December 5 2021 Forecast (8:48AM)

90 Comments

COMMENTARY

It’s not often you get two of these in a row out of me, but I feel compelled to comment again here in the blog post (and not the comments section only) about what I said yesterday, and a couple other things. As we often see, many people (including some media members) nearly skip over a weather situation in the short term (in this case Monday), because it doesn’t have snow involved in it, and jump right to something beyond day 3 (in this case Wednesday, which is currently day 4) because they can use the “s” word. Fine if you want to talk about it, but if you are in media you better have your focus on the event sooner-to-come, especially since it may result in localized damage due to strong wind gusts. I’ve been disappointed by media that should know better already this weekend. I’ve seen an on-air snow map for a system that was 4 days away, with detail, and spoken about as if it was absolute. I’ve seen discussions putting emphasis on tools that just 24 hours before were declared unreliable. No, they don’t have to answer to me. I’m not their authority. I may be a meteorologist myself, but I am also a viewer, and they owe their viewers something a little better in my opinion. There’s a logical method to all of this. But we still have to jump to the exciting thing because it gets people listening, right?! I don’t agree with it, at least the way it’s done in today’s media world. I never have and I ever will. So on I go, my way as usual…

DAYS 1-5 (DECEMBER 5-9)

If you were out and about last evening you may have seen a few flakes of snow or drops of rain. I drove through some of each between Milford and Woburn MA. This was the last gasp of a dissipating clipper system that prompted me to put the insignificant precipitation in last night’s forecast. With that out of the way, we enjoy a dry but somewhat chilly day today, but with a lack of wind out there it won’t really feel all that bad. But we have some changes on the way, so get ready to ride the weather roller coaster once again. The rest of this discussion will be very similar to yesterday’s. Today’s high pressure area will shift offshore tonight and we’ll come under the influence of a strong low pressure system passing to our north Monday. First, its warm front will produce some rain Monday morning (which may start as a brief mix of rain and frozen precipitation over the interior higher elevations in the pre-dawn hours of Monday). Right after that we’ll be in the warm sector of the system with a gusty southwesterly wind and lots of clouds, but a lack of rainfall, with the exception of the South Coast region which may experience some isolated but potentially strong showers and even thunderstorms, a few of which may produce locally damaging winds. The cold front trailing the low passing by to our north will charge across the region from west to east Monday evening, accompanied by rain showers and possibly a thunderstorm, along with gusty and shifting winds, followed by a sharp temperature drop after an unseasonably warm day. Tuesday’s weather will be dry but blustery and up to 25 or 30 degrees colder than Monday – a bit of a shock to the system. We then can turn our attention to the next low pressure system approaching, clearly set to take a track much further south than its predecessor, and with cold enough air in place here we’ll be talking about at least some frozen precipitation (yes, snow) for at least a portion of the region. With the track and strength of the low center still in question, it’s still too early to determine precipitation type and intensity for any specific location, but with it being day 4 at this point, I can say that odds continue to favor a mostly snow event for interior areas such as southwestern NH and central MA, with odds favoring more of a rain event for the South Coast, and some combination of liquid and frozen precipitation in between. I’ll bring this into better focus for tomorrow’s blog post, but for now just be ready for our first fairly widespread winter weather threat. Following that system, expect fair, chilly weather Thursday as low pressure moves away and high pressure moves in.

TODAY: Partly cloudy. Highs 37-44. Wind N up to 10 MPH.

TONIGHT: Increasing clouds. Chance of light rain overnight that may begin briefly as snow and/or sleet interior higher elevations. Lows 30-37 evening, rising into the 40s overnight. Wind variable under 10 MPH evening, SE 5-15 MPH overnight.

MONDAY: Cloudy with a chance of rain early, then mostly cloudy to partly sunny. Slight chance of an isolated rain shower or thunderstorm near the South Coast mid morning to early afternoon. Highs 61-68. Wind SW 10-20 MPH, frequent gusts 30-40 MPH and occasional gusts above 40 MPH.

MONDAY NIGHT: Mostly cloudy evening with a passing rain shower and potential downpour with possible thunder and/or small hail west to east. Partly cloudy overnight. Lows 33-40. Wind SW 10-20 MPH gusting 30-40 MPH and potentially higher in any convective activity, shifting to NW from west to east.

TUESDAY: Partly cloudy. Temperatures steady 33-40. Wind NW 10-20 MPH with higher gusts, diminishing later in the day.

TUESDAY NIGHT: Increasing clouds. Lows 23-30. Wind variable up to 10 MPH.

WEDNESDAY: Cloudy. Snow/mix likely southern NH and interior MA, snow/mix/rain elsewhere with rain favoring the South Coast region. Highs 33-40. Wind NE 5-15 MPH, higher gusts.

WEDNESDAY NIGHT: Cloudy with precipitation tapering off. Lows 26-33. Wind N 5-15 MPH, higher gusts.

THURSDAY: Sun/cloud mix. Highs 35-42. Wind NW 10-20 MPH.

