Tuesday Forecast

71 Comments

7:37AM

DAYS 1-5 (DECEMBER 5-9)
No big changes. Pattern transition, stage 1, as talked about a few days ago, takes place during the next couple of days as we have a mild Tuesday, a cold front bringing some wet weather tonight into Wednesday, cooling temperatures during Wednesday, and a colder/dry Thursday. A couple waves of low pressure following the frontal passage, one on the front itself, a second from another disturbance, will pass southeast of the region but can both be close enough to produce a period of precipitation. Timing for these looks like late Friday and late Saturday as it stands now and precipitation type can be rain, mix, or snow, depending on timing and locations. Neither look significant in terms of snow accumulation at this point but will keep an eye on it, just in case.
Detailed forecast…
TODAY: Mostly cloudy. Increasing risk of rain showers in the afternoon. Highs 48-55. Wind SE to S 5-15 MPH.
TONIGHT: Cloudy. Rain showers likely. Temperature rising to 53-60. Wind S to SW 10-20 MPH with higher gusts.
WEDNESDAY: Cloudy through early afternoon with periods of rain. Breaking clouds later in the day. Temperatures falling to the 40s. Wind SW 5-15 MPH shifting to W and increasing to 10-20 MPH with higher gusts.
THURSDAY: Partly cloudy. Lows in the 20s. Highs from the upper 30s to lower 40s.
FRIDAY: Mostly cloudy. Chance of rain/mix/snow, mainly afternoon and night. Lows in the 20s. Highs from the middle 30s to lower 40s.
SATURDAY: Mostly cloudy. Chance of rain/mix/snow, mainly afternoon and night. Lows from the lower to middle 30s. Highs from the upper 30s to lower 40s.

DAYS 6-10 (DECEMBER 10-14)
Look for dry and colder weather December 10-11 and a rain/mix/snow threat December 12-13 depending on timing and track of the next system, and dry/cold weather to end the period.

DAYS 11-15 (DECEMBER 15-19)
A more consistent cold pattern, with a trough of low pressure dominated by the polar jet stream and 1 or 2 clipper type systems possible during this period. Will have to watch for additional moisture available for either system from the Pacific or Gulf of Mexico, depending on the set up, but the odds of this are low based on the northern stream dominated pattern.

71 thoughts on “Tuesday Forecast”

  4. This is a re-post from earlier this morning to answer a question from Matt.
    Of course if others would like this info, here it is.

    for Matt:

    to make an animated gif for a model on Tropical Tidbits, click on Forecast Gif
    on the bottom right.

    https://imgur.com/a/wUsme

    the enter hour 1 to hour 384

    https://imgur.com/a/sxTOS

    and click create gif

    BTW, will NOT work in Chrome. Use IE to ensure it works.

    Can alos make these animations in College of Dupage Weather.

    Enjoy

  5. NWS discussion from earlier this morning:

    Friday/Saturday/Sunday…

    Tremendous uncertainty in this portion of the forecast as a strong
    northern stream shortwave drops south into the Great Lakes. This
    will help to carve out a deep trough to our west. Several pieces of
    shortwave energy will round the base of the trough along with a
    couple weak waves of low pressure. Timing/strength/location of
    associated shortwave energy and surface reflections are extremely
    uncertain at this point.

    Numerous possible outcomes and scenarios are possible Friday into
    the weekend. If the shortwave energy is on the weaker side and
    trough amplification is limited most of Fri/Sat/Sun will be dry with
    just a few brief passing rain/snow showers. Stronger shortwave
    energy would carve out a more negatively tilted trough and a better
    chance for a wave or two of low pressure to track closer to the
    coast. This would bring a bigger threat for a period or two of rain
    and/or accumulating snow with ptype determined by the exact track.
    Keep in mind this is 4+ days into the future and specific outcomes
    are highly uncertain. While it is far from set it stone, the
    potential for some locations to receive their first measurable
    snowfall exists sometime Friday into the weekend.

  6. Thanks TK. Looks like a decent rain event on the way today/tonight. We need it; been on the dry side lately. Thinking most places get in the 0.75-1.50″ range.

