C2K'S Severe Weather Page is a collection of weather graphics designed to help locate areas of possible current or future Severe Weather. The images may be viewed by selecting them from the menu on the right side of your screen. Below you will find a brief description of the images, and links to more information where applicable.

SPC Day1 Convective Outlook

This graphic is supplied by the Storm Prediction Center, and indicates areas where Severe Weather may occur over the next 24HRS. For a detailed explanation of the how the Outlook is generated click here. A discussion of the Outlook is issued along with the graphic that provides a detailed look at the forecast.

SPC Day2 Convective Outlook

This graphic indicates areas where Severe Weather may occur from 24 to 48HRS after the Outlook is issued.

Probability Forecasts

Probability forecasts are issued by the Storm Prediction Center for Tornado, Severe Hail, and Severe Thunderstorm Wind Events. These are experimental products that give the probabilities of these events over the next 24HRS. For more information on these products click here. Also take a look at Severe Weather Climatological Probabilities. This is a a very interesting page that gives the climatology of Severe Weather for every day of the year. Loaded with graphics.

Convective Precipitation

These graphics are supplied by the Aviation Weather Center, and use the current RUC2 model to forecast Convective Precipitation over the next 12HRS. For more information click here.

Vertical Velocity Storm(VVStorm)

Also issued by the Aviation Weather Center, these graphics show maximum vertical velocity over the next 12HRS. For more detailed information click here.

12-48HR Thunderstorm Probabilities

These graphics show the Thunderstorm and Severe Thunderstorm probabilities over the next 48HRS at 12HR intervals.

Rapid Update Cycle(RUC)

The Rapid Update Cycle is a forecasting model used for short term forecasting. We have only shown a selected number of parameters. The complete model parameters can be seen at The Real Time Weather Data Page.The parameters shown are:

Theta-E( or Equivalent Potential Temperature)

A measure of atmospheric instability. Severe Weather or excessive rainfall often occur near or just upstream of an axis of high values of theta-e.

CAPE(Convective Available Potential Energy)

CAPE represents the amount of energy available for convection.Higher values indicate a greater potential for Severe Weather. Values <1000 indicate a relatively stable atmosphere. Values >2000 indicate enough energy to produce thunderstorms. Values >3000 indicate enough energy to produce strong thunderstorms.

SREH(Storm Relative Helicity)

A measure of storm relative rotation. Helicity is needed to allow a thunderstorm to develop into a severe or supercell storm. Values above 150 will favor development of mid-level rotation. Values of 400-500 are are often needed to produce severe storms.

Precipitation

This field shows the amount of precipitation expected to fall in the given time period.

Precipitation Type

This field shows the type of precipitation expected to fall(i.e. rain, ice, snow).

850MB Temperature

The 850MB Temperature needs to be colder than the air at the surface for storms to develop.

Further definitions of these terms can be found at the Weather Glossary.

MM5(Mesoscale Model)

This forecast model is a product of the National Severe Storm Laboratory. Forecasts are generated for 48HRS from initialization at 3HR intervals. This model focuses on Severe Weather threats. Again we have only shown selected parameters. All output fields can be seen at Real-Time MM5.

Tornadic Potential/Convective Precipitation

A representation of the tornadic potential and convective precipitation over the forecast time.

CAPE

See RUC CAPE explanation above.

Relatvie Helicity

See RUC Storm Relative Helicity above.

BRNSHR(Bulk Richardson Number Shear)

A number relating vertical stability and vertical shear. Values in the range of 50-100 suggest conditions favorable for supercell development.

Further definitions can be found at the Weather Glossary.

Satellite Images

These images are derived from GOES soundings. They show values of the selected index in areas where clouds are not present. They indicate areas where Severe Weather may develop.

CAPE(Convective Available Potential Energy)

See RUC CAPE above.

Lifted Index

A measure of atmospheric instability.Negative values indicate instability, the more negative the more unstable the air. Values of -4 or lower indicate areas where Severe Thunderstorms may develop. Values > 10 indicate areas where the weather is stable and skies are clear.

CIN(Convective Inhibition)

A measure of the amount of energy needed to initiate convection. Values of CIN represent the strength of the cap.

Further definitions can be found at the Weather Glossary.

Once you have reviewed these images you can keep an eye on the Current Weather by viewing our Current Weather, Radar, and Satellite Pages.