Monday September 18 2023 Forecast (7:08AM)

126 Comments

DAYS 1-5 (SEPTEMBER 18-22)

The final 5 days of summer will contain one rainy Monday and 4 nice days. We’ll get the nasty day out of the way first as low pressure tracks just offshore today. This track is a little bit of good news though. Even though we don’t “need” any rain right now, and this looks like a healthy 1 to 2 inch rainfall for most of the region, a band of potentially 2+ inch rainfall will stay south and east of areas that were hit hardest by recent flash flooding. An offshore low track prevents a warm sector from coming onto land in southeastern New England, greatly reducing the threat of damaging wind gusts from thunderstorms, with now only some embedded thunder possible from more elevated convection – not typically the kind that will produce hail and/or wind damage. Also, this system will not carry much wind with it – just a little gusty along the coast / Cape Cod, but not really any damage. Despite that though, we do have to watch for a few vulnerable/weakened trees from recent rain and wind, so I can’t 100% rule out isolated power outages due to any that might succumb. Conditions improve tonight as low pressure pulls away, and then from Tuesday through Friday we’re governed by high pressure with fair weather – cool nights and mild days, with a slight warming trend as the week goes along. Enjoy that!

TODAY: Cloudy. Rain overspreads the region early and continues all day. Heaviest rain and possible embedded thunder, mostly to the east of I-95. Highs 63-70. Wind SE 5-15 MPH, a few higher gusts around the South Coast.

TONIGHT: Cloudy evening with rain ending and patches of fog developing. One more quick shower or thunderstorm may occur mainly near and north of I-90 late evening. Breaking clouds but areas of fog continuing overnight. Lows 55-62. Wind variable to W up to 10 MPH.

TUESDAY: Sun/cloud mix. Highs 67-74. Wind NW 5-15 MPH.

TUESDAY NIGHT: Mostly clear. Lows 50-57. Wind NW up to 10 MPH.

WEDNESDAY: Mostly sunny. Highs 68-75. Wind NW 5-15 MPH.

WEDNESDAY NIGHT: Clear. Ground fog patches low elevations. Lows 47-54, coolest low elevations inland. Wind N under 10 MPH.

THURSDAY: Sunny. Highs 67-74, coolest coast. Wind calm then NE up to 10 MPH.

THURSDAY NIGHT: Mostly clear. Ground fog patches low elevations. Lows 50-57. Wind variable under 10 MPH.

FRIDAY: Mostly sunny. Highs 70-77, coolest coast. Wind variable up to 10 MPH with coastal sea breezes.

DAYS 6-10 (SEPTEMBER 23-27)

Dry weather hangs on into the weekend for the first day of autumn September 23, but we’ll then be vulnerable to the return of cloudiness, higher humidity, and a rainfall threat September 24-26 as one low pressure area approaches and moves in from the south, and a second one arrives from the west on its heels. Dry, cooler weather should end the period as the unsettled weather pushes away.

DAYS 11-15 (SEPTEMBER 28 – OCTOBER 2)

Dry weather for the most part with a return of a zonal flow pattern, but around mid period a disturbance may bring some showers through the region. No big storms or extreme temperatures are indicated.

126 thoughts on “Monday September 18 2023 Forecast (7:08AM)”

  2. This comment will be outdated soon, but as of 7:10 a.m. that area of rotation between Norwich & Mansfield CT is broad, weak, mid level rotation (a little meso low circulation) and not a threat to produce any surface wind damage along the path of that elevated enhanced rainfall.

  6. Definitely more rain from this event than Lee brought at least for me.

    It’ll be nice to experience a few dry days with decent temps and low dew points!

  11. Good morning and thank you TK.

    Let’s get the rain over with so we can enjoy a nice stretch of beautiful September weather!!

      1. The direct impact of Hunga Tonga is clear now.

        Cause and effect.

        We’ve never observed that amount of water vapor put into our atmosphere so suddenly. Well, here you are…

        Even the effects of a warming planet are not as sudden and drastic as that. That is a trend, and slower occurring.

          1. This is an excellent report.

            Hunga Tonga, from a scientific standpoint, is a tremendous benefit for the science.

            1. Tis fascinating for sure.

              I wonder how this will translate to winter and the effect on snowfall???? Would stand to reason that at least some areas would see above average snows.

              Will it be our area?????

