Wednesday Forecast

96 Comments

8:26AM

DAYS 1-5 (FEBRUARY 14-18)
High pressure moves offshore today and temperatures moderate. A warm front will bring a period of rain to the region late tonight into early Thursday and lead even warmer weather into the region for Thursday. The degree of warmth will be somewhat dependent on how much sun breaks out during the day. For now, leaning toward more dominant cloudiness and temperatures remaining under 60. The last time Boston hit 60 or greater was January 13 when it hit 61, which is also the record high temperature for Thursday set back in 1939. I think that record will stand. Cold front will come through early Friday preceded by a period of rain showers. A second cold front will come through Thursday evening, and may be accompanied by a rain or snow shower, but more notably will usher in a cold air mass for Saturday. This will set the stage for a chance of snow except snow or rain South Coast as a wave of low pressure passes just south of the region Saturday night and early Sunday. Although the details are still being worked out, this system has the potential to bring a light to moderate snowfall to at least a portion of the region during the middle of the weekend before conditions improve and temperatures moderate just behind the system.
Forecast details…
TODAY: Mostly cloudy through mid morning, then clearing. Highs 45-52. Wind S to SW up to 10 MPH.
TONIGHT: Mostly clear evening, then increasing cloudiness. Lows 32-38. Wind SW under 10 MPH.
THURSDAY: Mostly cloudy to partly sunny. Chance of rain showers early. Highs 53-59. Wind SW 5-15 MPH.
THURSDAY NIGHT: Mostly cloudy. Rain showers likely late evening on. Lows 43-49. Wind SW 5-15 MPH.
FRIDAY: Mostly cloudy with rain showers early, then sun and passing clouds. A brief rain or snow shower possible at night. Highs 45-52 morning, then cooling through the 40s. Wind SW 5-15 MPH shifting to W and increasing to 10-20 MPH with higher gusts.
SATURDAY: Sun and high clouds day. Cloudy with a chance of snow at night. Lows from the middle 10s to lower 20s. Highs in the 30s.
SUNDAY: Cloudy with a chance of snow early, then clearing and breezy. Lows in the 20s. Highs from the upper 30s to lower 40s.

DAYS 6-10 (FEBRUARY 19-23)
After the brief winter interlude of early to mid weekend the Presidents Day holiday on Monday will be milder but with a late-day rain risk. Tuesday-Thursday February 20-22 a frontal boundary will be nearby, dividing very mild air induced by a ridge of high pressure over the southeastern US from colder air banked across Canada. The position of the boundary will determine the details, so for now calling for the mild air to win at first, then the colder air, with episodes of unsettled weather. Drier/colder by the end of the period if things trend the way they are expected to.

DAYS 11-15 (FEBRUARY 24-28)
The trend looks a little colder but there will still be somewhat of a battled between cold north and mild south. Additional unsettled weather including the possible threat of a winter weather event during the final days of the month.

96 thoughts on “Wednesday Forecast”

  2. Waiting on 12z runs for comparison for Weekend event/non-event. We shall see.
    I find this stuff totally fascinating!!!

    1. Puzzle pieces are still pretty far out there so we’re just seeing the usual. I don’t have a strong feeling in either direction. It’s pretty much impossible at this point.

  6. Thanks TK. I see signal that end of month into early March will be interesting.

    1/2 or euro ensembles have a snow storm and 1/2 don’t.

  7. Thanks TK!

    Recall what I said yesterday concerning the weekend system. The synoptic pattern is heavily against a snow event. Possible not probable. At this time, a suppressed solution looks more likely, but a wide range of outcomes remain on the table, only a narrow window of which would result in widespread accumulating snowfall.

    1. That may be true, but this is New England, so we wait to see. 😀

      At this point, I could care either way.

    2. Correct. What will be favorable is the amount of cold air at 850. What will also be favorable is the amount of moisture available to tap just south of and right to SNE. What is uncertain is how amplified the wave becomes. All in the short-wave.

      These things coming along in a pattern that looks highly unfavorable can almost sneak in undetected. However, our ability to see them, or at least their possibility, is much better now than it once was.

