Don’t leave home Thursday without checking the sky and your forecast. Forecasters are warning of a double threat across southern New Hampshire: strong to severe thunderstorms in the afternoon, followed by air so humid and hot it will feel close to 96°F in the evening. It’s a rare mix of storm danger and summer sizzle all packed into one volatile day.
If you’re planning outdoor Juneteenth celebrations, expect weather disruptions—and prepare to pivot indoors.
Thunderstorms Could Arrive Fast and Furious
A strong cold front is charging into the region Thursday afternoon, setting the stage for severe weather outbreaks across the Granite State. That means:
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Wind gusts up to 60 mph, capable of knocking down branches and power lines
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Torrential downpours that can flood low-lying areas in minutes
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Frequent lightning, especially dangerous for those at parks or public gatherings
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A small risk of hail or even a brief tornado, particularly in southern zones like Manchester and Nashua
The National Weather Service has flagged this event as a potential severe weather threat, particularly between 2 p.m. and 7 p.m., right when people are commuting, attending events, or out enjoying the holiday.
Heat Will Linger—And It’s Not Just Uncomfortable
Here’s where it gets even more intense: once the storms pass, the heat and humidity will dig in, pushing the heat index—the “feels-like” temperature—up to around 96°F by late afternoon and early evening.
What’s making this worse is the timing. Thunderstorms can briefly cool the surface, but once they clear, the sun often reappears and combines with saturated ground and heavy air to create a kind of post-storm steam bath.
This type of heat is:
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Tough on the elderly, kids, and anyone without air conditioning
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Dangerous for athletes, construction crews, or anyone exerting themselves outside
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Amplified by New Hampshire’s recent humidity levels, making even 85°F feel much hotter
What to Expect – Hour by Hour
Morning: Warm, muggy, partly cloudy. Nothing major yet—but don’t be fooled.
Afternoon (2 p.m.–6 p.m.): Thunderstorms roll in. Sudden gusts, heavy rain, thunder, lightning. Watch for quick-onset flooding and warnings.
Evening (6 p.m.–9 p.m.): Rain tapers off, but humidity spikes. Air feels sticky and uncomfortable. Heat index stays near 90–96°F well into sunset.
Overnight: Temps drop slightly, but humidity sticks around, making it hard to sleep without AC.
What You Should Do Today
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Check the weather every few hours—conditions can change quickly
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Secure outdoor furniture or tents if hosting an event
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Charge your phone and backup power in case storms knock out electricity
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Cancel or move outdoor plans indoors after lunchtime
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Drink water all day, even if you’re just sitting outside
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Watch for signs of heat exhaustion: dizziness, headache, nausea, confusion
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Keep pets cool and inside—pavement and humidity are dangerous for animals
What Comes After
The good news? Friday offers a break. Clear skies, cooler temps in the low 80s, and a drop in humidity will make the day much more comfortable. The weekend will stay warm but manageable—so long as you’re not caught off guard today.
Final Word
Thursday is a day for caution and flexibility. From lightning bolts in the afternoon to oppressive heat in the evening, Manchester and much of southern New Hampshire will experience extreme weather contrasts that could affect everything from your commute to your health.
Plan early. Move smart. And don’t let the skies fool you—this is a Juneteenth forecast you’ll want to take seriously.