          2. When TK mentioned this quite a while ago, I found it fascinating. I did find this great articleI. I took it a step further talked to three meteorologists I respect re Tonga. One actually reached out to another individual whose name I recognized. All acknowledged there would definitely be an impact. All were also concerned climate change deniers would use it to do to use to continue to deny. Of course our climate was changing long before Tonga. One of the folks I spoke with sent me a link to a highly reliable source.

            https://www.livescience.com/planet-earth/climate-change/did-the-tonga-eruption-cause-this-years-extreme-heat

            That said, I asked from a standpoint of temperature increases. I now need to do some reading on flooding.

        1. NIGHT and DAY!!!!
          And I agree, current radar trends SUPPORT the HRRR solution.
          Build your ARK!

          and btw, the HRRR highest totals dangerously close
          to the areas impacted last time with Providence up through N. Attelboro.

    1. Oh no, so sorry to hear that. Best of luck on the job search.

      On the other hand, happy to see you here more often.

  20. Thanks, TK!

    Picking up my brother at Green Airport at 3 pm today. As of now, flight is still “on time.”

    Hope you find something soon, Hadi!

  24. Another sign that the heavy rain may extend closer to HRRR and reg NAM vs 3Km NAM …..

    I believe the current sfc winds kind of portend that the low is coming somewhere into SE Mass and not SE of Cape Cod.

    All of eastern Mass obs have mostly SE winds. I’m guessing that sfc low could be headed over Prov to Boston or maybe a little SE of that, but probably northwest of the Cape Cod Canal.

    Which might put the outer Cape, MV and Nantucket at risk for a strong thunderstorm later on.

  26. https://www.pivotalweather.com/model.php?rh=2023091812&fh=126

    This regular low possibly transitioning to hybrid seems to keep trending a little more impressive with time.

    There was a run or 2 there just before Lee past our latitude where the models hinted at calmer, maybe even somewhat drier times ahead, but then today suddenly came about and now, we’re probably dealing with something next weekend that will have a lot of atmospheric moisture to play with.

  28. Thanks TK.

    A met-to-met question/thought: to me, the prevalence of large scale blocking patterns over the past 8-12 months, not just over one specific area but the Northern Hemisphere as a whole, has been unprecedented in my forecasting experience. You probably have some experience with similar patterns, but would guess you’d agree the past year is up there in terms of the prevalence of them both in frequency and duration.

    Maybe El Nino is playing a role, but I strongly suspect the Tonga eruption continues to outweigh any other short or long term climate influences right now. An increasing balance of research supports this and suggests that there are certain parameters, such as stratospheric water vapor, that are far outside the realm of anything modern society has seen, and that we probably have another year or two before this effect attenuates. Going to be really interesting to watch this coming winter (a “blockier” time of the year to begin with), and what I suspect will be some pretty extreme outcomes in terms of “winners and losers” for winter weather across the Northern Hemisphere….

    2. Thanks WxW. I did send a couple of emails this am asking about Tonga in this area. Your comment is very timely. To me this is fascinating

      1. Great minds think alike!

        It’s worth mentioning too that long term, our greatest climate influence will continue to be manmade climate change and the rapidly shifting baseline of the climate we live in. But history suggests that volcanic eruptions on Tonga’s scale typically take the driver’s seat for at least a couple of years, and I think that’s what’s happening here.

          1. Certainly don’t have a lot of confidence in it. Even in a blocking dominated pattern, some areas are bound to end up “on the fringe” and close to normal, and I would lean towards SNE being in that boat. But if things do go in one of the extreme directions, I’d guess it would be in the stormy/snowy direction…

        2. Oh my. You are kind. I wouldn’t begin to think of my mind close to the level of yours. But this is the type of thing that has always fascinated me. And yes on climate change. I mentioned the concern earlier that deniers will focus on this.

        1. Thanks. Just checked totals in that area and saw most have 1/2 inch. Son said as of now blackstone river behind their house is not threatening.

  37. Not a good situation in my building, once again. My walls – exposed brick – are `leaking’ again, which of course will cause mold and mildew.

    It’s just way too much water and almost no drying taking place in recent months.

    Sure, it will sort of dry out for a few days, but if I was a betting person I’d gamble on us getting heavy rain again as soon this weekend or early next week.

    I don’t trust any of the long-range models. Remember, just a few days ago GFS was saying for Boston <0.5 inch of rain over a 380 hour time span.

  39. I am quite concerned what may happen rain wise the next 2-4 hrs rain wise in interior southeast Mass

    I say this because on that Obs page SAK gave us a link to previously, you can see a healthy inflow of SE winds over all of the Cape and the islands almost up to Marshfield. This boundary extends west out to Fall River and New Bedford

    So, tons of moisture adverting right into this next rain band.

