Tuesday Forecast

150 Comments

7:29AM

DAYS 1-5 (DECEMBER 10-14)
Day one of a two-day warm up has taken the majority of the snow and ice away, and today will pretty much finish off the job, leaving only snow piles behind, so if you were relying on a December 1-3 snow event to get your white Christmas over 3 weeks later, try again. Well we will likely get some snow back on the ground as cold air returns and some moisture is still in the region Wednesday morning, but I can guarantee you that won’t do it either. As is that snowfall is questionable as usually these types of “behind the cold front” events are. Moisture is streaming up along a front parallel to the upper flow and little ripples in the atmosphere that we can only guess the location of may focus narrow bands of heavier snow while elsewhere very little falls. We’ll also see a little ripple of low pressure pull it all eastward pretty quickly around midday, and it may also never get that far northwest of Boston. We’ll need to see more snowfall closer to the holiday to increase the chance. Having a white Christmas around Boston, while not rare, is also not typical. The chance, based on climatology, runs at about 23%. After Wednesday’s threat, we go dry and chilly for a couple days, and it currently looks like the next low pressure system, due for a Saturday arrival, will be a rain producer.
The forecast details…
TODAY: Cloudy. Areas of fog over any remaining snow cover. Scattered rain showers through midday. Steadier rain arriving later in the day.
Highs 55-62. Wind SW 10-20 MPH, higher gusts.
TONIGHT: Cloudy. Periods of rain, changing to sleet then snow west to east. Lows 28-35. Wind NW 5-15 MPH.
WEDNESDAY: Cloudy with snow likely morning, accumulation a coating to 2 inches, with an isolated 3 inch amount possible in Boston’s southwestern suburbs to northern RI. Mostly cloudy afternoon. Temperatures steady 28-35. Wind NW 5-15 MPH, higher gusts.
WEDNESDAY NIGHT: Clearing. Widespread icy ground. Lows 16-21. Wind NW 5-15 MPH. Wind chill near 10.
THURSDAY: Sunny. Highs 28-35. Wind NW 5-15 MPH.
THURSDAY NIGHT: Clear. Lows 0-7 interior valleys, 8-15 elsewhere except 15-20 urban centers. Wind N under 10 MPH.
FRIDAY: Sunshine followed by increasing cloudiness. Highs 35-42. Wind N to E up to 10 MPH.
FRIDAY NIGHT: Cloudy. Rain arriving pre-dawn. Temperatures rising into 40s. Wind E to SE increasing to 10-20 MPH.
SATURDAY: Overcast with rain likely. Highs 47-54, mildest southeastern MA. Wind SE to E 10-20 MPH, higher gusts, becoming variable 5-15 MPH.

DAYS 6-10 (DECEMBER 15-19)
Behind the storm earlier in the weekend will come a windy, drier, cooler day December 15, with more cold air settling in December 16-17 as high pressure sits to the north. A wave of low pressure brings a snow/mix threat December 17 to early December 18 with dry weather to follow.

DAYS 11-15 (DECEMBER 20-24)
Watching for potential precipitation-producing systems over this 5-day period, but not sure how it will set-up just yet. We’ll have to watch for possible interaction, or lack-of-interaction, between 2 jet streams and there will be a lot to figure out.

150 thoughts on “Tuesday Forecast”

  2. So to clarify, the coating to 2 inches. I think the city of Boston to the South Shore and toward northern RI will be closer to the 2, with areas to the northwest being close to the 1 inch or less. 3 inch amounts should be isolated southwest of Boston as it stands now.

    This was never to be a big system. I had 2-4 out on yesterday’s update to cover MAXIMUM potential. But maximum does not translate to “big snow storm”. This is a swath of snow behind a cold front when it gets cold enough to support snow instead of rain. These are extremely rarely anything more than minor events for southeastern New England.

    The next threat of a significant snow event is 7 days away.

    1. Tk do you have a timeframe around when the snow starts in Boston are we thinking like 2-3 am or earlier & it should be gone first thing in the morning

      2. Funny watching some of the snowpack go away. Kids across the street made a snow wall near the bottom of their hill to smack into instead of going into the street. The center melted faster (where they were smacking into the most) and by last night two tiny snow towers were left.

    2. Its been consistent, I’ll give it that. Typically this model is pretty good at this range. I wouldn’t discount higher totals but the trend with the runs this morning has definitely been further S/E with the heavier QPF.

