Wednesday October 7 2020 Forecast (7:04AM)

45 Comments

DAYS 1-5 (OCTOBER 7-11)

Discussion…

A cold front sweeps across the region later today. Ahead of it we will have varying amounts of clouds. A rain shower threat exists but is greatest from mid through late afternoon from northwest to southeast across the area. Thunder is possible in any of the heavier showers but the biggest threat today will be wind, becoming gusty ahead of the rain shower threat, but also existing within the shower activity as well when some damaging gusts may occur. Drought-stressed trees still foliated are quite vulnerable to gusty winds at this time. After a mild day ahead of this front, it will turn much cooler tonight and we’ll have 2 cooler days coming up Thursday and Friday, along with a gusty breeze, especially Thursday, as high pressure approaches from the west. The center of this high will slip south of New England by Saturday and we’ll have a day of westerly wind and a significant warm-up. In fact, it will feel a little bit like summer on Saturday. But that won’t last as a cold front slips down from the north, pushed but another high pressure area in Canada, to give us a cool-down by Sunday. While Saturday likely to be a day filled with plenty of sun, Sunday may end up less so, as a lot of high cloudiness may be moving in ahead of the remains of what is currently a major hurricane near the Yucatan Peninsula of Mexico, and will have made its way across the Gulf of Mexico and into the southern US later this week.

Details…

TODAY: Variably cloudy. Scattered showers and a slight chance of a thunderstorm mainly afternoon hours. Highs 67-74. Wind SW 10-20 MPH with gusts 25-35 MPH and spotty gusts 35-50 MPH Cape Cod area. Brief gusts above 50 MPH are possible with the passage of some of the rain showers.

TONIGHT: Clearing. Lows 48-55. Wind W 10-20 MPH with gusts over 30 MPH evening, diminishing slightly overnight.

THURSDAY: Sun and passing clouds. Highs 57-64. Wind NW 10-20 MPH with higher gusts.

THURSDAY NIGHT: Mostly clear. Lows 32-39 except 40-47 immediate shoreline and urban centers. Wind NW 5-15 MPH with higher gusts.

FRIDAY: Mostly sunny. Highs 53-60. Wind NW 5-15 MPH with higher gusts.

FRIDAY NIGHT: Clear. Lows 38-45, except a little milder in urban centers. Wind NW up to 10 MPH.

SATURDAY: Mostly sunny. Highs 72-79. Wind W 5-15 MPH.

SATURDAY NIGHT: Mostly clear. Lows 52-59. Wind W under 10 MPH.

SUNDAY: Sun and high clouds. Highs 62-69. Wind NE 5-15 MPH.

DAYS 6-10 (OCTOBER 12-16)

A quick look at medium range guidance this morning to give me an idea of what the computers “think” about the moisture from the remains of Hurricane Delta: GFS says rain here October 12 while ECMWF (Euro) has it dry. In fact, the Euro model never brings any rain into this area from that system or any other system through October 16, while the GFS keeps a few showers around through October 14 then has an offshore low with rain nearby but not over the region on October 15 until both models finally agree on dry weather for day 10 (October 16). The fun of guidance, and why the meteorologist has to know what not to believe as much as what to buy into a little bit more. With all of that said, I’ll lean today toward a day of lots of clouds and a slight chance of insignificant remnant rain on October 12 here, and a few rain showers around around October 14 from a passing system from the west, and will agree with both models about a dry ending to the period. Temperatures mostly above normal, cooling to normal later in the period, based on my expected timing of systems.

DAYS 11-15 (OCTOBER 17-21)

Looking for a generally zonal (west-to-east) jet stream flow with mostly dry weather and temperatures variable but averaging close to normal.

45 thoughts on “Wednesday October 7 2020 Forecast (7:04AM)”

  3. Thank you TK!
    Would you say the core of the strongest winds here in central mass would be in the 3:00 to 7:00 timeframe?

  4. Thanks hoping the wind won’t be as bad in pembroke as last week . My son was securing the haunted house last night . Thanks for the forecast Tk

  7. Thanks, TK…

    Hatches battened again. I am remote the rest of the week with my classes. Hope the power stays on for everyone involved. This is tough enough as it is!

    1. Discussion:

      …NY/New England…
      Widely scattered thunderstorms are possible during the daylight
      hours, sweeping roughly eastward across the outlook area. Isolated
      severe/50-kt+ gusts are possible, as well as sporadic gusts that are
      subsevere but still locally damaging.

      Large-scale ascent is forecast to increase across the outlook area
      today ahead of the mid/upper trough, both as warm advection and
      DCVA, while diurnal heating occurs erratically amidst cloud breaks.
      Resulting deep-layer destabilization (increasing lapse rates in the
      midlevel and boundary layer) will combine with meager but sufficient
      low-level moisture to yield surface-based buoyancy and minimize
      MLCINH ahead of the main UVV plume. A swath of 200-600 J/kg MLCAPE
      (decreasing southward with weaker midlevel lapse rates) should
      develop across northern NY and shift eastward, in the presence of
      strong deep-tropospheric wind fields beginning just above the
      surface. The nearly unidirectional nature of vertical wind profiles
      will limit bulk shear somewhat; however, sufficient speed shear
      still will develop as the trough approaches to yield 35-50-kt
      effective-shear magnitudes.

