The SPC Convective Outlook is a set of forecasts from NOAA's Storm Prediction Center (SPC) covering severe and general thunderstorm threats across the continental United States. Separate outlooks cover Day 1, Day 2, Day 3 and Days 4 to 8.
What the outlook contains
The Day 1, 2 and 3 outlooks include both a categorical risk map and probability maps, along with a text narrative. SPC writes the narrative in scientific language for sophisticated users, but opens it with a summary for general readers.
Day 1 and Day 2 give separate probabilities for tornadoes, wind and hail. Day 3 gives one combined severe probability, and the Days 4 to 8 outlook only outlines areas of 15 percent or 30 percent or higher for severe thunderstorms.
How often it updates
SPC issues the Day 1 outlook five times a day, at 0600, 1300, 1630, 2000 and 0100 UTC. Day 2 comes out around 1 AM Central time and again at 1730 UTC.
Day 3 comes out around 2:30 AM Central time and at 1930 UTC, with the afternoon issuance added on 08/14/24. The Day 4-8 outlook is issued once a day by 4 AM Central time.
What changed in 2026
Beginning 03/03/26, the Day 1 to 3 outlooks carry Conditional Intensity Groups, which show how intense tornadoes, wind or hail could be if they occur. These groups replaced the older 10 percent significant severe area.
SPC now converts probabilities to risk levels with tables that also weigh the intensity group. A 10 percent tornado probability converts to Slight Risk without a group but to Enhanced Risk with CIG1, so the conversion is no longer probability alone.
How to use it
The outlook works best as a first look at where to pay attention a day or more ahead. The mesoscale discussion and watch entries cover the shorter-range products that add detail as an event nears.
Reading the hazard probabilities and intensity groups, not only the category color, gives a fuller picture of what kind of day the forecasters expect.
What the outlook is not
A Moderate Risk does not mean a given town will be hit. Some points inside a risk area will see nothing, and storms can still form just outside a drawn line.
The outlook also does not pin down storm timing or location at high precision. Those details sharpen as the event approaches.