Heat Wave Begins

Discussion: Upper-level dynamics suggest a prolonged flow gradually fluctuating between W/SW and SW. No pronounced ridges are modeled for the E US. The flow is almost zonal. But this flow will be tapping a very hot region in the C US as well as a humid air mass off the Gulf of Mexico. The hot and humid sources should combine for a prolonged and relentless stretch of heat and humidity. It starts today and goes at least through this Sunday, possibly well into next week. We’re looking at surface temperatures this week in the 90s with dew point temperatures ranging 65-75. That will make for heat indices above 100. It took a while to get here after such a cool spring and anticlimactic (heat-wise) start to summer. But here we are. Aside from being hazy, hot, and humid all week, most of the time looks clear from showers and storms. However, in this kind of environment, micro stuff like sea breeze fronts and general heat lifting could produce isolated storms on any day, especially during peak diurnal afternoon into evening hours. These kinds of air mass storms can produce frequent lightning and flash flooding, if stationary enough. They are low wind shear events and typically pulse with adjacent cells from updrafts dying, becoming downdrafts, and sparking new storms via outflow mesofronts. They like to hug the ECNJ/SENJ Coastal GSP area and a little W of such. Just something to look for on an isolated basis. But otherwise, hazy, hot, and humid will have the headlines this week as a heat wave begins today. A good week for the beach just mind any cumulus clouds that turn cumulonimbus in the afternoon/early evening.

Monday (July 18) high temperatures should get close to/break 90 for much of NJ. Skies should be mixed with sun and clouds with a very humid feel. Thunderstorms are possible, especially later tonight. WNJ is favored for thunderstorms (could reach severe) over ENJ/Coastal NJ but expect storms to weaken/fizzle as they near the coast. Winds should be light-to-breezy out of the S. Overnight lows should stay at 70 or above.

Tuesday (July 19) high temperatures should reach into the lower-90s for most areas, maybe slightly higher away from the ocean. Skies should be mixed with sun and clouds but hazy, hot, and humid. Can’t rule out an isolated pop-up shower or t-storm in the afternoon but heat and humidity should have the headlines. Winds should be light out of the W/SW. Overnight lows should stay at 70 or above.

Wednesday (July 20) high temperatures should reach well into the 90s for most and possibly near 100 away from the ocean. Skies should be mostly sunny but remain hazy, hot, and humid. Super small chance of isolated PM activity maybe off the sea breeze front but otherwise clear. Winds should be light out of the SW. Overnight lows should struggle to dip below 75 statewide.

Thursday (July 21) high temperatures should reach into the 90s for most areas. Skies should be mixed with sun and clouds with the hazy, hot, and humid feel persisting. PM pop-ups are possible. Winds should be light out of the SW. Overnight lows should stay above 70.

Friday (July 22) high temperatures should reach into the 90s for most areas. Skies should be mostly sunny with, wait for it, a hazy, hot, and humid feel. Again, have to include super small caveat chance for isolated pop-ups in this kind of environment. Winds should be light out of the SW. Overnight lows should again stay above 70.

An early look at the weekend indicates more hazy, hot, and humid conditions with more isolated pop-ups possible during afternoon-evening hours. The heat wave looks to last straight through the end of this weekend. After that interior/NWNJ could stay in the heat wave while the lower-2/3 of NJ still reaches the high-80s with elevated humidity. Have a great week and please stay as cool and hydrated as your situation allows. Be safe! JC

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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 and social media. 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.™