Saturday August 21 2021 Forecast (7:36AM)

230 Comments

DAYS 1-5 (AUGUST 21-25)

First, a fairly nice though humid late August day today to start the weekend. All eyes on Henri now, though we still have about 24 hours or a little less to nail down the final details and make any preparation needed, though it must be stressed at this point that while Henri is going to cause some local flooding and power outage issues, this is not going to be a classic New England hurricane either. In fact, I don’t even think Henri will be a hurricane anymore when the center reaches land, which I am becoming more confident is going to take place somewhere on the western half of Long Island (though there is still some room for adjustment here). This represents the “left turn” scenario I described as a possible scenario. This scenario would spare our region a significant storm surge and the heaviest rain area, and while we’d still be on the storm’s windy side, its smaller size, westward turn, and weakening would also mean that wind would not be as strong as a storm with a larger wind field and further eastward track would bring us. Since we will be on the eastern side, and the precipitation will be convective and showery, there will be the conditions in place once again that can support the development of small, brief tornadoes, so we need to be on the look-out for that during the day Sunday. The timing of the system is a touch faster than I thought about 24 hours ago, so we can see these showers at any time. Henri’s movement is far enough west that we can see breaks of sunshine as well. I am still a little unsure how the center responds to steering once it gets across Long Island. It probably goes into western CT and possibly NY. Not quite sure if the then small and weaker center drifts northward before heading back eastward, or goes stationary before coming back eastward. These details will have implications on wind direction and precipitation orientation. Whatever is left of the system should take its time exiting the region from west to east during Monday, so we can expect unsettled weather that day as well. Finally, drier air arrives Tuesday into midweek as high pressure builds in from the west.

TODAY: Partly sunny. Highs 78-85, coolest coast. Dew point upper to middle 60s. Wind SW up to 10 MPH shifting to E during the day.

TONIGHT: Mostly cloudy. Showers arriving South Coast overnight and up to I-90 and Greater Boston by dawn. Patchy fog. Lows 62-69. Dew point middle to lower 60s. Wind E to SE 5-15 MPH.

SUNDAY: Mostly cloudy. Occasional to numerous showers and possible thunderstorms. Highs 75-82. Dew point lower to middle 70s. Wind SE 10-20 MPH inland and 15-30 MPH coastal areas with higher gusts, and locally damaging wind gusts possible.

SUNDAY NIGHT: Mostly cloudy with areas of fog and periodic showers, some possibly heavy. Lows 68-75. Dew point upper 60s to lower 70s. Wind SE to S 10-20 MPH, higher gusts.

MONDAY: Mostly cloudy to partly sunny with occasional showers and possible thunderstorms. Highs 75-82. Dew point upper 60s to lower 70s. Wind variable to SW to W 5-15 MPH, higher gusts.

MONDAY NIGHT: Clearing. Lows 61-68. Dew point near 60. Wind W 5-15 MPH.

TUESDAY: Mostly sunny. Highs 78-85. Dew point lower 60s. Wind W 5-15 MPH.

TUESDAY NIGHT: Mostly clear. Lows 60-67. Dew point upper 50s. Wind W 5-15 MPH.

WEDNESDAY: Mostly sunny. Highs 78-85. Dew point upper 50s. Wind W 5-15 MPH.

DAYS 6-10 (AUGUST 26-30)

High pressure will be the dominant force in the weather with mostly rain-free conditions and near to above normal temperatures.

DAYS 11-15 (AUGUST 31 – SEPTEMBER 4)

High pressure is expected to dominate, with limited rain chances and fairly warm weather.

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230 thoughts on “Saturday August 21 2021 Forecast (7:36AM)”

  1. Thanks TK—any chance they get tomorrow’s game in at Fenway? Trying to take my son once more before the school year and associated weekend activities kick in.

      1. Red Sox need all the help they can get. This might even be a worse collapse than in 1978 in a sense.

  3. Thanks TK !

    Hopefully not a lot of power outages JJ and Mark !

    And hopefully limited flooding wherever the heaviest rain area ends up.

  4. Tom I am hoping not to have a repeat of Isiais but I am preparing mentally to have no power for a few days. Even though it shows Henri as a tropical storm making landfall in CT it does not mean there won’t be widespread tree damage and power outages to the right of the storm track. We saw that last year with Isiais going up through the Hudson River Valley and not make a landfall in CT.

    2. I noticed on a rainfall map by Zack that had the “warmer” colors in much of CT except for a bit of “green” in the CT Valley. I immediately thought of shadowing much like in some winter snow events sometimes.

