The Storm Prediction Center provides severe weather forecasts in the form of convective outlooks and fire weather outlooks. These forecasts are critical to the public, aviation community, local forecasters, news stations, and organizations responsible for the safety of outdoor events. hodo.graphics pulls up to date outlooks from the SPC for display in a mobile friendly map. View current SPC outlooks here.

What is a Convective Outlook?

A Convective Outlook is a weather forecast that highlights the potential for convective severe weather, such as tornadoes, large hail, and damaging winds. They are based on forecasts of conditions conducive to intense, rapidly developing storms, and attempt to predict the types of threats made possible by those conditions.

These outlooks forecast severe weather for 8 days, with day 1 being today's forecast. Because forecasting becomes more difficult further into the future, the outlook types become less granular for later days.

The Different Types of Convective Outlooks

Days 1 and 2

These shorter-term forecasts include a categorical outlook as well as probabalistic forecasts for specific types of severe weather, like wind, hail and tornadoes.

Categorical

The categorical forecast provides an estimate of the overall threat of severe weather. More details can be found at the SPC's product page, but in summary, the threat level is divided into categories:

Wind, Hail, and Tornado

These products display the probability of their respective severe weather for some area. The probability is for this weather occurring within 25 miles of a given point within the region. For the purposes of this map, each phenomena is defined as follows:

hodo.graphics displays each area, colored based on probability.

Significant Wind, Hail, and Tornado

If conditions are predicted to support it, the SPC will provide probabilities for "significant" severe weather. hodo.graphics provides these as a separate product in the interface. The Storm Prediction Center uses the following qualifiers for these areas, using the same probability definition (occurring within 25 miles of a given point):

Day 3

The Storm Prediction Center provides the same categorical product for day 3, but rolls the phenomena-specific products into just probability and significant probability. The criteria (within 25 miles of a point) remains the same, but instead of wind, hail, or tornadoes, it represents the probability of any severe weather, or significant severe weather, respectively.

Days 4 through 8

For the longer term outlooks, the categorical product is removed. Longer term forcasts have much more uncertainty, so days 4 through 8 only show the probability of severe weather in an area.

Fire Weather Outlooks

In addition to convective outlooks, the SPC provides outlooks for fire weather. These products are based on the existence of dry fuels, winds, relative humidity, and predicted dry thunderstorms.

hodo.graphics provides the wind and humidity fire weather products separately from dry thunderstorm products. The categories for wind and humidity are:

And the categories for thunderstorms are:

See the SPC's product page for more information about their fire weather products, or see today's fire weather on hodo.graphics.

Making Weather Information Accessible

The Storm Prediction Center's forecasts are a vital public service, helping protect lives and property by providing advance warning of dangerous weather conditions. Thanks to the SPC making their data freely available, hodo.graphics can enhance its accessibility by providing a mobile-optimized interface for viewing their forecasts and outlooks with a simple, clean design.