Heat and humidity will build through the first half of the week, peaking Wednesday, Thursday, and lingering into Friday. With all the heat and moisture, the atmosphere will be primed for thunderstorms if there are small disturbances present to trigger storms. At this time, Tuesday and Saturday look to have the highest chances for widespread showers and storms, though uncertainty remains high.
Published Monday, June 29th
Monday
What: Sun and clouds.
The week will start out quiet and warm as temperatures make a notable jump upward. Most areas will top out between 85-90 degrees today. Dewpoints will be in the 60s, so a bit humid but not yet oppressively uncomfortable. No rain is expected with nighttime temperatures falling back to around 70 degrees. Winds will be nearly calm during the day, then turning to the south tonight.
Tuesday
What: Getting hot. Showers and storms possible.
How hot it gets Tuesday will be partially determined by the potential for thunderstorm activity. A small atmospheric disturbance, associated with thunderstorm development today to our northwest, will track southeast across Canada and into New England. Computer models are mixed on the timing, location, and intensity of the associated thunderstorms.
The highest impact scenario would be for heat and humidity to build unabated during much of the day, allowing highs to be near or above 90 degrees, followed by late afternoon and early evening storm development. This would likely lead to at least some isolated severe weather, with the highest risk over the eastern Finger Lakes.
Other scenarios include showers and storms mainly in the morning, an earlier afternoon event, or no rain at all. Each of these would have different and varied impacts on the temperature, but unless the rain comes during the middle of the day, highs should at least approach 90 degrees. Dewpoints will be higher than today, so it will start to feel increasingly muggy.
This is the type of set up where computer models, even the ones designed for thunderstorms, really struggle.
Wednesday
What: Hazardous heat. A few storms?
The heat and humidity will go up another level on Wednesday. High temperatures will range through the 90s and a few urban areas could even flirt with hitting 100 degrees. Dewpoints will climb over 70 degrees. Heat index values will be over 100 for most areas, and a few areas could see a heat index approach or exceed 110 degrees. These levels of heat and humidity can be hazardous, especially since we have had so little heat this year so far and we are unaccustomed to it.
There is again an uncertain chance for showers and thunderstorms, though the overall chances for rain look less than on Tuesday at this point.
Nighttime temperatures will only drop to the mid 70s, but a few urban areas may have a hard time even getting below 80 degrees.
Note: If you are an administrator/event organizer familiar with the more technical “wet bulb globe temperature”, know that it will be approaching the extreme classification near 90 degrees both Wednesday and again on Thursday.
Thursday
What: Hazardous heat.
Thursday is currently looking dry, though the same uncertainties that are in play Tuesday and Wednesday will persist as long as this pattern continues. Thursday should be as hot and humid as Wednesday, if not even more so. With such high nighttime temperatures, heat stress will continue to build, making health complications increasingly likely as the heat and humidity continue. Again, some areas may see temperatures in the upper 90s to near 100 with heat index values of 110 of higher.
Friday
What: Still hot. A few late storms.
The core of the heat will pull back a bit on Friday, leading to temperatures and humidity levels that are just a bit lower. Practically speaking, with the continued building heat stress, the slight drop in temperatures and dewpoints may not matter much. Temperatures are more likely to stick to the 90-95 degree range, but some heat index values will still be over 100 degrees.
The chances for some pop-up showers and storms will increase slightly, with the usual caveats about the uncertainty in how it all plays out. At this time, the rain chances for any individual location still look lower than on Tuesday, but overall across the entire region, there is perhaps a bit more confidence in at least some rain falling somewhere.
Saturday
What: Scattered showers and storms.
Temperatures will continue to back off on Saturday in a slightly more meaningful way. Most areas should stay below 90 degrees, though heat index values will likely climb above 90. Morning lows will still be in the 70s, though.
Scattered showers and storms are possible. The overall set up looks more favorable for showers and storms than Friday, but it should not be a washout and some areas may stay dry.
Sunday
What: A few showers.
By Sunday, temperatures and dewpoints should return to a level similar to today. Some showers and perhaps a storm will be possible, but the precipitation chances are quite uncertain this far out.
Next Week
The heat and humidity look contained to this week. Next week, temperatures will be closer to the climatological averages with daily highs somewhere around 80 degrees. Precipitation will come and go with some frequency, so it will not be a dry period… but I suspect that the day-to-day weather will still have plenty of dry time to get outdoors.
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