      Let’s set up a hypothetical scenario in which SNE gets a moderate snowfall Saturday night. If this was 1985, it would probably have been almost a complete surprise. Now we know it’s at least of the solutions on the table.

      1. TK,

        A while back you said something about a snow possibility
        that the models would not see right away. In light of your above post, is this weekend’s situation EXACTLY what you meant??

        Pretty cool.

        IF Boston is to reach average or close to average snow this season, it just “may” need this event to do so. In that regard,
        I am highly rooting for it.

        1. Yes this was the type of event I was referring to and the Feb 16-19 window has been on my radar for such a possibility for some time.

          WxW is correct in noting the pattern sucks “overall” but all we need is a tiny amount of amplification and that thing comes right in here. It’s still fast-moving, and not “big”, but this type of system can drop a few to several inches of snow with not a lot of effort.

          1. Thanks TK. Thought so.

            12Z NAM, although not quite in range and certainly not in its wheelhouse, “appears” to show
            just enough amplification to get the good stuff in here. Still possible the bulk of it just barely slides South.

            https://www.tropicaltidbits.com/analysis/models/nam/2018021412/nam_mslp_pcpn_frzn_us_28.png

            https://www.tropicaltidbits.com/analysis/models/nam/2018021412/nam_z500_vort_us_29.png

            https://www.tropicaltidbits.com/analysis/models/nam/2018021412/nam_uv250_us_29.png

  11. The expected clear-out of the warm-advection clouds is ongoing, but an inversion has stratocumulus locked in over NY, VT, NH, flirting with the MA border. Will keep an eye on that but it should erode with time.

  12. TK – Did a similar setup occur in 1985 or was that just a random year in the past off the top of your head as a general analogy?

    1. I think he simply means that the models and other data available to the mets
      was not good enough to clue them into the set up. With this weekend’s
      “possible” situation, the data was good enough to clue them in.

    2. It was random. We only had 1 snowstorm of note in the 1984-1985 winter in southern New England. About 4 to 8 inches fell and the last 2 or 3 inches fell from a clear sky. 😉

    2. Thanks Mark. Looks like the jury is still out.

      Wonder what the good ole euro thinks of the 12Z packet of data???
      We shall see shortly.

      1. I suspect based on where the initial players are, ECMWF will look similar to or slightly wetter than last run.

  16. You snow hounds crack me up. Wont give the CMC the time of day. Junk model, sucks, yada yada. Unless of course it shows some snow. 😉

    ICON?? really?

    Nickel and dime events the rest of the way maybe. Logan will be lucky to see another 10 inches. After this thing on Saturday, nothing after that till March. Then you got maybe 3-4 weeks and climo says its east wind, backdoor freeze your butt off April.

    Come on, embrace the dark side, call it a ratter and move on to spring. 🙂 🙂

      1. Why? Oh yea, the vast majority just hate 75 and sunny. Much rather have a foot of snow, zero degrees, and icy wind that will rip your face off.

        This blog is mostly winter “enthusiasts”. Just bringing a little balance, and busting Mark’s chops. He knows that.

        1. I know, and I was just joking also. There are very few winter lovers out there. I personally don’t love it but just enjoy that we get to experience the changing weather in New England. I am one of those crazy people that enjoy change. 🙂

        2. I hope you feel better soon, Blackstone.

          As far as winter enthusiasts, there are many on here – myself included – who truly enjoy all weather. Perhaps it would help if you understand it is as much the event – any event – that catches the attention of weather enthusiasts….summer, winter, spring, fall…..doesn’t matter. It is the event.

          If you want to point me in the direction of anyone who hates sunny and 75, I’ll be happy to bust their chops for you.

            1. I have always loved Winter ever since I could walk.

              Skating
              Sledding
              Ice Hockey
              Ice Fishing
              Snow Forts and snow ball fights
              No School days
              Don Kent
              Diving into snow banks head first
              Walks in snow storms
              and on and on and on…..

              Roll with the seasons. Take it all in and ENJOY! Life is too short.

  17. Snowdrops starting to pop up in my backyard. A sure sign of spring. 🙂

    Crocuses should follow in another couple weeks.