      The main change to the outlook for this cycle is to add some more of
      ME to the severe probabilities, given forecast soundings and planar
      fields reasonably showing enough diurnal destabilization to permit
      the preconvective field of around 500 J/kg MLCAPE to extend over
      this area briefly. Some consideration was given to a 15% area,
      given the strength of ambient flow. However, lack of greater
      low-level instability/moisture, and associated potential for
      convection to be rather shallow and skeletal, still indicates
      organized wind potential is rather conditional at this stage.

  9. Thank you, TK.

    Some Indian Summer this week. Yesterday’s sun was powerful. I haven’t been out yet, but I’m assuming it’s more of the same. A really warm sun, still. By the way, because of Boston’s latitude – much lower than Northwestern Europe – it’s virtually impossible to have days like these in the Netherlands in October. There, by early to mid October the sun has no `strength.’ I’m sure Indian Summer days surprised the Pilgrims. They must have been confused by it, as it wasn’t something they’d ever experienced before in East Anglia or Leiden, the Netherlands.

    1. That’s a max heating / instability result there. It won’t carry eastward like that.

  14. https://www.spc.noaa.gov/products/outlook/day1otlk.html

    Discussion:

    SPC AC 071929

    Day 1 Convective Outlook
    NWS Storm Prediction Center Norman OK
    0229 PM CDT Wed Oct 07 2020

    Valid 072000Z – 081200Z

    …THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR EAST-CENTRAL
    NEW YORK INTO PARTS OF SOUTHERN NEW ENGLAND…

    …SUMMARY…
    Strong to locally severe wind gusts are possible this afternoon and
    perhaps persisting into the early evening from parts of the Hudson
    Valley into southern New England.

    …Discussion…
    Have upgraded to 15-percent wind probabilities for parts of
    east-central NY eastward into southern New England ahead of a squall
    line quickly moving east across NY. Several NY Mesonet sites in
    Chenango, Montgomery, and Herkimer counties have observed gusts in
    the 50-56 mph range during the past hour.

    Water-vapor imagery shows a potent mid-level shortwave trough moving
    into the Northeast. The flow associated with this disturbance is
    quite strong (50 kt at 1.5 km ARL) as sampled by the KENX (Albany,
    NY) and KBOX (Boston, MA) 88D VADs. Although the earlier rain
    shield has progressed across southern New England, cloud breaks and
    peak heating in wake of these showers will enable at least some
    steepening of the low-level lapse rates and a few hundred J/kg
    SBCAPE to develop. Given the strongly forced squall line with
    adequate instability developing ahead/downstream of the convective
    line, it seems plausible strong to locally severe gusts (50-60 mph)
    via horizontal momentum transport, will continue or possibly
    increase in coverage over the next few hours and result in widely
    scattered wind damage.

    ..Smith.. 10/07/2020

    1. Has a bit of that look but not quite there – just a squall line. The severe thunderstorm warnings are for the wind potential.

        1. For the moment, yes. But once it gets into more stable air and is in an area that was not heated significantly, that will change rapidly.

  16. Time to put betting cards on the table. Line of storms fall apart by the time it reaches eastern NE!

      1. I may loose that bet. Storms are 30 miles or less west from me and still holding…

        Queue drum roll

  17. TK question. When there are strong winds accompanied with fast cold front like today, does less rainfall make it to the ground because of the rain being primarily blown all over the place from heavy wind? It’s a confusing question but one that ponders me.

  18. All of northern CT under a severe t-storm warning now. Sky is pitch black to the north.

    74 mph wind gust just reported at Westfield with this line!!

  21. Ok, well ….. October 7th for the best thunderstorm of the year ????

    Holy moly did that move in fast !!!

  22. That was insane in pembroke I was on the front porch watching all I heard was snapping . The haunted house went airborne & it’s destroyed for tree mmmmm the second time but this one brought it to pieces . Multiple trees down been without power for about an hour

  24. Umm, I think it held together. My daughter texted from
    Hopkinton saying it was the worst storm she had ever seen.

    Held pretty much together right to the coast.

    Picked 0.19 inch of rain here in JP.

  25. Wow! Blew through Harvard at 6’ish – trees down everywhere. Power still out. Possibly the most exciting 5 minutes of weather in my life – we are wondering if it was a microburst as it spun up so quickly and so many trees went down!

  26. In my years living in SNE, I don’t recall a more impressive thunderstorm wind event in terms of how widespread the severe winds were, though I’d be open to comparisons. Either way, a very impressive serial derecho over NY and SNE.

    1. I’ve seen a couple comments on FB saying “derecho, confirmed” etc. Yes, it was an impressive event. I’ve seen worse for sure, but this was pretty decently sustained and fairly widespread.

      It wasn’t a derecho though, at least in the classic sense. Those are self-perpetuating. This was a cold front. The conditions just turned out to be good right over SNE for the length of the squall line’s trip. If NWS terms it a derecho (one of the other varieties) then I accept that. But You don’t confirm a derecho as a weather enthusiast just because it had a lot of wind. I saw one comment out there that said “I saw big wind and big rain. That confirms it.” No, it doesn’t. Another said: “It’s confirmed, because I watched it on Radarscope.” Um, NO. Ignorant statements like that irk the ever living crap out of me.

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