  12. It still looking like a 1-3 inch snowfall. It’s not a lot of snow but the timing stinks for the Wednesday morning commute. I am more interested in what happens next Tuesday and Wednesday as both the GFS and EURO show accumulating snow.

    1. 3″ for my area on the NAM, 4″ on the RGEM, and 6″+ on the HRDPS. I’m not going to discount a more moderate snow event quite yet…

  15. Thank you, TK.

    My skepticism regarding snow chances in the Boston vicinity this month remains in effect. I do think the ski areas will do fairly well, and the NNE/SNE dichotomy in terms of snowfall that held most of last winter may resume.

    Downtown Boston pretty much lost all its snow yesterday. There wasn’t a whole lot to melt. I do realize that almost everywhere else except the South Shore there was a lot more snow, and therefore still some on the ground (mostly in the form of piles).

    2. We’ve lost pretty much everything here as well Joshua. But we’ll be white again tomorrow AM and that should last until the end of the week.

      I disagree on the snow chances….Boston will see accumulating snow again this month after tomorrow and probably more than once.

    1. Well I am not a fan of that stinken rain, however it is on board for the storm
      with plenty of time for things to line up just right.

      btw, the ONLY thing rain is good for this time of year is washing away
      salt from our vehicles.

  17. Well, the HRDPS will NOT back down and we are less than 24 hours from
    lift off!

    Here is the 12Z HRDPS 10:1 snow:

    https://www.tropicaltidbits.com/analysis/models/hrdps/2019121012/hrdps_asnow_neus_34.png

    Surface at height of snow:

    https://www.tropicaltidbits.com/analysis/models/hrdps/2019121012/hrdps_mslp_pcpn_frzn_neus_23.png

    That is a pretty intense looking band there. WHY, oh WHY is this the ONLY
    model portraying intensity and accumulation like this?

    wouldn’t it be something IF this model were the ONLY one to verify???

    1. btw, because of the rapidly falling temperatures, this 10:1 accumulation
      would be at worst be equivalent to the Kuchera and may in fact be LESS
      than Kuchera.

    2. See my comment above. While this is probably overdone, I wouldn’t discount a more “moderate” snow event, especially SE of a Hartford to Boston line.

      1. I “think” that we best be on the lookout for that.
        NWS discussed this as an outside chance of a general
        4-6 inch snow event, even though their “official” forecast
        is 1-4 inches.

        1. I suspect this one will be a headache for the poor superintendents that are tasked with decisions on school openings. Certainly far from a block-buster storm but the timing will make it a challenge .

          1. Sue I’m betting with the up to 2 inches Tk is calling for Boston / south I would think a delay is at least a solid bet as the timing could not be any worse

  19. SSK, thanks for the correction. I should have said CC and the Islands.

    I’m always hopeful regarding snow, but a realist at the same time. Yes, there will be a little snow tomorrow. But, the trend I’m seeing after that is not conducive to accumulating snows in SNE. The lows and troughs have to dig much deeper and to our south. At the moment, they mostly come in flat from west of us.

    Even though we’ve had snow and a couple of fairly cold days thus far in December, it’s paled in comparison with the first 10 days of March. It’s remarkable how even historically the first 10 days of March tend to be colder than the first 10 days of December.

    March 2019 (high/low day 1 through 10): 38°/23°; 34°/32°; 41°/32°; 40°/25°; 31°/19°; 27°/18°; 30°/15°; 38°/18°; 46°/26°; 40°/31°

    December 2019 (high/low day 1 through 10): 39°/22°; 42°/29°; 36°/30°; 41°/29°; 45°/32°; 38°/29°; 35°/27°; 41°/23°; 61°/41°; (projected) 61°/34°

    A friendly wager on the mean temperature and snow accumulation the first 10 days of December 2019 compared to the first 10 days of March 2020 in coastal SNE. I’m not exactly going out on a limb by saying that the mean temperature the first 10 days of March will be colder and that it will be snowier in coastal SNE.

    1. There have also been plenty of first 10 days of April that have been colder and snowier than the first 10 days of December. Of course, not many. But, I can remember a few in recent years.

      To me, this has always been the most fascinating (and sometimes frustrating) aspects of weather in New England. Early spring is often an extension of winter.

