Saturday Forecast

54 Comments

7:55AM

DAYS 1-5 (SEPTEMBER 17-21)…
High pressure offshore to the east of the region today will send a southerly air flow into the region allowing it to warm up and become slightly more humid. The humidity will become more noticeable later tonight and Sunday as a cold front approaches, bringing lots of clouds and then risk of isolated showers at first. A general area of showers and possible thunderstorms may stay well to the west and northwest of Boston for much of the day then run out of fuel as the front finally comes through the Boston/Providence areas. The front doesn’t get too far southeast after that and allows additional moisture to come up through the region into Monday. The question is whether or not beneficial rain occurs during this time. Much of that may end up staying offshore to the southeast, but the jury is still out on this. High pressure takes over the weather again for the final two days of astronomical summer on September 20-21, with the warmest day being Tuesday followed by some cooling on Wednesday after a cold font goes through with little or no fanfare.
TODAY: Sunshine, filtered at times by high clouds. Highs 70-77. Wind light SE.
TONIGHT: Increasing clouds. Lows 54-60. Wind light SE to S.
SUNDAY: Mainly cloudy. Episodes of rain showers possible but may favor areas well west and northwest of Boston during the day. Increased chance of more widespread showers at night. More humid. Highs 68-75. Wind S to SW 10-20 MPH.
MONDAY: Mostly cloudy. Showers likely, and heaviest may be near Cape Cod and the Islands. Lows 60-68. Highs 70-78.
TUESDAY: Mostly sunny. Lows 60-68. Highs 77-85.
WEDNESDAY: Mostly sunny. Lows 50-58. Highs 65-73.

DAYS 6-10 (SEPTEMBER 22-26)…
Timing of systems is a little uncertain during this period but the best call for now is a quick warm-up on September 22, a dry cold front early on September 23 with a cooler day as high pressure tries to move in but stays mostly to the north, then the previous front being an avenue for some cloudiness and perhaps a touch of light rain about September 24 or early September 25 before being pushed back to the south by high pressure and fair weather to end the period.

DAYS 11-15 (SEPTEMBER 27-OCTOBER 1)…
1 or 2 rain chances during this period but the overall pattern will still be fairly mild to warm compared to normal.

54 thoughts on “Saturday Forecast”

  2. Good morning and thank you TK.

    Let’s see how much rain we can generate.

    Much model divergence, so who knows.

    I know you’re pretty much in camp GFS with this one.

    1. I don’t see any reason not to be. Here are my reasons which are a mix of science (1-3) and non-science (4)…

      1) As SAK and I have both said in one way or another, PERSISTENCE. You are more likely to be correct on the vast majority of systems by forecasting less rainfall while you are in the midst of a drought. Yes eventually if you do this every time you’ll be wrong. It’s going to happen anyway. And if the result of an event that was forecast incorrectly is beneficial rain, great!

      2) Extremely dry land areas diminish and sometimes destroy precipitation areas. These systems that come through are not solid entities, but “zones” of air that include lift, condensation, and precipitation. It’s an ongoing process, and some of what they pull from is moisture that’s already on the ground, not just in the air. Once you limit this, and then build on it, the process builds on itself until an event or series of events can overcome this influence. That often takes quite a bit of time (hence “persistence” being a good method).

      3) The GFS has outperformed most guidance on systems such as this recently. And I often say “past performance doesn’t guarantee future results” but it does not necessarily mean that it won’t matter at all if there are some similarities in the system and the overall pattern. This must be taken into account.

      4) I’ve heard more than on Boston TV meteorologist say things like this paraphrase: “I know we’re in a drought, but this looks promising.” They have said such things before, every time based on a couple models that were forecasting larger precipitation numbers. That is not science. It’s wishful guessing.

      1. Thank you for the thoughtful and concise explanation.
        And it makes perfect sense.

        While we are at it, what do you make of the 6Z GFS uptick in
        rainfall? Let’s hope that the 12Z stays with that theme. 😀

        1. Well, not a huge uptick. I see this as the potential rainfall but most areas will come under the top #’s from the model.

    2. re: Model divergence
      I take that back. I hadn’t looked at the latest. I was going by the 0Z runs
      I looked at late last night.

      With the latest runs, the NAMS and GFS are quite similar with actually now
      the GFS showing more rain. These models generally about 1/2 inch
      to 3/4 inch with the GFS the higher. CMS is a couple of tenths is all.
      The Euro is “about” the same as the GFS.

      So some rain to be sure. Drought buster? NOPE. All of this promise for up to 3 inches of rain. HA HA HA. TK warned us.

      Still, I’ll take 3/4 inch. That would be nice.

      Still room for change.

      Now I will check in on TM (tornado man at the NWS) and see if he is still
      barking.

      Hmmm still there but tempered to “Rotating Updrafts” and the actual word
      tornado is not mentioned:

      Thus, heavy downpours are possible. In
      addition, cannot rule out isolated strong to severe thunderstorms
      during mid to late afternoon. Model consensus suggests 0 to 6 km
      shear may be at least 30 or 35 knots. There is low level shear,
      including some helicity, as well. The low level speed/directional
      shear and low lifting condensation levels set the stage for isolated
      storms to possibly have rotating updraft columns Sunday late
      afternoon into the evening, especially across the western half of
      the area.

