Friday December 11 2020 Forecast (7:41AM)

98 Comments

DAYS 1-5 (DECEMBER 10-14)

High pressure delivers a nice December day today. The weekend will turn out somewhat unsettled as low pressure cuts across the eastern Great Lakes then down the St. Lawrence Valley, its warm front never really making much progress through the region during Saturday, when some periods of wet weather will occur. Although an partially occluded front / cold front will pass by during Sunday, that day itself may not be all that bad, with limited rain shower activity confined mainly to the early part of the day, and fairly mild air for December. Colder air will filter in early next week. Monday, low pressure passes south of the region and may be close enough to bring some light precipitation at least to southern areas while a low pressure trough may bring a few snow showers to northern locations. Dry weather is expected Tuesday with high pressure extending into the region from eastern Canada.

TODAY: Sun and high clouds. Highs 40-47. Wind SW up to 10 MPH.

FRIDAY NIGHT: Increasing clouds. Lows 30-37. Wind SE under 10 MPH.

SATURDAY: Mostly cloudy. Chance of light rain, mainly in the afternoon. Highs 45-52 except 38-45 in northern MA and southern NH Wind SE up to 10 MPH.

SATURDAY NIGHT: Cloudy. Spotty light rain except possible pockets of freezing rain southern NH and northern MA. Lows 31-38. Winds NE under 10 MPH.

SUNDAY: Variably cloudy. Rain showers likely, mainly during the morning. Highs 46-53. Wind variable 5-15 MPH becoming W.

SUNDAY NIGHT: Variably cloudy. Lows 28-35. Wind W 5-15 MPH.

MONDAY: Mostly cloudy. Chance of light snow/mix/rain favoring South Coast. Chance of passing snow showers southern NH and northern MA. Highs 35-42. Wind variable 5-15 MPH becoming NW 10-20 MPH.

MONDAY NIGHT: Partly cloudy. Chance of snow showers early. Lows 22-29. Wind N 5-15 MPH.

TUESDAY: Mostly sunny. Highs 33-40. Wind N to NE 5-15 MPH.

DAYS 6-10 (DECEMBER 16-20)

Storm threat (rain/mix/snow) December 16-17 with details depending on track of low pressure. Colder/dry December 18-19. Risk of snow and rain showers at the end of the period, slightly milder.

DAYS 11-15 (DECEMBER 21-25)

Watching the period December 21-23 for a potential storm threat. Temperatures variable, close to normal overall.

98 thoughts on “Friday December 11 2020 Forecast (7:41AM)”

  1. Good morning and thank you TK.

    Well Euro has had next wrek’s storm for 3 consecutive runs. Will 12z make 4 or will it get suppressed or go poof?

    1. Hoping this is like that 2013 blizzard where it had it consistently for a week…that’s the only time I can ever remember that happening.

      1. Fat chance of that happening. 🙂

        If you read JMA’s comments from late yesterday, you might
        be convinced of a suppressed solution or if it makes it, a much weaker version.

    1. I don’t recall that event, but I do remember the ice storm that covered the same area in 1998. I forget though if it was December or one of the other winter months. That was a really bad one.

  6. Thanks TK.

    Another chilly morning with temps in the low 20’s but warming up nicely now. Still 100% snow cover at the house after last Saturday’s 3″. Love this time of year with the low sun angle when a few inches of snow falls and it actually sticks around for awhile. The heavy wet nature of the snow and cold nights that followed certainly helped.

    Should melt today/tomorrow and then we need to replenish next week! The GFS and Canadian have a grazer with a period of light snow. Euro is still a sizable 8-12″+ snowstorm. Great to have that nice 1035mb high pressure over eastern Quebec but too strong and too far south, and we will have a grazer or miss. We keep watching….

      1. Indeed, for us anyway. But threading the needle. There is not much of anything in north central MA or southern NH.

    2. At this point, I’ll take anything as long as it’s not a total miss. According to TK, there should be one more opportunity thereafter just before Christmas.

  10. I´m hopeful with the projected position of that high, that if the low were to pass too far south, we might still get some snow because there could be a good influx of moist air into the region just from the onshore flow between the low and the high.

