Friday will act as a transition day away from the blocking pattern we've been in since the start of the new year. Blocking patterns are stubborn and slow to break down, and this one is no exception. The improvements will be gradual. The wind will lessen today, but still remain breezy. Temperatures will climb a notch higher as well, likely back to seasonal averages. Weak ridging will also bring an end to the mountain snow showers, albeit very temporarily.
Below: Flow pattern this Friday afternoon (1st image) versus the past Sunday afternoon (2nd image):
The weak ridging New England gets into for Friday will be very temporary as the next low pressure system scoots through the region Saturday. A northern stream system will push through the region from west to east Friday night through Saturday. This will bring a period of light snow showers to the region. A stronger southern stream system will remain well south of New England, but it is still poised to inject some energy into the northern system, allowing it to overcome dry air and weaker forcing to produce snow showers.
Widespread light snow showers will likely spread into western New England just before sunrise Saturday. These snow showers will fill in and steadily spread east as the morning goes on. By late morning, most of New England outside of eastern Maine will likely be seeing snow showers. Snow showers will likely be widespread with varying intensity for several hours Saturday morning, but never more than light.
Below: HRRR showing potential weather around sunrise Saturday (1st image) and late morning Saturday (2nd image):
This will be a quick moving system with less blocking downstream. Many will see snow showers just about coming to an end in the early afternoon. With that said, an inverted trough looks to develop in the afternoon with enhanced convergence and lift near the coastal plain. This setup may allow for snow showers to linger longer across eastern Massachusetts, New Hampshire and the Maine seacoast. On and off snow showers may last much of the day here.
Below: HRRR showing potential weather late afternoon Saturday:
With minimal interaction occurring with the southern stream system, New England's snow will be coming pretty much exclusively from the moisture-starved northern system. This does not bode well for high snow totals. A majority of New England will likely end up with a dusting to 2 inches of fresh snow by Saturday night. The coastal plain, particularly southwest Maine, southeast New Hampshire and northeast Massachusetts, have the best chance at up to three inches.
With an inverted trough expected to develop in the afternoon, the coastal plain could see a period of enhanced snowfall along with a longer lasting period of snowfall. An inverted trough occurs when pressure increases from south to north, which is typically the opposite of mid-level troughs. Normally, the lowest pressure and heights are located on the south side of the trough, not the north side. Inverted troughs can look more like ridges.
These troughs can create enhanced precipitation rates on the northwest side of the system, which, in this case, is where the coastal plain is located. This is why the coastal plain from Boston to about Portland may have the best chance at seeing 2-3 inches rather than a dusting to an inch. This isn't a major development and won't create a more impactful storm as snow amounts will remain light all around, but it will be something to watch in the final snow totals.
After this system, the break in the colder-than-average temperatures will likely last through the weekend and into Monday. Temperatures during this time will be seasonal rather than above average. Another weak clipper-like system will scoot by northern New England around Monday night to Tuesday with some snow showers. This system will swing the door back open for another shot of cold air heading into the middle part of next week as it creates a deep and strong northwesterly flow once again.
While there remains some uncertainty in the exact timing of the next cold air intrusion, the general idea will be a cooling trend as the week progresses. Winds will also pick back up heading into next week, but the overall setup this time around doesn't look as strong as this past week. This will mean a cold wind, but not to the extent of this past Tuesday to Thursday.
Overall, the mainly dry pattern is set to continue with no large, organized storms in the picture. The next week or two looks to continue the theme of cold and dry. There are no big time warm-ups in the picture and highs for the next two weeks or so are likely to hover around or below seasonable levels.
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