Friday Forecast

113 Comments

7:30AM

DAYS 1-5 (MARCH 9-13)
An upper level low pressure area will cross the region this afternoon and evening, triggering some snow showers and possible snow squalls. Anybody that experiences a snow squall can see visibility drop very low in brief heavy snow and gusty wind, but it will not last long. High pressure builds in for a decent weekend, though it will still be breezy and chilly between the advancing high and low pressure offshore especially early in the weekend. Watching the next storm system that will pass south of the region later Monday and early Tuesday, but perhaps close enough for a period of snow/mix. Upper level low pressure lingering over the region Tuesday will at least produce snow showers.
TODAY: Variably cloudy. Scattered afternoon snow showers except rain or snow showers South Coast. Isolated heavier snow squalls possible. Highs 33-40. Wind NW 10-20 MPH with higher gusts.
TONIGHT: Partly cloudy. Scattered snow showers/squalls early. Lows 23-30. Wind NW 10-20 MPH with higher gusts.
SATURDAY: Partly cloudy. Highs 37-44. Wind NW 10-20 MPH with higher gusts.
SATURDAY NIGHT: Mostly clear. Lows 20-28. NW to N 5-15 MPH.
SUNDAY: Mostly sunny. Highs 38-45. Wind N 5-15 MPH.
MONDAY: Cloudy. Chance of rain/mix/snow. Lows from the upper 20s to middle 30s. Highs from the middle 30s to lower 40s.
TUESDAY: Mostly cloudy. Chance of snow showers. Lows from the middle 20s to lower 30s. Highs from the middle 30s to lower 40s.

DAYS 6-10 (MARCH 14-18)
Another upper level low pressure system crosses the region March 14-15 with a snow shower risk, and will watch for the spawning of a stronger offshore storm system. A faster-moving weather pattern evolves and advancing milder air may bring a risk of light precipitation by March 16, high pressure brings fair weather March 17, and a low pressure wave and cold front brings a risk of rain showers by March 18. Timing a little uncertain with this being beyond 5 days away.

DAYS 11-15 (MARCH 19-23)
A more progressive pattern means up/down temperatures and passing weaker weather systems.

113 thoughts on “Friday Forecast”

  5. Thanks, TK…
    Beautiful late winter’s morning.
    It will be dark again for the commute come Monday, but not for long.

    Found out that 64% of the neighboring town of Norton was without power early Thursday morning. 80% of the town lost power last weekend. Double-whammy this week for the Lancers.

    Here’s hoping that everyone gets power back soon and that we get a stretch of tranquil weather for clean-up and “de-stressing” as opposed to distressing which many of us have been doing in the last week.

    Take care, and have a great weekend, y’all!

    1. I read on FB this am (and we know how reliable FB can be šŸ˜‰ ) that two substations went in our area. That makes sense and explains why large areas went dark at the same time and returned online at the same time. One has been repaired. The other is still a work in progress.

  6. Thank you, TK.

    Tom, I’m happy folks down your way had a chance to see the sun. Do you still have pockets of folks down that way without power? I seem to recall seeing yesterday that most of Humarock is now accessible so that people can get to their homes. I have not seen anything on Brant Rock/Green Harbor area.

    I am keeping fingers crossed that there are no more off shore systems that can kick anything back at our coast.

  8. Good morning and thank you TK.

    Re: Snow shower/squalls today

    Last night Eric made it sound like armageddon with the snow squalls.
    He said Squalls and not Showers. Did he over do it? Or presumably he really
    feels that the squalls will materialize and be quite potent.

    You mentioned the upper low passing through, but does today qualify as
    a possible WINDEX event?

  9. Interesting feature from the EURO. ALthough the main low is off shore,
    there is snow extending back to the NW.

    Here is the surface map with precip and the 500mb Vorticity Advection.

    https://imgur.com/a/pTlMT

    The Vorticity advection shows strong upward motion in the atmosphere.
    It looks somewhat like a Norlon, but I think more a function of the 500MB
    configuration. IN any case something to monitor.

    TK, WxWatcher your thoughts?

    1. From NWS re: Snow Squalls

      There is the potential for scattered,
      hit or miss, snow squall activity over S New England. The highest
      confidence over the W-facing slopes of high terrain. The threat
      of white-out conditions continue with the potential for a quick
      1 to 2 inches in a very short amount of period of time. Could
      catch motorists off hand with the creation of hazardous travel
      conditions. Close eye on conditions as we go through the day.
      The atmosphere primed for convective activity given the cold air
      advection yielding steep lapse rates through a column that is
      fairly well saturated in the lowest levels. Parameters necessary
      for netting snow squalls.

