Thursday Forecast

254 Comments

2:31AM

DAYS 1-5 (MARCH 30-APRIL 3)
A very nice day often precedes the arrival of a storm, and that will be the case today as high pressure dominates with plenty of sunshine. The March Lion will bring southern New England a storm of rain/mix/snow to end the month and linger into the opening hours of April – not really atypical of this time of year, and only ironically on the 20th anniversary of the much larger and more impacting “April Fools Storm” of 1997. With this system just a day away from arrival, it is now time to try to pin down some details. What I do know is that low pressure will approach from the west and track eastward, passing just south of New England, spreading a large shield of precipitation across the region during Friday, peaking Friday night, and lingering into Saturday. The critical part of the forecast will be the position of a rain/snow line during the event, as well as whether or not enough warm air gets in aloft to result in sleet rather than snow for a portion of the storm. Also, a strip of freezing rain needs to be considered as temperatures may be warm enough aloft for rain and cold enough at the surface for it to freeze. I don’t think this will occur over a widespread area, however. This is how I think it plays out: Friday, precipitation moves eastward during the day in a couple batches, fighting dry air, but with periods of snow, which will have difficulty accumulating when it falls as is typical for spring daytime snow. Lighter mix/rain would likely occur in southern MA/CT/RI. Later in the day and into the evening a more solid area of precipitation is likely to move in from west to east, peaking during the overnight hours. During these hours is when the position and movement of the rain/mix/snow areas are most critical as this is when most of the snow accumulation would occur. It continues to be most likely that the most significant snow accumulation will occur away from the immediate coast and favor the higher elevations especially from central MA into southwestern NH, but this does not eliminate the possibility of significant accumulation elsewhere. For now I am going with a slightly colder scenario with a rain/snow line and a narrow band of sleet moving into eastern MA and Seacoast NH to about I-95 and in most areas south of the Mass Pike (I-90) with a tendency for this to happen more quickly in valley areas and more slowly in higher elevations. Where a changeover occurs except a narrow band of sleet and also some freezing rain favoring the southern higher elevations of central MA. During Saturday, the rain/mix/snow line will waver around as precipitation gradually tapers off from west to east, finally becoming mostly patchy light rain/drizzle with a little mix to the north. Current call on total snow accumulation: Under 1 inch South Coast and most of southeastern MA, 1-3 inches NH Seacoast to Cape Ann MA to Boston to Providence westward to Hartford, 3-6 inches from just west of I-95 to near I-495 in northeastern MA down the I-95 belt to I-90 then westward along I-90, 6-10 inches central MA into interior southern NH with higher amounts possible in highest elevations. Some adjustments may still be made to this forecast! A weak disturbance will bring some cloudiness and possibly a passing rain/snow shower Sunday. High pressure moves in Monday with nice weather, and combined with afternoon opening day baseball at Fenway Park will make the recently-departed storm seem like a distant memory. Forecast details…
TODAY: Sunshine, high clouds late. Highs 44-51. Wind N 5-15 MPH.
TONIGHT: Increasing clouds. Lows 27-34. Wind light N to NE.
FRIDAY: Overcast. Periods of snow except mix/rain southern MA/CT/RI. Highs 34-40. Wind NE 5-15 MPH.
FRIDAY NIGHT: Overcast. Snow except rain near South Coast then mix/change line advancing north and northwest into areas mentioned above. Lows 30-38. Wind NE to E 5-15 MPH, higher gusts in coastal areas.
SATURDAY: Overcast. Precipitation tapering off west to east with snow/mix interior NH to central MA, rain elsewhere. Highs 35-42. Wind NE to N 10-20 MPH, higher gusts possible.
SUNDAY: Variably cloudy. Chance of a few rain/snow showers. Lows 30-38. Highs 38-45.
MONDAY: Mostly sunny. Lows 28-35. Highs 44-51.

DAYS 6-10 (APRIL 4-8)
Active pattern. Rain/sleet possible April 4. Additional unsettled weather April 6-8. Temperatures below normal.

DAYS 11-15 (APRIL 9-13)
A break in the active pattern as it turns drier but temperatures remain mostly below to near normal.

254 thoughts on “Thursday Forecast”

      1. Arrival during the day Friday but trouble with accumulation where it is snowing due to high sun angle. This is going to be a Friday night event in terms of snow accumulation, wherever and whatever it ends up being.

    2. Gonna love the 00z Euro coming out with 25-30 inch snow totals in north central MA and nearby NH…

      Of course we know all about Euro snow totals…

  3. Thank you, TK…
    GREAT job as usual.
    High school baseball team opens its season in Falmouth tomorrow.
    Don’t think that’s happening!

    Enjoy your Thursday, y’all!

  4. I think you’re 1-3 for Boston is a good call however how come not c-3 . And as you said anything during the day is just wasted this time of year. I’m curious to see later runs. Thanks Tk.

  8. Thanks TK. All the meteorologists this morning are currently sticking with their maps from yesterday. Fun times.

  10. Good morning and thank you TK. Outstanding discussion.

    Euro still not on board for an all out snow event for boston, however, some of the other
    models concern me. The GFS has not backed down one bit, if anything more bullish
    for Boston. The 12KM and 3KM NAMS are very bullish and FWIW, the CMC has now
    come on board in a big way.

    I have not checked with the NWS just yet.

