Thursday Forecast

57 Comments

9:42AM

DAYS 1-5 (NOVEMBER 30-DECEMBER 4)
A quiet last day of November as high pressure dominates. A cold front will cross the region early Friday with limited rain shower activity. Fair weather will then dominate for the balance of Friday as well as most of the weekend, though some cloudiness on Sunday will be caused by a weak disturbance crossing the region on its way to ignite an offshore storm that will stay east of the region as high pressure returns through Monday with more fair weather.
Detailed forecast…
TODAY: Mostly sunny. Highs 41-47. Wind variable up to 10 MPH.
TONIGHT: Clouding over. Isolated rain showers by 10PM. A band of rain showers crossing the region overnight. Lows 35-41 early then rising back into the 40s. Wind SW 5-15 MPH.
FRIDAY: Mainly cloudy with rain showers lingering southeastern CT, RI, and southeastern MA through mid morning. Clearing late morning. mostly sunny afternoon. Highs 46-52. Wind W 10-20 MPH with higher gusts.
FRIDAY NIGHT: Clear. Lows 21-27. Wind light NW.
SATURDAY: Mostly sunny. Highs 42-48. Wind light N to NE.
SUNDAY: Variably cloudy with a slight risk of very light rain/snow morning. Clearing afternoon. Lows in the 30s. Highs in the 40s.
MONDAY: Mostly sunny. Lows in the 20s. Highs from the middle 40s to lower 50s.

DAYS 6-10 (DECEMBER 5-9)
We reach pattern transition period number 1 here. I believe the pattern, on its way to colder, will go through it in a couple stages as blocking begins to develop in the northern hemisphere, rearranging the large scale pattern. Though it is difficult for timing of systems which can make for a forecast that can blow up in your face easily, here is my best shot. Milder December 5-6 with an episode of rain showers somewhere later December 5 to early December 6. Turning colder later December 6 into December 8 with mainly dry weather, then a warm up and a chance of precipitation, likely rain, somewhere between the later December 8 and December 9 period. The late-period unsettled weather is far from etched in stone and could end up further south and timed even later.

DAYS 11-15 (DECEMBER 10-14)
Blocking will strengthen and transition period #2 will take place here with a couple periods of unsettled weather and a switch to below normal temperatures. This will, of course, lead to an increased risk for snow threats. Snow is not a guarantee on any given day, but the overall pattern will start to support it more during and beyond this period, looking ahead a little bit. Much more to come.

57 thoughts on “Thursday Forecast”

  1. Many thanks TK. We have to be patient, but at least it is looking like some
    interesting times ahead. To be honest, as long as we have a White Christmas,
    I really don’t care what the season total is. 😀

    2. The closer to Christmas we get the snow, the more likely it will stick around on Chridtmas Day itself. As Dr. Cohen pointed out, frequent warmups will be following snow events this winter as it is.

      1. I’m not sure I am in complete agreement with the doc. I think his amount may be high, and I’m not so sure about the warm-ups after snow events. That is more likely be the case heading through the back half of winter, especially if we should lay down a snowcover of up to a few inches by December 20. If we do that, moderation will be harder to come by into at least early if not mid January.

  2. Thanks TK !

    I lean heavily on the EURO and much less so on the GFS.

    With that said, one thing I enjoyed seeing on the 00Z GFS was where each subsequent shot of cold air entered the US. Most of the entry points were the western Great Lakes, but one shot in the late range came in further west (the Plains), implying a retrograding trof … and then, once the trof retrogrades, that in turn affects storm track and so on. Pretty cool stuff, though I don’t trust actual details on the GFS much beyond day 3.

    1. Yes, but what can we rely on??? We generally know that a Cool Down is likely.

      The trough will set up, but we certainly do not yet know the specific alignment(s).

      The key is in TK’s discussion:
      Snow is not a guarantee on any given day, but the overall pattern will start to support it more during and beyond this period

      So, we sit back, watch and wait. Occasionally, we will, to use Mark’s term, salivate over a particular model run, but until we get closer, it is all for naught.
      Not that it will stop me from looking.

      One more player and that is the Ocean temperature. After our 60 degree day yesterday the water temperature at Boston Buoy ,

      Station 44013 (LLNR 420) – BOSTON 16 NM East of Boston, MA
      Boston Approach Lighted Buoy BF NOAA 44013,

      is sitting at:

      Water Temperature (WTMP): 49.5 °F

      For coastal sections this could be a huge player. By the time any Real snow threat arrives, that temperature could be down by 1-3 degrees or so.

      Snow along the coast would be somewhat greater IF we can get that
      water temperature to 45 Degrees or of course preferrably much lower.

      With water temperature near 50, very very tough for snow with any Easterly component to the Wind. We would have to get a backing wind more]
      to the North BEFORE any precipitation were to quit.
      The more Norherly component, the better.

      One more caveat: IF and I say IF we can get a coastal to bump into
      PURE ARCTIC air over NE, then a 46-49 Degree water just won’t matter.

      Saw this with an early season snow event in December, 1960.
      I was out in Millis at the time and it was in the teens during the event.
      It was all snow even at Logan even with NE wind off of the Water which
      had to have been into the 40s somewhere.

