Fall has arrived in New England and it will certainly feel that way this week with cool temperatures, plenty of clouds around and another chance for widespread rain later this week.
MONDAY & TUESDAY
Both Monday and Tuesday will see high pressure at the surface build into New England from Canada. Despite the high pressure, mainly cloudy skies will prevail across most of New England as a persistent onshore flow will keep the mid and upper levels moist, allowing for cloud development. This onshore flow will also keep temperatures on the cool side. The surface high pressure should keep New England dry during this time despite the cloud cover at times.
A system moving over the Great Lakes during this time will remain to New England's west as an expansive blocking high remains over eastern Canada. This system will help paint the skies gray, but, again, the ridge of high pressure will keep New England dry at least for the start of the week. This system will be weakening as it sits to our east.
WEDNESDAY & THURSDAY
This time frame will represent New England's next chance for rain. There is somewhat lower confidence in this time frame as a developing tropical cyclone in the Gulf of Mexico will influence the overall setup across the United States late this week. Depending on what this system does, it will affect the outcomes over much of the east coast.
A trough over the Mississippi Valley will likely interact with a developing tropical system rather than the system over the Great Lakes. At this time, another northern stream low pressure will move across Canada during this time, eventually moving southeast out of James Bay and dragging its fronts across New England. Currently it appears this will occur Wednesday night into Thursday.
Image below: 500mb anomaly map (which shows blue troughs and red ridges) for Wednesday morning. This gives a good visual for what is written above:
All of this is to say that more unsettled weather is likely to return heading toward the latter part of this week. As of now, it does look like Wednesday will be dry for most, if not all, of the day. Showers will break out with this system across northern and western areas, so Vermont and northern New Hampshire will stand the best chance at seeing wet weather during the daytime Wednesday.
The bulk of this system will move through New England Wednesday night through Thursday. Showers will move generally west to east during this time as a warm front gets dragged over New England followed by a cold front as the center of the system moves to the north of New England. This will result in periods of rain during this time, the exact timing of which will become clearer soon enough.
With the system now expected to move to the north of New England, it currently appears that northern areas will have the chance to see more rain. At this point, this isn't looking to be a major rain event, with a half inch to an inch being shown for northern areas and less in southern New England, though trends will continue to be watched. After a very dry September, this rain continues to be needed anyway.
Current 5 day rainfall forecast:
This northern trend in rainfall is in part due to the developing tropical cyclone affecting the east coast's weather, namely the southern stream system remaining to the south and interacting with the hurricane. This hurricane is currently poised to make landfall somewhere around the Florida Panhandle or Big Bend region Thursday or Friday.
FRIDAY
There were some questions over the past couple days on whether this system would cut off and hang around for the rest of the week, but the trends are currently pointing toward this clearing out late in the week. High pressure behind the system looks to build into New England, bringing drier weather. Eastern Maine will (naturally) hold onto showers the longest as the system moves out from west to east. We'll continue watching the trends to see just how quickly the system pushes away and how Friday ends up weather-wise.
WEEKEND
High pressure does look to build into New England for the weekend, but this will be contingent on the system moving out in a timely manner. The current setup does bode well for a dry, seasonable early fall weekend in New England.
Current weather map for Saturday:
The other factor to watch late this week will be the remnants of the tropical cyclone over the southern states. While the system doesn't look to come to New England immediately, the fact that there will be tropical moisture shifting around in the United States during this time will keep confidence in the longer range lower than usual.
Comments