  11. The 3Z SREF ensemble Mean has 4.87 inches for Boston, Which most likely means
    the 1-3 inches TK has. 😀

  12. Yes, I know, I am posting maps backwards. But I just looked at the 0Z FIM out of curiosity. Knowing that at least some here share my curiosity, here is the FIM
    10:1 snow map. Take 33% of this and it’s still 4-6 inches of cement. I am concerned
    about this. Want to look at the 12Z runs and I’ll make a call, but I am leaner a little higher than most current forecasts, at least as of now.

    Here ya go:

    https://fim.noaa.gov/FIM/for_web/fim7_jet/2017033000/t3/totsn_sfc_f084.png

  13. Thanks TK! It sounds like my colleagues flying home from Logan tomorrow afternoon are going to be saved by the high sun angle.

    Looking forward to seeing the phrase “above normal temperatures” in the forecast!

  14. The Pivotal Site does not have the NAM snow maps avaialble.
    COD only has the regular NAM and has virtually Nothing South of the MA/NH border.

    However, when I look at Tropical’s 12KM and 3KM NAM the 10:1 maps show
    close to a foot for Boston. Something is whacked out.

    The Tropical “may” not be accounting for a crapload of SLEET? We saw that
    earlier this season.

    Here are the 2 Tropical TidBits NAM 10:1 Maps

    12KM

    http://www.tropicaltidbits.com/analysis/models/namconus/2017033006/namconus_asnow_neus_29.png

    3KM

    http://www.tropicaltidbits.com/analysis/models/nam3km/2017033006/nam3km_asnow_neus_61.png

    CMC

    http://www.tropicaltidbits.com/analysis/models/gem/2017033000/gem_asnow_neus_11.png

    GFS

    http://www.tropicaltidbits.com/analysis/models/gfs/2017033006/gfs_asnow_neus_11.png

  15. The Difference between the Kuchera Snow and the 10:1 snow probably represents
    more than just the ratio. I think the 10:1 does NOT account for sleet, while the Kuchera
    takes into account temperatures at different levels and perhaps does adjust at least some for SLEET.

    We shall see.

    Given this, the GFS and FIM and CMC keeps it more snow. The NAMS more sleet.
    Euro snow/rain/sleet/snow.

    It’s going to be awfully close.

    1. I really like the thinking of maybe a rain / mix event never transitioning to straight snow . I’m looking forward to what Sak has to say later today as well.

      2. I disagree. Boston will see a period of snow. Now, could that
        transition to sleet and/or rain? Certainly.
        Could it hold down the accumulation? Yup
        We’ll know soon enough.

      3. Is it that you really would like that result OR your fine meteorological skills are telling you this will be the result?

        1. You have an opinion as well as I . You are 500% Better than me at this but at times I think you go to high. It doesn’t matter if we here are right or wrong . I don’t think this is a set up for high totals for the city of Boston again in my opinion . Let’s see how it plays out we will both be in the city as I’m sure I’ll be on watch for the night . Always enjoy your contribution to this blog as again your one of the experts here not I but I do understand what’s going on ,

          1. We’ll know soon enough.

            For the record I have not given my total for Boston. I did say I was “leaning” higher.

            However, I am still digesting it all and want to see the 12Z runs. I need a better handle on this
            possible warm layer at the 850-700MB level.
            Even TK mentions that. That is the WILD card here. IF that moves in, POOF goes the accumulation. If it stays to the South you will
            be surprised at how much snow will accumulate
            even in Boston.

            Time will tell as it could go either way.

          2. I beg to differ. JPD doesn’t necessarily have an “opinion”, he is able to interpret models and use meteorological knowledge in his forecasts.

            1. Thank you Sue….

              Oh, I sometimes have a gut feeling which probably goes as an opinion, but I try hard to keep that out of the way, not always successfully, mind you. I do try to look at the data.

              It is very easy to let wishful thinking creep into a forecast or opinion for that matter. That is a danger.

              I am well aware of that and try hard not to let in.

              I am aware of the situation for tomorrow. This one is a really tough call, especially for Boston and the Immediate surrounding area. I think so far most forecasts are in the “Safe” mode, however, I believe forecasters are well aware that their totals for Boston could bust in either direction.

              I would NOT want to have to make a public forecast on this one. Absolutely
              would not.

              1. Nothing wrong with gut feelings JPD. The fact remains, you know your stuff and it is quite clear in your posts.

  16. Thanks TK! Great discussion. I agree on just about everything. I do think it will be very difficult for snow to accumulate in the Boston area, and anywhere right along the coast. Mark me for under an inch at Logan, maybe a slushy inch elsewhere in the city. But in general, I think TK’s numbers are right on.

    1. Ha! Your thoughts don’t surprise me since you did predict less than an inch of snow in Boston for the remainder of the season. Should be a fun little storm tomorrow 😀

      1. That fact that you are here Arod, tells me something.
        This one may hold a bit of surprise, albeit with bust potential.

  17. Thanks TK. I don’t envy the meteos trying to forecast this one. It is going to be tough and seems like there could be some impacts in some places due to the ratios.

    1. Not to mention the warm layer wild card.

      Looking closely at the NAMS, they show considerable SLEET across
      the area which would greatly impact the accumulations but make for a mess.

      I could see my area getting 4-6 inches of heavy wet snow OR an inch or 2
      of Snow/Sleet mess Or Next to nothing at all. Impossible to say right now.

      NAMS have a ton of Sleet while CMC and GFS have much more snow.
      Euro is in the middle with Snow/rain/sleet.