      1. Agreed ! Its nice to finally see a cold high to the north. Tired of depending on dynamic cooling. It looks hopeful and I hope it works out.

  11. 12z GFS gets light precipitation into coastal CT RI South Shore Cape and Islands for Monday
    Looking at the 6z EURO which eweather posted on his twitter page it is showing some very light snow for most of SNE the exception being South Shore Cape and Islands where very light rain is being shown.

  12. 12Z GFS looking a tad flat for next weeks storm (Where did I hear that before????)
    Perhaps it will amplify? we shall see in a few minutes.

  13. Southern CT RI South Shore Cape and The Island coming in the 6-8 inch range for Wed into Thursday. Boston back to Hartford in the 2-5 inch range.

  14. Has a signal of being a long duration event because of onshore flow. Not necessarily heavy precip, but one of those where its hard to shut the precip off in eastern areas due to NE flow.

  16. If that low comes north a little bit you could shift the the 6-8 inch area further north. The last several runs of the GFS has shown at least snow snow.

  18. I was thinking the same thing. If you are a snow lover you are happy with that model run. Still a lot of time between now and then and I just can’t get excited yet.

  19. Thanks, TK.

    Am I correct that the lions share of snow next week will be later Wednesday and even more so into Thursday? I’m watching RI more carefully since Wednesday is my grandsons eye surgery day.

  20. The timing right now appears to be later Wed and finishing up late Thursday morning. Take this with a HUGE grain of salt right now.

    1. And even that was more of a fluke. Iirc it was not really forecast all that well in advance. It’s like pulling teeth getting a white Christmas around here. Once in every “gazillion” years it seems.

  25. In addition to Christmas Eve, looks like the GFS is gearing up for another one on the 27th….

    I’m liking the looks of this pattern for the remainder of the month!

    Eric Fisher’s seasonal snow forecast will not be looking good for the third year in a row if a couple of these systems produce. He went 15-30″ for Boston on the season and Boston only needs another ~10″ to get into that low end range.

    1. The GFS is even looking colder for the system on 12/20-12/21 and showing some coastal redevelopment. Oh what a little blocking will do!

  29. Perhaps we should not be overlooking the Monday storm….

    12z Euro now has a period of accumulating snow with a swath of 2-4″ accumulation….

    Monday Surface Map:

    https://www.pivotalweather.com/model.php?m=ecmwf_full&p=prateptype_cat_ecmwf&rh=2020121112&fh=78&r=us_ne&dpdt=&mc=

    Monday Snowmap:

    https://www.pivotalweather.com/model.php?m=ecmwf_full&p=sn10_acc&rh=2020121112&fh=102&r=us_ne&dpdt=&mc=

    It’s also a decent hit for Wed/Thurs, especially Pike south.

    Thursday Surface Map:

    https://www.pivotalweather.com/model.php?m=ecmwf_full&p=prateptype_cat_ecmwf&rh=2020121112&fh=144&r=us_ne&dpdt=&mc=

    Total Snow at 10:1 for both storms. I assume Kuchera would be higher in this case:

    https://www.pivotalweather.com/model.php?m=ecmwf_full&p=sn10_acc&rh=2020121112&fh=192&r=us_ne&dpdt=&mc=

  30. Thank you, TK.

    Last year we got a short-lived but definite period of winter right around now. It lasted about 10 days. People were skating in the Public Garden. It snowed a little. It looked like winter. I’m hoping we get some of that soon. Mild days in December don’t awe me.

  31. No model works for me beyond Sunday.

    I really don’t think cold air going to be the problem. There will be plenty, so unless there a wind right off the water at the immediate coast, temp profiles are going to be good.

    It going to be location and intensity. Both of which I don’t believe any model has defined at this point.

    I did see the first headline at a credible local news site that a a powerful nor’easter could bring significant snow to New England Wednesday or Thursday.

    As for all the PV, severe winter weather events, and cold winter social media posts, remember the sycophants don’t keep consuming the media if it says dry conditions expected and warm weather coming.

