So far, rain has been underwhelming for most of North Alabama. In the classic line of any infomercial: But wait! There’s more!! Don’t expect several inches of rain in one day; however, each day brings a good chance of locally-heavy rainfall, thunderstorms, and some spotty, lighter rain as well.

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That means it won’t rain much at your house in one period (a few hours, a day, etc.), but it may come down in buckets shortly before or after that time. Thursday’s showers move out, and more showers (and a few spotty storms) replace them late this evening and tonight. Short-term model guidance brings some significant rain for a few and a little rain for many: ranging from as little as a few hundredths of an inch to as much as two full inches of rain by Friday morning.

Forecasting rainfall totals: Weather forecasts are estimates of the future impact of weather; most of the time those estimates are close and have a small range, but sometimes the estimates incorporate a lot of uncertainty.

Uncertainty involves placement, timing, and intensity of heavy showers and storms in this case. While model guidance is helpful, it cannot ‘resolve’ a correct answer for every spot. Take the past three ‘runs’ of the Baron (3K) Futurecast for example. The guidance is clearly sending us a message that some heavy rain is likely in North Alabama overnight and early Friday, but it can’t pinpoint which county will get the heaviest action.

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Why does it work like this? Models like our Futurecast or any of the other produced by government and academic institutions run on a grid that is larger than the processes that happen within individual thunderstorms. The grid spaces on the shorter-range, higher-res models are squares about 2 miles by 2 miles in size. Thunderstorms themselves have smaller parts than that, so the model has to estimate how storms interact with other storms, the environment, and the landscape. There’s a lot of estimating there, and the more estimating you have, the less likely the final ‘thought’ will be precise.

They generally do a good job with the ‘area,’ but the margin of error due to estimation will always leave us with some uncertainty in the exact view of what will happen tonight or tomorrow.

By the way, the midday Thursday model run through Saturday afternoon shows a lot of place-to-place variability; take it with a grain of salt seeing it as a range and not a specific, guaranteed amount:

So should I cancel plans? Friday, Saturday, Sunday and Monday all have an 80% chance of rain. That’s an 80% chance that you will get more than 0.10” of rainfall on that day. It won’t rain evenly every single day. Some days it will rain for a few hours, then you’ll see some sun. Other days it may be the opposite for your specific location.

The best advice is to have a back-up plan for large outdoor events; if there’s no way to have a back-up or ‘Plan B,’ then you’ll be taking a big chance that you’re lucky enough to dodge the rain this weekend.

Will it get rough?  Be on the lookout for a few severe storms! June isn’t really thought of as ‘severe weather season,’ but we can get some nasty storms with high winds, hail, excessive rainfall and intense lightning this time of year.

Sometimes summertime storms can be the worst ones you will deal with all year long, so be sure you’re in tune with what’s happening around you if you’re outdoors Thursday, Friday, this weekend or next Monday! Read more about what makes summer storms so rough here on WHNT.com!

Track heavy storms with WHNT.com’s Interactive Radar or swipe over to the radar feature on Live Alert 19!

Looking for the rest of the forecast? It’s always online at WHNT.com/Weather and in the “Daily Forecast” section on Live Alert 19!

-Jason
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