Our week started with a little heat, but quickly transitioned to a week with high heat and severe weather threats. North Haven saw a confirmed EF-0 tornado yesterday, and we’re expecting more severe potential and the highest heat indices of the summer over the next few days. In this evening’s post, I want to break down all of the weather hazards of the next few days.
Like the heat wave last month, this latest bout of heat is significant and dangerous. For this heat wave, we’re looking more at the combination of heat and humidity, rather than just air temperatures. The culprit is a ridge of high pressure pumping heat and deep tropical moisture into the region.
Tomorrow and Saturday are the biggest heat and humidity days, but heat could extend into Sunday. There has been some guidance suggesting that a backdoor cold front makes a powerful push into Connecticut Saturday, stunting heat in the state, but I’m not biting on it. I anticipate two of the hottest day in a long time for folks—based on the heat index. Heat indices were in the upper 90s to 108 in Hartford today. Tomorrow they will be worse. Saturday will be worse than that. We’re looking at potentially dangerous days, especially in the cities should the heat and humidity verify.
Now, I say that, but heat related illnesses are preventable! Make sure you heed the following tips. With this type of humidity, it becomes very hard to cool down. Make sure you take the heat seriously.
The severe weather forecast is not as high confidence as the heat forecast, but I believe there is a real threat of severe weather both Friday and Saturday. Within this section, we have to break things down by hazard type.
This is by far the biggest threat over the next few days. As we saw today, if thunderstorms are able to sit over an area for a while, we could see flash flooding situations. Glastonbury received over 3 inches of rain in 100 minutes, which can cause problems both with streams/rivers, and urban flooding of roads. This is an airmass that is loaded with moisture, all it takes is a thunderstorm to gain traction over your area for the sky to open up. Remember, if you see a flooded road, turn around!
These kind of air masses can be conducive for prolific lightning events. We saw one today in central and eastern Connecticut, and it was reported that someone in the state was struck by lightning. I cannot emphasize enough how important it is for people to go indoors when you hear thunder.
Straight line winds are probably the next biggest hazard. With high temps comes strong instability, and if a storm pops, there could be strong winds in isolated spots. In an intense enough updraft, hail also becomes a threat but I think there is small risk for significant hail.
I want to be abundantly clear—we are not looking at a widespread severe weather event or widespread/high tornado threat. However, I am concerned that thunderstorms that become severe tomorrow and Saturday could develop enough spin to produce an isolated tornado. The flag is seeing guidance show significant instability and developing low level wind fields that could potentially support spin at the surface. As we saw yesterday in North Haven, everyone should be on alert even if a tornado watch or warning has not been issued. Even though the risk is low, this means that everyone should be paying close attention to radar and updates, and get inside if there is a severe thunderstorm warning issued for your area.
Heat is likely to remain for interior Connecticut on Sunday, but we gradually cool down by the start of next week. There is the potential for a low to trek across the region Sunday or Monday, which introduces the risk of a widespread wet period. For those with weekend plans, I’d continue for now, but be ready to cancel depending on the radar and modeling early Sunday.
The bottom line
- The latest heat wave will continue through at least Saturday, with the heat getting worse each day.
- The heat index will be potentially dangerous at times for individuals who our outside for long periods of time and do not take steps to protect themselves.
- There is a severe weather risk on each day, with flooding rains being most likely.
- Although low, there is a non-zero tornado risk Friday and Saturday, which requires everyone to pay close attention to all severe warnings.
- The heat begins to relax by early next week, but the rain threat continues.
Friday: Hazy, hot, and humid with a late day thunderstorm chance. Some storms could be severe. Highs in the low to mid 90s with heat indices in the upper 90s to over 100. Chance of rain 50%.
Saturday: Hot and humid with a late day thunderstorm chances. Some storms could be severe. Highs in the mid to upper 90s with heat indices over 100. Chance of rain 60%.
Sunday: Hot and humid with thunderstorm chances throughout the day. Highs in the upper 80s to low 90s. Chance of rain 50%.
Monday: Partly sunny with a chance of storms. Highs in the mid to upper 80s. Chance of rain 40%.
Tuesday: Mostly sunny with a chance of storms. Highs in the mid to upper 80s. Chance of rain 20%.
Wednesday: Partly sunny with a chance of storms. Highs in the mid to upper 80s. Chance of rain 20%.
Thursday: Sunny. Highs in the mid to upper 80s.
Thank you for reading. Over the next few days, many of my real time updates will come on Twitter, though we will of course try to provide coverage on our Facebook page as well. Make sure you follow us @SouthernCTWX! Share this post, stay cool, and keep an eye to the sky!