  5. Thanks TK.

    TK – I will be working a double shift tomorrow from 7:00 am -11:00 pm. Will my am commute actually end up being the wetter/windier one?

    1. Located at 34.7 N, 72.2 W

      Henri, at 8 am at 33.6 N, 72.7 W, so Henri might go over the buoy in a few hours

  7. 6z GFS has Henri going into Narragansett Bay. The funny part is that area is not in the hurricane center’s cone. GFS out to lunch or it is seeing something the other models haven’t picked up on yet???

  10. With the current track, NYC subways could very well be flooded out. As it is here in Boston, the MBTA is closing Aquarium Blue Line station or at the very least, considering it.

  11. 6z runs of the HWRF and GFS are east. I am watching this to see if those are outliers or other models jump on as that would put the worst of the winds east of CT and we would be on the heavy rain side. These tropical systems have minds of their own. I won’t forget Charley in 2004 when the models had it go into the Tampa area and it went far south of that.

  13. That has major implications. The east track happens eastern New England look out as you will be on the windy side. If the west track happens most of CT on the windy side.

        1. Tom we are probably going to escape Down here ya think . Im deciding if I should even bother getting batteries now

  20. Thank you, TK.

    While Governor Baker’s warning yesterday to folks emphasized the Cape and the Islands, they might wind up mostly dry (especially the Islands and Outer Cape), with some wind and churn to deal with but not much else. Of course, nothing is set in stone, so I do understand the Governor’s concern.

  21. AUGUST 21, 2021 AT 9:30 AM
    12Z HRRR did slowly turn left and makes landfall on
    Central Long Island.

    https://maps2.pivotalweather.com/maps/models/hrrr/2021082112/027/sfcwind_mslp.us_ne.png

    REPLY
    JpDave
    AUGUST 21, 2021 AT 9:32 AM
    Concerning tornado risk for tomorrow, depending on the final track, but assuming it is West of the Boston area, would that not allow for possible discrete convective cells on the East side thus
    possibly increasing the chances of some tornadoes. And if we get sunny breaks in between, boosts the chances even more?

    Something to watch tomorrow for sure.

      1. If I am reading correctly, that would be max flight level winds
        at 80 knots. Take off 20% and we get about 64 knots at the surface or 73.6 mph. With an hour 1/2 to go, NHC might
        categorize Henri as a Hurricane with the 11 AM update.
        We shall see. If not, then certainly at the 5PM update.

  26. Thanks TK.

    Go figure we are 24 hours out and still no model consensus.

    JJ, to answer your question from yesterday, we are scheduled to fly out of Turks and Caicos tomorrow and arrive in Miami at 445pm. Our second flight is supposed to leave Miami at 930pm and arrive at BDL at 12:30am. I am expecting the airport will be closed and we will need to stay over in Miami look for something back on Monday. Hoping what is left of the storm on Monday is not enough to cancel additional flights.

      1. Thank you all very much for your well wishes and for your help here. TK has been helping a ton on the side with advice also. You are all amazing

    1. 12z NAM, I think, is trending towards TK´s idea of a loop/left hook thats not too far north of the south coast.

  31. Thanks, TK!

    Adding to SAK’s play list:

    Hurricane by Bob Dylan
    Stormy Weather by Etta James and Lena Horne
    A Hard Rain’s A-Gonna Fall by Bob Dylan
    Thunder and Lightning by Chi Coltrane
    Thunder by Imagine Dragons

    I love how you have Frank Sinatra and Queensryche on the same list, SAK! 🙂

    Everyone, be safe, especially you, Mark (in your travels) and SSK (on the job)!

    Off to do yard prep!

    2. We’ll wait in stone circles
      ’til the force comes through —
      Lines joint in faint discord
      And the stormwatch brews
      A concert of kings
      As the white sea snaps
      At the heels of a soft prayer
      Whispered

  34. Philip … Passing showers possible, maybe a downpour and a gusty breeze for your commute.

  35. People jamming the gas stations here in pembroke as I put my $40 in lol . Not going to be a big deal ( here anyways )

    1. My tank needs to be filled. Hopefully I get lucky and there’s not a lot of panicky petes at the gas station lol

      1. It’s crazy I mean I’m not wrong right from Boston south it’s a very small event I think. I’m not even sure that I’m going to put lawn chairs & tables away

    1. From NHC

      Hurricane Henri Discussion Number 23
      NWS National Hurricane Center Miami FL AL082021
      1100 AM EDT Sat Aug 21 2021

