Progressive pattern keeps the weather moving for New England

A generally progressive pattern will keep systems, both low and high pressure, moving through New England over the next week or so, with neither high nor low dominating for an extended period of time. This will bring bouts of unsettled weather followed by a period of calm and pleasant weather.

After Monday's low brought a round of thunderstorms, a ridge of high pressure will build into the region, bringing warm and mainly sunny skies by the afternoon. On Wednesday, low pressure and an associated cold front drop into New England, bringing the chance for more unsettled weather.

Photo byNew England Storm Center

The front will drop into northern New England in the morning, allowing for a line of showers and maybe a couple thunderstorms to break out and move across the region in the morning. The afternoon is interesting, especially for southern New England. The cold front may take long enough to push through New England to allow for some storms to pop up across the southern half of the area. High resolution guidance isn't very excited about storm chances in the afternoon, with most not showing much development at all.

As of now, it looks like activity will be more numerous in the morning with only isolated activity popping up in the afternoon, mainly in central and southern New England. The ingredients for any afternoon storm to turn severe will be in place, which is why the Storm Prediction Center maintains southern New England in the "marginal" chance (level 1 of 5) for severe storms on Wednesday. The question is will there be enough forcing to get a storm to develop in the first place.

Potential weather mid-morning Wednesday (1st image) and Wednesday afternoon (2nd image):

Photo byWRF-ARW/Tropical Tidbits

Photo byWRF-ARW/Tropical Tidbits

After the cold front clears the region, a cool Canadian high pressure system will build in from the north, bringing dry and calm conditions back for Thursday and Friday. This high will slip to the east by Saturday morning, making way for the next frontal system, set to enter New England for the weekend. This cold front will likely slide across New England Saturday morning to Sunday morning.

This front will likely bring a line of showers moving across New England from west to east, entering into western New England Saturday morning and pushing eastward through the afternoon and evening. The day is highly unlikely to be washed out for anyone, with plenty of dry times for any given location. Another round of scattered showers will be possible for Sunday or Monday as another disturbance moves through. It remains to be seen which of those two days would be wetter, but, again, all day washout potential is very low at this time.

Photo byNew England Storm Center

As for temperatures and humidity during this time, it will be seasonable for the most part. The exception will be a drop below averages on Thursday and Friday as the robust cold front knocks out building heat and humidity. This cooler air will be reinforced by an expansive area of high pressure to the north. This helps generate an onshore flow, keeping the coast the coolest.

Photo byNew England Storm Center

Major late season heat continues to build into midweek across the center of the country, but this heat will fail to spread into New England due to the aforementioned cold front and disturbance making its way into the region. Heat advisories and excessive heat warnings are in effect across the Great Lakes region and even into Pennsylvania and New York today as heat index values surge well into the 90s, and in some cases, toward the 110s in the Chicago area.

Heat alerts today (August 27):

Photo byNational Weather Service

Humidity will briefly build Tuesday into Wednesday before the cold front knocks it right back out for later Wednesday into Thursday. Dew points will likely gradually build back up heading into the weekend.

Photo byNew England Storm Center