Wednesday December 22 2021 Forecast (6:29AM)

57 Comments

DAYS 1-5 (DECEMBER 22-26)

The previously-prognosticated active pattern with no big storms is ongoing. Keep in mind that when I mentioned this pattern many days ago, I also told you that we could not provide details for timing and impacts of any systems that far in advance, but now in the 5-day period we can elaborate more. We start with a grazing by an offshore storm system today which will be moving rapidly northeastward. Though the center will be quite a distance to our southeast, its precipitation shield is large enough that it will produce a period of rain for several hours this morning. However, surface temperatures will be cold enough over the interior areas, especially west of the I-95 belt, that the rain will be freezing on untreated surfaces, making it slippery for travel. This will have some impact on the morning commute. The good news is that not only does the precipitation exit by midday, but the temperature climbs above freezing in all areas so that any ice will melt. We’ll also see clearing with dry air and increasing wind as the day goes on, which will dry off any surface so that we don’t see any re-freezing tonight. High pressure will bring dry and seasonably cold weather on Thursday. Once we get to Friday and Saturday, Christmas Eve and Christmas Day, we will see a couple of disturbances moving east southeastward across our area. This will be the broken up remnants of a low pressure and frontal system that will be blocked from cleanly passing through the northeastern US by high pressure in eastern Canada. With enough cold air around, we may see some festive snowflakes for at least parts of the region from these systems, with no significant impact expected for travel. Model guidance is not handling the second half of the weekend well, with different models showing different outcomes. Right now it looks like a lingering disturbance passing through on Sunday will produce some scattered snow showers, but some fine-tuning of this part of the forecast will still be needed.

TODAY: Cloudy morning with a period of rain except pockets of freezing rain west of I-95. Gradual clearing afternoon. Highs 39-44 except 45-50 South Shore through South Coast of MA. Wind NE 5-15 MPH morning, NW 10-20 MPH with higher gusts afternoon.

TONIGHT: Clear. Lows 22-29. Wind NW 5-15 MPH, higher gusts.

THURSDAY: Mostly sunny. Highs 35-42. Wind NW 5-15 MPH, higher gusts.

THURSDAY NIGHT: Increasing clouds. Chance of light snow overnight. Lows 23-30. Wind variable up to 10 MPH.

FRIDAY (CHRISTMAS EVE): Cloudy with a chance of light snow morning. Variably cloudy with a chance of snow showers afternoon. Highs 33-40. Wind variable up to 10 MPH.

FRIDAY NIGHT: Mostly cloudy. Chance of light snow late evening and overnight except rain/mix South Coast. Lows 28-35. Wind variable up to 10 MPH.

SATURDAY (CHRISTMAS DAY): Cloudy. Periods of light snow/mix except mix/rain South Coast. Highs 35-42. Wind variable 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Chance of mix/snow showers. Lows 28-35. Wind N 5-15 MPH.

SUNDAY: Variably cloudy. Chance of snow showers. Highs 35-42. Wind N-NW 10-20 MPH and gusty.

DAYS 6-10 (DECEMBER 27-31)

Temperatures variable averaging near normal. At least once disturbance brings a precipitation opportunity favoring mid period.

DAYS 11-15 (JANUARY 1-5)

Variable temperatures, averaging close to normal. One or two disturbances may bring precipitation threats.

57 thoughts on “Wednesday December 22 2021 Forecast (6:29AM)”

  4. Good morning and thank you TK.

    So with the light snow threats, will there be an inch of snow on the ground Christmas morning?

    Or just a coating?

    Thanks

    1. I would like a tad more than festive. I’d like to see at least
      2 inches on the ground Christmas morning. Can we make that happen? I am not asking for much.

  8. I thought the 00z GFS might correct its 18z projection of 12/26, but it didn’t.

    I don’t have time to look at the ensembles, I wonder what general story its telling for 12/26

      1. Operational run actually shows some snow down to Boston and a bit to the South with much more snow to the North.

        We shall see.

