WREX Probability Scale

Here at the 13 Weather Authority, we do not forecast snowfall amounts until a system’s onset is within 24 hours of Rockford. We began this practice at the beginning of the winter season two years ago for a few reasons. First, we are able to give a more accurate forecast once instead of changing the outlook depending on small nuances in stormtrack and intensity. It also made it easier for us to verify our forecast after the fact since we then had a forecast amount versus actual reports.

However, as soon as snow makes its way into the forecast, most people want to know what the prospects are…whether it will be a small, nuisance snow versus an ice storm or even a full-fledged winter storm!

So, how do we accurately forecast this when we may not have all of the answers a few days out? Obviously, we have an idea of how the solution would be if it warrants us putting a wintry movie under a day on the 7 Day Outlook. Because of this, I developed a “probability scale” so you can get an idea of what is possible versus what will happen exactly.

Below is the current probability scale for the system that will affect the Rockford region this weekend. You will find this on the side bar of the main blog page (to the right). On specific blog posts, it may appear on the left side of the page. Because this is a new trial for me, I will update this Monday through Friday around 4pm. If it seems to be a well-liked addition to the blog, I will update it every day at 4pm.

First, we will give a probability of snowfall accumulation of at least one inch.

Next, because a 2 inch snow is drastically than a 6 inch snow, there is a probability of each condition being met, 2″, 4″, 6″, 8″, 12″, and 18″.

Because there are systems that don’t just yield snow, there is a probability of the storm giving us all snow, all rain, or a combo of rain, sleet, snow, and ice.

Lastly, there is a probability of the amount of precipitation (either rain or melted snow).

I’d like to hear from you about this trial. Does this give you the right amount of information ahead of time? Honestly, it’s hard to get specific when I don’t have all of the details. I hope this lets me get the information across to you in a timely fashion. Thanks in advance for your input! -ERIC

Sat PM through Sun PM
Exclusive WREX Probability Scale:
* 24% Snowfall Accumulation
* 10% Snow > 2 in.
* 02% Snow > 4 in.
* 00% Snow > 6 in.
* 00% Snow > 8 in.
* 00% Snow > 12 in.
* 00% Snow > 18 in.
* 20% Precipitation type: All Rain
* 30% Precipitation type: All Snow
* 50% Precipitation type: Hybrid
* 27% Precipitation >0.25 in.
* 12% Precipitation >0.50 in.
* 01% Precipitation >1.00 in.
* 00% Precipitation >2.00 in.


Posted under weather geek

This post was written by qni_it on November 28, 2011

7 Comments so far

  1. Guest-Woodstock IL November 28, 2011 5:28 PM

    I like this new system of yours! Keep it up! It will especially be fun in the thick of winter, when we have multiple storms to look forward to!

  2. Nikki November 28, 2011 6:23 PM

    i actually understand it!

  3. Justin November 28, 2011 6:27 PM

    I dont see any reason why this would not work. Its a great tool so that people can make plans accordingly up to a week in advance, instead of waiting til the day before and realizing we’re forecasted for several inches of snow (and you can’t be seen as “wrong” for just saying we MIGHT get a big storm… The numbers are right there). If the use of this system seems to take off, you might even be able to include more factors (Blowing snow, freezing rain accumulation, etc.)

    I think its a great idea and am kind of surprised nobody thought of it before. I can’t wait to see it being used throughout the winter.

  4. tony November 28, 2011 7:56 PM

    Can you imagine seeing this scale during the groundhogs day blizzard? that would have been something. I think this will work wonders.

  5. WI Wx Buff November 29, 2011 12:22 PM

    I like it a lot. I originally thought it might be too “weather-geeky” for a lot of people, but maybe I was wrong judging by the comments here.

    Go for it!

  6. maria November 29, 2011 12:41 PM

    This is fabulous!! Very easy to understand. How does it work if we were to get say, 2-4 inches? Would the percentages be roughly the same for each possibility; 2,3, and 4 inches?

  7. Eric Sorensen November 29, 2011 5:25 PM

    Thanks for your comments you guys! It is a little weather-geeky and would need some work before it made it to air. But it allows you guys to get into my head when we’re looking at a storm system longer-range. -ES

Leave a Comment

Name (required)

Email (required)




More Blog Post