Hot and Unsettled Weather Expected (July 6-8)

Hot temperatures with elevated humidity are expected to take us right into the weekend.

A weak and broad ridge is currently dominating the pattern from the central US through the eastern US. It’s hard to even call it a ridge. This is evident by slightly higher 500mb heights for said area carved between two upper-level troughs. Regardless, high pressure will position itself off the SE US and work with several passing low pressure disturbances to keep the flow out of the S and W in our region for the next several days, hence the warmth and humidity. A frontal boundary will remain somewhat stationary from the Mid-West through the Mid-Atlantic, allowing for unsettled weather to move across it from W to E. With that said, we’re subject to showers and possibly some thunderstorms in addition to the heat and humidity. Nothing widespread is modeled so any action would be isolated-to-scattered in nature. Let’s break it down:

Wednesday (July 6) high temperatures should have no problem reaching into the 90s away from the ocean. Even the coast could break into the 80s. I wouldn’t be surprised to see temperatures flirt with 100 along the I-95 corridor through the Philly and Trenton area. Skies should be partly-to-mostly sunny with elevated humidity. As with any hazy, hot and humid NJ summer day, an isolated shower/t-storm can never be ruled out, especially with any sea breeze front interaction. Otherwise, winds should be light out of the SW. Overnight lows should only fall into the 70s away from the ocean and 60s along the coast.

Thursday (July 7) high temperatures should be a degree or a few hotter than Wednesday with sustained elevated humidity. With that said, temperatures could again flirt with 100 for interior CNJ/SNJ. The coast should reach the mid-80s. The rest of the state should easily reach into the 90s. Skies should be partly sunny with a better chance for isolated afternoon/evening thunderstorms than Wednesday. Winds should be light out of the W/SW. Overnight lows should have trouble falling below the 70s statewide.

Friday (July 8) high temperatures should reach into the 90s away from the ocean and mid-to-upper 80s along the coast. This will be the cooler of the days between now and the weekend, if you can call it that. For that reason, flirting with 100 for interior CNJ/SNJ is less likely than Wednesday or Thursday. Skies should be partly sunny with sustained humidity and therefore, showers and thunderstorms are possible again during afternoon/evening hours. Winds should remain light out of the W/SW. Overnight lows should fall into the 70s for most of NJ with NNJ elevations possibly dipping into the 60s.

Notes of Interest: We’ve reached that time of year where the entire lower atmosphere is on the warmer side.

Therefore, instability-driven thunderstorms have a harder time rising within the overall warmer environment. This is known as a capping inversion. Simply, when looking at a cross section of the atmosphere, the capping inversion is represented by an increase in temperatures around the ~700mb level instead of the expected decrease that normally occurs as you climb in altitude towards the stratopause. Therefore, thunderstorm development is stunted except for areas that receive an extra boost in lift. The sea breeze front mechanism, that naturally occurs around 2-4pm, can provide this extra lift boost along the coast. Once the cap breaks, it can lead to flash flooding and severe thunderstorms (often stationary). Such a mesoscale situation can only be detected in the 11th hour and it’s something I will be watching out for until the cold front passes through later in the weekend.

Also pollution, especially surrounding the I-95 corridor, has trouble rising (just like t-storm development) and therefore has triggered air quality alerts and heat advisories by the National Weather Service.

Ocean surface temperatures have cracked 70F for a few beaches between Sandy Hook and Cape May. These temperatures will continue to rise until they level off around 80 in late-August/September.

Lastly, I love watching the sun set in hotter weather such as this. I took the above image under similar circumstances during a heat wave last year. The extra humidity influences light refraction and particle scattering in a way that magnifies the sun’s size and orange/red color. When I was younger, my father used to say “You know it’s going to be hot when the sun sets like that.”

An early look at the weekend indicates cooler temperatures than this week. I’m seeing highs in the 80s statewide with less humidity and a nice summer breeze out of the W/NW. This might all come at the expense of a cold frontal passage with some rain and storms along and ahead of such. The actual frontal passage should be short-lived on Saturday and might even be dry. Let’s revisit Thursday night when I put the weekend outlook out. In the meantime, please stay cool and be safe! JC

Jonathan Carr

Jonathan Carr (JC) is the founder and sole operator of Weather NJ, New Jersey’s largest independent weather reporting agency. Since 2010, Jonathan has provided weather safety and forecasting services for New Jersey and immediate surrounding areas through the web, social media, and app spaces. Originally branded as Severe NJ Weather (before 2014), Weather NJ is proud to bring you accurate and responsible discussions ahead of high-stakes weather scenarios that impact the garden state. All Weather. All New Jersey.™