Thursday Forecast

40 Comments

4:02PM

COMMENTARY
First, I’d like to apologize for the delay in this post and to thank you for being patient. Second, I was going to editorialize about the general public’s widely-held habit of bashing weather people for “getting it wrong”, but I don’t really think that’s necessary. The readers (and lurkers) of this blog know better, and for that I am grateful. Those who comment day in and day out are well aware of the process, some of them from dabbling in it themselves, and all from the experiences that I and a few other meteorologists share in the comments. There is a process that I and others go through daily to produce a forecast. Although there is slight variation day-to-day in this process, much of it is the same as the day before, but no matter how much experience a forecaster has, there are going to be exceedingly challenging forecasts. This was definitely one of them. At first, several days ago, I had this thing as a miss with “high confidence”. I should have known better. That’s the kiss of death on a forecast, declaring high confidence more than a couple days in advance. Alright, harsh reminder there. Then when I knew this would not be a complete miss the process of trying to figure out its impact began. This in itself is now more complicated that it should be. Oh the forecasting part is hard enough, but it’s a challenge I welcome and very much enjoy. The greater challenge and often losing battle is doing it the way I feel is right, but that puts me in a tiny sailboat on a chaotic sea of media hype. And I’m not talking about my fellow TV meteorologists. We all have our opinions on how they present their information, but we are all really working toward a common goal – informing the pubic. Unlike myself, they are under intense pressure from managers and others who scrutinize everything they do to not only get the information out there but “entertain” the audience. I’m not sure what words are used, but they are told to play the hype game. And what a difficult spot that leaves them in, as they really want to just get the information out there, but have to “please the boss” in the process. Yes, it is a ratings game, but somewhere along the way that took precedence over delivering quality information, correct or incorrect. I’m not even sure the public is getting the message any more. In talking to people I encounter during the day, they are not really getting it. Perhaps having a “bust” storm like this one is a good thing in that it teaches a lesson to the media outlets what too much hype can lead to. But are they really paying attention enough to learn the lesson? And if they do learn it, how long until complacency sets in and its forgotten, leaving the cycle to begin anew? All I can do is keep sailing my boat…

A QUICK LOOK BACK AT THE STORM THAT WAS (AND WASN’T)
I don’t need to go into too much detail here as it was already explained in the comments section of the previous blog posts, but in case anybody missed it. I referred to my forecasting process in the commentary above. For this event, once I knew it was going to impact us, I was nervous about the dry air to the north, as depicted, it turns out quite accurately, by several runs of the ECMWF (European) forecast model. But since it was basically the only model doing that, it naturally lead to a little skepticism about its solution, but not enough in me to completely ignore it. I’ve seen this before, more than once, with a somewhat similar set-up, and that model being the only one to see something. I couldn’t shake that, so I opted to play it safe, forecasting enough snow to give the idea of decent impact, but leaving it just above a level I could adjust to if my drier scenario worked out, without looking like I was hacking my forecast to shreds with a hatchet. The fact is, this rather impressive storm system was up against a brick wall of dry air, and took quite some time to eat into it. Why did it rain for a while in areas that snow was forecast? Simple. The forecast of colder air was depending on steadier and widespread precipitation helping to cool the atmosphere enough to support snow. When the storm held off to the south pretty much all day, the atmosphere was able to warm enough to not support snow in a good portion of the region, so once areas of relatively light precipitation moved in, it was rain, not snow, and then the process had to take place when finally, in the overnight hours, enough precipitation had eroded the dry air to do the process that was forecast hours before. While this was going on, the heavy bands of precipitation that were forecast to be working into southern New England were instead about 25 to 40 miles further south, thanks to a little wobble in the elongated low pressure center, keeping the storm just a touch further offshore than had been expected. With 5 inches of snow falling at Islip, Long Island, NY, in a little over 1 hour, it is clearly evident just how close Southern New England was to having a much different outcome. In terms of a forecast miss, distance-wise it is not that much, but impact-wise, it made a world of difference. All I can say is I am glad I took the chance and lowered snow amounts by late evening to reflect that the full potential of this was not to be realized. This is not a claim of victory by any stretch, but a sigh of relief that my forecast didn’t have as far to fall flat on its face. So, on we go to look ahead…

