Every morning, the Storm Prediction Center releases a set of severe weather outlooks covering the next three days. On active weather days, meteorologists, emergency managers, and serious weather watchers check these maps first. But the outlooks are more nuanced than most people realize - and in February 2026, SPC added a new category that almost nobody in the indie forecasting community has written about yet.
This guide covers everything you need to read an SPC outlook with confidence: what each risk category actually means in terms of probability, how Day 2 and Day 3 outlooks differ from Day 1, what tornado, wind, and hail hatching indicates, and how to interpret the new Conditional Intensity designation that changed how SPC communicates its highest-end severe weather threats.
What Is the SPC, and What Does an Outlook Tell You?
The Storm Prediction Center (SPC) is a NOAA facility in Norman, Oklahoma. It's the national authority on severe thunderstorm and tornado forecasting in the United States. Every day, SPC issues:
- Day 1 Convective Outlook - Valid through midnight the following day. The most detailed and operationally significant outlook.
- Day 2 Convective Outlook - Valid for the following calendar day.
- Day 3 Convective Outlook - Valid for the day after that. Uses both categorical risk areas and probabilistic contours.
Each outlook includes a categorical risk map (with color-coded risk areas) and a probabilistic graphic (showing percentage contours for tornadoes, damaging winds, and large hail within 25 miles of a point). These two views serve different purposes.
Section 1: The Five Risk Categories
SPC uses five categorical risk levels, introduced in their current form in 2014. From lowest to highest:
Marginal (MRGL) - Level 1 - Dark Green
A Marginal risk means isolated severe thunderstorms are possible, but they'll be few in number and likely short-lived. Think: a couple of brief tornadoes, a few wind damage reports, or some large hail events. The overall severe weather threat is real but limited.
What it means in practice: Keep an eye on the sky, especially if you're in an area prone to severe weather. Not a day to cancel outdoor plans over, but worth checking back in the afternoon.
Slight (SLGT) - Level 2 - Yellow
A Slight risk is the most common "headline" level where multiple severe weather events occur. Scattered severe thunderstorms are expected, with a meaningful chance of tornadoes, significant wind damage, or large hail. Most significant tornado outbreaks start as at least a Slight risk.
What it means in practice: This is a day to have a plan. Know where you'd shelter. Have the Wireless Emergency Alert system enabled on your phone. If you're in a mobile home or vehicle-dependent situation, have an alternate shelter in mind.
Enhanced (ENH) - Level 3 - Orange
An Enhanced risk means more widespread or intense severe weather, or both. The probability of significant severe weather events (EF2+ tornadoes, 75+ mph winds, 2" hail) goes up meaningfully at this level. Enhanced risks often precede major outbreak days.
What it means in practice: This is an active severe weather day. Emergency managers typically brief up at Enhanced. If you live in the outlined area, you should review your severe weather safety plan and know the difference between a watch and a warning.
Moderate (MDT) - Level 4 - Red
Moderate risks are relatively rare - a few dozen per year nationally. They indicate widespread severe weather with a real possibility of significant long-track tornadoes, destructive wind events, or widespread large hail. Multi-day outbreaks often include Moderate risk areas on their most active day.
What it means in practice: Take this seriously. Schools sometimes dismiss early. Emergency management agencies often pre-position resources. If you're in a Moderate or higher area and you have flexibility in your schedule, consider adjusting plans.
High (HIGH) - Level 5 - Magenta/Pink
High risks are rare. SPC issues roughly 3-6 per year in a typical year, sometimes fewer. A High risk means SPC is highly confident in a major severe weather outbreak - the kind associated with significant tornado activity, widespread wind damage, or both. These are days like April 27, 2011 and May 20, 2013.
What it means in practice: Treat this like a forecast for a life-threatening weather event in the outlined area. Anyone who can safely relocate out of the High risk area should consider it. This is a day for serious preparation, not reassurance.
