Good evening from Southern Connecticut Weather.
The last two days brought increasing severe weather and widespread storms to Connecticut, but the heat has not fully broken. Tomorrow we expect the last hot and humid day under this hot period, but it will break as an energetic trough/front looks likely to bring another round of strong to severe thunderstorms to the state. The last two days the threat seemed relatively low and we saw scattered to unusually widespread severe/damage reports, complete with a confirmed EF-0 tornado in Harwinton yesterday and a supercell that brought tornado warnings to central Connecticut today.
The environment tomorrow looks even more robust on paper for severe potential. Tomorrow is a day to be weather aware no matter where you are.
The last two days brought increasing severe weather and widespread storms to Connecticut, but the heat has not fully broken. Tomorrow we expect the last hot and humid day under this hot period, but it will break as an energetic trough/front looks likely to bring another round of strong to severe thunderstorms to the state. The last two days the threat seemed relatively low and we saw scattered to unusually widespread severe/damage reports, complete with a confirmed EF-0 tornado in Harwinton yesterday and a supercell that brought tornado warnings to central Connecticut today.
The environment tomorrow looks even more robust on paper for severe potential. Tomorrow is a day to be weather aware no matter where you are.
Above: the latest SPC outlook for tomorrow. Most of CT is under a slight risk while parts of central and northern New England are under an enhanced risk due to the potential tornado threat.
Severe Weather Perspective
Not all slight risk days are created equally, and these risk categories are forecasts just like everything else. Friday didn't have any tornado probabilities but we saw a lone tornado under the right conditions. Today started out with everyone in a marginal risk for severe weather, and by the afternoon I was frantically writing to tell locations to shelter in place because of a potentially tornadic supercell. The SPC identified the risk and put part of CT in a slight risk before the storms hit, which is great, but didn't issue a severe thunderstorm watch and we had multiple warnings over the course of the afternoon and evening. The bottom line, is that forecasting severe weather is extremely difficult, and because the risk is wide but the impacts tend to be local, everyone should be paying attention and not writing off anything.
Tomorrow is one of those days where at least at this time the threat for severe weather looks higher than we'd normally expect on a "standard" slight risk day, but these things are never a slam dunk.
First, although it is tempting, it's really important not to take the last two days of widespread strong storms and scattered severe weather as fully informing what happens tomorrow. Friday and today we saw storms take off under high instability and moisture, and just enough shear in the atmosphere for severe weather. The setup is different tomorrow in a meaningful way.
Second, even though everyone should be on alert, truly severe weather--defined as 58mph wind gusts or higher, hail an inch in diameter or greater, or a tornado--doesn't happen for most people, even on "widespread" days. That's no reason to take severe weather potential any less serious, but it's important to keep perspective.
Severe Weather Perspective
Not all slight risk days are created equally, and these risk categories are forecasts just like everything else. Friday didn't have any tornado probabilities but we saw a lone tornado under the right conditions. Today started out with everyone in a marginal risk for severe weather, and by the afternoon I was frantically writing to tell locations to shelter in place because of a potentially tornadic supercell. The SPC identified the risk and put part of CT in a slight risk before the storms hit, which is great, but didn't issue a severe thunderstorm watch and we had multiple warnings over the course of the afternoon and evening. The bottom line, is that forecasting severe weather is extremely difficult, and because the risk is wide but the impacts tend to be local, everyone should be paying attention and not writing off anything.
Tomorrow is one of those days where at least at this time the threat for severe weather looks higher than we'd normally expect on a "standard" slight risk day, but these things are never a slam dunk.
First, although it is tempting, it's really important not to take the last two days of widespread strong storms and scattered severe weather as fully informing what happens tomorrow. Friday and today we saw storms take off under high instability and moisture, and just enough shear in the atmosphere for severe weather. The setup is different tomorrow in a meaningful way.
Second, even though everyone should be on alert, truly severe weather--defined as 58mph wind gusts or higher, hail an inch in diameter or greater, or a tornado--doesn't happen for most people, even on "widespread" days. That's no reason to take severe weather potential any less serious, but it's important to keep perspective.
Top: SPC tornado risk
Bottom: SPC wind risk
The Overall Setup
It's important to look beyond the SPC probabilities above, which are impressive in their own right relative to what we usually see in CT. Note the higher probabilities to our north.
Tomorrow will have all of the ingredients we need for thunderstorms, and many of the ingredients we need for severe thunderstorms. First, we will have more shear as a result of a trough (front) that will be advancing toward the state. This will allow for storms to potentially organize more efficiently than the last two days which had a lower shear environment. We will have lift with the energetic trough. We will have instability as tomorrow will be another hot and humid day, though there is a caveat here to be discussed shortly. Finally, we will have plenty of moisture, which will also be important to the forecast tomorrow.
These ingredients combine to bring us an environment conducive for strong to severe thunderstorms, particularly storms that turn with height. In order to analyze severe weather potential aside from the new parameter metrics that you find, the fundamental tool is a sounding. This is a forecast of each layer of the atmosphere.
Tomorrow the soundings for the afternoon all say the same.
Bottom: SPC wind risk
The Overall Setup
It's important to look beyond the SPC probabilities above, which are impressive in their own right relative to what we usually see in CT. Note the higher probabilities to our north.
Tomorrow will have all of the ingredients we need for thunderstorms, and many of the ingredients we need for severe thunderstorms. First, we will have more shear as a result of a trough (front) that will be advancing toward the state. This will allow for storms to potentially organize more efficiently than the last two days which had a lower shear environment. We will have lift with the energetic trough. We will have instability as tomorrow will be another hot and humid day, though there is a caveat here to be discussed shortly. Finally, we will have plenty of moisture, which will also be important to the forecast tomorrow.