  18. For absolutely no reason that is based in science or any other rational tool, I have a weird feeling this one will surprise us with an extreme on either end – like almost nothing or an unexpected extreme clobbering. And I think it may be the latter. Why? Because my gut says so. Next I will consult my Ouija board and magic 8 ball. However for what it’s worth the last time I had this strong a gut feeling was in beginning of the 3rd quarter of the Super Bowl – I didn’t think we could still win, I knew we would win. Hoping my gut can go 2-2 but we shall see… that’s asking a lot of the stars!

  20. I don’t sense that the warm air intrusion on this particular event is a straight line moving from south to north.

    Early in the event, I think the full column is going to be colder longest in eastern and northeastern areas.

    I get this sense by looking at the shape of the isobars on the models, where the high is and how it will be retreating.

    For instance, take Boston and Marshfield. I think after they begin as rain or mix or a very wet snow, I think both locations may well switch to snow for a few to several hours into Friday evening and certainly accumulate at least on grassy surfaces and the trees. Then, in mid to 3/4 of the way thru the storm, there may be a switch to rain as a layer of mild air moves in above, then may switch back to snow before then ending as mix or rain again mid Saturday.

    Contrast that with say Springfield, MA or Hartford, CT which may switch to sleet or rain more quickly Friday night, because I think that mild air aloft may have an easier path northward in western parts of New England.

    That’s my theory. 🙂 🙂 🙂

    1. Well, Looking at the models, it bears out your theory.

      Eastern sections will be Closer to that retreating High and thus closer
      to the cold air source, what there is of it.

      I think it will be most interesting.

      1. Me too.

        I’d kind of go with 2-5 in Boston (lawns, trees) … perhaps its 1-3 at Logan, with 4-5 out in the immediatewestern Suburbs

        1-3 in Marshfield and frankly right down to the Bridges, again mostly on lawns and trees

        I kind of think Boston to South shore will need a winter weather advisory from late afternoon tomorrow to about midnight, then the rain/sleet line starts to arrive.

        1. Tom,
          You are usually conservative with snow amounts,
          but I think you are onto something here.

          NAM is cooking. 😀

          1. Definitely going with a colder solution.

            Low track (moving due east), retreating high into New Brunswick and not out into the ocean east of us …. upper levels cold enough for part of the storm, yes, I believe this is one time to go higher on snow amounts. 🙂 🙂 🙂

            1. With the heaviest falling at NIGHT,
              Sun angle is taken out of the equation.
              yes it will limit accumulations tomorrow
              afternoon, But once evening arrives, all bets are off. Then it will only be boundary layer temperatures and possible warm
              layer intrusion. We shall see.

    1. Thank you.

      That warm layer intrusion is the thing that will kill this for any snow
      accumulation. Will it get in here or will it be delayed enough? Ahh the million dollar question.

  22. The 12Z NAM puts the warm layer above into the Boston Area by about 10PM or so.
    AND to add to that there is no really heavy precipitation prior to that happening, thus little to NO accumulation. NAM is really sticking to this.

  23. If I’ve been paying attention, the NAM has been upgraded.

    Whatever happens on its 12z run, it won’t sway me too much from my thinking listed above.

    1. I don’t like this 12Z run at all. Brings in the warm layer above RAPIDLY.
      I don’t know how much sleet would be involved, but clearly not much in
      the way of snow. This appears to be LESS than the 6Z run.

  24. The NAM is cranking out the juice! If that warm layer weren’t happening…oh boy.
    Let’s see how the 3Km deals and then the 12Z GFS and Ultimately the Euro.

  26. 12Z NAM does show the warm layer crashing to the South, passing well South of
    Boston before precipitation quits. Wants to hit NE Massachusetts pretty good.

    Wouldn’t take much to keep it colder.

    And this thing is getting juiced up really good.

  28. I have not taken a good look at the models for a little bit, been busy with college stuff, like getting ready for summer research/ calc exam today (grrrrr) and doing a geological survey on the National seashore this Sunday. It was going to be both sat and sunday, but convinced my professor not to go Saturday 😉 .

    I nterms of weather, when I looked on the models quickly while I should of been studying, looks like areas in the interior. North of the pike has best shot of 5+ inches of snow with highest amounts Berkshires and Worchester hills above 800 ft. with 2-5 west of I95 and less than 2 east of I95. freezing rain threat western mass. Sleet mixing in with the snow will hinder snow accumulations for most west of I95 (interior southeast mass) Snow will change to plain rain along and east of I95. We shall see when it falls the heaviest. Is it more Friday night or is it more Saturday.

  29. In my interpretation, the latest NAM verifies one theme.

    Look at where the heaviest snow bullseye is. It’s not to the west or northwest, it’s to our north and northeast. It’s also getting the idea that eastern and northeastern areas will have the coldest column throughout the event.

    1. agree with that assessment. I am just wondering IF
      it pushes the warm layer too far north and too fast?

      3KM Nam even worse with the warm layer.

      Why has virtually every forecast this season been oh so difficult.
      Snow, Rain, sleet, yes, no, maybe, I dunno FIIK!!!!

      I am going to label this storm FIIK

      1. I know the NAM has been upgraded and we haven’t had enough time to analyze it’s upgraded performance but I’ll bet it’s still carrying a bit of it’s too warm bias. Perhaps not as bad as before, but not fully corrected.

        1. I dunno. GFS is about to crank. Let’s see what it has to say. Before long we’ll be going with the HRRR and the RAP.

  30. 12Z 3KM Nam Kuchera snow

    http://maps3.pivotalweather.com/maps/models/nam4km/2017033012/060/snku_acc.us_ne.png

    10:1

    http://maps3.pivotalweather.com/maps/models/nam4km/2017033012/060/sn10_acc.us_ne.png

    3KM probably more realistic than regular NAM and quite a difference there.