  8. 12Z NAM takes initial wave for Friday off shore, however, it “looks” like there
    may be some shenanigans for Saturday based on looking at the 84 hour surface
    and upper data from that run. 😀 😀

    http://www.instantweathermaps.com/NAM-php/showmap-conusncep.php?run=2017120512&var=PCPPRSTMP_2m&hour=084

    http://www.instantweathermaps.com/NAM-php/showmap-conusncep.php?
    run=2017120512&var=VRTHGTGRD_500mb&hour=084

    http://www.instantweathermaps.com/NAM-php/showmap-conusncep.php?run=2017120512&var=GRDHGT_300mb&hour=084

    http://www.instantweathermaps.com/NAM-php/showmap-conusncep.php?run=2017120512&var=GRDHGT_200mb&hour=084

  9. If the we don’t see snow late week or weekend I am hoping we could get some here.
    Tweet from meteorologist John Homenuk
    The first in a series of potentially substantial winter weather threats for the Northeast may arrive near 12/13-12/14. How meridional is the amplification of the polar shortwave? ECMWF EPS suggest rapid deepening possible off New England coast. #winter

  10. Will see if the Farmers’ Almanac finally gets one. That time period in the tweet they are predicting a snowstorm with significant accumulations.

  11. A track like that image you posted JPDave a track which could give interior areas a good amount of snow. Areas near or at the coast that low close enough to draw in mild air.

    1. And again on Sunday.

      Gfs just doesn’t want to deliver.

      Last night’s Euro was a no Go as well for this weekend. We shall see what the
      12Z runs shows.

  16. 12z GFS has something cooking for Wednesday(12/13) next week. That’s both the GFS and Euro with something in the area for that time frame…details to be ironed out of course. Purely unscientific, but I am feeling a white Christmas this year

    1. I was just out. Spitting here and there. Not all that much at the moment.
      Streets barely wet, but they are wet.

    1. Not impressed. It drops “about” 4 inches across the area, that is all.
      Let’s see how it handles it as it garners more information.

              1. Remember my story. Saturday will be Macs and my 39th anniversary. The actual day as well as the date. It rained all day 39 years ago and then we had a ton of snow with thunder snow in Boston. I am hoping for a memory and an inch qualifies. That is why I keep saying I’m relying on the ANGEL model 🙂

    1. I know it’s splitting hairs, but I consider 10” a moderate storm. Needs to be at least a foot for me to consider it big, and even that’s a stretch.

  24. 18z GFS grazes SE CT, RI and SE MA with an inch or two of snow on Saturday. Close call.

    And it’s got quite the bomb of an ocean storm for next Wednesday….977mb SE of the benchmark and 966mb south of Nova Scotia. Just a bit too far wide right for us but still delivers a few inches to eastern MA.

  25. I don’t judge snowstorms by amount of snow.

    I judge them by timing and impact.

    15″ of powder sometimes is less of an issue than 4 or 5 inches of pure cement falling during the heart of a commute.

    1. I remember a couple winters back getting ocean effect snow that paralyzed marshfield because, when it set in, the temp was tremendously cold and the first wave melted on pavement, then iced up in a sudden temp drop, then was covered with powdery snow from more ocean effect bands. The total snow was less than 2 inches and I think a normal 5 minute ride took over 1 hour.

        1. You make a point I have made before and am glad you reiterate because it’s very important. Many folks focus on snow amounts. Snow amounts are partially irrelevant in many cases.

  26. Well Ace….then I assume you are not in agreement with NOAA’s new Northeast Regional Snowfall Index (RSI) scale:

    https://www.ncdc.noaa.gov/snow-and-ice/rsi/nesis

    A 6-10″ storm is considered a Cat 4 – “Crippling”
    10″ plus is considered Cat 5 – “Extreme”

    LOL. If it’s a powder snow, I can take care of Cat 4 with my leaf blower.

    1. Hahaha, true that! I don’t think the “score” is equivalent to the number of inches of snow, but I could be wrong.

      1. > NESIS scores are a function of the area affected by the snowstorm, the amount of snow, and the number of people living in the path of the storm.

        Not perfect but good enough in this case, I guess.

    3. Oops, I misread it…you guys are right. Those are calculated scores, not snow accumulations. The ranges are similar to snow accumulation ranges given in forecasts so it fooled me.

  28. I wouldn’t give up on next Wednesday’s possible event. Will it happen? Don’t know.
    Could it? Yup. Could it miss and go ots? Yup
    Could it fizzle? Yup

    1. For Natick, slight chance Friday night, slight chance Saturday night, and slight chance of the snow shower variety sometime on Sunday.

        1. Nope. Slight chance. The precip shield from wave 1 and wave 2 both have shots of being far enough west. The Sunday daytime threat of snow showers is from northern stream energy coming along too late to have done anything for the offshore stuff.

  31. Wind is whipping here. I’m hoping my manger scene stands. The ground is not even close to being frozen so stakes may come out easily.

  33. Blue Hill ASOS reporting a peak wind of 54kts so far there. Screaming low level jet… good thing most of it isn’t quite hitting the very lowest levels, but it’s a windy night and will remain so.

  35. New post!

    It’s a bit brief. Heart in a-fib for a few hours but slowing it down with my magic meds and should be all normal soon. 😉

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