New England's dry spell set to end (for some)

After a very dry start to September, at least a portion of New England will be getting beneficial rain over the next few days. This will come as an area of low pressure to New England's south will cycle rounds of showers into the region from Thursday through the end of the week. These showers will still struggle to push into northern New England with high pressure and an advancing cold front acting as a shield. Overall, showers have trended northward over the past 24 hours.

Photo byNew England Storm Center

The northern extent of the system should begin to push into the southern third of New England early Thursday morning. From there, showers will gradually push northward into most of southern New England. Showers will continue to rotate into the region around the system through the day Thursday.

There's a good chance most areas won't see a steady rain the entire day, but showers will be cycling through all day. Showers will be more frequent the farther south in New England you are. There will also be a chance for a few showers across northern New England from an advancing backdoor cold front, but moisture and instability are both highly limited with this feature, so it won't produce much for northern New England compared to the showers in southern New England during the day Thursday.

GFS showing potential weather around Thursday mid-morning (1st image) and Thursday evening (2nd image):

Photo byGFS/Tropical Tidbits

Photo byGFS/Tropical Tidbits

Heading into Thursday night and Friday morning is now looking like the time where the system makes its furthest push to the north. Showers will continue to rotate around the low pressure system, which will slowly meander around offshore due to a blocking high pressure. Western Massachusetts, southern Vermont and southern New Hampshire have the highest uncertainty with the frequency of showers as this area will be the battleground between the wet and dry air.

CMC showing the potential for continuing showers into Friday:

Photo byCMC/Tropical Tidbits

Scattered showers may linger into Saturday for eastern Massachusetts and the coastal plain of northern New England. This trend toward a longer period of showery weather isn't unexpected as this remains a blocking pattern. An area of high pressure is still blocking the area of low pressure from advancing north, it's just the high pressure is weakening and being pushed northward.

Blocking patterns are extremely stubborn and often last longer than what models originally depict with them. This is also why this has been a very changeable forecast. Blocking patterns come with the highest uncertainty since storm systems can't move where they naturally want to since they're blocked in.

A new area of high pressure building to the north of New England will lead to an eventual drying trend at some point this weekend as the system gets shoved back southward and out to sea. When all is said and done with this system, the South Shore and Cape Cod will likely see upwards of an inch if not more. Amounts will still taper off moving north and west from the south coast.

Photo byNew England Storm Center

This will be a very beneficial rain. All of New England is running a deficit when it comes to normal precipitation for the month. Portland, Providence, Worcester and Concord have all seen 5% or less of usual September precipitation with less than a tenth of an inch of rainfall so far this month. Boston has seen 0% of usual September precipitation with no measurable rainfall this month. Boston has not seen measurable rainfall since August 20th. This streak will end tomorrow.

Photo byNortheast Regional Climate Center

This system still looks like it will be a case of the haves and have-nots. While all of New England is running behind on precipitation, this system will primarily affect southern New England. Northern New England is still looking pretty dry for the next several days at least with very minimal rainfall from this incoming system as well as the approaching backdoor cold front. Below shows the current Weather Prediction Center 7 day rainfall forecast as of Wednesday morning.

Photo byWeather Prediction Center