  40. WxW…

    In order to avoid making you scroll all the way back I am replying to you here. I agree with the thoughts you laid out above. I think a lot of what we are seeing right now is tied to that eruption. There are a lot of questions to be answered and I think some of them are in the process of being answered and will continue to be for another year or two, maybe even a little beyond that. We don’t have a precedent in modern science to compare to so we’re making a best guess that it’s a couple of years but who’s to say it won’t be three or four…or?

    I don’t think it will extend that far out but still it’ll be interesting to observe any other effects that we have not seen yet, that said I think we’ve probably seen the most extreme and it kind of holds steady and then gradually subsides. It is going to be interesting to see what it does to the northern hemisphere winter. And I will be taking that into account when I formulate my winter forecast.

    As always thank you for checking in!

    1. Those yellow areas in central New England.

      I think that’s the stuff percolating around Long Island.

      It’s almost like the development of a comma head during a warm season storm.

      So, central Mass may still have another round of heavy precip to go.

  43. https://radar.weather.gov/station/KOKX/standard

    Right now, New Bedford, sandwich and Plymouth in the zone of heaviest rain.

    Unfortunately, they’re more and it’s further west, so in an hour or 2, probably providence and maybe Worcester for another round of soaking rain.

    And then the stuff in Long Island, might be aimed at the rte 2 area.

    Interesting next 3-4 hrs.

  44. Well it now looks to me as if the main rain area is moving off shore and we are left with a period of lighter rain incapable
    of reaching the projected totals.

    1. Logan is at 0.67 and unless something else develops
      they won’t even see 1 inch. TK’s projected .25-1 inch ffrom the other day might be spot on 🙂

    2. There is still the ability to generate additional moderate rain with pockets of heavier in the I-95 belt through about 7PM, followed by a lull.

      A pseudo comma-head should swing through later on, toward midnight, and may be focused a bit further NW, and may have thunder embedded. But I do think even though it may pour under the heaviest band in it, it will move quickly enough not to cause any real issues.

  45. more rain bubbling up this way. oh well Let’s see what the final total is. Now looks to pass 1 inch nut I don’t think it makes it to 2. We shall see.

  48. Drenching rains in Boston. Not as much rain as in some parts of the state, but it’s a lot of precipitation nonetheless. I’ll reiterate, I’ve never seen so many prolific rain producers over a 100 day stretch in my lifetime. And I’ve lived in some rainy places.

    1. And we could very well have another prolific rain producer within 5 days or so. I’ve followed the forecasts on TV and online carefully this summer and what starts out as showers in the mid to long range inevitably turns out to be a lot more than that. I hope we just have passing showers Sunday and Monday, but I think the only passing shower we’ve had this summer was ironically when Hurricane Lee sat off shore and tickled the area.

    2. I was following it, too. The fact that so many people thought it went to Cuba was both hilarious and sad. Sad because social media nowadays tends to breed misinformation.

  51. Yesterday, the ECMWF brought the rain right in on Saturday night into Sunday and the GFS kept the system to the south.

    Today, the two models have completely reversed. haha!

        1. 1.37 thankfully! We had somewhat of a Charlie hole today, which I am not complaining about. Yellows and orange returns we’re heading here and then all of a sudden it was like they hit kryptonite!

  53. Figuring out the rain total at Logan today is like deriving an equation in meteorology.

    They have a 6 hr total I think around 8.

    They have 3 hr totals at 5pm and 11am and I feel like they missed in their multi hour totals, what fell from 11am to 2pm. The individual hr Obs are there from 11am to 2pm, but it feels like a 2pm (6hr) total would have made life easier.

    Anyhow, I had a total and forgot it, but maybe something slightly above 1.20 inches ?????

      1. Yes, thanks Vicki, that’s exactly what I am looking at 🙂

        That 0.50 at 7:54pm is a half inch btwn 2 and 8 pm.

        I just wish at 1:54pm, they would have had another 6 hr total which would have been what fell btwn 8am and 2pm. But I think it’s missing.

        And then, had they had it, they have the 6 hr total at 8am which captured the start of the rain, so we could have just added those 3 numbers.

        But without that 6 hr total at 2pm, I found the middle part confusing 🙂 🙂 🙂

  54. Amesbury has had approximately 35 inches of rain since June 1. As of last Tuesday, we had had the 3rd most rain out of all Massachusetts communities since June 1, at 29.21 inches. And we had torrential downpours last Wednesday and a lot more rain today. Only Conway and Andover had received more.

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