        1. Well they may take their hands off of the wheel
          and crash, so it still fits. šŸ˜€ šŸ˜€ šŸ˜€

    2. Could this be a similar case of the storm being 500 miles south and moisture feeding off the ocean like a few years back?

      1. Not sure, I thought that with the set up you are referring to,
        we had an Easterly fetch at 850 mb as well as 500mb.

        This current Euro set up does not feature 850mb Easterly winds.
        This appears to be a function of the powerful 500mb feature.
        Of course just because the Euro has this, does not in any way
        mean it will happen.

        I just find it extremely interesting. IN fact this whole Winter
        has been interesting and not just snow set ups.

  11. Not only is next week the last full week of winter, but the last week of “winter threats”as well, assuming there are no spring snows on the horizon.

  12. Thanks TK. I’ll be keeping an eye out for those squalls today. Funny enough, I’m driving out to eastern NY for the second weekend in a row, on completely unrelated business. Saratoga Springs this time for the 2018 Northeast Storm Conference. Should be a fun weekend, this conference is a traditional meetup for college met students across the Northeast.

    Seems like we’ve had very few “squall days” this winter.

  13. Iā€™m off today do I need to worry about a call in tonight Iā€™m still recovering.

    1. the feature is a closed upper level low that moves in from Canada, that keeps the main storm well south and east but interacts with it to create areas of snow showers spinning around the circulation.

  17. Will the snow showers currently over Boston Harbor move westward into the city itself and beyond? Just wondering.

  18. In reading comments with regard to power loss, it seems that many in very different areas, lost power a couple of hours either side of the 3:00 am hour Thursday morning. Am I correct that is the period that the comma head (mentioned by you, TK, and a few others) brought us the heaviest snow/accumulation?

    I follow several different towns from Sutton to metrowest and perhaps that is not representative enough.

    1. Somewhere around that time frame for that area.
      TK can confirm for you. At my house we were more into it around 4-5 AM ish.

      1. I am seeing about 2 hours on either side of 3:00 am – probably more on the latter end. I just found it interesting since we went out at 3:00 but so many others have said the same in areas far removed from Sutton. Just one of those silly things that fascinates me.

      1. Considering yesterday morning it didn’t even have it, I’d say
        things are looking up or down depending upon your perspective. šŸ˜€

    1. More in Western MA and Eastern NY. We could be looking at off and on
      Snow Showers for quite a while. IF we were to get a few heavier ones or
      squalls could see and inch or 2 of snow, perhaps enough to put Boston
      at or above average snowfall for the Winter. šŸ˜€

    2. I’m under one.

      Radar is more impressive.

      Bright sky this time of year makes these totally innocuous.

    1. ps, red means higher impact, blues and purples near no impact.. Most of the reds come from euro ensemble members that have 960-970 lows near our coast.

      1. Matt, did you create that map or do you have a website for it
        and if so, would you mind sharing.

    2. That is AWESOME!!
      Can you share a link? OR did you create this? If so, way cool and thanks

  24. From Eric Fisher
    If I were placing odds on effects of Monday PM into Tuesday AM storm potential…would go:

    60% fringe (some snow/wind but not huge)
    30% significant snowstorm
    10% total miss

    1. Thanks JJ.

      That sounds “about” correct at this point.

      On could argue for any of the percentages to move a bit in either direction, but
      I’m comfortable with them.

      Subject to change of course.

  25. Clear message this storm should not be written off. Those EURO ensembles look closer than they did yesterday.

  29. the later it takes the better chance of this storm giving us a decent hit due to the uppler level low moving a bit further northeast.

  30. 18Z NAM is in….

    Has system WELL off shore, however,
    It has another weaker system just North of us.
    It has an negatively tilted 500 mb trough just NW of us.

    Here is the surface

    https://www.tropicaltidbits.com/analysis/models/nam/2018030918/nam_mslp_pcpn_frzn_namer_28.png

    another look

    http://www.instantweathermaps.com/NAM-php/conusncep.php?run=2018030918&var=PCPPRSTMP_2m&hour=084
    Here is the 500mb vorticity chart

    500mb Vorticity

    https://www.tropicaltidbits.com/analysis/models/nam/2018030918/nam_z500_vort_namer_29.png

    500 mb chart

    http://www.instantweathermaps.com/NAM-php/conusncep.php?run=2018030918&var=VRTHGTGRD_500mb&hour=084

    Makes one wonder if some sort of funky interaction occurs here????

