By Doug Schneider
I've been taking some heat on social media for my dry forecast for the Indy 500. I've had people pointing at their weather apps, showing me how their apps said it would be raining on Sunday. With today's update, I'm sticking with a dry forecast, and here's why:
The pattern for the weekend will have a low pressure system nearly stationary over New England, with a high pressure system over the northern Plains and south-central Canada. This will create a northerly flow across Indiana. A front will be located near the Ohio River, across Kentucky and through Missouri. This front will be the focus for rain over the weekend. With the northerly flow across Indiana, I expect the front and moisture associated with it to stay south of Indianapolis. There were some models that had this front farther north with previous runs, but the latest model runs are coming into better agreement that it will stay to the south.
Some weather apps will use a blend of models, or an ensemble, for their forecast. While a model blend is good to use in some situations, it will sometimes tend to overdo the aerial coverage of rainfall as different model rainfall depictions get smoothed together. Most models may be dry at one location, but a few wet models will get blended together with them and increase the chance of rain at that location. A human forecaster can recognize these situations and mentally correct for the models using experience and pattern recognition.
This forecast can certainly change before we get to Sunday. A lot can change in the models between now and then, and I'll post another update if necessary. For now, I think a dry day is the most likely scenario.
I've been taking some heat on social media for my dry forecast for the Indy 500. I've had people pointing at their weather apps, showing me how their apps said it would be raining on Sunday. With today's update, I'm sticking with a dry forecast, and here's why:
The pattern for the weekend will have a low pressure system nearly stationary over New England, with a high pressure system over the northern Plains and south-central Canada. This will create a northerly flow across Indiana. A front will be located near the Ohio River, across Kentucky and through Missouri. This front will be the focus for rain over the weekend. With the northerly flow across Indiana, I expect the front and moisture associated with it to stay south of Indianapolis. There were some models that had this front farther north with previous runs, but the latest model runs are coming into better agreement that it will stay to the south.
Some weather apps will use a blend of models, or an ensemble, for their forecast. While a model blend is good to use in some situations, it will sometimes tend to overdo the aerial coverage of rainfall as different model rainfall depictions get smoothed together. Most models may be dry at one location, but a few wet models will get blended together with them and increase the chance of rain at that location. A human forecaster can recognize these situations and mentally correct for the models using experience and pattern recognition.
This forecast can certainly change before we get to Sunday. A lot can change in the models between now and then, and I'll post another update if necessary. For now, I think a dry day is the most likely scenario.
