Monday May 17 2021 Forecast (7:43AM)

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DAYS 1-5 (MAY 17-21)

Deeper into May we go, and as we start this new week off we’ll be talking a little bit of spring and a little bit of summer preview. First, we have the continuation of the active pattern today, this time a weak cold frontal boundary moving down from the north which will help trigger more cloud development and a few showers and possible thunderstorms, somewhat similar to what we saw yesterday. So it will start bright and sunny across most areas (except a few cloud patches) but we’ll see lots more clouds pop as the day goes on. Some areas will get wet, and many will not, but those that do will not see it linger very long. And yes once gain a few locations may see rainbows later in the day if the timing and placement of a departing rain shower or thunderstorm is just right. Things will settle down tonight. On Tuesday, we transition toward a preview of summer, but we won’t be fully there yet. It’s still going to be a little bit chilly aloft, so we’ll see some clouds pop again, and again some of them may build enough to produce a shower or thunderstorm in some locations, so if you do have plans to be outside, keep an eye on the sky (and the radar if you can), especially during the afternoon. Wednesday, high pressure aloft and a surface high centered to the west will combine to produce the sunniest and warmest day of this week. Areas away from the direct influence of the ocean should easily break 80 for a high temp, but with the gradient wind not all that strong, there is always the chance for some sea breeze development near the coast. While the upper level pattern says “warm” for later this week, the high pressure ridge being centered far enough west is an unlocked door for cooler air to slip down from the Canadian Maritimes via the Gulf of Maine, and by Thursday we’ll have to watch for the potential arrival of a back-door cold front. While at least inland locations should warm nicely, that warming may be thwarted closer to the eastern coastal areas, and then depending on how far southwest that expected boundary pushes will determine how cool the remainder of the region trends through Friday. There should also be some cloudiness with this air mass change, but any rainfall should be limited to just a few showers, if that. Back-door fronts don’t often produce much precipitation unless they are combined with tropical moisture, which we won’t have, or a stronger disturbance coming along in the jet stream, which we also won’t have. Keep in mind that there is still the possibility that a back-door front never quite does make it all the way into or across the region, but given past history, I’ll lean toward it doing so for now and adjust the forecast if necessary going forward this week…

TODAY: Lots of sun to start then lots of clouds popping up during the day. Isolated to scattered showers and thunderstorms developing this afternoon. Highs 69-76, coolest near the coast. Wind variable to N up to 10 MPH with some coastal sea breezes.

TONIGHT: Lots of clouds and a lingering shower possible early, then clearing. Lows 47-54. Wind N to variable under 10 MPH.

TUESDAY: Sunny start, then a sun/cloud mix with isolated afternoon showers and thunderstorms possible. Highs 72-79, coolest in coastal areas. Wind variable up to 10 MPH with coastal sea breezes developing.

TUESDAY NIGHT: Clearing. Lows 50-57. Wind variable under 10 MPH.

WEDNESDAY: Mostly sunny. Highs 80-87 except 70s in some coastal locations and 60s on parts of Cape Cod and the Islands. Wind variable up to 10 MPH with coastal sea breezes developing.

WEDNESDAY NIGHT: Partly cloudy. Lows 55-62. Wind variable under 10 MPH.

THURSDAY: Partly sunny. Chance of a shower late in the day. Highs 77-84 but may turn considerably cooler at least in eastern coastal areas by late. Wind SW to variable 5-15 MPH possibly shifting to NE by later in the day especially in southeastern NH and eastern MA.

THURSDAY NIGHT: Variably cloudy. Possible showers. Lows 55-62. Wind variable to NE 5-15 MPH.

FRIDAY: Sun/cloud mix. Highs 63-70, coolest coast. Wind NE 5-15 MPH.

DAYS 6-10 (MAY 22-26)

Frontal boundary hanging in the region May 22 means clouds and possible showers, then this front should push back to the north allowing a warmer May 23 but still with a chance of showers and thunderstorms as a cold front approaches. There’s a chance of some wet weather about May 24 if this front slows down and allows a wave of low pressure to move across the region. Drier weather should be back in place by later in the period.

DAYS 11-15 (MAY 27-31)

Overall pattern looks dry and mild, but ocean’s influence likely keeps coastal areas cooler some of these days.

41 thoughts on “Monday May 17 2021 Forecast (7:43AM)”

  2. Good morning and thank you TK.

    We eeked out 0.01 inch in a brief show last evening.
    We remained dry all day long until evening.

  5. Thank you, TK. Was 45 at 3:30 and 65 by 8:30. Not as many recovered degrees as a few days ago but temp is sure recovering quickly. The grandkids spent much of yesterday in and out of the pool. Temp is mid 50s, but then they grew up playing in the south shore ocean 😉

    1. Up to 71 here. Nice.

      Mid 50s is chilly, but to kids it’s nothing.
      I can do mid 50s, but not for long. 🙂
      That is COLD!

  9. Showers popping up out there and unlike yesterdays’ mostly W to West to East movement, these are mostly NNW to SSE.

    Some lightening with them as well.

  10. Sun angle now the same as July 27. Ocean temperature 55 degrees at Block Island. We are getting there.

    1. Pretty strong sea breeze here in JP. I was just out and it
      is very very nice out. Warm, but feels a bit coolish when the
      EAST wind blows on one’s skin. Still my equipment is reading
      75.

      1. 64 at the airport.

        Boston Buoy, 16 nautical miles due East of Boston,
        water temperature: 55.22 degrees F.

  14. Perfect sea breeze set-up today, and it shows. We’re having about as classic a New England spring as we can possibly have.

  16. Just tried using the NWS radar on my laptop.
    Still takes forever to load.
    Once it loads can’t really use it. Won’t zoom right. Won’t loop right. Then, can’t exit. Once you’re in it, you’re stuck there until you close the tab.
    I’d love to say it’s a problem with my laptop. But so far, it’s the same on every computer I’ve tried it on, and on my phone. The problem is their radar set-up on the web page. It’s time for a re-design of the re-design.

  17. Should see some media forecasts start to back down from the warmth in Boston on Thursday. They should be about 10 to 15 degrees cooler than most forecasts showed last night & this morning. I displayed that thought process in today’s blog post, so no need to re-word anything at this time from what I had been saying yesterday and this morning.

    1. Indeed you did and you have been warning about the possibility
      for a while now. Remember the 500mb flow that you said
      screamed Back Door Cold Front?

    2. I’m confused. Nothing new I understand. They have higher 70s-83…I think one had 84. No?

      1. Yes, but the coast may end up considerably cooler than that, depending on timing.

        1. Ahhh Eric and one other….darned if I can recall which…mentioned that also. So if I understand, the range bottom number will lower?

  19. Still 70 here in JP with the sea breeze. Nice to have a few miles between here and the coast. 🙂

  24. Logan airport has received exactly 12.49″ of rain in the past 135 days.
    Lake Charles, Louisiana has received 12.49″ of rain in the past 18 hours.

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