    Sleet by 8PM and rain thereafter.

    http://maps3.pivotalweather.com/maps/models/nam4km/2017033012/036/refcmp_ptype.us_ne.png

    Change back to sleet around 2PM Saturday

    http://maps3.pivotalweather.com/maps/models/nam4km/2017033012/054/refcmp_ptype.us_ne.png

  31. 12Z GFS appears to be holding firm keeping the Warm Layer South, mostly along
    the South Coast or a bit North of there. So far anyway. Lays down the Snow
    all the way to the South Coast of Connecticut. I HATE MODEL DIVERGENCE!!
    Most especially this close to an event!!!!!!!!!!

    1. Arggh Still brings it North about 11PM tomorrow night. Certainly Some snow
      prior to that. Let’s see if it crashes South again????

  32. Since I just woke up, I’ll start looking at things shortly (after my morning Tim Horton’s), and will update my blog post. As I mentioned to TK very early this AM (right about when he posted this), I’m likely going to tweak my amounts up a bit, but probably not too much.

  35. Agree with colder GFS to a point. But not with its western edge of the snowfall, way too high. Agree with it Worcester, east, maybe less a little.

      2. I agree Joshua his style I Love it and there’s no sugar coating it he’s a straight shooter type of a guy like myself lol.

        1. John, I promise I am not picking an argument by asking this …… does that imply others who may have a different thought than SAK are not straight shooters ??

          For example, I certainly know SAK is way more accurate and meteorologically knowledgeable than most others here, but why cant others be telling it like they think also, when they give their opinions (this is my definition of a straight shooter). I don’t take straight shooter as right or wrong ……

          Thanks my friend. 🙂 🙂 🙂

          1. No they would be Tom as I believe others are the same as well I just like sak ‘s presentstion as much as Tk , and as much as you or old salty or arods just to name some . And I like the way you went about asking me this . I looks as you Tom ( you sure you want to know lol) your a straight shooter you tell it how you see it , a gentleman and a guy I’d enjoy having a cup of coffee with . Hope I answered your question . I find that texting can be tough sometimes.

            2. Thanks John. I appreciate that and find you to be a good person as well. I also hope this system does not turn into snow removal for you and your colleagues at the hospital which is an exhausting task, I’m sure.

  38. Caught up to the posts after being away for a good part of the day.

    TK, thank you as always for a tremendous discussion. Now for the fun.

    Today is just beautiful. 51.7, sunny, lov–er–ly.

    JPD – ALWAYS great to see your links and your comments, as well as discussion from Tom, JJ, and everyone else.

    Mama Mia…..I like your method. Same one I use. Although, I don’t have a feeling about this storm (my gut told me a while ago no more snow so clearly it is not working), I had that same feeling at what sounds to be about the exact same time you did during the superbowl!

    SAK – thank you very much as well.

  39. I’m looking at the euro 72 hrs.

    Now, while the 850mb 0c celcius line gets into north-central mass, it’s not like the 5 or 10c line makes it there. Seems that light shading is btwn 1 and 5c, mild enough to do the trick, but not super mild as to needing only to be slightly cooler. I can’t see projected temps at other important levels however.

  40. This is not what I want to read. I am hoping its just a cold rain.
    Tweet from Ryan Hanrahan
    Will trim snow/sleet amounts a bit shortly to account for more sleet & freezing rain with very little snow.

    1. So the 4c at Boston’s longitude is way way down by Martha’s Vineyard, which means that the 850mb temp over Boston could be 0.5c or 1c.

      Interesting …….

  43. Two more coastal storms on the 12z Euro next week….one Tuesday and one Thursday.

    Cold enough for snow/mix in the Berkshires and Worcester hills as well as in VT, NH, and ME with the Tuesday system. The Thursday storm is colder with mixed precip further south.

    Spring still on hold………..

  44. I think here in CT northwest northeast hills could get one heck of a sleet storm. Rest of state I think just a cold rain. However if it ever so slightly colder this will change and vice versa.

  45. Speaking of straight-shooting. There is a soap dispenser in my work that for months has shot basically sideways and will fire the soap in such a way to miss your hand if it’s underneath it, and land on the wall. Well, after months of forgetting this, I finally remembered today to put my hand to the left of the dispenser… Hah! This time I got you!

    ……..They fixed it yesterday.

    4. We have those here at work in the new bathrooms and the clean room’s gowning room. They spray soap every where but your hand!

      1. I’m not sure who designed those things. I’m guessing the same person who came up with the squirt guns you buy at the dollar store.

  46. So the consensus is the Euro being a blend of the NAM and the GFS?
    Is that the current thinking?

    I am not feeling it for a snow storm, but rather more of a Junk storm.

    We still have tonight’s runs for any last minute changes and then onto
    HRRR and RAP and the radars and observations.

    😀

    fwiw
    Euro has for boston: 1.4 then rain and then 1.9 for a total of 3.3 inches.
    How much sleet and how much rain. Seems like a crap load of rain in between.

    1. On WeatherBell, the Euro shows Boston mostly snow, occasionally mixing, with 11″ at Logan. Over 2″ liquid total.

    2. This is going to be somewhat of a typical very late season event. Not 1997. Not 1982. Maybe a little more like 1987, which came much later in April, but it reminds me a little of that one going into it.