DAYS 6-10 (DECEMBER 10-14)

The active weather pattern continues but model guidance remains unreliable. Watching for a weak low pressure area to bring a minor precipitation threat December 10. Another period of unsettled weather may occur in the December 12-14 window, with odds favoring a milder system.

DAYS 11-15 (DECEMBER 15-19)

Hints of a colder trend that may eventually lead to another winter precipitation chance or two. This is a very low confidence outlook.

90 thoughts on “December 5 2021 Forecast (8:48AM)”

  1. I like the low confidence outlook though 🙂 but mostly I’m commenting so I can be the first commenter.

  4. 40 years ago today: Dick Albert’s “oops” storm got underway late in the day and lasted into the following day. He often spoke about his bad forecast (along with others) on the system that was supposed to graze us with a few snow flurries and go out to sea on the Dec 5-6 1981 weekend. 12-18 inches of snow later……………….

        1. I don’t recall the 1987 event that “wasn’t” but I assume I was totally devastated at the time. Just as well.

  8. 500 mb flow is just too flat for Wednesday. Unless it digs some
    more prior to that, we’re looking at a fish storm.

    As Don Kent used to say long ago, “Not Enough Cyclonic Curvature”

  9. Thanks TK.

    Interestingly enough, Denver has yet to see measurable snow (0.1”). Will Boston see it before Denver? That would be a hoot! 😀

  12. This morning’s Norton NWS Discussion, basically repeats the one posted here early this morning. Pathetic.

    1. I don’t need to add anything more to what was said above but I will add one thing…

      I miss Walt Drag’s discussions. 😉

  14. Twenty shopping days left until Christmas. A rake or a leaf blower would be the more useful gift under the tree come Christmas morning. This is what our “new” climate has come to.

    1. FWIW (not much) the 6z GFS has 4 separate snow events during the next 16 days, which would result in above normal snowfall for December.

    2. If this is our new climate that has come about over the last few decades, it’s actually gotten snowier. 😉

  15. 12/9/2005. Correct me if I’m wrong but wasn’t that the widespread blizzard that came out of nowhere and stranded many schoolchildren in their schools on a Friday afternoon? If I further recall, many BPS students didn’t arrive at their homes until 8:30 that evening.

    1. It took Mac many hours to get from Watertown to Framingham. He had a couple of women co-workers following him. After sitting on 135 by the Marriott newton for over an hour, he took back roads through wellesley back to 135 closer to Wayland. We had thunder snow in Framingham and six inches in one hour.

      I think we had another around the same date in 2007??

      2. I think 2007 storm fell on or close to the Swedish day of St Lucia which celebrates the winter solstice. I have a tendency to relate storms to events in our lives as you can see 🙂

        1. Yep….the date of 2007 was December 13….date of Swedish celebration of candles/light for the longest night.

    2. That was a Friday and I was suffering from the most well-timed stomach bug I ever had.

      I had to call out from work that day. The guy that took the call thought I was lying. I was not lying. I was really sick for about 18 hours…

      If there was one other plus, I didn’t have to shovel any of that because I was too sick.

      1. I had a most interesting ride home as they let us out of work
        at the most intense time of the storm. I was driving a
        5 speed stick Mustang at the time. That car was USELESS in the snow and I mean USELESS. Even the slowest and slightest release of the clutch resulted in a rear wheel spin!

        It was only 3.4 miles to home and it took me 2-3 hours. By the time I got home, the sun was coming out in the West shining just below the cloud deck.

        1. Ahhhhh memories. My first car was a four speed 1969 390 Mach I….big engine block, rear wheel drive. I spent a lot of time in ski country with that car. I sure do miss it. I love that you had a mustang. Assume It was a later model as five speeds, to my knowledge, were not a thing in 69.

          As far as the storm. I’d been at Mac for hours to leave work. His company let him out at the height also just as yours did and I think every other darned company.

    1. And how many times in the past several years have we seen models keep adjusting storms to the south, and then within 48 hours suddenly start going north again? This is FAR from a done deal, especially since we’re still well beyond the range where the models have been competent lately.

      1. That’s happened many times…
        As we always say (in one form or another), knowing the errors is crucial.

        1. I have seen it turn on a dime on the very next run.

          12Z Out to sea
          18Z Monster hit.

          So, yeah I get it. I am just disappointed to see that the current
          “trend” is OTS.

      2. Of course, I understand that. And you think it will adjust back North? OR It could, so we have to wait and see?

    2. We’re not sure yet that anything is complete. It’s come closer to other model solutions, yes, but ALL of these solutions are for an event beyond day 3, and you know what that means. 😉

  19. Couple of thoughts. Writing individually to media doesn’t make a dent. We know it is not the faces or names we see who drive content….it is corporate. It would be great if collectively we wrote to them. Just a thought.