  32. I learn something new almost every day here. If anything, I always assumed that the PV needs to be very strong to get severe winter weather.

    I am referring to Dr. Cohen’s thoughts (weakening PV) that Mark posted above.

    1. u actually want a weak PV so the cold arctic air can come down. If the PV is strong then its locked up at the poles

    2. Last year we had one of the strongest PV’s on record, locking all the cold air over the North Pole as Matt said. When the PV weakens either by splitting or getting displaced, it sends lobes of colder air further south across the mid latitudes of the Northern Hemisphere. That is what we are rooting for if you want winter weather here.

  33. OK, what’s up with the NAM????? It usually starts spitting out
    panels 2:35 to 2:40 PM. It’s now 3:11 and NOTHING???????

      2. And it pisses me off no end that the NAM is not available
        at our favorite sites! )!@(#(*!Y#(&*$!&*@#*(!&@#(*&!@*(#&*(!@&(*$&(@$*&!(*@$*(@*!&@*(#&*(&@#*(!&(@(#&!(*

      1. Remember though that ensemble mean snow projections in the mid-long range are usually on the low end. That is not a bad look at this lead time.

        1. Yes, I am aware of that. I want to see what this all looks like along about Tuesday PM. Then maybe, just maybe we
          can get excited. Still awaiting my first Cowabunga for the season. Don’t see it at this time.

          A little aside on Cowabunga….

          Cowabunga!

          Where did cowabunga come from? Who’s to blame for such nonsense?

          Look north to West Bloomfield, Mich., and Eddie Kean for the definitive answer. The 79-year-old lounge pianist and composer coined cowabunga in 1949 while working as head writer for “The Howdy Doody Show.”

          Only, he spelled it “kowabonga.” The plot thickens.

          “On `Howdy’ we had a character named Chief Thunderthud,” says Kean, “and (host) Buffalo Bob Smith rightly thought the old boy needed his own greeting. Movie Indians said `How!’ in those days, you know, but I always felt `How’ sounded stupid and contrived. Did any self-respecting Indian ever say `How!’? I seriously doubt it.

          “Our Princess Summerfall Winterspring used kowagoopa as her greeting, so kowabonga seemed logical enough for Chief Thunderthud. At least Bob and I felt kowabonga worked .

          And yes, I used to watch the Howdy Doody Show as kid.

          “Say Kids, what time is it?” “It’s Howdy Doody Time!”

          https://imgur.com/a/8kWo6nt

  37. This is video from Kyiv, Ukraine, where it’s icy. The poor woman with a backpack trying to traverse the sidewalk. https://twitter.com/RexChapman/status/1337448804900024324

    One thing I noticed living in the Netherlands – far from Ukraine – was that the sidewalks and streets got very icy almost every winter at least once.So, while their winters aren’t as harsh as ours generally their climate is conducive to lots of freezing fog and misty freezing rain that creates an ice rink.

    By the way, it’s consistently somewhat colder across much of Europe than it is here, so far this winter. Certainly not brutally cold, but in Holland they’re not having any days in the 50s anymore. More upper 30s and low 40s, every day. That’s another theme from my experience of weather in Europe. Not much variability at all from day to day, and often week to week. Patterns become stuck for weeks on end, and you don’t see dramatic changes. One thing you never see in Holland, for example, is what we get all the time: Arctic High moves in, brisk 36 hours, then high sinks to our south and it warms up 20 degrees. Just doesn’t happen in the Netherlands, ever.

    2. That has to be a set up. Has to be.
      That can’t possibly be real.

      Pretty damn funny though.

      How many normal citizens would just glide down
      the the sidewalk incline like depicted? We might, but who]
      else would? They looked like pros do this and that is another
      reason why I believe the whole thing was staged.

    3. I feel guilty laughing, but that is pretty hilarious, staged or not. That must have been one hell of an ice storm!

  40. Friendly reminder: When analyzing runs, continue to keep in mind the uncertainty, and that it’s still autumn. 🙂 I follow a couple pages loosely in which I’ve seen followers analyzing things as if it’s mid winter. We can’t do that. We have to take into account the actual time of year and all of the conditions (like ocean temperature, etc) that impact weather depending on what time of year we are in.

