Cooling Trend Underway for New England

Another frontal system will continue to cross New England from west to east through the day today. This system is progressive and will move rather quickly across New England this afternoon and evening. Widespread rain across much of the region this morning will have pushed into Maine for the afternoon. This frontal passage will usher in a multi-day cooling trend that will likely last for a good week at least.

Once the front clears, the thick cloud cover associated with the rain will likely begin to break up rather quickly. Some sun is expected at times this afternoon outside of Maine. With that said, cooling temperatures aloft combined with surface heating will likely generate large, puffy clouds, keeping them in the picture for the entire day. The last of the widespread rain will likely move out of Maine this evening.

The cold temperatures aloft combined with surface heating may also allow for spot showers to pop back up across New England throughout the afternoon and evening. This will be supported by a trailing surface trough that will provide some lift and energy (this trough is represented by the orange dotted line on the map above). Should enough sun come out, instability will build, which could allow for a couple rumbles of thunder within these pop-up showers.

Below: HRRR showing potential weather around mid-afternoon today. Note the pin-prick showers across New England west of Maine:

The upper-level low responsible for the frontal passage across New England will remain north of New England through the end of this week. This will promote broad cyclonic flow across the northeast. Broad cyclonic flow is synonymous with partly to mostly cloudy skies building in the afternoon, cool temperatures and breezy conditions.

This time will be no exception as this will be the general weather for Thursday and Friday. Moisture will be meager across the region during this time, so showers will remain spotty and very isolated both Thursday and Friday. There should be just enough moisture to create plenty of clouds.

Below: 500mb height anomaly showing the upper-low north of New England keeping us in a rather deep trough:

The deep trough and its cold pool allow for some rather dreary days and chilly weather. The freezing level may drop below 3,000 feet above sea level. This would allow for some snowflakes across the mountains, especially later Thursday and into Friday. As stated before, the steady precipitation will have exited the region by this time, but a few spot showers will certainly be possible and the ski resorts may see their first flakes of the season.

Below: Potential freezing altitude Friday morning:

By this weekend, the trough axis will begin to shift eastward while high pressure builds in from the west. Overall, broad troughing is expected to persist over the region while surface high pressure keeps the region dry (something that was in question earlier in the week). This will allow for continued partial sunniness, but also continually dropping temperatures, with widespread highs in the mid 40s north to mid 50s south by Sunday.

Today will mark the end of this stretch of rather mild fall temperatures for most (eastern Maine will hold on for one more day). Each day will likely be a notch cooler than the last through this weekend. This trend may also push into early next week as a new upper-level low tries to take shape. While it won't be notably cold given the time of year, a mid-autumn chill will be settling over the region. This chill will have plenty of staying power as the milder temperatures get locked up to New England's west.

Looking toward Halloween week, a large-scale block may set up with a large, strong and expansive ridge to the north of New England. This will promote New England remaining in broad troughing. Whether or not a storm system is able to move into the region during this time remains to be seen.

Below: 500mb anomaly around the middle of next week, showing a deep ridge north of New England and broad troughing remaining over the region: