Good evening from Southern Connecticut Weather.
The high heat of July has faded away. The bite of the summertime sun has diminished some. The days are getting shorter. Time marches incessantly, but when it comes to weather and seasonal change, when the transition picks up in earnest varies by year. Some seasons, like last summer, the march toward fall began early, right around the time we turned the page to August. Pretty unusual.
Some years, the seasonal transition happens late. Think of the many recent winters where the start of it resembled extended fall more than winter itself.
For those new to us, while the march toward another season technically begins as soon as an astronomical season begins, we write around the time the seasonal change becomes more notable. Summer is not over. There will still be warm and humid days, but change is in the air, and it's time to talk about it. The biggest question we've gotten after an extraordinarily wet summer and building El Nino is...will our wet pattern will continue into fall?
The high heat of July has faded away. The bite of the summertime sun has diminished some. The days are getting shorter. Time marches incessantly, but when it comes to weather and seasonal change, when the transition picks up in earnest varies by year. Some seasons, like last summer, the march toward fall began early, right around the time we turned the page to August. Pretty unusual.
Some years, the seasonal transition happens late. Think of the many recent winters where the start of it resembled extended fall more than winter itself.
For those new to us, while the march toward another season technically begins as soon as an astronomical season begins, we write around the time the seasonal change becomes more notable. Summer is not over. There will still be warm and humid days, but change is in the air, and it's time to talk about it. The biggest question we've gotten after an extraordinarily wet summer and building El Nino is...will our wet pattern will continue into fall?
Above: a plot showing the departure of precipitation from May 25, 2026 through August 22, 2026. This was before even more rain fell today. As you can see, virtually all of Connecticut is well above normal through most of Meteorological Summer, even though the first month of that summer (June) was well below normal.
Recapping Summer
I don't want to jinx the last week of Meteorological Summer, but it looks pretty quiet--at least for most of the week. Winter, spring, and the first third of summer were very dry, but in July, the flood gates opened, in some cases, literally. Our pattern shifted in a big way, with a combination of high humidity, frequent thunderstorms in some parts of the state, and several unusual summertime synoptic storms--think of our coastal non-tropical systems focusing heavy rain along a warm front--leading to what seems like weekly deluges.
Recapping Summer
I don't want to jinx the last week of Meteorological Summer, but it looks pretty quiet--at least for most of the week. Winter, spring, and the first third of summer were very dry, but in July, the flood gates opened, in some cases, literally. Our pattern shifted in a big way, with a combination of high humidity, frequent thunderstorms in some parts of the state, and several unusual summertime synoptic storms--think of our coastal non-tropical systems focusing heavy rain along a warm front--leading to what seems like weekly deluges.
As you can see above, it's been wet! Parts of southern CT especially have seen upwards of two feet of rain between late June and now. That has all but wiped out significant rainfall deficits across the state.
We've gone from virtually the entire state being 3-6" below normal...
We've gone from virtually the entire state being 3-6" below normal...
To the departure being wiped out...
The image above is a bit deceiving. While it looks like northern and eastern CT is in a deficit, BDL and Groton are now ever so slightly above normal for the year, while Bridgeport is nearly five inches above normal for the year while being nearly five inches below normal as of July 1!
I expected an active summer with several troughs moving into the region, and that's proven to be right. However, I also expected a near to just above summer for precipitation. While that was a big departure from the previously dry six months, it wasn't enough. With a week left, Bridgeport has already broken the record for the wettest summer on record. This was a record that stood since 1972!
As for temperatures, I expected a slightly warmer than normal summer, and with seasonable temperatures likely the final week of Meteorological Summer, it looks like this will be spot on with departures not too warm. I thought the Nino would lead to a more humid than hot summer, and that's proven to be true. Once again, summer humidity has been the story outside of the big heat wave in July.
First Look at Fall
We're writing this now because the seasonal transition is accelerating to the point that it's meaningful. The last 90 degree day at BDL and Bridgeport was on August 9. Although the humidity has still be around, believe it or not it's been on the decline as well. Guidance is now united in bringing more persistent troughing in the coming weeks, meaning cooler conditions on balance, more rain, and a continued decline in warm and humid days.
