Friday Forecast

95 Comments

7:28AM

DAYS 1-5 (SEPTEMBER 6-10)
Hurricane Dorian will accelerate northeastward today through Saturday, the center making its closest pass about 200 miles southeast of Cape Cod early Saturday (around or a little after dawn). The hurricane will be undergoing transition to non-tropical during this trip, and when that happens, its coverage expands. This track and expansion will allow the remaining outer rain bands to make it to the South Coast of New England this afternoon and push northward through tonight, with the main rain area pushing across RI and southeastern MA overnight and first thing Saturday morning, before everything moves offshore and away. While a few of these showers some more likely some of the rain from the main area may be on the heavy side, the main impact from Dorian will be large swells and rough surf along the coast, where splash-over and some minor flooding is possible. Behind that will be a gusty northerly breeze and drier conditions for the remainder of Saturday, but in the evening or nighttime there may be a passing shower from a cold front dropping south from Canada. High pressure builds in with great weather Sunday and Monday, and this high sinks to the south with fair weather but a warm-up by Tuesday.
Forecast details…
TODAY: Mostly cloudy. Areas of showers arrive south to north during the afternoon, best chance of heaviest near the South Coast. Highs 67-73. Wind E up to 10 MPH.
TONIGHT: Cloudy. Rain arrives RI and southeastern MA, showers to the northwest. Lows 56-63. Wind NE 10-20 MPH except 20-30 MPH southeastern MA and RI with higher gusts, perhaps to 50 MPH or greater Cape Cod and Islands.
SATURDAY: Cloudy early morning with rain and showers ending west to east. Sun and passing clouds remainder of day. Highs 68-75. Wind N 15-25 MPH and gusty early, shifting to NW and gradually diminishing later.
SATURDAY NIGHT: Partly cloudy. Risk of a brief passing shower. Lows 55-62. Wind W 5-15 MPH.
SUNDAY: Mostly sunny. Highs 65-72. Wind NW 10-20 MPH, diminishing.
SUNDAY NIGHT: Clear. Lows 46-53. Wind light variable.
MONDAY: Sunny. Highs 68-75. Wind light variable.
MONDAY NIGHT: Clear. Lows 48-55. Wind W up to 10 MPH.
TUESDAY: Mostly sunny. Highs 73-80. Wind W 5-15 MPH.

DAYS 6-10 (SEPTEMBER 11-15)
West to east flow dominates. Cold front slides through September 11 with a shower risk. High pressure builds in with fair weather September 12-13. Weak front approaches with slight shower risk September 14. Fair weather returns September 15.

DAYS 11-15 (SEPTEMBER 16-20)
West to east flow continues. One or two minor systems may bring shower threats, but the overall pattern looks fairly dry with temperatures not too far from normal.

95 thoughts on “Friday Forecast”

  2. I attribute this to what I call meteorological luck more than anything, but I don’t think a hurricane has ever followed my personal forecast track so closely for a solid week than this one has. I found it to be a very little surprise hurricane, maybe a bit on the re-intensification as it neared the SC coast as WxW stated. It’s a classic otherwise, the tornado count was up and they were pretty strong. Analysis will show the storm was a perfect shear laboratory. There are tropical systems that tend to over-perform for tornadoes, and this was one of them.

    Today we see the classic heavy rain to the left, strong wind to the right set-up. Before long, the acceleration will be well-underway and Dorian will be an express train as it makes it closest pass to New England. All of this is typical.

    There are still a few folks I have caught in social media thinking Dorian is still a category 5 hurricane. Those are the ones that need to pay attention to actual updates. Dorian, by hurricane standards, is not that strong anymore, which we all realize. That doesn’t make it a non-dangerous event, however, which all people should realize.