      We must keep in mind March 31 / April 1 is certainly not January 15. 😉

        1. Great read. One of the storms I remember well. Sadly, we didn’t lose power but it was fun nonetheless.

  47. Is there a possibility of a layer of sleet accumulation more down this way where I seem to think you are all saying the rain/sleet line will appear first.

    I may be incorrect in my thinking that you are saying that. 80+ responses to read at once is a lot for my old mind to take in.

  48. I’m not questioning whether there’s going to be sleet …..

    I am surprised that this type of precip would be seen in a spring storm. I guess that speaks to a chilly lower layer in this setup.

    I guess I’m assuming that spring storms should feature more wet snow or rain as usually it’s the boundary layer that’s in play, especially during the daytime this time of year. But, I guess it’s the middle layer of the column that’s more in doubt this go around ????

      1. No, not at all.

        Like you, I have been hearing a lot about sleet and it’s surprising to me not because I disagree with it, but rather that I wouldn’t expect it in a spring storm. I would think we should see it more in the heart of winter when there can be very cold air sitting under a mild layer of air in the middle of the column.

      1. Sleet to the point of accumulating sleet where it causes power outages and tree damage, JPD? That is what I’ve been trying to figure out from the discussion here.

        1. Wet snow or ice is a tree issue, sleet usually doesn’t stress them much, just doesn’t stick to the trees. 🙂 🙂

  53. I think that ww advisory will eventually end up being dragged right to the coastline in SE Mass …..

    Besides the track, another big difference btwn this storm and the one a few weeks ago that saw Logan get 6.6 inches but Marshfield substantially less is that the high ahead of that system retreated east-southeast from New England out into the ocean east of us.

    The high on this storm is retreating a few hundred miles further north of us. I think that will help keep the lower level of the atmosphere colder in SE mass near the coast this go around, especially after sundown tomorrow night for some snow going to sleet.

  54. 18z NAM spitting out ice accretion amounts across parts of interior CT and MA through hour 33.

    1. Interesting.

      I keep trying to keep my mindset geared to a spring type storm system and yet at the lower levels, it feels like we’re trending towards a rather chilly winter type system.

  55. This 18Z NAM is pretty juiced and it appears to be winding up a little.
    Therefore, I “think” it has the warm layer extended too far North.

    It will probably get to Boston for a period of sleet and perhaps briefly rain
    or rain/sleet mix, but then go back to snow.

    If one goes only by the NAM, then it would be some front end snow, sleet, rain, sleet
    and ending as snow.

    How do you make an accurate forecast?????

    I think the NAM is TOO WARM with this solution.

    We shall see.

    And yes I am wimping out and not making a snow forecast for Boston.

    I was actually very Much liking TKs forcast from this morning, but now I don’t know.

    And here is another problem:

    There may be 2 separate accumulations, 1 before the sleet/Rain and one after.
    Could have 2 inches up front and 2-4 inches on the back for a total
    of 4-6 inches but there might only be 1-3 inches on the ground when all is said and done.

    1. How you ATTEMPT to make an accurate forecast is use your experience and meteorological knowledge to adjust off guidance that should really only be loosely relied on to begin with.

      You do this, then hope your attempt is successful. If it is not, you learn from it and move on to the next challenge. 🙂

      1. Pretty rough. The Good Mets truly earn their pay with systems
        like this. I mean really good ones, NOT the model huggers.

        You say experience. Mine says that there will be more snow than modeled. I am NOT saying it won’t sleet, just that there is likely be more snow that at least the NAM is modeling.

        Do you plan on adjusting upward at all? OR are you good
        with your figures from this morning? Just curious.

        1. AND OF COURSE you are included with the really good as are SAK and JMA. NOT a model hugger among you
          and we very much appreciate that.

  56. Tom looking at the cod site some places near Worcester area NAM is spitting out 1.5 of ice. Probably over done but NAM for sometime has been consistently showing this icing potential in the interior parts of CT and MA.

    2. OH NO…….My head is spinning. I just got my thoughts cleared up on sleet not being an issue and now we are back to ice. 1.5 inches? Is this something that would cause tree and power issues? That is a lot of ice.

      Confused vicki below….

      http://i.imgur.com/cYGLKfn.jpg

        1. Thank you, JPD. Greatly appreciated and it sure is close. We are either on line or just to the east as you say. Now is this the ice that accumulates or the sleet Tom explained earlier? As much as I like power outages, I am not a fan of accumulating ice. Far too dangerous on so many levels. However, it is what it is.

            1. Thanks JPD. In the quieter times, I will try to remember to ask for a definition of the ice/sleet/hail etc. Right now I think talk ofmtje storm should tske priority

  57. I just see that cutoff of the snow in Maine and visualize part of that cold dome of air, relatively speaking north of New England. and the redevelopment tracking east or even slightly ESE from NJ to south of Nantucket.

    I think this trends even colder through the 00z and 12z runs tomorrow because of all the signs showing resistance to our north.

  59. One thing I noticed with this run of the 18z NAM the snowfall amounts not confined to northern New England as it was in previous runs.
    This to me has surprises written all over it.

  60. Oh Boy.

    The 3KM NAM has MUCH MORE SNOW
    than the regular NAM. Maps Shortly.

    Now I am thinking higher totals, NOT what the Kuchera says, but higher than I was thinking.

    Logan “could” come in at around 6 inches total, not on the ground at the end.

    2. If the high to the north does its thing for the boundary layer, as I think it might and the entire column stays cold enough, I think this might be a chilly enough storm that the sunlight aspect wouldn’t kick in until late morning to midday Saturday. So, there could be a lot of hours to accumulate snow or sleet before the whole solar angle aspect of early April kicks in.

