Monday June 21 2021 Forecast (7:27AM)

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DAYS 1-5 (JUNE 21-25)

Summer has arrived and this first full day of it will surely make you know it. Heat and humidity will be the story of the day as high pressure offshore pumps that air in from the south. A gusty breeze will counteract some of the heat if you are outside, however. As a cold front approaches New England from the west, it will likely spawn a line of thunderstorms in NY today that will make it into far western New England by this evening before fading out as it tries to move eastward, having run out of support to survive. Only a spot pop-up storm is possible well in advance of this during the afternoon, but even these I believe should stay outside the WHW forecast area. A tropical low pressure area (maybe classified as a tropical storm) will be passing to the southeast of New England on Tuesday. Once thought to have a shot at bringing our region more widespread rainfall, all it will do is add a bit of moisture to the cold front that is moving across the region during the day, bringing the chance of showers and a few thunderstorms to the region. The greatest chance for any heavier downpours may be over southeastern MA and Cape Cod as that area has the chance to warm the most before the front arrives. Regardless of rainfall coverage and intensity, the front does clear the region by Tuesday evening at which time the air mass will change as the humidity breaks and much drier air flows in from Canada via the Great Lakes. High pressure will move across the region by Thursday providing another very nice day, then offshore Friday, at which time a warm front will approach then cross the area from south to north, bringing more cloudiness and the risk of some light rainfall or shower activity as the humidity starts to creep back up again…

TODAY: Partly cloudy. Highs 78-85 South Coast, 85-92 elsewhere. Dew point rising to 70-75. Wind S 10-20 MPH, gusts above 20 MPH.

TONIGHT: Variably cloudy. Foggy areas especially near South Coast. Isolated showers possible. Lows 68-75. Dew point upper 60s to lower 70s. Wind S 10-15 MPH, gusts 20-25 MPH.

TUESDAY: Mostly cloudy. Episodes of showers and thunderstorms especially midday and afternoon, greatest chance for heaviest and most widespread rainfall southeastern MA & RI. Highs 78-85. Dew point upper 60s to lower 70s. Wind S to SW 10-20 MPH, higher gusts.

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

WEDNESDAY: Sun and passing clouds. Highs 75-82. Dew point falling to 40s. Wind NW 5-15 MPH.

WEDNESDAY NIGHT: Clear. Lows 51-58. Dew point 40s. Wind NW under 10 MPH becoming variable.

THURSDAY: Sunny. Highs 77-84, coolest coast. Dew point lower 50s. Wind variable up to 10 MPH with coastal sea breezes developing.

THURSDAY NIGHT: Partly cloudy. Lows 56-63. Dew point lower 50s. Wind variable under 10 MPH becoming SE.

FRIDAY: Variably cloudy. A period of light rain or a few showers possible. Highs 76-83. Dew point rising toward 60. Wind SE 5-15 MPH shifting to SW.

DAYS 6-10 (JUNE 26-30)

A cold front will approach from the west then move into the region during the course of the June 26-27 weekend, with Saturday having only a small risk of late-day showers/thunderstorms mainly well to the west of Boston and Sunday having the better chance of showers/storms in the region. With high pressure offshore the frontal boundary may hang around for a couple days, with additional shower/t-storm chances, before being kicked offshore by a stronger westerly flow by the end of the period when an upper low may bring a few additional showers.

DAYS 11-15 (JULY 1-5)

A weak frontal boundary may cross the region somewhere in the first few days of July with a risk of a few showers and thunderstorms, but the overall trend is for a westerly air flow and typical summertime warmth with mostly rain-free weather and moderate levels of humidity overall.

58 thoughts on “Monday June 21 2021 Forecast (7:27AM)”

  8. dp now 70 at Logan and Norwood and 72 at Bedford and Beverly.

    YUUUUUUUUUUUUUUUUUCCCCCCCCCCCCCCCCCCCKKK!!!!!!!