Section 2: Probability Contours - What the Percentages Mean
Behind the categorical map is a set of probabilistic outlooks for three severe weather hazards:
- Tornado probability: chance of a tornado within 25 miles of any given point
- Wind probability: chance of damaging thunderstorm winds (58+ mph gusts) within 25 miles of a point
- Hail probability: chance of large hail (1" diameter or larger) within 25 miles of a point
On the Day 1 outlook, tornado contours typically start at 2%, 5%, 10%, 15%, 30%, 45%, and 60%. Wind and hail contours follow a similar scale. These numbers are calibrated - if SPC draws a 30% tornado contour, they mean it. Their probability forecasts are well-verified over time.
Hatching = Significant Severe Weather Threat
On each probabilistic map, certain areas may be hatched (cross-hatched with diagonal lines). Hatching means a significant severe weather threat exists within the outlined probability contour:
- Tornado hatching (10% or higher contour): Indicates a 10% or greater probability that a significant tornado (EF2 or stronger) will occur within 25 miles of any point.
- Wind hatching (15% or higher contour): Indicates a meaningful probability of extremely damaging winds (80+ mph) within 25 miles of any point.
- Hail hatching (15% or higher contour): Indicates a probability of very large hail (2" diameter or greater) within 25 miles of any point.
Hatching is the SPC's way of saying: it's not just the probability that's elevated, it's the potential severity of what could occur.
Section 3: Day 2 and Day 3 Outlooks - How They Differ
Day 2 Outlook
The Day 2 outlook covers tomorrow. It uses the same five-category risk scale as Day 1 but with less spatial precision - the meteorological signals are less certain 48+ hours out, and the outlined areas are typically broader.
One important difference: Day 2 outlooks include a 15% tornado probability contour on their categorical map. When SPC draws a 15% tornado probability two days in advance, that's a significant signal. It tells experienced forecasters that a meaningful outbreak scenario is in play regardless of categorical label.
Day 3 Outlook
The Day 3 outlook covers the day after tomorrow. At this range, SPC uses a simpler probabilistic format:
- 15% - General severe weather threat
- 30% - Enhanced severe weather threat (roughly maps to Slight or Enhanced categorical level)
- TORNADO, WIND, HAIL contours at lower probability thresholds
Day 3 outlooks are less reliable in specific placement but highly useful for situational awareness - they let emergency managers, broadcasters, and indie forecasters know what may be coming so they can pre-communicate.
Section 4: The New Conditional Intensity Category (February 2026)
In February 2026, SPC added a new designation to their probabilistic outlook system: Conditional Intensity (CI).
This is the update that the hodo.graphics post - the one that currently ranks for "SPC outlook interpretation guide" - doesn't cover.
What Is Conditional Intensity?
Conditional Intensity addresses a gap in how the tornado probability contours communicated forecast uncertainty. The traditional probability contours blended two distinct uncertainties together:
- Whether severe thunderstorms would occur in a given area
- How intense they would be if they occurred
On some days, SPC would have relatively high confidence in the storm mode and placement, but low confidence in intensity (e.g., a complex messy setup where storms might go linear). On other days, they'd have lower confidence in whether storms would even initiate, but if they did, they'd be discrete supercells with tornado potential.
The traditional probability contour collapsed these into a single number, which sometimes masked important nuance in the forecast.
Conditional Intensity separates these signals. When SPC includes a CI designation, it indicates that the intensity of severe weather events, conditional on them occurring, is elevated - even if the base probability contour looks modest.
How to Read It
A Conditional Intensity area will appear as a hatched or labeled zone within a probability contour. The CI label tells you:
- Storms that fire here could be especially intense or long-tracked
- The base probability may be 10-15%, but the outcome if those storms develop is more extreme than a typical 10-15% event
Think of it this way: a 15% tornado contour in a disorganized setup might mean 15 tornadoes if a squall line develops - mostly EF0 and EF1. A 15% tornado contour with Conditional Intensity might mean a lower number of tornadoes, but the ones that do occur have a higher likelihood of being EF2+ and long-tracked.