      In other words, from Friday overnight to say 11am Saturday, I’m starting to think we’re looking at sfc temps of 30 to 33 and not 34 to say 37

      1. Could be. IF the sleet doesn’t happen, we’re looking at 8-10 inches
        of heavy wet snow for the city, perhaps even more. I DO think
        there will be a period of sleet and perhaps some rain, just not as long as the NAMS are depicting. That’s just my feeling.

        1. Feeling the same. Maybe slightly less than 8-10, lol, but a bit more than my earlier 2-5 thought.

            1. Well it depends upon how much sleet.
              The more sleet, the lower the accumulation. how about 4-6?

  61. 18z run of NAM 12km and 3km go bonkers and probably overdone. Now remember this not all snow and probably most will fall as sleet as both show all of SNE getting involved in wintry precipitation.

  63. One thing were seeing with this run is a colder run of the NAM with snow and sleet amounts showing up in SNE where it was up in Northern New England. Now we wait for 0z run. GFS run after run has been the coldest of the guidance.

  65. The slightest change here is going to make a huge difference.
    I am glad I am not a meteorologist and have to forecast this one.

    1. I wouldn’t be surprised if Boston gets more snow & sleet than the tv mets are thinking. Harvey has a 2-4 inch range and he emphasized a lot of sleet as opposed to rain for Boston. We will see.

  66. Since it now appears that a lot of sleet will be involved, will those accumulations be counted towards the final snow totals?

    1. Sleet is always included. The actual measurement is “frozen precipitation” which officially includes sleet, snow, and hail.

    2. Yes, but sleet doesn’t accumulate rapidly.
      Sleet ratios are somewhere between 1:1 and 3:1 Depending on the diameter.
      Figure 2:1. So during the sleet if there were say .5 inches of qpf that would equate to “about” 1 inch of sleet accumulation. Sound close to about right.

      I remember a SLEET storm while I was in High School It was March I believe as well and it sleeted all day. I never measured, but I recall it being somewhere between 2 and 3 inches of Sleet and was that ever heavy to move around. I came down in buckets ALL day. There wasn’t a period of rain, it was sleet from the get go and all out SLEETORAMA!

  67. Today was a glorious March day, about as good as it gets in Boston this time of year. I know that we can do better, but we usually don’t. I’ll take it, as the coming period looks unsettled to say the least. While I’m a fan of snow in winter and generally love the winter months I’m not the biggest supporter of spring snows. They’re interesting to follow, but sloppy, muddy, and a frank reminder that spring is not our season in SNE.

    The birds are instinctively preparing for family expansion. I see them with twigs in their beaks (clearly a sign they’re building nests). I also observe the males chasing after the females. It often looks more like sexual harassment (or worse) than courtship. But, in recent weeks their chirping and singing has been muted at times. What began as an unbelievable prelude to spring in late February (when the birds were really loud) unraveled this month. First with rather bitter and sustained cold. Then, the snowstorm. Birds don’t have second thoughts. But if they did, I believe the ones who migrated would want to return to warmer climes.

    1. Went out to pick up a pizza and saw my first red winged blackbird of the season. I know you and Matt have seen them already too. I need to find out how to attract them

        1. Ohhhhh one of my favorites. Are they nesting near you? I have several that keep exploring the bluebird house I have but so far no one has moved in. I need to work on setting up meal worms for them too.

          1. I’m not sure if they will nest but they were checking out our neighbors’ birdhouse. I’ll have to tell them about the mealworms.

            1. I started looking into them and was sidetracked. I think you can get dried mealworms which sounds a lot better to me

  68. I’m not quite sure if we should buy this latest shift. For now I think the more moderate approach of 1-3 for Boston is best. But the potential certainly exists for a lot more.

  71. Thanks JPD for that sleet storm story. That is very unusual for even well inland areas let alone Boston. I can’t recall no more than maybe 10 minutes worth of sleet falling at any given time.

    1. We’ve had numerous occasions of prolonged sleet around here.

      I recall an event in the late 1970s in which I measured over 2 inches of ice pellets. My brother has photos of it.

      1. We had one the week of January 7 1991. But it accumulated in trees etc so perhaps it was not sleet. I am clearly confused today

  73. It looks like Harvey used the Euro snow map from 12z and modified it, basically taking the amounts and building downward to add a range.

  74. Valentine’s Day 2007 comes to mind with prolonged sleet and in my area back on 24th of January in the overnight hours had a couple inches of sleet.

  75. JP Dave to address your comment about the abrupt end to the snow on the 3km NAM…

    The model has the low moving E or even ESE. The “backlash” in this case is actually north of the low and can be seen near the Maine Coast. It’s not a classic set-up of a northeastward-moving and rapidly deepening storm.

  76. In the “for-fun” category: 18z GFS has really taken to the trough moving through late next week and has a pretty intense offshore storm with accumulating snow in southeastern England on April 8. What you take from this, and the fact the ECMWF has been showing trough during that same time period, is the usual rule of not ruling snow out in April applies, and more directly, the chilly/unsettled pattern has a way to go yet.

  77. What I would like to know Tk is how often it snows in April I would suspect it’s not that often I think .

    1. Are you kidding? It snows quite often in April. Growing up I can
      remember it snowing in April nearly every year. I am not talking about major snowstorms, not that they can’t happen, but small events like 1-3 inch type things.

      1. Agree, JPD. Ones in top link I posted were a few. I remember more, not earth shattering Easter snows and just plain April snows.

