe Weather

Flash Flood Guidance: Translating Data into Risk

Flash flooding is catastrophic. It moves fast, and it can happen without warning. The National Weather Service uses flash flood guidance to translate complex data into a risk level that everyone can understand. It offers different levels with the possible severity of rainfall. If a flash flood is coming, the risk of rainfall exceeding flash flood guidance within a 25-mile radius can range 5% to 70%. That’s why you’ll see a risk breakdown, broken into those categories. HIGH is the most dangerous, indicating a 70% or greater chance that rainfall of the most critical flash flood guidance for that area will occur. Marginal (MRGL) denotes the lowest risk, with a 5% chance of the threshold being met. The levels between MRGL and HIGH show an increasing probability of exceeding flash flood guidance. A rising flood level means that risks are increasing with the possible water levels in that area.

Understanding Flash Flood Guidance Levels

With these categories, NOAA/NWS held the essential role of presenting forecast across Day 3.

Marginal (MRGL): A MRGL risk level indicates a 5% or greater chance of rainfall exceeding flash flood guidance over a 24-hour period, so small streams or urban areas might overflow, but widespread or significant flooding isn’t expected. Still, it’s important to stay aware of weather updates and be prepared to act if conditions change. Even a low chance of severe weather can turn dangerous quickly.
Slight (SLGT): At a SLGT risk level, there’s a 15% chance of rainfall exceeding flash flood guidance. Flooding is possible, but typically not widespread or prolonged. Heavy rain might happen unexpectedly, so it’s crucial to monitor weather conditions and be ready if flash flooding happens. Remember, just 6 inches of fast-moving water can knock you off your feet. A SLGT risk level indicates a 40% chance. Conditions are favorable for heavy rain, and flash flooding is possible. Flooding may occur in low-lying or poor drainage areas, or in urban regions. High Risk (HIGH) means widespread and extreme heavy rain is expected or occurring with a 70% chance. Multiple locations could be affected, with flash flooding a real possibility. Stay vigilant for rapid changes in weather conditions, and be prepared to take immediate action if necessary. If you see high waters, turn around, right away—do not try to cross.

The Expert Behind the Forecast: Meet Forecaster WEGMAN

Forecaster WEGMAN works at the National Weather Service and his her National Center for Environmental Prediction, where the Excessive Rainfall Outlook is made. The Outlook comes from the National Weather Service's National Centers for Environmental Prediction. The Weather Prediction Center predicts dangerous weather and how technology and weather forecasting models helps them to make the forecast. That map and places are the essential point for the outlook. Forecaster's colleagues issue the Day 3 Outlook every Monday morning. How he does the forecast? Develops the risk of an excessive rain forecast for the next three days. He relies on hydrological data, with the threat of flash flooding in mind at all times. Forecaster WEGMAN is one of several forecasters who contribute to the Day 3 Excessive Rainfall Outlook. And the prospect of this forecast is a better outlook in front of the population.

The Essential Roles of TechTimes Weather Alerts

How to Interpret the TechTimes Weather Alert

A National Weather Service outlook offers a guided way to take necessary precautions. But, what should you do with this information? Here are some practical steps to understand the TechTimes Weather Alert:

Stay informed: Pay attention to updates from your local National Weather Service office. Weather conditions can change rapidly, so it’s important to stay tuned for the latest information.
Understand the risk: Familiarize yourself with the risk categories and what they mean for your area. Knowing the difference between Marginal and High risk can help you make informed decisions about your safety.
Prepare your home: Clear clutter from gutters, drains, and downspouts to help prevent water from accumulating. If flooding is expected in your area, consider protecting your property with sandbags or other barriers.
Have an emergency plan: Know your evacuation routes and have a plan in place in case you need to leave your home quickly. Keep important documents and valuables in a safe, waterproof location.
Stay safe during severe weather: If you’re outdoors when a storm hits, seek shelter immediately. Avoid driving through flooded areas, and never attempt to cross a flooded roadway on foot—even if it looks safe. Fast-moving water can sweep you away in an instant.