    2. March 1-10 (winter) has always been colder than December 1-10 (autumn) from a climatology standpoint. Nothing remarkable about it.

      1. And I’m pretty sure the first ten 10 days of September are warmer on average than the first 10 days of June.

        Can’t rush the seasons ….. heat budget of the planet.

  22. After review of the 12z guidance, no changes. Most models are in the ballpark except the HRDPS which is completely over forecasting some kind of banding-type feature.

  24. We won’t be dreaming of a White Christmas with the latest run of the 12z GFS. To me perfect timing the day before Christmas Eve and for Christmas Eve and Day people could get to where they need to be.

  26. I know its way early but I am wondering is the theme of this winter going to be rainorama then snoworama/mixorama then rainorama then snoworama/mixorama.

  27. Thanks TK.

    I like the idea of a general 1-3″ for most tomorrow, probably more 1’s and 2’s. Definitely not a big storm, and most accumulation will be on grassy surfaces. I think the main risk to the forecast, not that we’re talking huge numbers to begin with, is that most areas underperform and come up with near nothing, as opposed to seeing more 3-5″ totals. These setups rarely deliver much. You typically need a well defined wave of low pressure riding up behind the front to get good snow in cases like this, and we don’t have that here.

  28. Latest from NWS

    Snowfall accum forecast is quite challenging for several
    reasons. First, initial QPF as the rain changes to snow may be
    wasted on melting, the exact location of a mesoscale snow band
    is uncertain, and low level drier air may impact snowfall
    intensity. The previous forecast accums still look reasonable
    and will not make significant changes. Looking at 2 to 4 inches
    from near the Mass Pike to the south coast, and 1 to 2 inches
    to the north. But this will depend on where any banding sets up
    and this could shift north or south of current forecast. The
    worst case scenario would be a 4-6 inch snowfall which is a low
    probability occurrence.

        2. Yup. I do. I was just making a lighthearted funny. What I said was the truth. They essentially went for 1 to 6 inches and gave valid reasons why. 🙂

          In today’s discussion I went for a coating to 3 inches and also gave valid reasons why. That’s my style too. 🙂 I may not always agree with our NWS but I very much like them. We have the best office in the country, IMO. 🙂

  32. For long range model followers, I feel that the CFS is a little more on its game the last several days.

    1. That system is in the range of time where we often see GFS (both old version and new so far) kind of lose track of the system and then get it back later. There has always been a zone around 7 days out that the model has struggled.

  35. Speaking of the NWS, they have issued Winter Weather Advisories for 1-4″ of snow for all of CT, RI, and MA from Worcester to Boston and points SE.

      1. It won’t be about the amount of snow, but the timing. Thankfully the pavements are a bit “warmer” after 2 mild days but they will cool rather rapidly once the stuff starts falling frozen.

        1. Boston is not immune a 3 or 4 inch amount of there is indeed a narrow banding feature in the right place. I do feel that 3 is most likely the max number for anybody though.

    1. I’ll start venturing details when we get to about 4 days out for storm size and about 2 days out for snow amounts, if applicable.

        1. Ah yes…
          They are “fun”. I did see that telecast and I think Pete was definitely not trying to give the impression that he was sure that the storm was going to drop x amount of snow, just speaking more of the type of pattern it would be occurring in, which is rather progressive and less likely to produce a “blockbuster” type storm.

  39. I am noticing each run of the HRRR there has been slight increases in snowfall. HRRR did a great job last week nailing the heavy snowfall areas in CT last Monday night into Tuesday.

  40. TK, thanks for sharing the Bolivia tornado. Wow!

    I do understand that climatologically (is that a word?) it’s normal around here (emphasis on around here) that March 1-10 is colder than December 1-10. But, I’ve lived in several places overseas where that is most definitely not the case. I haven’t checked the data for June 1-10 and September 1-10, Tom. You may be right about that. And again, if so, I’ve lived in several places overseas where June 1-10 is most definitely warmer than September 1-10. I’ve always found it fascinating that coastal New England in particular has these lags, if you will, climatologically. A lot of it, I guess, has to do with the deep ocean to our east that is slow to warm up in spring and slow to cool down in fall.