Why This Matters for Indie Forecasters
For anyone publishing their own severe weather forecasts, Conditional Intensity changes how you should communicate your forecast to your audience:
- Without CI: Your message can focus on coverage ("expect scattered severe thunderstorms across central Kansas")
- With CI: Your message needs to address potential severity, not just likelihood ("if supercells fire on the dryline, intensity could be significant - even a modest outbreak could include long-track tornadoes")
The distinction is meaningful. It's the difference between a day where your audience needs to be aware and a day where your audience needs to be prepared.
Section 5: Translating an SPC Outlook Into Your Own Regional Forecast
Understanding the SPC outlook is step one. Translating it into your own regional forecast - for your specific audience, on your specific platform - is where indie forecasters add real value.
Here's a workflow that works:
1. Start with the Day 3 and Day 2 outlooks on Monday/Tuesday Pre-communicate the threat range. Your audience benefits from 48-72 hour awareness even if the details aren't locked.
2. Check the Day 1 categorical and probabilistic maps on the morning of the event Note which risk category your audience's region falls in, which hazard contours cover them, and whether CI is indicated.
3. Draw your own regional forecast map The SPC outlook covers the entire country. Your readers care about their county, their neighborhood, their commute. Use the SPC probabilities as your foundation, then apply your local knowledge. If you know that your region typically sees storms that struggle to stay discrete due to terrain, your tornado probability for your specific audience may be lower than the SPC contour suggests.
4. Specify the primary hazard Is it tornadoes, wind, or hail? Your audience can only prioritize one response strategy. Tell them which hazard you're most concerned about and why.
5. Verify after the event This is where structured forecast publishing pays off. When you've drawn your predicted risk region before the event, you can verify afterward whether your placement, hazard designation, and intensity call were correct. That track record is what separates forecasters from commentators.
On Forecaster HQ, you can draw your severe weather risk regions on a map before the event, publish your forecast with timing phases and confidence notes, and then pull verification data from NWS observation stations after the storm to see how your prediction scored. It's the forecast-first model - the same approach the SPC uses, applied at the local level.
Reading SPC Outlooks: A Quick Reference
| Risk Level | Color | Meaning | What to Do |
|---|---|---|---|
| Marginal | Dark Green | Isolated severe storms | Situational awareness |
| Slight | Yellow | Scattered severe storms | Have a plan |
| Enhanced | Orange | More widespread/intense severe | Review safety plans |
| Moderate | Red | Significant outbreak possible | Take action |
| High | Magenta | Major outbreak highly likely | Serious preparation |
| Hatching Type | What It Means |
|---|---|
| Tornado hatching (10%+) | 10%+ chance of EF2+ tornado within 25 miles |
| Wind hatching (15%+) | Meaningful probability of 80+ mph winds |
| Hail hatching (15%+) | Meaningful probability of 2"+ hail |
| Conditional Intensity (CI) | If storms fire, intensity could be higher than base probability suggests |
Where to Go From Here
The SPC outlook is the foundation of severe weather situational awareness in the U.S. Understanding how to read it - including the new Conditional Intensity designation - puts you in a much better position to communicate severe weather threats clearly and accurately to your audience.
If you want to go deeper:
- Storm Forecast Verification: How to Measure Your Accuracy - How to use NWS observation data to score your own forecasts
- How to Publish a Severe Weather Forecast Online - The step-by-step guide to publishing structured forecasts on Forecaster HQ
- How to Become an Independent Weather Forecaster - The full roadmap from hobbyist to credible indie forecaster
The SPC outlook tells you what's coming. What you do with that information - how you communicate it, how you apply your local knowledge, and how you track your accuracy over time - is what makes you a forecaster rather than a weather watcher.
SPC outlooks are updated daily at spc.noaa.gov. The Conditional Intensity designation was introduced in February 2026. Probability values cited in this post are based on SPC's published forecasting methodology.