Good morning from Southern Connecticut Weather.
It was as good a weather weekend as you could get, with seasonable high temperatures, chilly nighttime lows, and dry conditions. In fact, despite being warmer than normal overall so far this June, we've had a number of beautiful days and the big rainfall periods have stopped--for now at least--as we're below normal in June rainfall.
If you weren't paying attention, you'd think that this week will be a continuation of this beautiful stretch.
Unfortunately, that's not the case. Now, while I think it's a good bet that someone who won't read this discussion will slide into the comments and claim that the coming heat wave is no big deal and is just typical "summer", folks that have followed SCW know that we don't do hyperbole.
No, this isn't likely to be an epic all-time heat wave. No, this isn't something that folks need to be afraid of. However, there are a few things that make the coming heat wave notable, significant, and not typical summer.
First, the development of the heat wave is coming from a highly anomalous ridge of high pressure. You may have heard it being called the "heat dome". There is high confidence that the kind of ridge to setup over a very large part of the region will likely break June records for strength, and challenge annual records going back to 1950.
Second, this kind of ridge, its placement, and its timing means that we're likely to experience an unusually strong heat wave for this time of year. Usually, our biggest heat comes in July. Both daily and monthly records may be challenged this week.
Third, the duration of the heat wave is also going to be unusual. As a reminder, a heat wave is three or more consecutive days above 90 degrees. Those are common. What's less common is a stretch with highs above 95 degrees, and a stretch longer than three or four days. The impacts of heat on a person compound with the number of days the heat lasts. That's especially true on big heat days.
This is likely to be a high impact and relatively long duration event for much of Connecticut. The coming heat is something to take seriously, even if we're not necessarily approaching all-timer distinction.
It was as good a weather weekend as you could get, with seasonable high temperatures, chilly nighttime lows, and dry conditions. In fact, despite being warmer than normal overall so far this June, we've had a number of beautiful days and the big rainfall periods have stopped--for now at least--as we're below normal in June rainfall.
If you weren't paying attention, you'd think that this week will be a continuation of this beautiful stretch.
Unfortunately, that's not the case. Now, while I think it's a good bet that someone who won't read this discussion will slide into the comments and claim that the coming heat wave is no big deal and is just typical "summer", folks that have followed SCW know that we don't do hyperbole.
No, this isn't likely to be an epic all-time heat wave. No, this isn't something that folks need to be afraid of. However, there are a few things that make the coming heat wave notable, significant, and not typical summer.
First, the development of the heat wave is coming from a highly anomalous ridge of high pressure. You may have heard it being called the "heat dome". There is high confidence that the kind of ridge to setup over a very large part of the region will likely break June records for strength, and challenge annual records going back to 1950.
Second, this kind of ridge, its placement, and its timing means that we're likely to experience an unusually strong heat wave for this time of year. Usually, our biggest heat comes in July. Both daily and monthly records may be challenged this week.
Third, the duration of the heat wave is also going to be unusual. As a reminder, a heat wave is three or more consecutive days above 90 degrees. Those are common. What's less common is a stretch with highs above 95 degrees, and a stretch longer than three or four days. The impacts of heat on a person compound with the number of days the heat lasts. That's especially true on big heat days.
This is likely to be a high impact and relatively long duration event for much of Connecticut. The coming heat is something to take seriously, even if we're not necessarily approaching all-timer distinction.
Above: the 18z Sunday GEFS 500mb heights and anomaly depiction courtesy of Tropical Tidbits. This shows the movement, expansion, and amplification of a truly big ridge. For the most effective delivery of heat, you generally need to be north of the center of the ridge for southwest flow to advect in the greatest heat. As you can see above, Thursday and Friday look to be the days where the heat peaks.
Monday
After another night of cool temperatures, the ridge is in place and will start to build today. That means that we start warming up with highs in the low to mid 80s inland. Along the shore, the theme will be a double edged sword. It will be slightly cooler with a southerly breeze, but humidity will be higher. The humidity today won't be too bad, but then the heat really begins. One thing to keep an eye on today is whether temperatures over or under perform.
Tuesday
The formal start to the heat wave is likely Tuesday. There are two things to watch. First, is the standard definition of heat wave. How many locations have consecutive 90 degree days and how many. The second is how many go and stay higher. Whether most hit 90--that's a near lock during the week. The second question of how many go and stay higher is much more tricky, even with consensus on the guidance about the strength of the ridge, because nuances like pop up thunderstorms, cooler than expected mornings, cloud cover, 850mb temperatures, and even wind direction will determine daily highs.
For coastal CT, temperatures will be lower, especially in SE CT because of the sea breeze, but like I said in the paragraph above, that means humidity and possibly lots of it. Inland, the hot spots of the CT River Valley will bake. Tuesday may be the easiest day of them all, too. At the shoreline, while the temperatures don't look record breaking, the duration of the heat will be notable.
An Excessive Heat Watch has been issued for Hartford and Tolland counties, the first in over a thousand days for inland CT.