  13. I’d love to see some snowflakes on Christmas morning. As we all know and as Frosty and Santa say, There is magic in christmas snow

  17. Continue to be surprised by the GFS’ 12/26 projection.

    I don’t get caught up in the snow projections, but I’m surprised by the projection of a decent strength low.

    If this verifies, looks rain to some snow potential in eastern areas.

  18. Bow NH schools are closed today due to poor driving conditions

    I heard Sutton treating in the night….or dreamed it

  19. The weather’s been variable here. That’s a given in New England. It’s also been variable in Northwestern Europe. While there’s always some variability there, it usually does not oscillate from one cold day, followed by a warm-up, followed by rain, followed by a cold day, followed by a mix. But, that’s been the story in the Netherlands. It’s a curious pattern, in which the southwesterly isn’t as dominant/prevailing as it often can be. Nor, however is an easterly/northeasterly flow (their continental wind direction; translates to cold in winter and warm in summer) persistent as it sometimes is in winter and summer (much less common than the southwesterly).

  20. The GFS appears to be an outlier with the weekend system, and as such, I will likely be ignoring it.

    However, the Thursday night/Friday morning system might do a little better than I was thinking earlier. On the forecasts I wrote early this morning, I just had snow showers in for all of our local clients, with a dusting to 1/2″ for accumulations. Based on what I see this afternoon, on tonight’s forecasts, I am probably going to go with a general 1/2-2″ across the area. It’s not much, but it might be enough for Boston to have an “official” White Christmas.

  22. Herein lies our problem. Check out this loop of the ridge over the northern Pacific and look at what it does across the US. No surprise the West is cold and buried in snow while we are struggling to get much winter weather underway….

    Brian Brettschneider
    @Climatologist49
    5h

    I’m calling for a total and complete shutdown of the North Pacific upper ridge until we figure out what the Hell is going on.

    https://twitter.com/Climatologist49/status/1473710315435089937?s=20

  23. Funny to think a number of days ago some of our guidance had Christmas Eve’s weather as high temps in the 50s to near 60° with a brisk southwesterly wind and a big storm in the Great Lakes. 😉

    Is it a surprise to me that it will look nothing like that? Well if you have been paying attention then you will know it is not a surprise whatsoever.

  24. Arctic air will be building across western Canada over the next several days. Some models have temperatures as cold as 30 to 60 degrees below normal. It looks like that arctic air spills down the west side of the Rockies, instead of the east side as usual. Some ensemble members have Portland getting as low as -10 and Seattle as low as -7 next week. Their all-time record lows are -3 and 0 respectively. In Spokane, where the all-time record is -30, a few ensemble members get temps as low as -32. So, there is the chance that some cities in the PNW could set all-time record lows just a few months after setting all-time record highs.

      1. Yes, I am well aware. It’s just a feeling, plus I don’t like what I have seen and what I see ahead. Sure, it could change on a dime. Fat chance of that.

  26. Re: SAK’s post above ….

    I think Seattle hit 107F or 108F in late June of this year.

    Might be interesting to see if they get below 0F, what their temp range for the year ends up being.

    I must admit, I don’t know their coldest temp from Jan-Mar earlier this year.

  27. As far as a white Christmas goes this year, no much snow will fall tonight, so whatever does fall will likely melt or sublimate
    prior to Christmas morning. I do NOT believe it will be a white Christmas. Hope there is a surprise, just doesn’t look likely.

    1. I’ll go on the record of saying I don’t like the “official definition” of a white Christmas for Boston (1 inch or more on the ground at Logan at 7 a.m.). Based on this, your local media is telling you the last time this happened is 2009, and they would be correct. HOWEVER, December 2017 ended up as a white Christmas throughout the city from a snow event that began there after 7 a.m. – that was really the last time – not all that long ago. The city will have some light snowcover on the ground for Christmas. Whatever falls won’t be melting, except on surfaces that force it to melt (like treated roads, etc). It’s going to stay rather cold.

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