The Tale of Several Lows

Discussion: Tomorrow I’ll provide an extended holiday weekend outlook covering Friday-Monday in detail. Today I wanted to cover the broader pattern that has locked in until likely Sept-10ish, possibly longer. It’s the tale of several lows.

As we know, low pressure systems, in the N Hemisphere, rotate region-wide synoptic air masses counter-clockwise (cyclonic circulation). A low can be colder coming off a mid or upper latitude jet (what we know as mid-latitude or upper-latitude cyclones – nor’easters and snowstorms) or it can be warmer and turbo-fed coming off the sub-tropical jet or tropical westerlies in the S Atlantic Basin (tropical storms and hurricanes). In either case, synoptic lows pull warm and humid air upwards in front of it (to the E of the low) and colder drier air down behind it (to the W of the low).

Starting last week with Erin, and with what is expected over the next 7-10 days, we’re in an active pattern of low pressure systems despite none hitting us directly. Erin was the first and although grazing NJ with secondary impacts, missed NJ directly (thank goodness). A weak low will rotate through tomorrow (Friday) bringing the chance for showers. Then a coastal low is expected in the Sept 3-5 period. Models are spread on exact track but it will still be another low rotating through whether it hits NJ or stays offshore. Lastly, 1-2 more lows are possible through about Sept 6-7ish.

Again, even though most of these low centers are missing NJ directly, they are all pulling cooler and dryer air down behind them on the W side of their synoptic-scale cyclonic rotation. They are all riding the front of a trough which means the trough settles in behind them with its own upper low of colder air to reinforce the colder lower level cold front. And this is why we are locked in a below-average temperature/lower humidity pattern, starting just after Erin and lasting through at least Sept 10. Low after low after low…missing us in NJ to the N, S and E but bringing and reinforcing the cooler drier air mass for the NE US and Mid-Atlantic US. If you wanted hot weather, we would need the opposite upper level look with a settled ridge over the E US pulling warm and humid air northward ahead of lows missing us to the W.

Whereas NJ air conditions were temps 90+ and dew points 70+ leading up to Erin, we are now dealing with temps in the mid-70s to lower-80s with dews in the 45-60 range. Get used to it as we open up September with classic morning bus stop chill. What sucks about it all is the ruining of beach summer for the students and teachers milking out the end of summer as they know it.  Erin took ocean swimming off the table last week and this week has felt more like end of Sept/early Oct conditions. A bummer for the beachgoer/boat/pool crowd who likes it hot. However, if you’re like me and love the first early tastes of fall, opening up windows, breaks from humidity, etc., then you’re in heaven. Can’t make everyone happy. What we can all agree on is that it feels pleasant.

In English: A series of atmospheric physics (surface lows and upper lows) are expected to work together to keep NJ on the cooler/drier side through about September 10ish, possibly longer. Some rain chances exist tomorrow (Friday), Sept 4 and Sept 6ish but otherwise conditions are expected to be below average in temperature and with pleasant levels of humidity until then. I’ll have a detailed Labor Day Weekend Outlook posted tomorrow (Friday) but Friday looks like the only day with rain possible. The rest of the weekend looks good. Have a great rest of your Thursday and please be safe! JC

Premium Services

KABOOM Club offers ad-free content, inside info forecast discussion, your questions answered, and early storm impact maps and video releases (ahead of the public). At $1.99 per month, it’s an extremely feasible way to show additional support for Weather NJ and you can can turn it on and off for however many months you wish. Think of it as a tip jar with perks. The public eventually sees all info discussed in premium areas. Available onFacebook or Patreon. 

My Pocket Meteorologist (MPM), in partnership with EPAWA Weather Consulting, offers professional/commercial interests, whose businesses depend on outdoor weather conditions (snow plowing, landscaping, construction, etc.), with hyper-local text message alerts/forecasts and access to the MPM premium forum—the most comprehensive and technical forecast discussion available for PA and NJ.

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 discussion and forecasting services for New Jersey and 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 forecast discussion ahead of high-stakes weather scenarios that impact this great garden state of ours. All Weather. All New Jersey.™ Be safe! JC