Monday
After another night of cool temperatures, the ridge is in place and will start to build today. That means that we start warming up with highs in the low to mid 80s inland. Along the shore, the theme will be a double edged sword. It will be slightly cooler with a southerly breeze, but humidity will be higher. The humidity today won't be too bad, but then the heat really begins. One thing to keep an eye on today is whether temperatures over or under perform.
Tuesday
The formal start to the heat wave is likely Tuesday. There are two things to watch. First, is the standard definition of heat wave. How many locations have consecutive 90 degree days and how many. The second is how many go and stay higher. Whether most hit 90--that's a near lock during the week. The second question of how many go and stay higher is much more tricky, even with consensus on the guidance about the strength of the ridge, because nuances like pop up thunderstorms, cooler than expected mornings, cloud cover, 850mb temperatures, and even wind direction will determine daily highs.
For coastal CT, temperatures will be lower, especially in SE CT because of the sea breeze, but like I said in the paragraph above, that means humidity and possibly lots of it. Inland, the hot spots of the CT River Valley will bake. Tuesday may be the easiest day of them all, too. At the shoreline, while the temperatures don't look record breaking, the duration of the heat will be notable.
An Excessive Heat Watch has been issued for Hartford and Tolland counties, the first in over a thousand days for inland CT.
Above: IEM (Iowa State) data on the last time an Excessive Heat Watch was issued.
Above: the current listing of watches and advisories. These may change depending on the heat and heat indices this week. Even SE CT should be prepared for hot and humid conditions, though the intensity of the heat will be least there.
Wednesday
By Wednesday, we're kicking the heat into high gear. Inland areas should be in the low to mid 90s, but humidity is likely to be up a bit and for the hot spots, upper 90s are on the table.
Wednesday
By Wednesday, we're kicking the heat into high gear. Inland areas should be in the low to mid 90s, but humidity is likely to be up a bit and for the hot spots, upper 90s are on the table.
Above: GFS (top) and Euro (bottom) depiction to temperatures Wednesday early afternoon. These are not necessarily the highs for the day. Both model runs are from yesterday.
Thursday-Friday
The end of the week is the period to watch for the highest heat. This is when the ridge starts to slide south, putting us in the region where the greatest heat advection is likely. This is where we go from run of the mill heat wave to higher end, should Tuesday and Wednesday fall a little short temperature wise. Expect higher humidity and temperatures in the upper 90s to near 100 for inland spots, and even at the shore, temperatures may reach over 90 in addition to potentially oppressive humidity. Heat indices over 100 are likely around the state. These are certainly the days to limit outdoor activities and check on the vulnerable. Nighttime temperatures will not fall that much, providing little relief to many.
Each of these days, but especially Friday, will have the chance for pop up thunderstorms. These could be quick strong storms due to the amount of instability that builds.
Now, let's talk about rarity. Yes, much of inland Connecticut sees temperatures in the mid to upper 90s during the summer. I wrote about that in our summer forecast. However, we don't see these kind of temperatures this early, and the duration of 95+ temperatures is rare.
Thursday and Friday have potential to reach 100 degrees at both Hartford (city) and BDL. The last time BDL saw 100 degree temperatures was July 21, 2019. For Hartford (HFD), it was July 22, 2016. For either to hit 100, it would be the earliest on record.
The last time BDL or HFD hit 100 in June, it happened in 1964 for BDL and 1952 for HFD.
In fact, analysis from the fantastic Tomer Burg shows how anomalous June highs near 100 are. Even during the peak of the season, we hit 100 less than 1 out of every 3 years inland, and as you can see above, it hasn't happened recently.
Thursday-Friday
The end of the week is the period to watch for the highest heat. This is when the ridge starts to slide south, putting us in the region where the greatest heat advection is likely. This is where we go from run of the mill heat wave to higher end, should Tuesday and Wednesday fall a little short temperature wise. Expect higher humidity and temperatures in the upper 90s to near 100 for inland spots, and even at the shore, temperatures may reach over 90 in addition to potentially oppressive humidity. Heat indices over 100 are likely around the state. These are certainly the days to limit outdoor activities and check on the vulnerable. Nighttime temperatures will not fall that much, providing little relief to many.
Each of these days, but especially Friday, will have the chance for pop up thunderstorms. These could be quick strong storms due to the amount of instability that builds.
Now, let's talk about rarity. Yes, much of inland Connecticut sees temperatures in the mid to upper 90s during the summer. I wrote about that in our summer forecast. However, we don't see these kind of temperatures this early, and the duration of 95+ temperatures is rare.
Thursday and Friday have potential to reach 100 degrees at both Hartford (city) and BDL. The last time BDL saw 100 degree temperatures was July 21, 2019. For Hartford (HFD), it was July 22, 2016. For either to hit 100, it would be the earliest on record.
The last time BDL or HFD hit 100 in June, it happened in 1964 for BDL and 1952 for HFD.
In fact, analysis from the fantastic Tomer Burg shows how anomalous June highs near 100 are. Even during the peak of the season, we hit 100 less than 1 out of every 3 years inland, and as you can see above, it hasn't happened recently.