    Also, here is the culprit keeping the main system off shore. It is the 200mb flow which
    is just too flat.

    http://www.instantweathermaps.com/NAM-php/conusncep.php?run=2018030918&var=GRDHGT_200mb&hour=084

    1. All eyes are on this, but weighing it all, it appears more likely than not
      that there will be some sort of graze or Norlun-like precipitation event
      with something like 1-3 or 2-4 inches.

      I shall monitor with great interest, which is always the case.

      1. That is NOT to say that there isn’t some non-zero probability
        that it could end up being a big hit. Time will tell.

          1. Of course. That is a given. Just looking to see what it had to say. Looking at the set up and possibilities as I always do.

            This “could” end up being most interesting.

            or NOT. šŸ˜€

  36. I have two issues with this model run. 1) It’s the 18z suite and 2) It’s the GFS šŸ˜€

    1. Also showing more coastal development off the Outer Banks immediately on the heels of the first system.

  38. Reminder: Snow showers that look unimpressive on radar can be heavier than they appear, especially more distant from the radar. They are rather low-topped.

  41. I get the impression that the storm will be so huge that just a few flakes or nothing falling from the sky would be highly unlikely. Correct?

    1. If the precip from the main storm is offshore, ours would come from upper level low pressure.

  42. Eric Fisher said:

    If I were placing odds on effects of Monday PM into Tuesday AM storm potential…would go:

    60% fringe (some snow/wind but not huge)
    30% significant snowstorm
    10% total miss

    1. Based on everything I have analyzed to this point, I agree completely with Mr. Fisher.

  49. Good morning. NWS has NOT written off the next event.

    Part of the NWS discussion Concerning Monday night/Tuesday:

    Discussion…

    For this time period, the primary focus is on how close a
    coastal/ocean storm will pass southeast of New England. There are at
    least two sources of energy at play with this scenario. One is a
    southern stream shortwave, and the other is a strong short wave
    trough dropping south in an amplified northern stream. The key
    question would appear to be whether the surface system that develops
    off the east coast in association with the southern stream
    short wave outruns or becomes captured by the northern stream
    upper trough. The consensus of models and their ensembles would
    suggest at least a glancing blow for southeast New England, but
    there is modest spread among individual models and considerable
    spread with their ensembles. Both the 00Z GFS and 00Z ECMWF have
    some ensemble runs that keep the surface center quite far
    offshore and other ensemble runs that would equate to a big
    impact for snow and wind across much of southern New England
    with a deep (sub 980 mb) surface centers passing near or even
    slightly inside of the benchmark. There seems to be a trend of
    the consensus at least modestly toward the west and suggestive
    of greater interaction between the southern and northern
    systems. In short, confidence on the surface low track for
    Monday night and Tuesday remains below average given the spread
    in ensembles. A look at the 500 mb pattern may be more revealing
    as it suggests the northern stream short wave trough will be
    quite strong and by itself produce upper level difluence over
    the area late Monday night into Tuesday with consequent lift
    across the area.

    1. Here are some Euro charts for Tuesday Afternoon at 18Z (normally 1PM, but with DST 2PM. I believe for this run it still would be 1PM)

      https://imgur.com/a/zZdah

      The surface shows precipitation well NW of low center

      The 700MB Heights shows a norlun-like feature at that level. LIke a 700mb inverted trough.

      The 500 mb vorticity chart shows the spin in the atmosphere at that level.

      Synoptic scale vorticity is analyzed and plotted on the 500-mb chart. Vorticity is a clockwise or counterclockwise spin in the troposphere. 500-mb vorticity is also termed vertical vorticity (the spin is in relation to a vertical axis). This vorticity is caused by troughs and ridges and other embedded waves or height centers (speed .

      The 500mb Vorticity Advection leads to rising/falling pressures at the surface. Vorticity is the localized rotation of the air. Air that rotates counterclockwise, such as in … More specifically, vorticity advection is indicative of rising motion/falling pressures at the surface.

      I think this shows what the NWS meant when they said: ” A look at the 500 mb pattern may be more revealing
      as it suggests the northern stream short wave trough will be
      quite strong and by itself produce upper level difluence over
      the area late Monday night into Tuesday with consequent lift
      across the area.”

  50. The NWS should definitely not write off a snow event, even if the offshore storm doesn’t solidly impact the area. There will be a northern stream system, quite strong, and some connection between the 2.

    Updating…

    1. I was noticing that just a bit ago. Waiting for run to complete.
      Looks like the streams want to dance a bit more. šŸ˜€

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