    1. Overdone. It is most of the time. If you call for it every time, eventually you’ll get one right (happened recently).

      1. Right the Concord one.

        Why do they keep doing that? I just don’t get it.

        My wife thinks the person responsible has Asperger’s. 😀

        1. 😀

          I’m not sure. The truth is the conditions that make them mention tornadoes happen more often than people realize, but most times nothing major results from it.

          Now people are under the impression that we suddenly have more tornado threats than we’ve ever had. That is simply NOT TRUE.

          1. Interesting. So then there are tornado 2 types of tornado threats:

            1. The type mentioned all of the time by the Taunton Office.
            2. The Real threats like when the SPC issues a tornado watch.

            I know which one means something to me. 😀

            1. It’s interesting, because on one hand they are right many times in mentioning the conditions, since they do occur more frequently than folks realize. But given the percentage of time these conditions actually lead to something, your false alarm rate is going to be massive if you mention if every time. But what if the one time…. you know how it goes. They have chosen the hit it every time route.

              1. That is exCtly where I am coming from. As an average Joe-ette, I’d rather know and plan accordingly. I think most are smart enough to get that and I hate dumbing it down for the person who will complain no matter which way you choose.

                I fully understand why you are all skeptical because you KNOW. I have this blog which is an advantage. Too many do not have that advantage.,..silly them 🙂

                1. Silly them, indeed. Best weather info on the Planet, hosted by the best Met on the planet. A win-win situation. Spread the word. 😀

        2. I do not agree but then you know that since I disagreed when there was discussion prior to Concord. We have had several storms this summer where rotation was discussed. There may ….may…have been just one tornado but there has been straight line wind and macroburst damage. If people are prepared for a tornado, then they are prepared for something that can be darn near as damaging. If there is any chance at all, I’d rather be aware of the worst case and hope for the best. I have not heard anyone complain about tornado warnings going unfulfilled and, in my opinion only, people will remember concord.

          Just an opinion from a person who is looking at it from a layman’s perspective.

          1. I understand, however, I am completely in camp
            TK on this one.

            I look at it as the “boy who cried wolf”.

            Whenever I tell my wife that the NWS has mentioned tornadoes, she laughs her face off.
            Her come back to me is: I’ll believe it IF
            Eric says so. 😀

            Frankly, I am getting tired of their constant mention of shear, helicity and spin ups.

            But that is just I, an old jaded curmudgeon.

  5. According to Barry, no more 90s expected. AFAIC 22 is 22 too many. 😉

    It wouldn’t surprise me though if a couple more “89’s” aren’t in our future at some point.

      1. I would not rule out another 90. I have seen it come awfully close
        in October, so it is certainly possible. 😀

        1. Just like you don’t rule snow out until April’s essentially over, you don’t rule out a 90 until you get by about the first week of October.

          RARE: Extremely.
          IMPOSSIBLE: Not at all.

  7. So during the last week we have seen the Patriots, without Brady and Gronk, beat a respectable Arizona on the road, and we have seen the Sox, WITH Buchholz and Farrell, beat the Yankees.

    I figured Taunton would have a better chance of verifying their spin ups but now I’m not so sure…

  13. Models cranking out less and less precipitation overall.
    Gee. What a SURPRISE!

    The GFS has developed an old familiar error of generating excessive precipitation right along the eastern MA coast into the nearby offshore waters. This is the 4th or 5th system this error has shown itself. I really wish I knew why it does that. It usually shows up inside 48 hours for these types of systems.

      1. There may be a few areas that get around an inch or so, but that will be a big exception. I think just about the entire region comes in well under 1 inch and many areas under 1/2 inch.

  14. John and all. when do we aerate and seed? My thought is to wait and hope that we have consistently cooler weather so the seed needs less water. Although my fear is we will aerate and seed and they will post an all out water ban. Except it that happens we’d lose the seed anyway

    Can you tell I’m arguing with myself ? 😉

  15. Now is the time to work on your yard Vicki . I did a small backyard
    Today 1 yd of quality loom scattered about for bare spots and Scott’s seed.
    I raked it nice first. The fall is the best time for lawn repairs . Hope that helps
    Vickie and again I wouldn’t wait.

    1. Thanks John. We will have to wait 2 weeks but I suspect we will do it then. We just need to do front yard. Back will hopefully bounce back in spring

    2. I would love to do my yard but unfortunately my town is still under a strict water ban until at least Oct 1st and probably later if the drought continues into the fall.

      1. I’m debating for that reason, Ace. It seems wrong even though we do not have a full ban. But if we do it we will have to water every day and that is against ban.

        SIL said Ashland is now going to buy water from MWRA. I wonder how many towns MWRA csn support

  16. Some sort of pipe bomb explosion in Chelsea section of manhattan. 25 may be injured but im hearing not severe. This after an IED in NJ today

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