Forecast discussion: Over the last few days, eastern Massachusetts has been very muggy, with off and on periods of showers, heavy rainfall, and isolated to scattered thunderstorms. Unfortunately, this weather pattern will not change much over the next seven days.
So, why have we had this muggy weather recently? Well, it is all part to an upper level low that remains over the Ohio River Valley. Usually, an upper level low bring cooler, wetter conditions. It also helps steer storm systems at the surface into a region. Well, over the last few days, this low has remained stationary. So, instead of moving off to the east, this low has been blocked. Therefore, surface lows over the Ohio River Valley continue to rotate in that general area. The southwest winds help bring moisture in from the south, and this keeps our dewpoint temperatures high. With high humidity, all you need is for the atmosphere to get some instability. In this case, a weak cold front remaining over the region is the trigger.
Unfortunately, the computer models suggest we will remain in this weather pattern right into Tuesday. Eventually, an upper level ridge to our east will actually move west, or retrograde. This will push the upper level trough into the central U.S. This will allow for some drier air to move over the region. However, until this happens, we will see isolated showers and thunderstorms from time to time. Some areas may see heavier rainfall, due to some strong thunderstorms.
As we move into the middle of next week, the Bermuda High will extend its ridge over Southern New England. We should see continuous sunshine, along with temperatures slightly warming each day. However, the computer models suggest that this weather pattern will not break up until Monday of the following week. Right now, my confidence in my forecast beyond Wednesday remains low.
72 hour forecast:
Tonight: Mostly cloudy with patchy fog and isolated showers and thunderstorms. Some rainfall could be heavy at times. We will see a low of 68.
Saturday: Isolated showers and thunderstorms, especially during the late afternoon and early evening. We will see a high of 78 with south-southwest winds at 11-14 mph.
Fenway Park Forecast (4:05 p.m. vs. Toronto Blue Jays): Cloudy with isolated showers and thunderstorms, 76.
Saturday night: Isolated showers with a low of 67. Winds will come from the south-southwest at 9-12 mph.
Sunday: Scattered showers and thunderstorms with a high of 82.
Sunday night: Scattered showers and thunderstorms with a low of 69.
Monday: Scattered showers and thunderstorms with a high of 79.
Monday night: Scattered showers and a low of 70.
Tuesday: Scattered showers/thunderstorms. Highs 81-84, lows 67-70.
Wednesday: Partly to mostly sunny. Highs 83-86, lows 66-69.
Fourth of July: Partly sunny with possible afternoon thunderstorms. Highs 84-87, lows 66-69.
Friday: Mostly sunny. Highs 83-86, lows 67-70.