  9. Thanks TK
    That is a STICKORAMA your describing JpDave on the first full day of summer.

  11. Thanks TK.

    Dewpoints in the 40s are now going to be very rare until October. Looking forward to them midweek though!

    1. Philip, did you read TK’s discussion?

      WEDNESDAY: Sun and passing clouds. Highs 75-82. Dew point falling to 40s. Wind NW 5-15 MPH.

      1. Yes, I did. That’s why I posted the fact that those 40-something dewpoints may not be back anytime soon for now during these summer months.

  12. I ranted about this in my blog, but the fact that they called that thing a tropical storm again when it was still over land 100 miles from the coast and lacked a well-defined center is further proof that NHC is making it up as they go along.

    11pm discussion: “the center of circulation itself is not very well defined”

    5am discussion: “The elongated low-level center of Claudette is located over eastern North Carolina this morning,”

    They claim they upgraded it at 5ambecause a buoy off the coast reported a brief period of sustained tropical storm force winds a few hours earlier. However, if you look at the data from that buoy, on their obs every 10 minutes, that reported sustained winds over 30 knots ONCE. (https://www.ndbc.noaa.gov/station_page.php?station=41013)

    NHC is a joke.

    2. I’m pretty much speechless about the practices there.

      And seeing all our colleagues in agreement just strengthens my opinion further.

    1. Yeah, I just hooked up our camper to our truck and am drenched by that short process.

      Headed to south-central VT for a while. A little wary of severe weather potential later today, right on the line of slight by SPC.

      Thank goodness we have A/C, but by Wed morning, maybe Thursday morning, we get some upper 40s lows. I like the varied weather.

  16. I think, since coming back on line, the Marshfield Airport sensor seems to be giving off more reasonable numbers, both temp and dewpoint.

      1. Checking in on the weather from the road, somewhere down rte 2. Thanks for this info JpDave !

  19. I was surprised the upgrade to an enhanced risk didn’t come sooner than the midday update.

  21. Dear GFS and ECMWF you are not good at your job ….

    Remember all those tweets last week with model output maps with no temperature above 85 through June 30?

    2. You know that “don’t trust model details beyond 3 or 4 days” rule? 😉 ‘Tis true! 😀

      1. The SREF model once again did a great job highlighting that area where tornadoes were possible.

  27. Watched the local Spanish-language station’s – WUNI – weather forecast just now. Good way to learn Spanish. While I can understand some Spanish I can’t speak it well. In any case, today I learned that a tropical storm is called a “tormenta.” Love that word.

  28. Keeping with the theme that the models aren’t good beyond a few days, the GFS is forecasting a high of 111 in Seattle next Monday, and 120 in Portland, OR.

    Odds of verifying: Blutarsky

    1. At the risk of sounding silly, if we know the models do not do well past three days…..and we all know this…..why pay attention.

      Asking for a friend 😉

      1. It’s really the details that are not good. A good model, performing as it’s designed to, can do an excellent job with the overall pattern and the larger scale trends. From there it’s up to the met. to start fine-tuning. 🙂

    2. Hottest temps ever recorded in those cities are 103 and 107 respectively. Wow are those records going to be shattered when the GFS verifies 🙂

      1. Ahhh but was the SeaTac Guage correct?

        Sorry. My middle name is snark tonight ….not sure if I’ll wake up with it tomorrow so consider this fair warning

          1. I have followed Cliff for years. I actually do know what I am talking about……occasionally. The sensors were checked more than once. Some problems but Some due location, jet heat and all of that fun stuff. I posted a comment from him to me last year suggesting contacting NWS and having them check was only way to know for sure.

            Phew. It is 10:38 and that was too much thinking for me when I want to be in snark mode.

    1. I have to add that most of my comments tonight are tongue in cheek. Other than the analysis by Joe Bomgard-zaragrodnick ..,,I’m sure that spelling is incorrect. I’ve discovered he id interesting to follow on Twitter too.

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