More important however, is the duration. Our record long heat wave using the 90 degree threshold is just 10 days in Connecticut. We're unlikely to top that here. However, for heat above 95 degrees, there's an outside shot of cracking the top 10-15 at BDL and HFD.
When the temperature threshold is raised, the potential heat wave becomes more rarified, but first we have to see the temperatures get there.
Saturday-Sunday
The heat wave is likely to extend into the weekend. The guidance is split however over just how long and intense the heat is. The Euro, which was once the most aggressive model, has pulled back substantially, while the GFS, has become more aggressive. This is a notable shift, but for now, I will expect the heat wave to continue through at least Saturday. Even if the heat declines, the humidity isn't going anywhere.
The heat wave is likely to extend into the weekend. The guidance is split however over just how long and intense the heat is. The Euro, which was once the most aggressive model, has pulled back substantially, while the GFS, has become more aggressive. This is a notable shift, but for now, I will expect the heat wave to continue through at least Saturday. Even if the heat declines, the humidity isn't going anywhere.
Heat Precautions
During this period it's important for everyone to take heat precautions. The human body doesn't care about historical records. First and foremost, never leave kids or pets in the car. Each year, deaths happen around the country, even in cooler temperatures, because cars heat up extremely fast and can overcome anyone sitting in it on a warm to hot day.
Heat is the leading weather related killer in America. This happens because folks don't have access to cooling, and because people underestimate the heat. Don't be one of those people. Stay hydrated, check on the vulnerable, and if you don't have access to air conditioning at home, know where your cooling centers are. If you work outside, it's essential that you take breaks and stay hydrated.
With the big golf tournament likely during the peak of the heat, spectators and volunteers alike need to take extra precautions given the extended amount of time outside.
During this period it's important for everyone to take heat precautions. The human body doesn't care about historical records. First and foremost, never leave kids or pets in the car. Each year, deaths happen around the country, even in cooler temperatures, because cars heat up extremely fast and can overcome anyone sitting in it on a warm to hot day.
Heat is the leading weather related killer in America. This happens because folks don't have access to cooling, and because people underestimate the heat. Don't be one of those people. Stay hydrated, check on the vulnerable, and if you don't have access to air conditioning at home, know where your cooling centers are. If you work outside, it's essential that you take breaks and stay hydrated.
With the big golf tournament likely during the peak of the heat, spectators and volunteers alike need to take extra precautions given the extended amount of time outside.
Know the signs of heat illness and be sure to take quick action if you or anyone else around you starts to show signs.
The Dailies
Monday: Mostly sunny. Warmer and more humid. Highs in the low to mid 80s.
Tuesday: Mostly sunny and hot. Highs in the low to mid 90s inland, mid to upper 80s at the shoreline. Heat indices of 95-100.
Wednesday: Mostly sunny and hot. Highs in the mid to upper 90s inland, mid to upper 80s at the shoreline. Heat indices of 100-105+.
Thursday: Mostly sunny and hot. Highs in the mid to upper 90s inland, upper 80s to low 90s at the shoreline. 100 degrees possible inland. Heat indices of 100-105+. Chance of thunderstorms 20%.
Friday: Mostly sunny and hot. Highs in the mid to upper 90s inland, low to mid 90s at the shoreline. 100 degrees possible inland. Heat indices of 100-105+. Chance of thunderstorms 40%.
Saturday: Mostly sunny and hot. Highs in the low to mid 90s inland, upper 80s to low 90s at the shoreline. Chance of thunderstorms 20%.
Sunday: Mostly sunny and hot. Highs in the upper 80s to low 90s inland, mid to upper 80s at the shoreline.
Bottom line: a high impact and long duration heat wave is set to hit the region this week. While not unprecedented, it's something to take seriously because of the duration and potential for multiple days of high end heat.
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.
-DB
Monday: Mostly sunny. Warmer and more humid. Highs in the low to mid 80s.
Tuesday: Mostly sunny and hot. Highs in the low to mid 90s inland, mid to upper 80s at the shoreline. Heat indices of 95-100.
Wednesday: Mostly sunny and hot. Highs in the mid to upper 90s inland, mid to upper 80s at the shoreline. Heat indices of 100-105+.
Thursday: Mostly sunny and hot. Highs in the mid to upper 90s inland, upper 80s to low 90s at the shoreline. 100 degrees possible inland. Heat indices of 100-105+. Chance of thunderstorms 20%.
Friday: Mostly sunny and hot. Highs in the mid to upper 90s inland, low to mid 90s at the shoreline. 100 degrees possible inland. Heat indices of 100-105+. Chance of thunderstorms 40%.
Saturday: Mostly sunny and hot. Highs in the low to mid 90s inland, upper 80s to low 90s at the shoreline. Chance of thunderstorms 20%.
Sunday: Mostly sunny and hot. Highs in the upper 80s to low 90s inland, mid to upper 80s at the shoreline.
Bottom line: a high impact and long duration heat wave is set to hit the region this week. While not unprecedented, it's something to take seriously because of the duration and potential for multiple days of high end heat.
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.
-DB
