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Upcoming Changes to Storm Prediction Center Convective Outlooks

Written by Henry Luker, Lead Forecaster

Out of the many new features that will help the Iowa Weather Network run severe weather coverage for the upcoming season, the Storm Prediction Center is doing the same to continue serving their mission of protecting life and property. But before we go on to discuss those changes, I should mention that the Iowa Weather Network will be providing new and enhanced severe weather coverage, including live video, green screen, and live alerts during any severe weather event. We will be in touch and connected to all of our staff, with live video from Meteorologist-in-Charge Jeff Wilcox in Anamosa and Lead Forecaster Henry Luker in Clear Lake, as well as live chasers in the field available at the click of a button. Look for the upcoming press release for further information regarding this.

Now on to the changes at the Storm Prediction Center, one of nine National Center Environmental Prediction departments. All of this is a branch under the National Weather Service, a department of the National Oceanic and Atmospheric Administration, who is a department of the United States Department of Commerce. That’s government for ya! Let’s first provide some small details about the Storm Prediction Center.

Here are some of the products they issue for the lower 48 states, or the Contiguous United States (CONUS):

  • Severe thunderstorm and tornado watches
  • Severe thunderstorm (convective) outlooks
    • Day 1 – categorical & probabilities for tornado, hail, and wind threats
    • Day 2 – categorical & general probabilities
    • Day 3 – categorical & general probabilities
    • Day 4-8 – general severe weather risk area
  • Fire weather outlooks
    • Day 1
    • Day 2
    • Day 3
    • Day 3-8 general & probabilities
  • Weather discussions (Mesoscale Discussions)
    • Severe thunderstorms (possible watches & outlook upgrades)
    • Winter weather (ice storms, freezing rain, snow, etc)

The changes they are making will affect the severe thunderstorm, or convective, outlooks that they issue daily. In past years, the SPC has used five categories to highlight these risks – thunderstorms, see text, slight, moderate, and high. The only change to these will be that ‘see text’ will be changing to ‘marginal.’ This is to make sure, you, the public, know what we are talking about.

Additionally, the SPC will be adding a new category to the lineup – ‘enhanced’. To simplify the need for this, if was a a 30% hail or wind risk, the categorical risk would still show ‘slight’. Since the public usually does not look at the probabilities, the SPC deemed this change was necessary.

While the Iowa Weather Network will not be using these exact categories, we figured we would let you know to avoid any confusion. For those weather weenies out there who would like to know the exact probabilities, the table below will describe that.

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