Saturday Forecast

65 Comments

10:30AM

DAYS 1-5 (SEPTEMBER 1-5)
Labor Day Weekend! The “unofficial” final weekend of summer, but we end summer in so many different ways and places I suppose this is really just Labor Day Weekend and you can label it anything you like. But one thing we can say is that the weather will be quite decent for outdoor activity, although as we get into tomorrow and Monday the heat and humidity will be on the increase after a rather comfortable start to the weekend today. This is accomplished as high pressure, which has been centered to the north of New England, sinks to the southeast and turns winds from easterly to southerly during the course of the next 3 days. A surface boundary that brought the cooler air in after recent heat will be returning as a warm front during Sunday, which will be a cloudier day to start with but will also turn out at least partly sunny. By Monday will be fully in a south to southwest flow of hot/humid air, though heat will not be as intense as the recent spell we had. Upper level high pressure again will be in full control of the weather as we get beyond the holiday weekend into the middle of next week. A surface boundary coming through later Tuesday may trigger a few showers and thunderstorms in the area and a wind shift to the northeast will take the edge off the heat by Wednesday. Forecast details…
TODAY: Sun/cloud mix. Highs 68-76, coolest coast. Wind E 5-15 MPH.
TONIGHT: Mostly cloudy. Lows 60-67. Wind light SE.
SUNDAY: Mostly cloudy to partly sunny. More humid. Highs 72-78 South Coast, 78-84 elsewhere. Wind S 5-15 MPH.
SUNDAY NIGHT: Partly cloudy. Patchy fog. Humid. Lows 64-70. Wind S to SW up to 10 MPH.
MONDAY – LABOR DAY: Partly cloudy. Humid. Highs 78-85 South Coast, 86-93 elsewhere. Wind S to SW 5-15 MPH.
TUESDAY: Partly cloudy. Chance of a late day or nighttime shower or thunderstorm. Humid. Lows from the upper 60s to lower 70s. Highs from the lower to middle 80s South Coast, upper 80s to middle 90s elsewhere.
WEDNESDAY: Partly cloudy. Less humid. Lows in the 60s. Highs in the 80s.

DAYS 6-10 (SEPTEMBER 6-10)
Winds turn southerly again as surface high pressure slips off to the southeast September 6 (familiar pattern recently) and the heat comes back along with some humidity. Another boundary moves through on September 7 which will trend cooler with clouds and occasional showers. High pressure to the north during the September 8-9 weekend should keep it cooler but it’s unclear yet on whether the boundary that had come through will be far enough south to allow fair weather or it slides back to the north somewhat and brings unsettled weather. Too far away for certainty but leaning toward a split decision dry start wet finish for that weekend and it may remain unsettled into September 10. Low confidence on this particular forecast period.

DAYS 11-15 (SEPTEMBER 11-15)
As we get into the middle of September, though the daily details are impossible to nail down beyond 10 days away, the large scale pattern is one we’ll have to pay close attention to. It does look like the subtropical high pressure ridge that’s been largely in control of the pattern lately will continue to be in control. What happens here will be determined by surface features, warm to hot/humid when a surface boundary is to our north, and cooler when it slips to the south and high pressure moves across eastern Canada. The other thing we will need to pay attention to is the tropics, which are becoming more active as we head toward and through the climate peak of the season. The weather pattern has not favored many systems this season so far, but this has shifted to allow more activity. I don’t foresee a threat to New England during this period at this time, however past history says the weather pattern upcoming is one you don’t let your guard down either.

65 thoughts on “Saturday Forecast”

  3. I would say that it is in all likelihood that the hottest September on record will be in the books. I daresay October as well, much above normal temps if nothing else.

  4. As much as we probably need some rain, I hope the tropical activity stays away. SNE is going to be in the crosshairs with this awful, relentless pattern.

    1. We’ll be more likely to see a series of pronounced cool shots when the ridge retrogrades. It comes back east again for the early part of October. September probably warm first half, up/down second half. October, perhaps similar.

