Scattered showers and a few storms are possible during the overnight hours. Nighttime storms are common in this type of atmospheric setup, using low-level winds as the energy to spur on cloud development. A few storms could bring a brief heavy downpour through sunrise Wednesday. After sunrise, the low-level winds will weaken and any showers in the area diminish. No severe storms are expected overnight.
WEDNESDAY: HOT AND COULD END VERY STORMY
The hottest air of the season along with the highest levels of humidity this season arrives in Central Indiana Wednesday. Afternoon temperatures will climb under a hazy sun into the upper 80’s and low 90’s. The combination of hot temperatures and high dew point temperatures (measure of moist air) will combine to produce a heat index of 93° to 98°.
The chance of storms looks small during the day Wednesday but later in the afternoon and into the evening, a complex of thunderstorms is expected to erupt. The high charged atmosphere will support severe storms with a potential of wide-spread damaging winds. Outlined by the Storm Prediction Center with a moderate risk – it’s very likely a watch box will be issued.
One weather forecast model from the National Weather Service, the SERF model, indicates a strong probability of severe storms in a corridor from Iowa/Missouri through Illinois into Ohio.
CAPE – the measure of energy in the atmosphere is forecast to be rather high Wednesday. It’s often used by meteorologists as a starting point to see how unstable the air mass is. Potential energy between 1000 to 1500 is the entry-level for severe storms to develop. CAPE values 3,500 to more than 4,000 usually indicate the potential for explosive thunder storm development. Some forecasts for Wednesday are above 4,500 and that could be dangerous.
The presence of a strong jet stream, an approaching upper level and surface low may be all the ingredients to trigger a wide-spread severe weather outbreak through Thursday morning. Be sure to check back and tune in Wednesday as these storms develop. We will be pinpointing the timing and location of this storm complex tomorrow and tracking its movement. Stay tuned!