        1. Nobody asked you to stop asking questions, but I have noticed a change in your approach lately. Is someone coaching you from elsewhere on the net? 😉

    4. Eric (ch 4) had a pie chart. 54% of Aprils have had no measurable snow at Logan, 46% have. He had the 46% further broken down to categories of 0.1 to 6 inches and 6+ but I don’t remember the exact breakdown of that. It was something like 39% and 7% respectively, but don’t hold me to that.

    5. This is a very easy question to answer. All you have to do is look up the stats. Obviously, odds are higher as you increase distance from ocean and increase elevation, which basically goes without saying. Boston has measurable snow on at least 1 day about 2 out 3 Aprils. The average snow for the month over a 30 year period is about 2 inches. This is for Logan. The amount would be a little higher in the actual city itself.

      1. For Lowell, we’ve had snow in 60 of the 88 years that I have record for.

        40 of those 60 years had 0.1″ or more.

        10 of those 40 years had 6″ or more.

        The average for the month is 1.7 inches.

        FYI – we’ve recorded snow in May 5 times in the 88 years we have snowfall records:

        5/11/1945 – Trace
        5/1/1953 – Trace
        5/9/1977 – 2.6″
        5/6/1996 – Trace
        5/18/2002 – 1.0″

  79. If there was no sleet and it was just snow I think we would be seeing a HOLY CRAP BATMAN comment from you JpDave.

  80. Last April Boston got 6.6 inches of snow for the month.
    I remember back in April 8th – 9th 1996 there was enough snow to shovel and plow and that same system had snow falling during the Yankees home opener.

  81. I’m reluctant to get too jazzed up on upper range in any zone not only for the obvious reasons but also because the storms with winter have generally underperformed against top end this winter. And yes, it’s still winter. I don’t care what the calandar says.

  82. I wanted to get amped up but these snow maps this time of the year can be an issue. With that said nearly every storm has underproduced so why not one do the opposite.

  83. This tweet from Eric Fisher.
    Pattern ahead is heinous, generally speaking. Not likely that we’re done with snow after Saturday.

    1. I think the storm in the April 6-8 period will have at least some frozen precipitation with it.

      1. So no peaches again this year?

        I was surprised by Toms info that 46% of time snow at Logan. That seems like a big deal considering it is Logan.

  84. Haven’t had a chance to read the comments above so unsure of the current thinking; however, I am growing more and more concerned about a greater wintry impact in Boston. With the storm tracking a bit further south and a retreating high to our northeast, there is increased likelihood of a mix changing to several inches of snow in Boston tomorrow night with more to the south and less to the southeast. Nevertheless, there is the potential that much of the wintry precip that falls could be in the form of sleet which would significantly impact snowfall amounts. That is the wild card. What seems more apparent is that tomorrow night’s event is trending colder. Will enough warm air aloft rear it’s ugly head and to what extent? It will be interesting to see how this evolves. Either way, indeed a VERY trick forecast.

    2. I second Sue. Always good to see you. If we promise to talk snow into July would you stay with us?

  86. Projecting forward it could very well be that in some locales April turns out to be a snowier `winter’ month this year than December or January.

    The parade of `cold’ storms the next few weeks with distinct snow possibilities in SNE is a scary thought for spring lovers. Old man winter must be on HGH or avocado ice cream. Spring’s about to say “uncle.”

  87. Vicki, if we’re talking snow in July on WHW – as in “is the NAM trending colder for the July 4th nor’easter, or will the warm air aloft yield sleet and limit the snow accumulation?” – then we’ll definitely be in record territory.

    First things first, though. I don’t think Boston has ever recorded measurable snow in June. Maybe this year we’ll get a trace? A couple of years ago the highs on June 1st and 2nd were 48 and 49, respectively. And and night it felt like it could perhaps snow.

      1. June 2009 was unsettled with lot of days with showers and thunderstorms and that continued into the last part of July. June 2015 had the first two days of the month with those high temps Joshua mentioned.

        1. Thanks JJ. And I checked. It was 2011 that was cold, raw and damp into the middle of the month.

  89. Re: Summer “snow”…

    If it hails at a reporting station in the summer, is that recorded as a trace of snow?

  90. I might have mentioned this before, but there was an 8.5″ Nor’easter on an Easter Sunday (March 29) in 1970 and another 4.5″ on March 31.

    2. Was that a surprise storm on Easter? I remember one where my family and I went into the restaurant for dinner with no snow and came out to find a good amount.

  91. We’ll be watching that 850MB 0C line tomorrow like hawks. Trouble is it could
    be below freezing at 850mb and above freezing at 800mb or 750mb. The NWS
    mentioned a warm layer between 850mb and 700mb. That’s roughly between
    5,000 and 10,000 feet. We have 850mb temps on most models. With some we
    can get 700mb, but us mere mortals of the weather world do not have access
    to levels in between.

    So I guess we use those 2 levels as a guide along with Radar and observations tomorrow.

    I have this sneaky feeling that the High the our North holds and keeps the warm
    layer from moving this far North or at least halting it farther South than the models
    are depicting. In fact, the 18z GFS has it NEVER get as far North as boston. SO
    different models are interpreting this differently. I guess we’ll find out tomorrow.