    As far as the real-time weather, and keeping in mind the model uncertainty being above average, yes, we have several “chances” for something to happen during the next 15 days. I could see 3 to 5 opportunities for snowfall somewhere in SNE, if things evolve just so. One at a time really. My first focus is now for Monday. I’ve taken note of the ECMWF’s forecast for that while not being in agreement with other models. Just will keep an eye on that the next couple days and fine-tune it for Sunday’s update. Will continue to monitor for middle of next week, and will talk more about the other “possibles” when ready.

      1. I still lurk around once in a while. It’s funny, I think the models have burned us too many times recently. I expected a lot more excitement about the prospects of next weeks storm given the euro’s projections even in this timeframe. Used to be the sweet spot.

    1. Not for nothing, but this thing is trending juicier and it wouldn’t
      take much amplification of the upper flow to get it up here, at least to most of SNE. I think we need to watch this baby,

      It will be interesting to see what the rest of the 0Z suite has
      to say.

  46. I was thinking earlier the EURO is out to lunch or it is on to something. Will see how the rest of the 0z runs go but the NAM is bringing a touch of snow to the southern coastal areas of SNE on Monday.

  47. Hmmm…0z GFS now closer for Monday as well. Gets the northern fringe of the precip shield into SNE as snow for a short period. Not much accumulation but bears watching for a sneaky inch or two.

    Nice hit for the Wed/Thurs system as well with 12″ of snow Hartford to Worcester to Boston and points SE trending up to a solid 15″ swath from Washington to Philly to NYC and up the CT shore to RI and SE MA.

    00z GFS Snow:

    https://www.pivotalweather.com/model.php?m=gfs&p=snku_acc&rh=2020121200&fh=240&r=us_ne&dpdt=&mc=

  49. GFS and CMC ensemble means look good. Many GFS ensemble members are NW of the mean and all but one of the CMC ensemble members is near or NW of the mean.

    This is a mighty good look for 5 days out but need to stay the course with these runs for another 48 hours before the excitement level can officially begin to rise.

    Have to be weary of that sharp drop off in precip and snow amounts being modeled just to our north. If that high over Quebec is a bit stronger and the storm tracks out to sea a bit more, could be the difference between a foot of snow and not much snow at all in some places. That northern edge of the precip shield is going to get eaten away by the cold, dry air.

  52. If and big if this holds chances of a white Christmas are looking very good unless some big warm up or rain storm happens.

  53. Things are looking up for both Monday and Wednesday/Thursday.

    Most models are now on board for accumulating snow on Monday. Anywhere from an 1 or 2 upwards of 4 or 5 inches.
    Imho, “could” be 6+ inches for a sneaky nice one. We shall see.

    Then, the main event, Wed/Thurs.

    Here is a very nice write-up from the Norton NWS office.
    Please note what they say about Monday’s system possibly having an effect on the Wed/Thurs system:

    Southern stream system that clips Southern New England Mon phaseswith Northern Stream energy Tue, developing an intense cycloneover/near Newfoundland with both GFS/EC lowering MSLP down into the940s mb! Per WPC, the record MSLP for Atlantic Canada is close to940 mb. Models sometimes are too strong at day 5 time range but even
    the GEFS and ECENS mean is around 964 mb! What is significant hereis that this intense cyclone downstream will place cold confluentflow over the maritimes and may shunt upstream storm track farthersouth of New England for the mid week system. Thus uncertaintyrevolves around how far north will this southern stream systemtrack.

    Here is a GFS look at a 936 mb low just North of NewFoundland.

    https://www.tropicaltidbits.com/analysis/models/gfs/2020121206/gfs_mslp_pcpn_frzn_namer_16.png

    https://www.tropicaltidbits.com/analysis/models/gfs/2020121206/gfs_z500_vort_namer_17.png

    https://forecast.weather.gov/product.php?site=BOX&issuedby=BOX&product=AFD&format=CI&version=1&glossary=1&highlight=off

    Hopefully, that feature at least allows the good stuff across
    SNE even it does not penetrate into NNE.

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