      Some info on said storm:

      https://en.wikipedia.org/wiki/December_1960_nor%27easter

      https://www.youtube.com/watch?v=_8Kq7MLpM9o

  4. JP Dave, you used the word “patient” regarding snow. I must be on the wrong blog. Sorry folks. 😉

    1. Nope, You are on the correct blog.

      I have been:

      a. Mellowing
      b. Listening
      c. Not giving a crap
      d. Hallucinating

      Take your pick.

      The snow will get here when it gets here.

      In the meantime, I watch the models. No harm in that as long as one does not
      hang their hat on any one run.

      1. I love looking at the models as much as anyone, even fantasy land. I still read it as half truth because yes, it’s a possible scenario, and much is to be learned about model performance whether they are spot on or celebrating “opposite day”.

  5. Well now, speaking of model runs and possible snow.
    The 12Z GFS has swallowed a basketball for breakfast.

    Have a look:

    https://www.tropicaltidbits.com/analysis/models/gfs/2017113012/gfs_mslp_pcpn_frzn_neus_32.png

    10:1 snowmap

    https://www.tropicaltidbits.com/analysis/models/gfs/2017113012/gfs_asnow24_neus_31.png

    Kuchera snow (not all that different)

    http://www.instantweathermaps.com/GFS-php/showmap-conussfc.php?run=2017113012&time=PER&var=ASNOWI&hour=204

  6. *** ALERT ALERT ALERT ***

    Sorry, had to. 😛

    This has nothing to do with the GFS though. It is your reminder that today is technically the deadline for the snow contest!

    But since we are all busy people and I could have sent a few more reminders, we shall accept guesses through Sunday December 3! But get them in by then just in case that GFS is right. 😉

    http://www.woodshill.net/?page_id=3218

    1. This person is slacking in creating the database but I will soon. Sorry for the delay. The good part is we can see everyone’s on the contest page. And SAK…….REALLY nice to see yours there!

    2. Hey, you have been derelict in your duties. Although you provided a very eloquent and detailed analysis of your Winter outlook, you Only provided
      ranges for the snowfall amount (Unless I missed something along the way).

      Shouldn’t you as well be providing PRECISE snowfall figures like the rest of us did. 😀 😀 😀

        2. OK, I give up. Where in the comments?
          Next day? I couldn’t/didn’t find it in the comments
          under the Winter Forecast????

          Thanks

          1. Contests page:

            Woods Hill Weather says:
            November 26, 2017 at 5:07 PM

            Ok here are mine…

            Boston MA: 41.0
            Worcester MA: 57.5
            Providence RI: 32.5
            Hartford CT: 44.5
            Concord NH: 60.5
            Burlington VT: 82.0
            Portland ME: 54.5

  8. Thanks JPD for sharing the info on that December 1960 storm. I was only a mere infant but I imagine you had a nice number of snow days from school. 🙂

    1. Actually, the storm came overnight Sunday lasting well into the day
      on Monday. I “believe” we only missed that Monday from School. I pretty
      sure we were back in session on Tuesday.

      I remember watching a COLTS football game from Baltimore on Sunday
      Afternoon and was excited that we may get the snow overnight. Sure did!

    1. Euro does have cold air drain in for a flip to snow for 1-2 inches at the end.

      So, between the Euro and the GFS (CMC has not part of this), then perhaps, just maybe, Boston gets its first inch on 12/7 or 12/8. Maybe? Kind of? Perhaps? wishing? maybe?

    2. I think that’s just the frontal boundary. It’s a piece of energy back to the west still that ignites the wave. I feel the timing may be later than what today’s 12z GFS indicates for whatever form and track that wave assumes/takes.

      1. Sure, it’s early. BUT, the important thing to garner is that
        “something” may be up for us in that time frame somewhere, even if a tad later.

        I look forward to seeing how this unfolds or as I said the other day Unravels. 😀

        1. Yes. I agree. I think the models may be overzealous on the first cold delivery and I expect them to back off some. Not saying we won’t feel a big change. We will, given that it will probably be 50+ Tuesday and maybe even Wednesday of next week, depending on the timing of the cold front. I think however that the 500mb flow is still going to be largely WSW to SW and we don’t blast that full cold air in here on the initial shot. We have to wait until something forms on the front – something I feel will be timed later than today’s 12z GFS and may not have much cold air to work with, assuming it’s close enough to precipitate on us, here in SNE. Of course that’s getting too detailed for something that is 6+ days away. I’m just talking about how I think it may evolve. Mild / quick cold / weak wave and slightly milder / second shot of cold which is more serious and longer lasting.

      1. Euro looks like what TK has been saying …. first wave of cold possibly lifting out some (day 9 and 10) ahead of a 2nd stronger surge of cold to come a bit later.

        1. Yes, and as I said. PATHETTIC,

          We wait until 12/15 or 12/16 and then we see.

          Then is when typical Winter weather begins anyway.

          1. Early December snows are nice and all to get in the mood, but around here mid-month warmups and cutters tend to occur then usually nothing is left for Christmas Day itself.

  17. JPD – Just curious, did Christmas 1960 end up being white? Since it was long before global warming, I would think so.

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