We have been discussing it in our forecasts for a while now, and the second heat wave of the year has arrived. Although inland areas are most likely to verify a technical heat wave of three consecutive days of 90+, this heat wave will be felt across CT, as an expansive upper level ridge brings not just hot air temperatures, but oppressive humidity and high overnight temperatures. For this reason, this heat wave to end June is expected to be more widespread and stronger than the first one we saw. Let's jump right in.
Below: The current advisories in effect. Note that even New London County is under a Heat Advisory. It's possible we see some Excessive Heat Warnings this week, which are our highest level of heat-related weather warnings.
It is already warm and very humid outside, with dew points in the upper 60s to low 70s. Anything over a 70 dew point tends to be oppressive in my book. Although it is cloudy currently, that is expected to change and sunny conditions should lead to high temperatures this afternoon reaching the mid to upper 80s at the shore and upper 80s to low 90s inland.
Even if the temperatures don't hit 90, it'll feel like it with the heat index--a measure of how it actually feels based on air temperature and humidity level. If you are outside today, stay hydrated, and never leave children or pets in your vehicle. Temperatures climb rapidly in a car without adequate air conditioning.
Each day should bring some of the hottest temperatures of the year, with Tuesday likely being the hottest of the heat wave. Humidity will be oppressive statewide, with heat indices above 100 in many spots. Tuesday could be the excessive heat day, with possible inland temperatures in the upper 90s and heat indices nearing 105. Keep in mind that we could see more westerly flow on these days, meaning that the shoreline, which tends to be cooler during these heat events, may not escape as much as they normally would. Below is the European Model depiction of the heat index tomorrow just before peak heating of the day. It'll be a hot one statewide!
The middle of the week should continue the heat wave, as we are likely to see high temperatures in the 90s again. Wednesday, however, looks to be the end of the heat wave. Depending on the timing of the front, we could see showers and storms break the heat later in the day on Wednesday, as depicted by the GFS image below. At this time, we're not expecting any severe thunderstorms, but it's something we'll be watching as some of our heat waves tend to get broken by big storms.
Although the oppressive heat will be a thing of the past by Thursday and Friday, it is still likely to be warm, especially Thursday. This period, unfortunately, is much more uncertain, as it is unclear how quickly the front will clear the area, and how active the trough will be in producing rain chances. That said, right now the guidance from both the Euro and GFS show an unsettled period, with rain likely. Whether it is washout rain remains to be seen, but it leans that way. Below is a GFS depiction of the period but the Euro is not too far behind in terms of rain chances increasing with at least one area of low pressure developing in the region.
That brings us to the holiday weekend. It's uncertain at this range but it looks unsettled. The GFS wants to bring near washout conditions and much colder than normal temperatures. I'm not buying that right now.
The Euro isn't too far behind with rainfall, but it does have more seasonable temperatures. I will blend the guidance here and just call for seasonable temperatures and a chance of rain each day, but nothing at this time that would make me change my holiday weekend plans. Stay tuned however for future forecasts as things could go south if the model trend continues toward a wetter and cooler weekend.
Monday: Hazy, Hot, and Humid. Highs in the low to mid 90s with the exception of the immediate shoreline. Heat Index above 100, especially inland. Chance of showers/thunderstorms 10%.
Tuesday: Hazy, Hot, and Humid. Highs in the mid to upper 90s inland, and upper 80s to low 90s at the shoreline. Heat Index above 100 and possibly near 105 inland. Chance of showers/thunderstorms 20%.
Wednesday: Hazy, Hot, and Humid early, followed by showers and thunderstorms during the afternoon. Highs in the mid to upper 90s inland and upper 80s to low 90s at the shore. Chance of showers/thunderstorms 50%.
Thursday: Mostly cloudy and warm, with showers and thunderstorms. Highs in the low to mid 80s. Chance of rain 70%.
Friday: Mostly cloudy with rain showers. Highs in the low 80s. Chance of rain 60%.
Saturday: Partly cloudy with a chance of rain showers. Highs in the mid to upper 70s. Chance of rain 50%.
Sunday: Partly cloudy with a chance of rain showers. Highs in the mid to upper 70s. Chance of rain 50%.
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