New Jersey starts September with heat, humidity, and poor air quality
We will make it an "official" heat wave today, with the third consecutive day of 90+ degree temperatures.
Welcome to September! And welcome to climatological/meteorological Autumn! (Meteorologists and climatologists are weird when it comes to seasons - we use full calendar months to demarcate seasons, as it makes record-keeping a lot easier.) It will still take a few days to compile the official final statistics for Summer 2015, but I suspect statewide temperatures will end up a bit above average. Meanwhile, precipitation was mixed this summer: below normal in North Jersey and above normal in South Jersey.
August ended with heat and humidity, and we're diving into September with more of the same. Abundant sunshine will push Tuesday's high temperatures right to where they ended up Monday, mostly in the upper 80s to lower 90s. The Jersey Shore will be kept a bit cooler, thanks to the sea breeze, with high temperatures potentially ranging between the upper 70s and mid 80s along the coast.
Additionally, the New Jersey Department of Environmental Protection has announced a Code Orange Air Quality Alert for 19 of the state's 21 counties. (The alert applies to all but Sussex and Warren counties.) We have seen several "Code Orange" alerts this summer, indicating ground-level ozone may be unhealthy for particularly sensitive groups. That includes the very old, the very young, and those with respiratory issues, who should consider limiting time outdoors during the heat of the day. As I often say, air conditioning will be your friend on days like today.
The short-term forecast includes more heat and humidity for New Jersey. Stifling mugginess will prevent overnight temperatures from dropping much below 70 degrees. Highs for both Wednesday and Thursday will climb to the lower 90s for at least part of New Jersey.
Our relief comes Thursday evening and night, as a cold front is expected to push through the state from north to south. Right now, the models are showing nothing more than isolated showers and thunderstorms associated with the frontal passage. But behind that front will be a much drier and somewhat cooler air mass that will settle into New Jersey through Friday and Saturday.
But there is a potential problem with this scenario... This front is showing characteristics of a "backdoor" cold front, which means brisk surface winds behind the front will be northeasterly - off the ocean. Many times, a backdoor front will bring a period of overcast skies and unseasonably cool temperatures for the eastern half of New Jersey (especially along the coast). The models aren't necessarily picking up on these dramatic side effects yet... But I remain concerned that Friday will be a bit "too cool" for many spots in the Garden State, as temperatures could be stuck in the 70s all day with that on-shore flow.
Of course, Friday night will kickoff the big Labor Day Weekend... arguably one of the most important weather forecasts of the year! By some point on Saturday, winds should become more westerly. That will become a warming wind for Sunday and especially Labor Day Monday, as temperatures rise each day through the 80s. With high pressure in control of our atmosphere on Saturday, Sunday, and Monday, I'm becoming increasingly confident that our weather will stay dry and pleasant throughout the holiday weekend!