    On the Patriots, I believe Belichick. And, I think he’s incensed at people in the organization for allowing this to occur the way it did, in addition to not getting permission from the Bengals (they had gotten permission from the Browns). Like in most marriages, there’s friction when you’re in each other’s hair for over 20 years. It’s not to the point of divorce in this case. But, in recent years I’m sure certain decisions (Jimmy G, for example) have rubbed Bill B the wrong way. This one’s a brain fart on the part of the Patriots’ production crew.

    1. The lags are very much linked to our proximity to the ocean. That’s why it’s normal. Another factor that results in a colder early March on many occasions are still-existing late-winter snowcover from the Upper Midwest through Great Lakes and Canada and sometimes New England, which is much more common to see than a widespread snowcover in the early days of December.

      1. The fact that we are located in the northern tier, we should be having a lot more White Christmases than 23%. Yet having HHH for July 4 is always virtually a lock around here.

        1. No sir, that is not how it works. We have a little thing called the Atlantic Ocean next to us. You should apply the same logic to Seattle and you’ll find yourself very wrong about that too.

          If North America was a big rectangle with equal elevation throughout it, your idea might work. As soon as you change anything, out the window it goes.

    2. No so normal in this area. Macs cousin….a brilliant woman in her own right….is working in retirement with a group (name escapes me…sorry) monitoring seasonal changes on trees, etc. It’s far from normal. Not to mention our ocean is creeping up along new England’s coast.

      1. The ocean is indeed “creeping up along NE’s coast,” abetted by Greenland’s icecap melt. But, my point was not related to climate change. It was related to the general weather pattern in these parts for as long as I can remember. I’ve always found it curious. TK explained it, which I appreciate.

        There are, however, changes in vegetation and insect and bird migration (hummingbird, cricket, among others, who have been venturing further north) that are climate change related. Indeed, I’m curious to know what Mac’s cousin has to say about this.

        1. She will tell you climate is changing. Seasons are shifting. But I’ll see if I can put you in touch. I think you would both have a lot in common.

          Ocean is warming and ocean species are moving north. That alone makes a difference.

  41. MJO … Weak phase 2. Its predictability is a little tougher than average right now as it wants to be close to neutral or a non-factor, but I do believe there is a fair chance it passes through a brief too-weak-to-be-determined phase and re-emerges in phases 8 and 1 in the next 2 to 3 weeks. If this prediction is correct, our white Christmas chances will rise above climatology.

  42. Another thing I wanted to address, if I may, is the sun angle and its impact on how warm the sun feels, even on certain cold days. Gosh, I hope I’m not boring people with this. The other day one of the TV mets compared the sun in early December to a (dim?) flashlight. Not sure what he meant. In any case, having lived in much higher latitudes, I find the sun in December and January in Boston – even on really cold days – to be quite strong and warm (so long as there isn’t much wind) relative (key word here) to, say, the Netherlands. Holland doesn’t get much sun or real cold in December and January. But, if and when it does, you really sense the sun is a very dim flashlight. And, if there is any snow on the ground, even an inch, it stays there and doesn’t melt. Nothing melts during these brief periods of cold in Holland. You don’t see dripping icicles, for example. The sun’s too weak to cause them to drip. Contrast this with a 28F day in Boston in January. You’ll see some dripping going on when the sun is out.

    1. Interesting. Even on Sunday we had water coming down our drain spouts and some …stress some….melting in yard. But this house has sun major part of day.

      Not boring me. I find this fascinating

    2. Sun angle is a big thing for me. It impacts so much, including the ability to melt snow/ice to people’s moods, etc.

      Personally I love the “dark days” but I can fully understand why I’m not in the majority with that opinion.

        1. Indeed, the “dark days” of December. They took on a different and sometimes wonderful meaning during my 15 years in the Netherlands. Gosh was it dark. Rode my bike to school in the dark. Classes began at 8:30am in the dark. There wasn’t much sun at all in December in Holland. So, sunrise was more like light began to show itself at 8:45am. Classes were over at 3:30pm. And yes, you guessed it. It was getting dark again. Completely dark by 4pm. It wasn’t easy to deal with the first couple of years. Pretty grim when it’s dark, in addition to being overcast and foggy most of the time. My first trip home during the winter was December 1982. First thing I remember was waking up at 7:30am in Boston and it was: a. light outside; b. the sun was shining; c. it was really cold. I recall enjoying the light and sun in Boston during that 2 week break.