DAYS 1-5 (MARCH 22-26)
So the storm is gone, or is it? Our double-barrel storm and its attendant upper level low pressure area isn’t really going away, and will actually have an impact on the weather here for this entire 5-day period. Today’s impact has already been seen, since I’m putting out this blog late in the afternoon. During the next few days, some instability on the back side of the upper low offshore will bring the chance of a few snow and rain showers to the region, especially midday and afternoon Friday and again for a portion of Saturday. A stronger lobe of energy may bring a more widespread area of snow showers in the early to mid morning hours of Sunday, so if you wake up Sunday morning to what looks like a snowstorm in progress, it should not be hanging around all that long. By Monday, it will be precipitation-free, but a northerly flow will persist, with chilly weather continuing. Forecast details…
THROUGH EVENING: Mostly cloudy. Spotty light snow and drizzle mainly near the eastern MA coast. Temperatures ranging from the middle 30s to middle 40s. Wind N 5-15 MPH, higher gusts.
TONIGHT: Mostly cloudy. Lows 27-34. Wind NW 5-15 MPH.
FRIDAY: Mostly cloudy. A passing rain or snow shower possible. Highs 38-44. Wind NW 5-15 MPH.
FRIDAY NIGHT: Mostly cloudy. Lows 27-34. Wind NW 5-15 MPH.
SATURDAY: Mostly cloudy. Scattered rain/snow showers, especially in the afternoon. Highs 38-44. Wind N 5-15 MPH.
SUNDAY: Mostly cloudy. Snow showers likely in the morning. Lows in the 20s. Highs in the 30s.
MONDAY: Partly cloudy. Lows in the 20s. Highs in the 30s.

DAYS 6-10 (MARCH 27-31)
The last 5 days of March will start out dry/cool as the final influence of the offshore storm hangs on while high pressure builds in. It looks like a weakening system may bring some cloudiness March 28 but may be absent of precipitation, and the March 29-30 period may be milder, starting fair and ending showery, but probably rain showery versus snow showery. Based on current timing, drier but windy/colder weather is expected for the last day of the month.

DAYS 11-15 (APRIL 1-5)
A more progressive west to east flow is expected as the blocking pattern will have broken down during the final days of March. This would mean up and down temperatures and weaker storm systems, one of these likely around April 2 or 3 dividing a milder start for the period from a colder finish.

40 thoughts on “Thursday Forecast”

    1. Funny enough… I think it may be rather mild on April 1 if current timing holds. But since it’s 10 days away, I’m not hanging my hat on anything except the coat rack in this room.

      1. Looking forward to some warmer days to walk around the neighborhood…someday. Amazed at how much melting we got without sun. Melted everything from today and some from last week.

        2. Wish more had melted here. We are on the shady side of the street and probably still have 6 inches in most of my yard.

  5. Thanks TK! Great discussion above, and agree with all your thoughts. As you said, with this storm, it was close, as those numbers from Islip showed. And a bust like this could definitely be a good thing in terms of controlling the hype. Of course, given we’re at the end of the season the media may not have much to hype up until next winter. I think they viewed this as a last hurrah, and given the recent pattern, were determined to squeeze as much out of this last storm as they could.

    Really liked JMA’s comment on the last blog also, and Vicki, thank you for your comment this morning as well and your constant kindness here.

    1. Channel 7 made the mistake a few days ago saying after this storm (today’s) we were done with snow. They said that last month and look what happened. I hope they are right but their track record with that statement worries me ha.

      1. I will never understand how any comment such as that can even be entertained as an idea under the circumstances. It’s proven wrong almost every single time it’s made. The exceptions are RARE.

  8. Thanks TK!

    Logan snowfall to date = 58.5″

    According to Eric:

    1.Boston 4th snowiest March = 23.2″

    2. Ocean storm next Tues./Wed. needs to be watched.

  9. TK – As always, you have nothing whatsoever to apologize for and that goes for the tv mets as well. 🙂

  10. Thanks TK, great blog write-up.

    I was surprised how mild it got here today…sunshine and 50 degrees. The 2″+ that fell was gone before noon + some of what was already on the ground.

  12. Thanks, TK. Great discussion you gave – and like others have said – no apologies needed. Although I am not on often, I always look at WHW before looking at the mets. But I believe that the mets all do their best ( I have my favorites). Unfortunately, the hype will always be there, I think. It’s just people. And thanks to all the comments I have read re: this storm and the others. This last storm gave us an inch of snow, maybe. But admittedly, really looking forward to warmer weather!

  13. It’s 3 days away so I won’t give numbers but I think there will be an accumulation forecast for Saturday night and early Sunday.

    2. No ——- big party Sunday no accumulation. Excellent presentation today TK you are a phenomenal meteorologist. Just woke up long boring shift that made it tough . Driving home this morning Pembroke received more snow than Boston received .

  14. Excellent write-up, TK. You’re a gifted forecaster and writer. I hope you’re writing a book. Maybe you are, with JP Dave and Vicki as the two main protagonists.

