New England remains on the active side with two systems moving through the region this week. A minor system will bring light rain, freezing rain and snow showers across New England Tuesday. After that comes the already much discussed Thanksgiving system, which remains under a cloud of uncertainty.
MONDAY
New England will be in between our departing system well to the east and our next system approaching from the west. In between these systems, high pressure will build, leading to a mainly sunny to partly cloudy day (there will be more lingering clouds in the mountains) and overall quiet weather. Winds will finally die down throughout the day today, though gusts of 20-25mph will remain possible for much of the day in New Hampshire and Maine.
TUESDAY
The system over the Great Lakes will pass through New England rather quickly, likely in less than 24 hours, on Tuesday. The setup for this system will involve a primary low pressure diving out of the Great Lakes to the north of New England with a surface low forming over New England. This will bring a period of rain showers to southern New England with the potential for some freezing rain and snow showers across the north.
This system will likely enter into western New England likely around sunrise Tuesday and steadily spread precipitation west to east through the day Tuesday, reaching eastern Maine by mid-afternoon. This storm will feature warm air advection, so low temperatures Monday night will likely be reached earlier in the night with rising temperatures after midnight. This will setup a situation with mixed precipitation.
Below: HRRR showing potential weather around mid-morning Tuesday:
Surface temperatures across higher portions of northern New England will likely drop into the mid 20s to low 30s early in the night before beginning to rise. A warm front will begin to spread across the region overnight, allowing for a warm nose of air to rise over this cold layer. This setup is primed for either freezing rain or sleet.
With a deeper layer of warmer air expected aloft, it will support freezing rain over sleet. Southern New England and the coastal plain of northern New England will not drop below freezing tonight, leading to plain rain showers. The far northern woods of New Hampshire and Maine will likely remain cold enough aloft to allow for mainly snow showers.
Areas that see freezing rain at the start will likely gradually change over to plain rain showers as the day goes on. This change over would occur in lower elevations first and gradually work higher in elevation as the morning and early afternoon wears on. Despite conditions in favor of efficient ice accumulations, only very light accumulations are expected of a trace to maybe a tenth of an inch. Freezing rain should flip to plain rain rather quickly in most areas. A winter weather advisory is in effect from 1am to 1pm for the morning risk.
Southern New England and the coastal plain of northern New England will likely see a decent quarter to half inch of rainfall, with more areas likely ending up on the lower end of that range. The system will likely wrap up for most of New England by early evening with eastern Maine naturally holding onto the precipitation later being the farthest east. The far northern woods may see an inch or two of snowfall by Wednesday morning.
Below: HRRR showing potential weather around mid-afternoon (1st image) and early evening (2nd image):
WEDNESDAY
Tuesday's system will usher in a chillier air mass for the rest of the week. Wednesday will be several degrees cooler than Monday and Tuesday with partly cloudy skies and dry weather (for most). Typical post-storm upslope snow showers will likely linger in the mountains at least for the morning.
THURSDAY & FRIDAY
New England's Thanksgiving day nor'easter remains on track in regards to the fact that it will form. The system will involve a southern stream piece of energy moving across the country during the week and a northern stream piece of energy across southern Canada. The level of interaction between these two will determine much about New England's impacts.
There remain two basic camps right now, which isn't a surprise since the main piece of energy with this system remains offshore of the Pacific coast. Once this low pressure system comes ashore of the western United States, guidance should come into better agreement. Despite this fact, some semblance of impacts may be coming into view.
These two camps can be broken into the Euro and GFS, both of which have remained persistent on their outcomes. The Euro favors a more northerly track with a stronger storm, heavier precipitation and more snow across northern New England. The GFS is more adamant about a weaker, faster moving storm suppressed to the south of New England.
Below: Euro (1st image) and GFS (2nd image) model runs from Monday morning. These show the early afternoon of Thanksgiving:
As of now, more ensemble members approve of the Euro's take. That is to say at this moment, the center of the storm is favored to track near, or over, southern New England and Cape Cod into the Gulf of Maine. This track would favor mainly rain across much of southern New England (except for the highest elevations) and the northern New England coastal plain. Central New England (Southern VT, NH; northern MA) may start as a mix or snow before a change over to rain from south to north occurs with ski country getting mostly snow. This scenario is currently favored among more ensemble members.
While the above scenario is the most favored as of now, there is still a large enough number that favors a more southerly track that it remains very possible. This would be a colder storm for New England, but with much lighter precipitation. Ski country would largely miss out and lighter rain/snow showers would occur across southern and central New England.
Either way, this storm will form, and precipitation will fall in New England on Thanksgiving day. The question is what will the precipitation type be and how intense will it be? Should the storm take a more southerly route, the question will be how far north can showers push? With these two camps, it's very possible we see something in between.
Weather Prediction Center chances for impactful winter weather from Thursday morning to Friday morning:
As far as how much snow, it remains very difficult to put any kind of figure on potential totals. There will be a chance for several inches of snow in a band across New England. Where this band sets up will have to do with the storm's final track as well as the elevation within the band. The northern tier of New England may be too far removed from the storm's center track to see heavier snowfall rates.
Another big factor to keep in mind is the potential lack of deep cold air. While colder air will filter into New England after the early seek storm, temperatures are still looking marginal with this system. Without a deep, cold high pressure system to New England's north to funnel polar or Arctic air into New England, a deep layer of very cold air won't be present. Also, ocean temperatures remain relatively mild here very early in the winter season.
A mild northeast flow off the ocean will make frozen precipitation difficult, especially near the coastal plain. This lack of deep cold air and a mild ocean could result in a rainier storm regardless of the final track, which will be something to watch. This would likely be a heavier, sticky snow, which doesn't exactly pile up quickly. Timing has also generally sped up. All of this will try to keep snow totals on the lower end. No matter what an accumulation map looks like later this week, bust potential will be on the high end with this one.
Below: Potential flow Thursday afternoon. This flow off the ocean will be mild, making snowfall very difficult along the coastal plain:
As far as timing goes, the storm, overall, has sped up. The bulk of the system is currently looking to move through from midday Thursday through Friday morning. There are still some ensembles that have a slower speed with the bulk of the system not starting to move through until later Thanksgiving. Friday will feature a drying trend for all of New England.
WEEKEND
The weekend is looking much drier for most of New England, with the potential for lingering showers across eastern Maine. The storm, regardless of impacts to New England with precipitation, will open the door for cold air to spill into New England. Meteorological winter will kick off with winter-like conditions for New England. A broad trough will develop and remain over the eastern United States with ridging developing across western New England.
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