Friday, July 23, 2021

Hot, Humid, & Hazy This Weekend, Severe Weather Possible Saturday

Here Comes the Heat:

The heat and humidity was much more noticeable yesterday. Thanks to a warm southerly breeze, afternoon highs at most of our local airports fell a few-degree short of the 90° mark. With the 90s in mind, the Rockford Airport has observed an astounding 17 90-degree days so far this year. This already puts us 2 days above what we see on average for the ENTIRE year. Crazy huh? What's even more crazy is that number will more than likely be in the 20s by the time we're heading into the middle of next week. 

Hot & Humid Friday:

Once again, the Stateline is waking up to another round of patchy dense fog and thick haze, especially along the Interstate-88 corridor. If you are making your way out the door early, give yourself a few extra minutes for travel. Otherwise, prepare yourself for another hot and humid day. Today's sunshine, along with a warm southwesterly breeze will help push our highs into the upper 80s, with a spot or two landing in the low 90s.

For those heading to Day 2 of the Lee County Fair or to Rockford's City Market, please take this heat seriously. With the humidity factored in, heat index values late this afternoon will be pushing the mid to upper 90s. Remember to drink plenty of water, and to take frequent breaks in the shade. 

Like Thursday, this hot and humid air will result in a chance for a few isolated late-day showers and thunderstorms. Again, severe weather is NOT expected. Conditions quiet down overnight, with temperatures falling into the low 70s by sunrise. Tomorrow's mild start will be a sign for things to come for the upcoming weekend as this hot and humid stretch shows no signs of slowing down. 

Cranking Up The Heat:

The worst of this extreme heat will be felt during the day on Saturday. With dew point temperatures sitting in the low 70s, our heat index will approach the 100° mark multiple times during the afternoon. Even with a cold front surging through the region overnight Saturday into Sunday morning, little to no relief is anticipated for the end of the weekend. Although our winds look to take a turn to the northwest following this cold frontal passage, high temperatures Sunday will end up in the low 90s, with heat index values back in the mid to upper 90s. 

Saturday's Severe Threat:

Along with Saturday's cold front does come another chance for showers and thunderstorms. Only this time around, the environment that will be in place ahead of this frontal boundary will allow for the potential for severe weather. 

As of this morning, the Storm Prediction Center upgrades areas west of I-90/I-39 to a Slight Risk (level 2 of 5), with the remainder of the area under a Marginal Risk (level 1 of 5). Gusty winds, small-sized hail, and heavy rainfall look to be the biggest concerns. With not much spin or turn in the atmosphere, Saturday's tornado threat remains very low. Guidance does show the potential for thunderstorms arriving after 3PM-4PM, with chances lasting into sunset. The one question that remains is the "Cap", or lid that will be in place just above the surface. If the "cap" holds, our chances will decrease. But if updrafts are strong enough to break the "cap", severe weather will be a big possibility. Stay up-to-date with the forecast for any changes. 

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