    3. Joshua, not boring at all. I think about the sun angle and these seasonal variations all the time. And of course, the big effect of “ocean air’. I wonder what latitude Holland is at. Gotta look it up sometime.

  43. Earth’s at perihelion, its closest pass to the sun around Jan. 4th at 91.4 million miles. It’s at aphelion, about 94.5 million miles from the sun July 4th.

    Slowly, as earth makes a complete turn on where the North Pole is pointing towards, the perihelion will again fall on northern summer solstice and aphelion will occur at Northern winter solstice. Those living at this time, tens of thousands of years from now, will feel an even greater change in intensity between the winter and summer sun.

    1. Just as precip is becoming better organized to our southwest in preparation for its journey over southern New England

  46. Snow cover will be heterogeneous across the area. One town may receive a half inch of snow while another town within several miles receives a few.

  47. OK, you guys are giving me no choice but to insert a quiz.

    On the first day of summer, the sun is 71 degrees above the horizon at the maximum. On the first day of winter how high does the sun get?
    A. 40 degrees above the horizon
    B. 35 degrees above the horizon
    C. 24 degrees above the horizon
    D. 10 degrees above the horizon

    Answer later today or maybe tomorrow.

  49. Latest HRRR, HRDPS, 12k NAM and 3k NAM all deliver 4-5″ of snow in Tolland County overnight. RGEM is about 3″. Still thinking this is going to overperform in a few areas where we get some nice banding setting up and sticking around for a few hours.

  50. As of 10PM, 35 and sleeting in Worcester.
    32 with moderate snow in Pittsfield.

    Raining and 39 where I am right now in Manchester CT.

  51. From Ryan Hanrahan
    Sizable uptick in our brand new HREF guidance. This would make 2″ and 3″ the rule with spot higher totals. Get up a bit extra early and join the morning team to help you get to work and school on time.

  54. TK, that’s interesting what you said above about our NWS office being the best in the country. We probably don’t realize how good we have it here.

    Having lived in York Harbor for a while, I depended on the Gray, Maine NWS office and used to try to follow their detailed weather forecasts. It was always interesting to see the variations in their coverage area, from the White mountains to the Lakes area and down to the sea. New England weather keeps you guys busy!

  55. Getting colder in the city everything is salted no action as of now it kind of stopped but I’m expecting that to change .

  56. Pounding snow here in Coventry CT. 2.5” on the ground and easily coming down now at 1”+ per hour rates. Radar looks like we have at least a few more hours of moderate to heavy snow to go. Looks to be an overachiever for sure. I had a feeling about this one!

  57. Same here mark. Moderate to heavy snow with about 3 1/2 on the ground. Just waiting for the call from the school. Wondering if it’s going to be a 2 hour delay or closed. Seems to be overachieving some.

  60. No school today, third time in the first 11 days of December. Still snowing moderately with about 4”

  62. Snowing Hard in the city but it’s having a very hard time sticking to pavement . More on people than roads .

    1. Thank Doc,

      It always fascinates me how different mets interpret the same information
      available to all and come up with different snow maps. Sure they are mostly similar, but yet different.

  64. Snowing decently in JP. Looks like about 2 inches on the ground.
    Back end rapidly approaching as it is almost to Worcester. Then there is a break
    and then another batch.

    https://radblast.wunderground.com/cgi-bin/radar/WUNIDS_map?station=BOX&brand=wui&num=6&delay=15&type=N0R&frame=0&scale=1.000&noclutter=0&showstorms=0&mapx=400&mapy=240&centerx=400&centery=240&transx=0&transy=0&showlabels=1&severe=0&rainsnow=0&lightning=0&smooth=0&rand=26267727&lat=0&lon=0&label=you

    1. Starting snowing here sometime around 3 AM, actually a little later
      than I expected. Oh well. But perhaps it over achieves just a bit.

  65. The 17th and 18th is looking more and more like a snow/sleet/rain situation with
    perhaps like 3-6 inches up front prior to changeover. Yuck! I’d rather all snow or all rain. Forget the mixorama.

  66. Yikes. 5.8” here. Didn’t expect that although I shouldn’t be surprised the way the bottom fell out of temps last night

    1. Nice. Is it done now?

      NWS did mention the outside chance of 4-6 inches. You slide nicely into
      that range. 🙂

  67. Batch of heavier snow expanding over NW Rhode Island. Will it make it up to Boston
    or slide out South of the city?

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