I expected an active summer with several troughs moving into the region, and that's proven to be right. However, I also expected a near to just above summer for precipitation. While that was a big departure from the previously dry six months, it wasn't enough. With a week left, Bridgeport has already broken the record for the wettest summer on record. This was a record that stood since 1972!
As for temperatures, I expected a slightly warmer than normal summer, and with seasonable temperatures likely the final week of Meteorological Summer, it looks like this will be spot on with departures not too warm. I thought the Nino would lead to a more humid than hot summer, and that's proven to be true. Once again, summer humidity has been the story outside of the big heat wave in July.
First Look at Fall
We're writing this now because the seasonal transition is accelerating to the point that it's meaningful. The last 90 degree day at BDL and Bridgeport was on August 9. Although the humidity has still be around, believe it or not it's been on the decline as well. Guidance is now united in bringing more persistent troughing in the coming weeks, meaning cooler conditions on balance, more rain, and a continued decline in warm and humid days.
Above: 12z EPS 500mb projections. Note the frequent periods of troughing all the way into September. With a ridge in the south we will still see periods of humidity, but this looks like a heralding signal for moving toward more fall like weather, especially as we turn the page into September.
The El Nino event is strengthening, and I think it will continue to have a significant impact on our weather, which is interesting considering that it hasn't been the case (yet) for other parts of the country. The plot that I shared when looking at the summer forecast ended up being pretty wise, as we ended up much wetter than normal. Updating it with similar strong and ascending El Nino events in the fall, both the temperature and precipitation composite analogs show a near normal fall.
The El Nino event is strengthening, and I think it will continue to have a significant impact on our weather, which is interesting considering that it hasn't been the case (yet) for other parts of the country. The plot that I shared when looking at the summer forecast ended up being pretty wise, as we ended up much wetter than normal. Updating it with similar strong and ascending El Nino events in the fall, both the temperature and precipitation composite analogs show a near normal fall.
That said, it's important to look at current conditions and how the overall pattern has evolved. I think we're right around normal for temperature in Meteorological Fall, which runs from September through November. I think there's at least one month in there that runs below normal temperature wise. It's just hard to forecast a season to be below normal with the warmer background state in our climate.
As for precipitation, I think a big part of the deluges we've seen this summer has been the oppressive humidity. Summer is a time when we can see very efficient rainfall due to the amount of moisture in the air, and the seasonal transition subtly removes that moisture and humidity. So as we see fewer high humidity days, I think we see fewer weeks with downright deluges. We're also past our summer thunderstorm peak climatology, so that also helps reduce the chances of big rain events.
That said, we start to transition from summer rainfall events to more nor'easter type events, especially as we get deeper into fall. So while the higher end rain events will start to decline in the coming weeks, I do still think we end up in a continued active and generally wet pattern. I don't think it's nearly as wet as summer, but perhaps slightly above normal.
Updating the Winter Outlook
With a strong El Nino all but a guarantee and likely peaking or holding during winter, I just wanted to take a second to update some of the strong Nino analogs. Not much changed on the temperature front. It's going to be hard for the northeast to escape a warmer than normal winter.
As for precipitation, I think a big part of the deluges we've seen this summer has been the oppressive humidity. Summer is a time when we can see very efficient rainfall due to the amount of moisture in the air, and the seasonal transition subtly removes that moisture and humidity. So as we see fewer high humidity days, I think we see fewer weeks with downright deluges. We're also past our summer thunderstorm peak climatology, so that also helps reduce the chances of big rain events.
That said, we start to transition from summer rainfall events to more nor'easter type events, especially as we get deeper into fall. So while the higher end rain events will start to decline in the coming weeks, I do still think we end up in a continued active and generally wet pattern. I don't think it's nearly as wet as summer, but perhaps slightly above normal.
Updating the Winter Outlook
With a strong El Nino all but a guarantee and likely peaking or holding during winter, I just wanted to take a second to update some of the strong Nino analogs. Not much changed on the temperature front. It's going to be hard for the northeast to escape a warmer than normal winter.
Much more goes into the winter forecast than just ENSO, but warmer than normal and wetter than normal continues to be favored.
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Thank you for reading SCW.
-DB
As always, please like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts. Hit the buttons below to join.
Thank you for reading SCW.
-DB