    It shall be interesting, that’s for sure. I think some folks here WILL be WINNING a friendly wager. 😀 😀 😀

    1. In the FWIW dept, here are some 850mb temp charts

      This the closes the warm layer gets to boston on the GFS

      http://maps1.pivotalweather.com/maps/models/gfs/2017033018/033/850th.us_ne.png

      NAM

      http://maps1.pivotalweather.com/maps/models/nam/2017033018/033/850th.us_ne.png

      3KM NAM

      http://maps3.pivotalweather.com/maps/models/nam4km/2017033018/033/850th.us_ne.png

      CMC

      http://maps3.pivotalweather.com/maps/models/ggem/2017033012/039/850th.us_ne.png

      The models other than the GFS may have warmer 850mb temps at other times. I was just comparing the same time for all these models.

  92. We had a cold, miserable spring 2 years ago as we were transitioning into an El Nino. Now, we’re starting what looks to be another miserable spring as we transition into another El Nino. Coincidence? Nope. Not in the least.

      1. For Lowell, temperatures were right around normal and precipitation was a little below normal. we only had 6 days with highs of 90 or 91, none higher – 4 in July, 1 in August, 1 in September. The normal is 14.

        1. That what I remembered. So is this summer looking similar ….I know it is wayyyy out there but wondered based on your comment.

  93. The 0Z NAM Is (@&#&!@*#&!(*@&#*(!@*(#&!(@&#*!@#&
    Pushes the warm layer north. And to confirm what I was saying above,
    NAM is showing Sleet as precipitation type with the 850mb temperature below
    freezing. Accumulations Farther North on this run.

    1. Not sure what level that warm layer is. Yesterday JMA was saying that he thought it would be at the 800mb level or “about” 7,000 feet or so.

    1. I know it’s day 7 but I wonder what thought process went into Fox’s being 10 to 14 degrees warmer than everyone else for next Thursday…

      1. Agreed. I also think all forecasts may be underestimating this storm’s impact at the coast. I realize it’s a tricky forecast. And, there will likely be no accumulation in Boston during the day tomorrow. Hence little or no impact the next 18 hours. However, I would not be surprised at all to see 4 inches in Boston when all is said and done, and 6 plus in the burbs, with 10 plus a distinct possibility north and west of 495. I think that Boston’s temp tomorrow night will easily get down to 31F, with little or no change until midday on Saturday. That leaves some time for accumulating snow in the city. Also, there’s some fairly cold air behind the system. Would not surprise me to see Boston in the mid to upper 20s in the wee hours of Sunday morning. Most forecasts are underestimating the cold. As for next weekend (Apr 7 and 8) it seems there’s some wishful thinking going on in terms of forecasts around the dial. Again too high on temps, and little or no respect for snow chances with a very potent system offshore. If I hear from forecasters “east wind will kill chances at snow accumulation” I think they’re a little off base. First, the easterly will not be predominant – a northeasterly and northerly will. Second, the ocean water is still quite cold. It’s not early November, it’s early April.

      2. It is a mighty fine question. Since I’ve been doing these it’s interesting to see the days when there are wild swings between the stations. I wonder how much of it could be a ratings thing. If they give a little hope seven days out of a warm-up do people tune in?

  99. Good morning,

    Winter Strom Watch replaced with Winter weather advisory for Boston.

    Here is the 6Z NAM Kuchera snow

    http://maps1.pivotalweather.com/maps/models/nam/2017033106/066/snku_acc.us_ne.png

    GFS

    http://maps1.pivotalweather.com/maps/models/gfs/2017033106/066/snku_acc.us_ne.png

    CMC

    http://maps3.pivotalweather.com/maps/models/ggem/2017033100/072/snku_acc.us_ne.png

    3km NAM

    http://maps3.pivotalweather.com/maps/models/nam4km/2017033106/060/snku_acc.us_ne.png

    NWS

    http://www.weather.gov/images/box/winter/StormTotalSnowWeb1.png

    fwiw, the latest SREF mean is 5.83 inches for boston

  100. Ah, finally, the last day of a miserable weather month.

    3 months in a row now at Logan, where the monthly temp will end up at + or – 4F compared to average. Autumn in winter, winter in spring ………

    TGIF ……

    2. If you are a skier this is a good month 🙂

      Just hope everyone stays safe in the slippery stuff and heavy shovelling.

  101. Some interesting HRRR charts

    11PM precipitation Type:

    http://mag.ncep.noaa.gov/data/hrrr/09/hrrr_east-us_01800_precip_type.gif

    composite radar 11PM

    http://mag.ncep.noaa.gov/data/hrrr/09/hrrr_east-us_01800_sim_radar_comp.gif

    that is some HEAVY crap falling from the skies

    850 mb temperatures at 11PM

    http://mag.ncep.noaa.gov/data/hrrr/09/hrrr_east-us_01800_850_temp_ht.gif

    925mb temps at 11 pm

    http://mag.ncep.noaa.gov/data/hrrr/09/hrrr_east-us_01800_925_temp_wnd.gif

    note: precip type is sleet to the south with 850 temps below freezing. 925mb temps below as well indicating an above freezing layer above 850mb. SAK and JMA both said the warmer layer was at around 800mb or somewhere in th neighborhood of 7,000 feet. eventuall that will move inot boston around midnight ot perhaps 1am or so. meanwhile that snow will be dumping and accumulating big time.

  104. Reading that the snow tomorrow morning should be where we get most accumulation in Boston. One thing for sure is that a decent slug of precip is coming. Big time help!!

  105. I still feel most of Boston’s precip will be frozen. And as usual, the Boston area will be the dividing line where the snow/sleet/ and some rain battle it out.

    I also have a feeling that the precip intensity may still be light into this evening and take until mid overnight in eastern sections to truly become moderate or heavy.

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