DAYS 1-5 (FEBRUARY 10-14)
A very mild Saturday is the feature for this weekend. Although today may start with dense fog in some locations, this will burn off and a sun/cloud mix is going to be met with temperatures rising to the 40s on the South Coast and 50s elsewhere. A couple locations may challenge records, set just last year, but I think they will fall short of those values. Example: Record high at Boston (Logan) is 60. I think they will peak at 57 or 58. Records or not, it will be a very nice mid winter day, feeling spring-like. Tonight, a cold front swings through the region with some rain showers, but this front is not delivering a quick shot of cold so I’m not expecting any black ice issues as low temperatures should remain above freezing generally across the region. In fact, behind the cold front, Sunday will still be a fairly mild day compared to the long term averages for the date, but we won’t challenge any records. Also, expect a dry day with sun and passing clouds. Colder air will continue to filter into the region gradually as we move through Sunday night and Monday. But once again, as we’ve seen many times this winter, the polar jet stream remains to our north, and the cold air delivery will be modest. This is also important in terms of our next storm threat, which we start to see increasing clouds from during Monday. Low pressure is going to be moving from the Tennessee Valley into the Appalachian Mountains late Monday. A redevelopment of this low pressure area will take place along the Atlantic Coast late Monday night and early Tuesday, after which it will track south of New England. The track of this low pressure area and its precipitation swath is key to our rain vs snow and snowfall accumulation forecast for the storm system, which is only going to be about a 12 hour event from pre-dawn to late afternoon on Tuesday. There are basically 2 main scenarios that can take place as I see it now. Scenario 1 is a low that develops near the Delmarva region and tracks just to the south of New England. This scenario would have the potential to see the precipitation start as rain along the coast, especially the South Coast, with a bit warmer lower atmosphere from a slightly stronger onshore flow (keeping in mind we’re lacking significant cold what the polar jet would have helped provide). The storm dynamics would still overcome this and flip those areas to snow, with a general snow event for the rest of the region. Snow-to-water ratios would be under 10:1 for most of the region in this scenario, with a ballpark guess for snowfall amounts being 2-4 inches along the South Coast and 4-8 inches for the balance of the region. Scenario 2 would be a low pressure system that redevelops a little further south, maybe northeastern NC or southern VA, then tracks a little further south of our region. While this would be a slightly colder scenario (but again not that much colder with the lack of the cold air from the polar jet), it would be cold enough to be basically a snow event for the entire region, but with a suppressed precipitation shield compared to scenario 1. This would result in lower snowfall amounts most on the order of 2-4 inches in southern NH and north central to northeastern MA with 4-8 inches being a good first guess for the remainder of the region. I don’t think this event lasts long enough and is heavy enough for enough time for anybody to hit double-digit snowfall amounts, even in the “snowiest” scenario for any given location. So for now, these ballpark snow guesses based on the 2 outlined scenarios will sit in this discussion and I’ll add updated forecast amounts to the detailed forecast on tomorrow morning’s blog update (sooner in the comments section if I feel more confident about how it plays out by tonight). Another aspect of the coming storm will be a coastal flood threat as astronomical tides will be high at the time of the storm’s passage. The Tuesday high tide is the most threatening for flooding issues. Regardless of the storm’s track and resultant impact, we see it depart late Tuesday, and Valentine’s Day Wednesday will be fair and cold, along with a gusty wind – finally feeling like mid winter around here.
TODAY: Areas of fog until mid morning, otherwise a sun/cloud mix with most sun late morning and more clouds this afternoon. Late-day rain showers southwestern NH and central MA. Highs 45-52 South Coast and tip of Cape Ann MA, 52-59 elsewhere. Wind SW 5-15 MPH.
TONIGHT: Mostly cloudy with rain showers early to mid evening. Partly cloudy late evening and overnight. Lows 33-40. Wind SW 5-15 MPH shifting to NW, a few higher gusts possible.
SUNDAY: Partly sunny. Highs 45-52. Wind NW 5-15 MPH, higher gusts possible.
SUNDAY NIGHT: Mostly clear. Lows 27-34. Wind NW 5-15 MPH, diminishing.
MONDAY: Increasing high clouds. Highs 40-47. Wind N up to 10 MPH.
MONDAY NIGHT: Thickening overcast. Rain/mix/snow likely toward dawn. Lows 30-37. Wind NE 5-15 MPH.
TUESDAY: Overcast. Rain/mix/snow becoming all snow, ending by late-day. Temperatures steady 30-37. Wind NE 10-20 MPH, shifting to N.
TUESDAY NIGHT: Clearing. Lows 15-22. Wind NW 10-20 MPH. Wind chill below 10.
WEDNESDAY: Sun and passing clouds. Highs 28-35. Wind NW 10-20 MPH. Wind chill near to below 20 at times.
DAYS 6-10 (FEBRUARY 15-19)
Watching for another possible low pressure area to bring a mix/snow chance around February 16 to early February 17 but this remains low confidence and the system may be further south. Fair weather to end the period. Temperatures below normal.
DAYS 11-15 (FEBRUARY 20-24)
2 potential snow threats to start and end the period with below normal temperatures. A suppressed storm track pattern is still possible as well (where those systems would stay to the south).