Another hot, but not quite as hot, day is in store for southern New England. In order to predict the high for the day, we look to what the temperature of the air is at around 5000 feet. This spot in the atmosphere gives us a good idea of the potential high temperature at the ground. For the past couple of days the temperature at around 5000 feet has been about 16C or around 60F. As this air is heated, it can reach the lower 90s in the afternoon. Today, the temperature structure is similar to the past couple of days, but with a few more clouds this afternoon and a slight change to the wind direction, most places around Boston will stay just shy of 90F this afternoon. If Boston does reach 90F, it will be an official heat wave.
Later this afternoon our focus turns to the possibility of thunderstorms and heavy downpours. Often when a bought of heat breaks it does so with severe weather. The cold front that will ultimately bring an end to the heat and humidity is still far to our west. However, energy in the atmosphere will help build thunderstorms this afternoon before the actual front passes Monday morning. This means we will have a prolonged chance for showers and thunderstorms from late this afternoon and evening until mid-Morning Monday.
The greatest chance for severe weather will be during the first part of the overnight, but heavy downpours are possible in waves of showers early Monday. The timing of the rain is such that the morning commute could be impacted.
During this upcoming severe weather threat hail, strong winds and lightning will be the biggest possible problems. Tornadoes have gotten a lot of attention the past week and while I can’t rule out the possibility, the set-up tonight isn’t entirely favorable for tornado activity.
As I wrote, the first part of tomorrow could be quite wet with one or two rounds of showers heaviest in the morning. Late in the day, as the main cold front passes, the air will become less humid. Tomorrow’s high temperatures will be in the 70s, but with all the moisture in the air, it will still feel muggy much of the day.
Finally on Tuesday, drier air will become firmly entrenched across the area. Temperatures are going to be quite pleasant with highs in the 70s. It’s been a bit uncomfortable for sleeping, if you don’t have air conditioning, the past several nights, but next week looks entirely different.
Several mornings will be in the 50s and I would not be surprised if some interior spots see readings into the 40s for several early risers. This will be a welcome change after the sticky weather of the recent past.
Late next week, more clouds and possible showers or steady rain is possible. It’s too early to nail down a forecast for the upcoming weekend at this point, but I can all but guarantee it won’t be a very hot and humid one.
Gardening this week
You might not know it, but a disease that is affecting impatiens is going to be a problem again later this summer. This bacteria, which came over from Europe two years ago is now in over 30 states. I recommend not planting impatiens as the spores are airborne and likely will kill your plants later in July and early August just as they are looking great. I did a video on some alternatives to them here. Check it out.
I’ll be updating the forecast throughout the week on Twitter at @growingwisdom Please follow me there. Feel free to comment or ask questions too.