    Here’s my sunset photo from Dorian last night, taken from my back stairway on Woods Hill in Woburn: https://scontent.fbed1-2.fna.fbcdn.net/v/t1.0-9/70127275_10157589849357265_975230272255557632_o.jpg?_nc_cat=102&_nc_oc=AQmCG0E716UHhtlGcBNMHOfF-zT__l54SEVpV9tyVTfblpUTeSQwV_S858TodCgHXSk&_nc_ht=scontent.fbed1-2.fna&oh=78c3906a2ebba6f1abdbd085049c6414&oe=5E062D97

    1. I’ve gotten slight amusement out of the fact that the old GFS had the most correct track the furthest in advance

  4. And the people I’m hearing today looo out big storm in Boston tonight & I am just like oh yeah !!

          1. We’re not on the same page.

            All I was stating was that the HRRR previously had less rain for Boston and the latest run has more.

            That is all. 🙂

            It will likely rain, even in Boston, but the question is how much. Euro has about 1.4 inches, Nam has about an inch, NAM 4KM has about 1/3 inch, Hrrr has nearly an inch while the GFS has nearly 3/4 inch. Take your pick.

            Rain, rain how much will there be. It will either rain or it won’t and if it does, we’ll get some. 🙂

    1. Because it depends on where it puts each cell. That will vary hour to hour and therefore its forecast for any given location will shift with that.

    2. Interested to see what explosive development (drop in central pressure) occurs when that Great Lakes disturbance/energy envelops Dorian.

    2. We’ve spent time on Ocracoke Island, camped there one summer.

      Beautiful island with amazing views looking out towards ocean or in towards Pamlico Sound.

      Most of the businesses and year round residential homes are on the south and southwest side of the island.

      Sad to see this ……. but, its not the Grand Bahama destruction, so I’m sure they will recover soon.

  14. I split the goal posts. This one moved just north of me and the 2013 funnel went just south. Glad to be able to call the tornado capitol of New England my home 🙂

    Ryan Hanrahan
    17h

    Our first video of the Coventry tornado comes from Derek in Mansfield on Rt 195 looking looking south toward Skungamaug Golf Course. The video itself is somewhat inconclusive but based on the damage survey results we know that the funnel was on the ground here. #nbcct

    https://twitter.com/ryanhanrahan/status/1169782351389442048?s=20

    Ryan Hanrahan
    15h
    Coventry is apparently the new tornado hot spot in CT. Nick Stanczyc grabbed this shot on 7/10/2013 as a tornado moved through Coventry. Yesterday’s tornado was a couple miles north of that one. #nbcct

    https://twitter.com/ryanhanrahan/status/1169802673702486021?s=20

  23. The 2 hurricane models bring Dorian down to 943 mb for the HWRF and 946 mb for the HMON on the closest pass to SNE.

      1. Deformation zone:
        Brief synopsis:

        Deformation Zones:

        Deformation zones are very complicated processes in the atmosphere, usually at the edge of an extratropical low pressure system. Deformation zones are areas where the atmosphere is being stretched and sheared in different directions. The way the deformation develops can either enhance frontogenesis or enhance the thermal gradient at the mid levels or can cause divergence at the mid levels and thus sinking air. The process and impacts of deformation in the atmosphere is very complicated and will not be covered here, but an excellent source of information on the process can be found here.

        Deformation zones usually form in a position of northwest to southeast or north to south. They can produce very heavy snowfall for a long period of time and can extend the influence of a winter storm for several hours. One of the best cases of deformation zone impacts was from the February 13, 2006 blizzard seen to the left. Note the banded feature from north to south that drove from western New Jersey through New York City, producing snowfall rates of 2 to 4 inches per hour. That is a deformation zone!

        Note that as drier air is working in from the west, the low pressure system is driving moisture in from the Atlantic. The low and mid level convergence of the moisture combined with the divergence aloft of the 700 MB and 500 MB pattern leads to the formation of the deformation band and thus the heavy snowfall.

  26. Thanks TK.

    I enjoy days like today.

    Had a real treat this morning and finally saw raw bobcat that has been in town a few years. It’s been on my wish list since we moved here. Silly me thought they were larger.