      The Air Force Reserve and NOAA Hurricane Hunters have been
      investigating Henri this morning and continue to provide very
      valuable data. The Air Force aircraft measured a peak flight-level
      wind of 82 kt at 700 mb, which easily supports hurricane strength,
      but the initial intensity is set at 65 kt as a blend of these data
      and somewhat lower SFMR winds. In addition, aircraft data indicate
      that the minimum pressure has fallen to 991 mb. The NOAA tail
      Doppler radar data indicate that the storm is becoming more
      vertically aligned and that a more symmetric eyewall appears to be
      forming. In addition, dropsonde data from the NOAA Gulfstream IV
      aircraft flying around Henri indicate that the 34- and 50-kt wind
      radii are a little larger than previously estimated in the
      southeastern quadrant. NOAA buoy 41001 located in the northeastern
      quadrant of the hurricane has recently reported 18 ft. seas.

  43. GFS somewhere btwn 982 and 988 mb at landfall, deeper than its 00z run and somewhere around eastern LI and/or western Rhode Island.

    Wise to upgrade warning for Naragansett Bay. Big storm surge quite possible.

    1. so, now the next 12-18 hrs is …..

      does it get down to the high 970s/low 980s mb pressure and come in at 982 mb. thats a pretty strong tropical storm hit with 45-60 knot winds down there.

      I think eastern long island, extreme western ri is settling in for landfall.

      1. And regardless of east or west solution CT is in line for heaviest rain and fresh water flooding. After Thursday’s rain, they don’t need that right now or In NYC.

  45. Now is the time to shift focus away from the global models and to the shorter range models that are more likely to handle this better now.

      1. Best guess…
        3 km is a little better up until landfall and 12 km is a little bit better after.

        2. So when a tropical is this close to landfall, then the high res shorter range models are OK, but farther out they are crap?

          How is the HRRR handling tropical systems?

  48. You all are going to have a stronger and higher impact storm than I have yet to seen down here on St. Thomas. I hope that it stays that way. Anyway, be safe everyone, its not the wind strength necessarily, its the amount of rain you all have had along with the wind that will cause the major power outage. I know many on here live in the southern part of MA, Ct, RI. I experienced Dorian back in 2019 when it was a strong tropical storm but rapidly started to intensify into a moderate cat 1 as it made landfall just to my west. I lost power for 3 days due to that storm my point is that it doesnt take a hurricane to cause major damage and hassles and people should be prepared for it.

  49. Well. Guy staying at house is here. We are off soon. I plan to take you all with me. Thank you once again.

  55. Hi all,

    We brought our sailboat from Edgartown to Winthrop which is still looking like a good call. Bummed that our Vineyard vacation has been cut short. Currently tying down the sails and making sure things are secure.

    At what point will the phrase “Tropical Storm conditions possible” be removed from the marine forecast for Boston Harbor? It’s calling for peak gusts of 25 knots for Monday/Monday night, which is just an ordinary windy day on the water.

    https://marine.weather.gov/MapClick.php?x=210&y=119&site=box&zmx=&zmy=&map_x=210&map_y=119#.YSEwlSU4bDt

    1. as long as there is a slight chance of TS force wind gusts they will keep it up. Heavy rain/thunderstorms can bring down stronger wind gusts even that far away from the storm. Also slight adjustments of the storm track can increase and decrease the wind threat. Back in 2019 with Dorian, the night before it was suppose to travel west of me, past the west side of PR, instead it was a cat 1 hurricane that made landfall just to my west.. Meanwhile Grace when she was around my area was looking to be a tropical storm that impacted me, instead it traveled well southwest of me, much weaker but still gave rain and some gusty conditions with low end TS force winds at one point. Point is these things can change, track so the risk probably wont be taken down unless they are extremely confident that it will not happen.

  57. Outer bands lighting off New Jersey. I remember this occurred just before Belle moved into sne in the mid seventies.

  63. I would like to offer a different view of how it looks on satellite.

    On the IR with the cold cloud tops/bright colors, this hurricane, in this setup, at this latitude was just not going to look like a hurricane looks in the deep tropics.

    In spite of the lack of cold cloud tops, I really think the visibles show the circulation is now vertically aligned, there’s a central ring around it and I think the circulation has tightened a bit closer to the center.

    Let’s see with the next recon plane. Wouldn’t be surprised by a significant pressure drop since 993 mb even without a good look on the IR satellites reading cold cloud tops.

      1. Although, I must admit, there is a hint of an eye forming.
        We shall see if that feature develops more with time.