    1. Cool. I have to check my yard. Although I have no idea what snowdrops are. I don’t think we have ever had them.

  20. 12z Euro is also on board for a decent snow event this weekend. Look at the differences between the 0z and 12z runs though. Has the atmosphere really changed that much in 12 hours? Of course not. Neither of those runs are more credible than the other.

    How would I be playing this from a public forecast perspective? Well, we’re still far enough out that you can get away with a simple “chance of snow” without any worry of needing numbers. Can definitely mention the high uncertainty as well. NWS is using likely POPs for most of the region, which I would not feel comfortable with outside of the South Coast, Cape/Islands at this point. I would be saying 40-50% chance of snow most places except 60-70% chance of rain or snow at the South Coast/Cape and Islands. My *non-model based* analysis tells me, in such a flat, progressive pattern, that a suppressed wave is more likely. I could be wrong, but at this stage I place more weight on my thoughts versus the rapidly changing models. If we get into tomorrow evening and the models start locking in on a snowier solution, then I would have to start giving them more weight.

    1. Think more snow than not. I think the flow will amplify just enough to bring
      a moderate snow event to SNE. Of course, around here anything can happen.

      The flow is certainly somewhat flat, but there is a bit of amplification, just enough to do the job. We shall see. It’s Wednesday and we are looking
      at overnight Saturday into Sunday AM 3 1/2 to 4 days out. Getting into
      decent range.

      I look forward to watching this play out. 😀

  21. I know that it may or may not happen–but if a moderate event happens, what’s the timing look like–i.e. am I likely to run into problems with a 7:30 am flight? I rarely fly–what kind of snow does it take to delay flights?

    1. Snow looks to start around 1 AMish and should be going decently around 7 AM and winding down around 4-6 PM in Eastern Sections.

      It being only a “moderate” event as it looks now, your flight “should” not be impacted too much. I imagine there “could” possibly be a bit of a delay, but in my wildest imagination I wouldn’t think so. I have seen Logan remain open
      in major snowstorms.

      Your biggest problem might be getting there. Just allow enough time (The time and day of week is in your favor) and you should be fine.

      Best of luck.

      I am sure TK will zero in on this for you as we get closer.

      1. I don’t think it’ll be snowing much past 7AM either way. That looks to be the shutdown time on all the models.

        1. 100% agree. ECMWF is a tidy 8 hour type event with 1/3 of an inch of liquid west 1/2 inch central and 3/4 inch south. Done most everywhere by 8am. Of course what do we know about the ECMWF in this range? Never believe the liquid amounts…

          As for pattern change, I believe it should happen, but believe it will be a bit later than progged. Please don’t assume that if it happens that it means lots of snow. But people will prognosticate just that…

          1. Also as warning watch out for modeled generated snow maps with this system. This type of system is a Kuchera method nightmare. Has many elements of a spring system.

          2. I think that pattern change would put us on the cooler side of normal more confidently than into a snowy end-of-winter regime. I’d figure 1 or 2 “duration” events of not necessarily all-snow, and a lower chance of getting a larger event in there. But there is not enough evidence to say “hey, we’re going cold and stormy for the winter finale!” … I also agree about the later versus sooner. I think it tease a couple times end of month and early March, peaks (if it’s going there) more in the March 8-15 time frame, then lets go.

      2. I don’t think it’s going to snow from Saturday night till Sunday night . Last I heard Sunday is going to be warm

    2. 7:30 Sunday? If the Euro were to verify, could be a little dicey with snow likely wrapping up near then. Even in a worse case scenario with this though, they’ll certainly be moving planes in and out for the duration. I wouldn’t worry too much at this stage. Plus, there shouldn’t be much of a “backlog” of flights given the overnight timing.

  22. I think support is growing for an end of month pattern change. AO crashing hard, and the NAO will start to head down as well. The SE Ridge is going to take a vacation. GFS/GEFS may be rushing things a little as per its usual bias, but the changes should come. Colder? Probably so overall, though doesn’t look bitterly cold. Snowier? Possible, but not necessarily. The PNA could be the new sticking point as it looks to remain negative. Much remains to be seen on how it plays out.

    2. They can vacation late February and all of March, but must behave so I can experience mild spring weather in the Outer Banks during April Vacation.