    1. I’ve always liked the overcast, increasingly windy type day when there is a large storm that will be passing either close by or coming into the region. It’s probably rooted in my early anticipation of big weather events when I was a kid. My brother would tell me what was on the way…

      1. Love it. I knew you were enjoying today too. There is an anticipation and also a comfort. Sounds at odds, but really isn’t

  27. Thanks TK. Agree on the Dorian track, at least for the past 3-4 days although I think you’ve had it pegged for longer. Turned into a very high predictability pattern.

    If you look at Dorian on satellite today, it’s grown better organized as it accelerates northeast. Not unheard of, but not the most common outcome. As it begins to interact with baroclinic features, it is unlikely to lose much intensity in the short term and could be a very serious threat to Nova Scotia. NHC increased the 5PM intensity forecast to reflect this. Wind radii have also increased; the storm is massive.

    This to say, if Dorian were a couple hundred miles further west, passing inside the benchmark and closer to Nantucket, it would not have been a good situation for southeast MA and especially the Cape/Islands. It wouldn’t have been “the big one”. You need a faster moving storm coming in on a somewhat different angle to make that happen. But it would’ve left a mark.

  28. According to JR, drier air will chew into Dorian and prevent the heaviest rain from moving northward into Boston and beyond.

      1. Absolutely. It was one of the reason I was going for heaviest southeastern MA (mainly CC & Islands) and downplaying the NAM’s development of heavier showers much further north and west.

    1. They take some big hits, not only from your winter storms, but these hurricanes on the way to the extratropical graveyard.

      2. They do have a long-term average of 1 hurricane every three years.

        There is a bit of clustering during peak warm phase of AMO.

        1. No idea what our recent average is but it isn’t one in three years but then we don’t stick way out in ocean.

          1. If you look at the average long term hurricane re-curvature paths, they average far more hurricane hits than we do.

  34. With respect and sympathy to the people that lost everything, Dorian has ended up as a hurricane that will be a teaching tool in the meteorological world. It was classic in many ways. It formed in the “classic zone” and moved in a very classic path. It provided real time examples of what hurricanes can do when they maximize their potential strength and also what they can do when they become stationary. It also illustrated interaction with mid latitude features perfectly, right down to its acceleration and transition (ongoing). As briefly discussed above it is also showing why a place like Nova Scotia Canada gets more hurricane landfalls than New England, taking out the possible assumption that just because an area is further south it should have a higher risk of landfall.

    Dorian may have caused major destruction in a relatively small geographical area, but it has taught some big lessons about weather and media communication that I hope are paid attention to and learned from.

  35. Good morning,

    A whopping 0.18 inch in the rain gauge from Dorian from showers. Main rain shield
    NEVER even made it close to here.

    2. Didn’t think it would make Boston, but it was even further southeast (maybe 25-30 miles) than I thought.

  36. Baccaro Point, NS which is a bit SE of Yarmouth, NS and right on the Atlantic at 9am

    Sustained wind of 50 mph, gusting to 63 mph.

    I’ll know my 1.6 division facts by days end.

    1. Liverpool, NS which is probably a good 100 to 150 miles to the east northeast is sustained at 32 mph, gusting to 50 mph.

      Extra-tropical transition, wind field is very expanded out.

  37. https://www.star.nesdis.noaa.gov/GOES/GOES16_sector_band.php?sector=eus&band=13&length=24

    https://www.star.nesdis.noaa.gov/GOES/GOES16_sector_band.php?sector=eus&band=GEOCOLOR&length=24

    As a tropical system, the appearance looks very poor (link 1)

    As a mid-latitude system, the appearance looks very impressive (link 2)

    I’ll be interested to see some of the landfalling pressures. My instinct tells me the pressure is much below the 965 mb on the current advisory.

  38. Updating now. I was awake 3 hours in the overnight that I didn’t plan on being, so I rested a bit after that. 🙂

    Brewing the coffee now… Blog should be done by about 10 or a little after.

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