  64. Nice back door frontal passage here a short time ago. All the cumulus are to my west and south now and the wind is east and the temp has gone down several degrees along with the dew point. Woburn.

    Also when this happens Logan switches their approach and the planes are now coming directly over me here. 🙂

    1. Nice East wind here, but it has NOT affected the dp.
      It is SICK MISERABLE here. Temp still 85 YUUUUUCK!

  72. True calm before the storm on cape as today was perfect beach day except for folks pulling their boats out or adding extra lines. Most folks are relieved with changing track.

    1. 1 or 2 days before any tropical system (without a PRE) are usually awesome beach days, except that sometimes there are surf issues to be careful of.

  73. Just saw the satellite of Henri for the first time today and I am less than impressed. Hopefully that’s a good sign.

  75. Henri’s main intensification will take place in the next 8 hours as it crosses water that is well over 80F. At this time it will continue to move NNE at a moderate pace.

    After that, it enters sub 80 degree water and starts its weakening trend. At this time, high pressure will start to slow and deflect the storm NNW.

    Landfall as a strong TS or minimal hurricane eastern half of Long Island Sunday late morning.

    Second landfall CT coast as a TS Sunday afternoon.

  78. 984-985 mb or so first pass through center.

    Decent southwest side wind wise, wonder what lurks in the eastern quadrant ?

  79. If I recall correctly, earlier today, when they encountered 70+ knots in the SE quadrant, the SW quadrant was like 30-35 knots at flight level.

    The first pass through the SW quadrant now has a small area of 55 knot flight level winds.

    1. This doesn’t mean eastern mass is going to have a hurricane, but it sure adds to the potential impact in eastern mass.

      It increases adding a bigger surge into buzzards bay and if you saw a simulated wind model on a tv forecast, take what you saw in western New England earlier today and slide that eastward potentially.

  86. According to JR, Henri may very well NOT be a hurricane by the time he reaches the CT coastline. He believes Long Island itself will weaken him and downgrade Henri to a tropical storm.

    So this could mean that Hurricane Bob (1991) will remain as the last “hurricane” to strike SNE.

    2. I’m not so sure Henri makes landfall over Long Island. The various envelope of solutions continues to nudge east. Landfall over RI as a low cat I seems more plausible which would mean greater impacts in central and eastern New England.

  89. Convection seems to be wrapping around the center of Henri better this evening on the southern, eastern and now the northern periphery. Further strengthening before entering a less favorable environment wouldn’t surprise me.

          1. Kind of feels like it…Will hope for the best. I enjoy your insights as well as everyone else’s on the blog. Thank you

      1. Thank you. Daughter was the photographer so I know has many better photos. But I snapped a few when I could see through the tears. He carried Macs wedding band in his pocket. I know Mac was there. Sorry. No idea what I’m toying. Can’t see again

  92. This will be only the 5th time since 1851 that New England/Long Island has 2 landfalling storms in the same year, and only the 2nd time that both storms were tropical storm strength only.

    1869
    9/8 Category 3 Hurricane
    10/4 Category 2 Hurricane

    1954
    8/31 Carol (Category 3)
    9/11 Edna (Category 2)

    1961
    9/15 Unnamed Tropical Storm
    9/26 Tropical Storm Esther

    1985
    9/24 Tropical Storm Henri
    9/27 Hurricane Gloria (Category 2)

    2021
    7/9 Tropical Storm Elsa
    8/22 Tropical Storm Henri

    Counting Elsa, 37 storms have made landfall in Long Island or New England as a tropical storm or stronger – an average of one every 4.6 years. The longest we’ve ever gone without a hit from a storm of tropical storm strength or stronger is 11 years, between 1897 and 1908, and again between 1923 and 1934. Elsa’s landfall earlier this year ended a 10-year drought without a landfalling storm.

  95. Henri is now a tropical storm, downgraded before landfall, so the New England hurricane drought going back to 8-19-1991 will live on…

    1. Still chugging to the north. Do we need to worry about getting into that center on the Rhode Island/MA line later this am? It did just update to a NNW direction now, so maybe not.

      1. It’s made its turn. Pretty much no changes now other than the official downgrade (strong TS & minimal hurricane are basically the same) and the slight overall eastward nudge since last yesterday (because the system had been a tad further east and north than yesterday’s forecast before it made the jog left).

    1. Thank you. I’ll re-post the link on the blog update I’m doing now when it’s posted!

    1. I was certain that it would not make landfall as a hurricane. still only a light breeze here, although gusting to near 30 at Logan.

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