      The BIG question, starting in October, is what kind of El Nino. Modoki or no Modoki?

        1. Not necessarily. Either one can be, or not be. This is what I mean when I say that you have to take ALL major aspects of the pattern into account before just making a forecast decision because there is an “El Nino”. In the research I have done, Modoki El Nino years have been more often colder than milder, and about 50/50 in terms of snowfall. Some of our driest, least snowy winters were Modoki, and some of our snowier ones were also. So there are other factors.

  10. some of the teloconnections that we should keep our eyes on as we go through the start of fall. Just for fun.
    ENSO: Neutral as of right now.
    PDO -0.23 trending towards 0 , as of the last available data I have.(july 2018)
    QBO is at — 29.10 as of the last available data ( July 2018) tends to mean weakened PV. Last time we saw it this low during this time of year/early fall was 2012, last time we saw close to these readings I believe was 2015 January through March. I find it fun to looking at all of these pieces of the larger puzzle.
    http://www.frontierweather.com/WinterClimateDrivers.pdf

              1. Nice enjoy SSK. 16 years for my wife and I on the 14 and 23 as a couple. My youngest celebrates a birthday the day after.

                3. Wow pretty close numbers there . We went in Boston two years ago top hotel , dinner etc & we decided to do it again. We will be spending some time in the North End during the day

  12. I’m sorry. I was busy all morning and then jumped back in without realizing you’d updated the blog, TK.

    Thank you for this update and for all you do.

  13. CFS 12z …
    Warm regime overall into mid September.
    Up and down period with 3 significant but brief cool shots Sep 18-Oct 2 window.
    Warm regime returns after that in early October.
    I see this as a valid and rough GUIDE only, not a gospel reading.

    1. I like the autumnal battle btwn warm and cool, that I don’t feel occurs in the spring, when cool dominates.

      In this pattern in a few weeks, it could be 85F on a warm day and 2 nights later, under clear, calm, cool conditions, it can be down to like 38F.

      1. I always want the cool to dominate, even in the summer. The sun strength should take the edge off any anomolous Canadian airmass. Of course 2009 was a bit extreme.

  14. I don’t wanna short-change the blog and use too much of yesterday’s entry so since I’m about to be on the road for a while I will update this during the 10AM hour today. 🙂

      1. The ladder one is the one I have my eye on as it’s least likely to experience shearing westerlies or to curve out harmlessly over the Atlantic.

  16. Starting to look like we may get a somewhat sneaky cool/unsettled interlude in this pattern next weekend, Friday-Sunday. TK pretty much nails it in his 6-10 day; there’s a boundary slipping through and we’ll likely end up to the north of it, likely leading to around three cooler days and perhaps some rainy periods as well. Still kind of a low confidence period though. I’m just getting the feeling that it could be one of those times when the upper level pattern looks like it supports continued warm/pleasant weather but the lower levels may not cooperate.

    1. According to Barry, next weekend is sunny, cool and dry. Hope that wet scenario doesn’t materialize instead.

    2. A lot of times those show up on the model then the result is everything is further south and we end up drier/cool. I’m kind of hoping for that solution to verify but I’m not taking out the chance of unsettled weather this soon. 🙂

  18. I’ve returned from morning errands. Gotta love it when my mom meets 3 friends at once in the same isle at the grocery store. At the end I said “meeting adjourned!”

      1. Sub 900? Not sure I recall that.
        I remember seeing numbers in the 910-918 mb range, so
        Perhaps it did go sub 900 and I missed it or don’t remember.

        In any case, Florence has become more interesting.

        Dying to see the Euro.

        1. Me too !

          There’ll be more ridging in the Atlantic and because Florence may not be terribly strong the next few days, it has a better chance of it’s somewhat disorganized center staying on a further westerly track.

          1. Precisely. That is what was mentioned in
            the NHC discussion, although they seem
            reluctant to bite too much just yet.

      2. At hour 16 near or over Bermuda, Best I could find from Pivotal Weather Was 91 knots in SE quadrant or 104 mph.

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