    Also. I count Wednesday as day three. Sunday to Monday is 24 hours, Monday to Tuesday is a second 24 hours. Etc. I’m having a flashback to the same conversation years ago but can’t recall the rationale for thinking of Wednesday as day four. I think I understand why for meteorological purposes. Just another thought 😉

    1. I think anything is worth a try, but corporate shells are tough to crack…

      For my forecast purposes, when I write TODAY in my forecast, it’s for Sunday, or day 1. Monday is then the day 2 forecast (not two days away, but day 2), Tuesday is day 3, Wednesday is day 4. Thursday is day 5. That’s why my DAYS 1-5 on a Sunday goes from Sunday thru Thursday. 🙂

      So Wednesday is definitely day 4 for a Sunday morning forecast issuance. 🙂 And that is most definitely on the other side of the fence when we apply the 3-day-rule. 🙂

      1. Thanks for the explanation.

        I see now why you say Wednesday is day 4, however, it is
        stlll only 3 days out.

        Add 72 hours to now and we are at 12;39 PM on Wednesday.

      2. Sadly you are correct about corporate America. Its face isn’t in the forefront so it doesn’t face the criticism.

        I was thinking that is the reason for four days. And it makes absolute sense for writing a forecast. Thank you.

        But…..are you laughing yet….technically, Wednesday is three days away sooooo wouldn’t that fit into the three days out rule?

  21. In the Millis area, is there a guess of rain timing and rough amount for tomorrow. The horses were very uncharacteristically wild Thursday night well before the front came through. My granddaughter had her first encounter with the ground from the back of a typically bomb proof horse. It always amazes me how in tune to events of nature animals are.

  22. Nearing the end of Hanukkah for those who celebrate it, and I spent a little time listening to the MusicChoice Hanukkah or Chanukah song channel today. This was the favorite one that I heard… https://www.youtube.com/watch?v=b6DtDgEF9ds

    Adam Sandler meant well when he wrote his song, but there are quite a few Hanukkah songs out there these days…

  23. Too bad this blog didn’t exist in 2005. It would have lit up like the WH Christmas tree. Comments would have easily been in the hundreds all evening, maybe nearing one thousand? 😉

    The first iPhone was still a couple years away. Everything was flip phones and “blueberries”.

  24. So just an educated guess (which includes thoughts of other mets), now we reach the stages where the model adjustment may be too far south, and they probably come back north a bit between now & “event time”. Nothing more to add about that system today!

    It’s time to focus on tomorrow’s…

  26. 12:59 PM NWS discussion STILL has NOT changed.

    It appears increasingly likely that at least part of southern New
    England could see its first widespread accumulating snow of the
    season. The dynamics are impressive. The 00z GFS shows a decent
    storm intensifying close to the 70W/40N benchmark with deformation
    band forming across the CWA. Omega within the favorable
    Dendritic Growth Zone of -12 to -18C looks to be in the 15-20
    unit range, along with negative 700-500mb equivalent potential
    vorticity and good 700mb frontogenesis should help set up a
    decent mesoscale band sometime Wednesday afternoon into evening.
    The question will be whether it is cold enough for 1 inch per
    hour snowfall rate to materialize and how much snow can
    accumulate before potential mixing or changeover to rain
    especially along the Boston- Providence corridor. Ensemble model
    guidance (GFS, EC and GEM) have continued to advertize decent
    probability of 24 hour 3-plus inches snowfall, with consensus of
    at least 40-50 percent for Wednesday into Wednesday night
    across interior MA and CT, using uniform 10:1 snow to liquid
    ratio. Dependent on how impressive the cold air injection is,
    this ratio could potentially be a little higher. In fact, the
    GFS shows SLR of around 14 to 16:1.

  27. Thanks TK!

    What is the anticipated timing of tomorrow evenings passing rainstorm? I’m tentatively scheduled to stay in Concord for a dinner then drive home to Boston around 7 – 8 pm but can leave at 5 pm instead if driving might become treacherous after 7.

      1. Thanks! I decided to skip the dinner & get home by 6! Either way I get to be home earlier so win-win!

  29. 18Z Showing signs of a slight shift Northward.

    https://maps1.pivotalweather.com/maps/models/nam/2021120518/072/ref1km_ptype.conus.png

    But still mostly South

    https://maps1.pivotalweather.com/maps/models/nam/2021120518/075/ref1km_ptype.conus.png

    Kuchera Snow

    https://maps1.pivotalweather.com/maps/models/nam/2021120518/084/snku_acc.us_ne.png

    I touch farther North with the snow distribution but not enough to make any difference.

    I just hope this run is a sign.

    1. Inching north Is at least right direction

      Thanks for all of your links JPD. They are fun to follow

      Why do some models say 12/8 and others say 12/9

      1. Look at the time. 0Z is Mean Greenwich time. Even though
        it is 7PM here on the 8th, it is already Midnight on the 9th
        in Greenwich UK.

        1. Ahhh. Thanks. I hang my head in shame. Mac set his watches to exact time long before watches set themselves. I should have figured that out.

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