    Sinclair, Maine (that’s waaaay up there, almost half way to Labrador City from Boston – Sinclair shares more in common climatologically with Labrador City than Boston) is trying to break a record.

    https://www.boston.com/news/local-news/2018/03/22/mainers-are-cutting-a-430-foot-across-circle-in-a-frozen-lake-to-make-a-giant-ice-carousel

    1. I do not think it will present any issue other than a north to northeast wind through Tuesday. Its precipitation will be hundreds of miles distant.

  16. re: convective Feedback
    We hear this term often when model qpf is over cooked (snowfall maps over done).

    JMA explained this a couple of times.

    I know some here are not a fan of DT, but he responded to a poster on the American Weather site. Here is his response:

    To elaborate, the real issue I have is in the phrase itself “convective feedback”. By design, the convective parameterization is supposed to “feed back” to the model grid. That’s the whole point. Without it, the model would be left with all sorts of unphysical, unstable profiles and precipitation would be totally messed up. Now, are there occasions where there is too much convection firing and the scheme is overactive? Sure. Are there cases where the convection is happening in the wrong spot? Sure. Is the scenario that Wes described possible? Absolutely.

    Deep convection causes substantial changes to a profile in the real atmosphere. Models are trying to mimic this. If strong convection is firing and there is substantial latent heating (and upward moisture flux), the model has to respond in order to restore some sort of quasi-balance. The generation of vortices is something that can really happen in the atmosphere.

    I think that two of the issues with present day physics, even mature deep convection schemes, are

    1) Many of the schemes were initially developed for, and are most appropriate in, the tropics; and

    2) Most model physics are done column wise-independently.

    With respect to point 2, this means that a single grid point can have deep convection fired while all surrounding grid points may not. Now, typically there will be some feedback to neighboring points through advection, etc.; but at the fidelity of the model physics time step, every vertical column is treated independently. A lot of work has been done using single column models to develop, test, tune, and calibrate these schemes, but there is some evidence that this may not be the best way to treat certain processes.

    If any of you are familiar with MetEd, there is a decent material on this topic in the “How Models Produce Precip and Clouds” Module.

    In addition to the current class of schemes, there is some pretty neat work on developing more “scale-aware” parameterization and using mini cloud resolving models within coarser model grid boxes (so-called “super-parameterizations”).

    2. Here is some more technical info from the site DT mentioned:
      https://www.meted.ucar.edu/

      The CP scheme accounts for the effects of sub grid cloud scale updrafts and downdrafts by removing the instability, dropping some precipitation immediately, and changing the vertical profile of heat and moisture.
      Convective changes in heat and moisture distribution stimulate the microphysics scheme to make hydrometeors and additional precipitation
      The microphysics scheme and dynamics become closely coupled, generating resolved mesoscale motions. Evolution of organized convective systems is then simulated through this coupling between the CP and microphysics schemes
      Cloud-scale updrafts, parameterized by CP, create moistening and heating in the middle to upper troposphere, leading to grid-scale ascent as model dynamics respond to the heating. The microphysics scheme creates hydrometeors where vertical motion and moistening result in supersaturation, releasing latent heat, leading to further grid-scale vertical motion. Coupling between dynamics and microphysics becomes the dominant response, generating mesoscale circulations driven by latent heating above and melting and evaporation below.
      The process culminates in a stratiform anvil precipitation region

  17. Our Nor’ Fools Easter Easter #5 on 4/1 is now a cutter on the 18z GFS and the 12z Euro doesn’t have it either. GFS does show another coastal though delivering snow on 4/4. Long ways off but I have a strong suspicion that this weekend wont be our last of the season for accumulating snow.

  18. My favorite thing about this blog is introducing others to it. I have turned our school superintendent into a fan and have brought it to the attention of many others I know. It is by far the best forecasting resource and the comments are the cherry on top. I have always been a weather nut and am so glad I found this place 3 years ago.

  20. It may not look it, but the synoptic pattern we appear to be heading for this weekend is rather remarkable. Essentially it’s cold air damming on a continental scale, with what is effectively a backdoor cold front dropping well into the Southeast US. Atlanta may get down into the 30s by Monday. And the whole East Coast of the US will be mired in not only an unseasonably cold air mass, but a damp one as well. I don’t see any snow accumulation coming from it for us, but Sunday will likely have a very nasty feel to it around here.

    1. If there’s any solace, the western side of that high will feature a mild push of air into Canada, north of the Great Lakes and up to James Bay. Perhaps a start at slowly melting some snow cover in southern most Canada.

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