These ingredients combine to bring us an environment conducive for strong to severe thunderstorms, particularly storms that turn with height. In order to analyze severe weather potential aside from the new parameter metrics that you find, the fundamental tool is a sounding. This is a forecast of each layer of the atmosphere.
Tomorrow the soundings for the afternoon all say the same.
Above are the 18z 3km NAM soundings. There's a lot of information there that's hard to see, but these soundings for BDL, Hartford, and New Haven show a tornado sounding. That does not mean that each location will see anything close to a tornado tomorrow afternoon. It shows that the ingredients are present as forecasted on this one model.
Let's look closer at the most recent sounding for Hartford from the 00z 3km NAM. Hot off the presses.
Let's look closer at the most recent sounding for Hartford from the 00z 3km NAM. Hot off the presses.
Once again, this is a tornado sounding. The first thing to look at for that is up in the hodograph in the top right box. You can see turning with height, but at the higher levels you have a potential messier mode for storms. Today's supercell was able to take off today in central Connecticut because it was a discrete cell. It was the only game in town and as a result it did not have competition ahead of it to disrupt its maturation and cycling. That is a potential limiting factor tomorrow for tornadic activity.
The second thing we see here are high dew points (green line) that gives plenty of low level moisture for storms. There is some dryness further up in the sounding so lapse rates look a little lower. That's another limiting factor. However, on the right side of the sounding you see high SRH, moderate to high CAPE, solid shear, and high moisture in the form of PWAT.
One thing to note is the over 1200 J/kg of DCAPE. This kind of CAPE is often associated with strong straight line winds. If we do not have discrete storms tomorrow, we could see storms congeal quickly and form lines like we've seen the last two days, bringing heightened severe straight line wind risk. We think that's most likely tomorrow.
Overall however, this setup is noteworthy for scattered to potentially widespread strong to severe storms. Adding to the tornado risk is the topography of the CT River Valley. This can be an area that develops a boundary that can further enhance turning with height, and pool moisture to overcome marginal lapse rates.
On days like tomorrow, we watch that zone closely, just as we watch were the warm front in advance of the trough/cold front, sets up. Tomorrow that warm front looks to be in central New England, but as TW reminded us earlier, often times it's difficult to pinpoint were these fronts will go.
The second thing we see here are high dew points (green line) that gives plenty of low level moisture for storms. There is some dryness further up in the sounding so lapse rates look a little lower. That's another limiting factor. However, on the right side of the sounding you see high SRH, moderate to high CAPE, solid shear, and high moisture in the form of PWAT.
One thing to note is the over 1200 J/kg of DCAPE. This kind of CAPE is often associated with strong straight line winds. If we do not have discrete storms tomorrow, we could see storms congeal quickly and form lines like we've seen the last two days, bringing heightened severe straight line wind risk. We think that's most likely tomorrow.
Overall however, this setup is noteworthy for scattered to potentially widespread strong to severe storms. Adding to the tornado risk is the topography of the CT River Valley. This can be an area that develops a boundary that can further enhance turning with height, and pool moisture to overcome marginal lapse rates.
On days like tomorrow, we watch that zone closely, just as we watch were the warm front in advance of the trough/cold front, sets up. Tomorrow that warm front looks to be in central New England, but as TW reminded us earlier, often times it's difficult to pinpoint were these fronts will go.
Above: the 3km NAM depiction of storms between midnight tonight and midnight tomorrow. Not meant to be taken verbatim, but it shows the manifestation of the storms in the environment.
The Forecast
Folks, tomorrow is a day to stay weather aware no matter where you are in Connecticut, but folks in northern and western CT need to be particularly vigilant.
We expect additional showers and thunderstorms tonight, and some of those storms may be strong. There are severe thunderstorm warnings west so western CT should keep watch.
Tomorrow should be hot and humid. We will be watching dew points as much as how much sunshine and destabilization we receive.
The timing of storms looks to be between 2-10pm. We really have to watch the earlier period to see if any discrete storms develop. Like today, any isolated storms could quickly become severe. Then we will be watching after approximately 5-6pm for a line of storms to congeal and bring a straight line wind threat through the state. Along this line we will be watching for notches that could cause brief spin ups, but the focus as it stands now would be on straight line winds with any line of storms.
The greatest risk is likely to be in northern and western CT, but again, everyone should be weather aware tomorrow. Early day and early afternoon activities look fine, but be prepared to change on a dime depending on the radar.
We expect an active day tomorrow. Stay tuned for updates throughout the day.
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 and trusting SCW.
-SCW Team (Written by DB)
The Forecast
Folks, tomorrow is a day to stay weather aware no matter where you are in Connecticut, but folks in northern and western CT need to be particularly vigilant.
We expect additional showers and thunderstorms tonight, and some of those storms may be strong. There are severe thunderstorm warnings west so western CT should keep watch.
Tomorrow should be hot and humid. We will be watching dew points as much as how much sunshine and destabilization we receive.
The timing of storms looks to be between 2-10pm. We really have to watch the earlier period to see if any discrete storms develop. Like today, any isolated storms could quickly become severe. Then we will be watching after approximately 5-6pm for a line of storms to congeal and bring a straight line wind threat through the state. Along this line we will be watching for notches that could cause brief spin ups, but the focus as it stands now would be on straight line winds with any line of storms.
The greatest risk is likely to be in northern and western CT, but again, everyone should be weather aware tomorrow. Early day and early afternoon activities look fine, but be prepared to change on a dime depending on the radar.
We expect an active day tomorrow. Stay tuned for updates throughout the day.
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 and trusting SCW.
-SCW Team (Written by DB)