  23. I am strange, I know that, I love Summer weather, hitting the beach and pool, swimming/sand castles/skimboarding/hiking/biking with 80s and 90 degree temperatures with a few 70s mixed in. I also love winter with the large winter storms, skiing, sleeding and hot cider.
    Like fall because of the excitement for ski season and use to be marching band season before I stopped. Apple picking/corn. Smelling those concord grape smell all over town.

    spring is ok, as I can start biking but disappointed with ski season ending, (especially this year as i have only gone out once so far) Spring is also hell for those of us with allergies.

  24. It’s early Thursday AM in Oymyakon, Sakha Republic, Russia … the coldest city in the world. The temp is -22 F, but it will get up to a balmy -9 F before the day is out.

  25. Regarding the weekend system, from what I am seeing tracing back the northern stream energy that would be responsible for “amplifying” this storm, it is still over a remote sampling area in the arctic and wont come on shore into Alaska/Western Canada until tomorrow AM. If we are seeing continued support for this in the models tomorrow AM, I think we can lock it in.

    The strength and timing of that northern stream energy is what really amplifies the storm and creates a stronger/closer system vs. the flatter/weaker solution. But even the latter could deliver a lighter accumulating snowfall region-wide.

  26. Regarding Blackstone’s earlier post, I have been following the CMC and ICON models the past several weeks and they haven’t been half bad. Certainly no worse than the GFS and Euro in the mid to long range. They have all been confused beyond 5 days quite frankly.

    But I do find it intriguing that these 2 models have been extremely consistent showing a decent hit with this snowstorm for the past 2-3 days while the Euro and GFS have been late to catch on and more inconsistent. If it verifies, perhaps they should be giving them more weight in a similar setup next time.

    1. Perhaps, but then there is that old saying: “Even a blind squirrel finds an acorn every once in a while” I think there are some verification sites that graph
      the accuracy of each model. I do not believe the CMC (don’t know about ICON)
      fares all that well compared to the Euro and GFS.

      Not sure I can find that site, but I have seen it before.

      1. I am not talking about historical verification over an extended period of time, more just recently over the past several weeks. Perhaps I am wrong. And the ICON is new I believe, so not much history to go by there.

        1. Mark, ok fair enough.

          I have an open mind. IF this event happens
          on Saturday night, then one of 2 things happened:

          1. The CMC and ICON have improved
          2. The CMC and ICON got lucky

          Whether or not they are considered good or inferior, I look at them none-the-less. I always like to see
          a “What if”.

  27. Blackstone you can give us our one day of snow as the 12z Euro maintains the all out torch for next week Tuesday – Thursday. 60’s up into Quebec. You can just let the white sh!t melt and then breakout your flip flops by Tuesday. Everybody wins!

  28. If it does snow this weekend enjoy it snow lovers as I will be away. Hopefully there will be one more snow event that I will be here for before winter is over.

  30. Hmmm

    The 18Z NAM looks to be just a tad juicy, no? Also looks to keep the brunt
    of the snow “just” South of our area, but room for adjustments.

    https://www.tropicaltidbits.com/analysis/models/nam/2018021418/nam_mslp_pcpn_frzn_us_28.png

    http://www.instantweathermaps.com/NAM-php/conusncep.php?run=2018021418&var=PCPPRSTMP_2m&hour=084

    500 mb

    https://www.tropicaltidbits.com/analysis/models/nam/2018021418/nam_z500_vort_us_29.png

    https://www.tropicaltidbits.com/analysis/models/nam/2018021418/nam_uv250_us_29.png

    Certainly shows some amplification. Enough to bring heavier snow in here?
    I dunno. Close that’s for sure. Can’t wait for the 0z run.

    3. Awesome. (Even though I’m going to be in Florida for business next week where it’ll probably be in the 80’s – yay me!)

  38. From Bernie:

    Anyone notice the 18z gfs?Not that I believe it 100% but it does illustrate my point pertaining to SW energy as 1 of the main keys. If the SW energy weaker/slower (doesn’t run ahead of N energy) there will be a very flat wave with little or no snow. Latest periscope explains

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