Thursday June 17 2021 Forecast (7:44AM)

39 Comments

DAYS 1-5 (JUNE 17-21)

An area of high pressure will control our weather through Friday with low humidity and a warming trend as the high center moves from the Great Lakes / Ohio Valley region today to the Middle Atlantic States by Friday. After that, the high moves offshore and low pressure tracking across southeastern Canada will first push its warm front through our region early Saturday morning when clouds increase and a possible round of showers may occur. Then we get into the warm sector between the warm front and approaching cold front with a shot of higher humidity, setting up the chance of showers and thunderstorms – a potential we’ll have to watch for stronger storms. Once that cold front moves by the region we’ll be set-up for a still warm but drier day on Sunday. At this time of year it’s not unusual at all for a “cold front” to be followed by air that’s pretty much the same temperature as what was ahead of it, but lower dew points. The air mass was originally cooler, but has been modified by a combination of the land it was moving over and a high sun angle, as well as more regionally by down sloping which warms air as it dries it out. So often you’ll hear the term “cold front” in a discussion, because that’s what it is by definition, but it doesn’t always bring significant colder or cooler air. In this case, it may be just a few degrees cooler Sunday in any given location than it is the day before, but it will be significantly less humid. But that won’t last, because the humidity and a bit more heat come right back on Monday. For now, I am keeping Monday’s forecast mostly dry with just isolated pop-up showers and storms possible later in the day, then a mention of showers arriving at night, but at day 5 this is already lower confidence and is further complicated by uncertainty regarding the approach of low pressure that originated in the Gulf of Mexico – not a large system, but one carrying a lot of moisture…

TODAY: Sunny to partly cloudy. Highs 76-83. Dew point near 50. Wind W 5-15 MPH.

TONIGHT: Mostly clear. Fog patches in lower elevations. Lows 52-59. Dew point lower 50s. Wind W under 10 MPH.

FRIDAY: Mostly sunny. Highs 80-87, cooler South Coast. Dew point middle 50s. Wind SW 5-15 MPH.

FRIDAY NIGHT: Mostly clear evening. Increasing clouds overnight with a risk of a passing shower near dawn. Areas of ground fog interior lower elevations. Lows 60-67. Dew point near 60. Wind SW up to 10 MPH.

SATURDAY: Partly sunny. Chance of showers and thunderstorms in the afternoon. Highs 83-90. Dew point middle to upper 60s. Wind SW 10-20 MPH.

SATURDAY NIGHT: Clearing. Lows 60-67. Dew point falling to 50s. Wind W 5-15 MPH.

SUNDAY: Mostly sunny. Highs 81-88, cooler Cape Cod. Dew point 50s. Wind W 5-15 MPH.

SUNDAY NIGHT: Mostly clear. Lows 61-68. Dew point upper 50s. Wind SW under 10 MPH.

MONDAY: Partly cloudy. Isolated afternoon showers or thunderstorms possible mainly interior locations then a chance of showers evening-night. Highs 85-92. Dew point rising through 60s. Wind SW 5-15 MPH.

DAYS 6-10 (JUNE 22-26)

Uncertainty for June 22 – a cold front approaches and we are warm and humid. There will be a chance for showers and thunderstorms at least with the approach of the front. The wildcard is whether or not the aforementioned Gulf of Mexico low adds heavier rainfall to the mix. This system has trended slightly less impressive and a bit further south on recent guidance but it will be something to keep a close eye on over the coming days. Regardless, mild/dry weather is expected behind the front for June 23 as high pressure builds in from the Great Lakes region. After this, the weather looks seasonably warm and mainly dry but we may need to watch another low pressure area or frontal system for wet weather toward the end of the period.

DAYS 11-15 (JUNE 27 – JULY 1)

Seasonal northward displacement of the jet stream becomes more pronounced during these days with early summer warmth, somewhat higher humidity at times, and a few opportunities for showers and thunderstorms with passing disturbances.

39 thoughts on “Thursday June 17 2021 Forecast (7:44AM)”

  3. Thanks TK. Interesting discussion!

    Perhaps that “cold front” should be called a “dew point” front? 🙂

    1. Doesn’t need to be. So long as the source of the air mass is known, that’s all we need. No need to further complicate it. Just explanation is good enough. 🙂

    1. Interesting how the threat almost always diminishes
      as the systems move to the East. 🙂

      That being said, this could easily be upgraded to a slight risk tomorrow. I’ll bet not, but we shall see.

      1. Oddly I had that discussion with Pete years ago. I’d often watch something moving in from the west and even in Framingham it would diminish or completely fizzle.

        1. You get that wind from the water creating a stable airmass and that is kryptonite for thunderstorms.

          1. That is certainly part of it. The warmer the water
            is South of LI Sound, the better the chances for severe weather up this way. I believe that is why
            August is sometimes referred to as our severe
            weather season.

            1. I might be wrong on this but it seems when we get thunderstorms that develop with the NW flow they have a better chance at surviving the trip to the coast.

              1. I don’t know about that, however, I do believe
                that as far as tornado chances with a severe set up, it can be better with NW flow aloft.

                With a SW flow aloft, the turning winds have to
                be SE to S turning to SW and W.

                With a NW flow aloft, the turning winds can be
                SW to W turning to NW and N

        2. And then there are the ones that are strong enough to get to the ocean an past. They are amazing. Watching lightning from the clouds into the ocean or at Humarock into the river is amazing

          1. That’s exactly right. When you have the right setup, the ocean will not be a storm killer.

  7. Quick peak at the latest SREF for Saturday afternoon and it has most of the SNE with the exception of Boston south shore Cape and Islands in the low tornado risk.

  10. Have you seen the most recent photos of Lake Mead, the waterway behind Hoover Dam …… Gotten used to seeing the low water levels with the whitened cliff walls showing the difference from high water. But, its gotten worse, if that´s possible. The height of this drop is almost beyond belief. And, it was 109-114F out there yesterday, with low dewpoints. Can´t imagine how much water is evaporating on a daily basis.

      1. Great article. I don´t side here with the states. Yes, I´m sure a few ponds here and there aren´t being used well, but I´ll bet the majority are, such as the farmer and his family, in the news story, for decades.

  11. Only because we do this in the winter 🙂 🙂 🙂

    The 12z GFS is truly baking the northeast June 29th-30th.

    Yes, its around hour 300, and the next run will probably have a deep trof and temps in the 60s.

        1. NOT happy about that. I am as unhappy about that
          as a snow hater would be about an impending snow storm. 🙂

          As you said, it is hour 300 or so, Hopefully, it does NOT
          materialize.

          My Summer order is:

          85 and dry during the day with mid to upper 50s at night.
          EVERY DAY!!!

          1. That is perfect, as has been the recent weather since the hot spell.

            I think Monday could be sneaky hot, if clouds from the system in the Gulf don´t make it this way.

            I think I´ve seen 90F on a few TV 7 days and TK has 85F – 92F. I believe its trending towards the higher end of TK´s range.

  12. Well, at least this one might actually be tropical….

    “A tropical storm warning will likely be required for a portion of
    the northern Gulf Coast later this afternoon, and Potential Tropical Cyclone advisories will likely be initiated on this system at 4 PM CDT (2100 UTC). “

    1. Spent lots of time at my nanas on Isle la Motte growing up. Absolutely spectacular part of the country’s

  15. On the latest SREF, severe parameters have shifted more the the SW of our area for Saturday.

Comments are closed.