Wednesday, June 18 is shaping up to be an extremely hot and unstable day across New Jersey, with sweltering temperatures, high humidity levels, and a significant threat of strong to severe thunderstorms developing by late afternoon and evening.
Severe weather alerts: extreme heat and storm threats in South Jersey
A severe thunderstorm watch has been issued for Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, Mercer, Monmouth, Ocean, and Salem Counties, and remains in effect until 7 p.m., according to the National Weather Service. Expect the possibility of wind gusts up to 70 mph, frequent lightning, and hail.
Meanwhile, a heat advisory is in effect for Gloucester, Camden, Mercer, and northwestern Burlington Counties from 11 a.m. to 8 p.m.. Heat index values could reach as high as 99°F (37°C), with very high humidity amplifying the discomfort.
North Jersey: heat and storms through Thursday evening
On Wednesday, expect cloudy skies and morning fog, followed by showers and thunderstorms especially after 4 p.m.. The high temperature will climb to around 83°F (28°C), with southwest winds at 5 to 10 mph. Precipitation chances are around 80%, with rainfall totals up to half an inch (13 mm) possible.
Wednesday night, thunderstorms are expected to continue through midnight, followed by patchy drizzle and fog before dawn. Lows will hover near 70°F (21°C).
On Juneteenth (Thursday), conditions will turn hot and unstable, with a high near 91°F (33°C). Storms developing after 2 p.m. could become severe, with gusty winds and localized downpours possible.
Central Jersey: large hail and damaging wind gusts possible
Wednesday evening is expected to bring a surge in thunderstorm activity, especially after 5 p.m. Temperatures will rise to about 86°F (30°C), with southwest breezes around 5 to 10 mph. Storms may be locally heavy, with an 80% chance of precipitation and potential flooding in poorly drained areas.
Overnight, storms taper off, though patchy fog may form between midnight and 3 a.m. Low temperatures will stay warm, near 71°F (22°C).
On Thursday, prepare for a dangerous heat wave, with highs near 93°F (34°C) and heat index values even higher. Severe storms may again develop after 2 p.m., and could be more intense than on Wednesday, with damaging winds, hail, and torrential rain. Evening storms could bring up to 1 inch (25 mm) of precipitation.
South Jersey: oppressive heat and storms with dangerous conditions
In Southern New Jersey, Wednesday’s heat will intensify through the afternoon, with highs near 90°F (32°C) and heat index values climbing to 100°F (38°C). Thunderstorms are likely between 3 p.m. and 5 p.m., with frequent lightning and brief, intense downpours.
By Wednesday night, conditions will gradually clear, though patchy fog may linger between midnight and 3 a.m. Lows will remain near 72°F (22°C) under partly clearing skies.
Thursday (Juneteenth) brings the peak of the heat, with temperatures reaching 93°F (34°C) and extreme humidity creating oppressive conditions. Severe storms are expected again after 2 p.m., with high winds, hail, and heavy rainfall possible through the evening.
Looking ahead to Friday and the weekend: dry but still hot
By Friday, a more stable pattern takes hold across New Jersey, with sunny skies and lower humidity returning. Temperatures will stay seasonally warm, ranging from 83°F (28°C) to 91°F (33°C) from Friday through Sunday, with a light northwest breeze offering some relief.
