DAYS 1-5 (JANUARY 27-31)
Down the home stretch of the first month of 2024 we go, and the pattern remains active in this El Nino winter. So far, the great majority of the winter has seen the polar jet stream well to the north of our region. It’s dipped southward plenty in other parts of the hemisphere, but hasn’t seemed to want to visit the northeastern US. There are changes ahead in that, but not enough to help put too much cold in place for our next upcoming storm. Before we get there, we have a break today between yesterday’s morning event and the Sunday-Monday event. But lots of low level moisture is hanging out with us and keeping it overcast and still on the damp side. But a weak frontal boundary coming down from the north will introduce drier air as we go through the day, and while clouds may break, I’m not looking for complete clearing. Any partial clearing we do get would be erased tonight as clouds from the next low pressure system move into the region. And then comes the next storm. Low pressure will pass south of New England between late Sunday and early to midday Monday, its track is what would be a typically good spot for a solid snowstorm through the region in late January. However, the aforementioned missing cold air mass makes that more difficult. Cold air will become involved though, both advecting in from the north and also from above through the “dynamic cooling” process. It’s the timing of these that will determine rain to snow changeover, how much sleet may accompany the transition, and in the end, what the final snowfall totals are across the region. My thought process on that hasn’t changed that much from yesterday. Snow accumulation ranges will be broad enough to account for the uncertainty, but tight enough so that you should at least have a good idea of what ballpark you’ll be in for snowfall. The following is a general breakdown of the storm…
Precipitation arrival time / type: Shield of precipitation enters via the CT/RI coast pre-dawn Sunday as rain, then overspreads the region southwest to northeast during the morning so that by noon the leading edge is arriving around the NH Seacoast. Anywhere away from the South Coast, but most especially in higher elevations, precipitation can start as mixed rain/snow or even just wet snow as temperatures will straddle the rain/snow production borderline. If dew points are low enough, a brief early-on period of dynamic can take place for earlier snowfall, at least temporarily. During Sunday afternoon and early evening the warm advection portion of the precipitation will take place, a moderate burst, which will fall as mainly rain for the South Coast, and Cape Cod to the MA South Shore, but mixed rain/snow to all snow at times in the I-95 corridor, and mix to mostly snow across interior southern NH through the Merrimack Valley and central MA. Mid level dry air will work northward later Sunday evening, creating a taper off for a few hours in the precipitation, especially south of I-90. Area that were raining continue to see lighter rain/drizzle, and some areas that were seeing mix/snow probably go over to a period of lighter rain for a while. The higher terrain of interior southern NH and MA from the I-495 belt westward stay cold enough for snow, and also are less affected by the dry slot, if at all. Beyond this, the overnight hours to early or mid morning Monday will be when the greatest amount of cold air is pulled into the system from the north, along with additional dynamic cooling from above. This is when snow will overtake the entire region from northwest to southeast in mix/rain areas, including but lastly Cape Cod, and there will be a temporarily increase in the intensity of precipitation in response to intensifying surface low pressure. This is when most of the snow accumulation will take place east of I-95 and south of I-90. Snow ends by late morning or midday Monday from northwest to southeast as low pressure begins to pull away.
Total snowfall: Keep in mind that this is for the entire event, and depending on precipitation type, the total snowfall will not be the amount of snow on the ground at any given location. Even in areas that stay all snow to the northwest have a wet snow for a good part of the storm, and compacting will occur there before it flips to a lower water content snowfall later in the storm. Looking for up to 1 inch Outer Cape Cod / Islands and immediate South Coast of MA/RI and eastern CT, 1-3 inches remainder of Cape Cod and Plymouth MA area to Providence RI area through interior southeastern CT, 3-6 inches in the majority of the I-95 corridor including Boston and northern RI to northeastern CT and lower elevations of south central MA as well as the NH Seacoast, and 6-10 inches interior southern NH and the western Merrimack Valley west and southwest through central MA. Highest snowfall occurs in higher elevations.
Flooding: No major issues, both rivers and coastal areas.
Wind: Top gusts may reach 50 MPH across Cape Cod early hours of Monday from the northeast. No major wind issues for the remainder of the region.
Power outages: Moderate risk of power outages in areas where heaviest snowfall occurs due to the higher water content nature of the snowfall for much of the storm. Lower risk of wind-related power outages Cape Cod.
Post-storm, we start to see clearing later Monday and then dry and seasonably cold weather is ours to finish off the month as high pressure moves in Tuesday and Wednesday.
TODAY: Cloudy morning with patchy drizzle and areas of fog. Mostly cloudy but breaks of sun possible afternoon. Highs 40-47. Wind NW up to 10 MPH.
TONIGHT: Mostly cloudy. Lows 30-37. Wind N under 10 MPH.
SUNDAY: Overcast. Rain/mix/snow develops southwest to northeast by midday and continues afternoon with greatest chance of snow interior higher elevations, but also periods of alternating precipitation type closer to the I-95 belt while mostly rain falls in the coastal areas especially south. Highs 37-44 by midday, then slowly but unevenly falling temperatures. Wind NE 5-15 MPH, higher gusts especially coastal areas by late-day.
SUNDAY NIGHT: Overcast. Precipitation of varying intensity may stop at times especially south of I-90 where more rain than snow is likely, and will be steadiest I-90 north where more snow is likely, with more of transition to snow working southeastward overnight when precipitation is steadier. Lows 25-32 by dawn. Wind NE 10-20 MPH except 20-30 MPH Cape Cod where gusts 40-50 MPH are possible.
MONDAY: Overcast with snow likely in the morning. Snow ending with breaking clouds afternoon. Temperatures steady 25-32. Wind NE-N 10-20 MPH, higher gusts especially coastal areas through midday.
MONDAY NIGHT: Clearing. Lows 13-20. Wind NW 5-15 MPH.
TUESDAY: Mostly sunny. Highs 27-34. Wind NW 5-15 MPH.
TUESDAY NIGHT: Mostly clear. Lows 12-19. Wind W up to 10 MPH.
WEDNESDAY: Mostly sunny. Highs 30-37. Wind W up to 10 MPH.
DAYS 6-10 (FEBRUARY 1-5)
Trough drops down from Canada with snow shower chances February 1-2. Dry weather follows. Temperatures variable but averaging near to slightly below normal.
DAYS 11-15 (FEBRUARY 6-10)
Storm potential somewhere in the early to middle portion of this period. Fair weather follows. Temperatures near normal for the period though somewhat variable.