Stair-Stepping Pattern Change

75 Comments

2:45AM

The very slow pattern change remains in progress, despite claims to the contrary. We’re much drier, and not as warm relative to normal, and this will continue to be the case for the coming days as well. This is in response to a split flow pattern in which the northern (polar) jet stream is dominating our weather with minor precipitation events and mostly just temperature changes while the southern (subtropical) jet stream is remaining to the south and keeping most storminess away from the area.

A weak cold front will drop southward across New England today with just some clouds associated with it. High pressure to the north will becoming dominant Wednesday with slightly cooler weather than today. We’re still not looking at any major cold outbreaks, but also gone are the big warm-ups. The next warming trend will be short-lived on Thursday as a warm front associated with a storm well northwest of us moves through. Ahead of this there is a very slight chance of some light rain (or mix if it comes in earlier enough). But most of the precipitation will come with a trailing cold front, and it will be in the form of scattered rain showers Thursday afternoon and evening. No widespread or heavy rain is expected. Friday will bring windy, chilly weather behind the cold front. The front will settle south of  New England over the weekend when a few disturbances may travel along it. At this time, it looks like any precipitation associated with these would remain south of New England, and we’ll just see chilly and dry weather.

A peek into next week reveals we will be in a battle zone between colder air to the north and lingering warmth to the south thanks to high pressure trying to hold on over the southeastern US. This should send at least 1 or 2 chances for precipitation our way in the days ahead of Christmas. It’s too early to call rain vs. snow on any of these potential threats, something to be fine-tuned in the days ahead.

Boston Area Forecast…

TODAY: Sunshine dominating much of the time but some clouds from the north later. High 43-48. Wind W under 10 MPH shifting to N late.

TONIGHT: Partly cloudy. Low 25-30. Wind N up to 10 MPH.

WEDNESDAY: Mostly sunny to partly cloudy – some coastal clouds from time to time. High 39-44. Wind N-NE 5-15 MPH.

WEDNESDAY NIGHT: Increasing clouds. Low 31-36. Wind NE 5-15 MPH shifting to SE.

THURSDAY: Mostly cloudy. Slight chance of very light rain (mix well NW of Boston) during the morning. Scattered rain showers during the afternoon. High 45-50. Wind SE under 10 MPH shifting to SW and increasing to 10-15 MPH.

FRIDAY: Partly cloudy and windy. Low 26. High 40.

SATURDAY: Mostly sunny. Low 18. High 36.

SUNDAY: Mostly sunny. Low 21. High 38.

MONDAY: Partly cloudy. Low 24. High 42.

75 thoughts on “Stair-Stepping Pattern Change”

  2. some cold 6am obs from northern New England….

    Whitefield, NH 9F
    Berlin, NH 10F

    In spite of the mid-upper 40s yesterday, the thin ice in the pool never fully melted yesterday and is frozen solid this morning. With the ground and bodies of water cooling off during these cold nights, its a factor that will somewhat temper the intensity of warmth within warm sector surges, if they happen in the coming weeks.

  3. Last night my town got down to 24, and they were expecting a low of only 32, I wonder why…
    But these cold nights should help get this pattern change moving along.

  4. Thanks TK! Battle zones are always good… but I think we may fall short of having enough cold air in place, especially in the city (Brighton). Still holding on to some (very little) hope for a white Chistmas yet!

  5. Thank you TK !!

    A friend gave me a pair of snowman socks last year. Every time I wore them it snowed. We had so much snow (as you know) that other friends threatened to find and burn the socks. I even finally buried them deeply in my bureau drawer. I think it’s time to dig them back out and wear them!!!

      1. Ok will put them on after the rooter man clears the sink drain – They are multi colored with snowmen all over them and he’ll think I’m nuts if I put them on now 🙂

        1. Vicki…this means you will have to wear them until our snowfall contest ends on April 30th, Lol. 🙂

          Having said that, more likely our -NAO had much more to do with our snowy winter than your socks. It will be interesting to see what happens though. 🙂

    4. Coastal – GREAT video!! I have such memories of that storm as I’m sure many here do. Early morning we headed to the barn in Holliston where my daughter’s horses were to make sure they were exercised and “tucked” in. I remember standing in the barn door, just looking out over the trees and feeling (gut instinct) that something huge was about to happen.

  9. Ugh….Watching successive runs of the GFS and Euro results in nothing but frsutration.
    Something on one run only disappears on the next. The fact that TK indicates a battle zone setting up next week can certainly lead to some sort of SNEAKY snow. Let us
    hope. In the meantime, I keep looking for something, anything. Don’t see it yet.

    btw, Here is the latest NAO forecast. Still not great, but “perhaps” a trend????

    http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/new.nao_index_ensm.html

  13. Remember that April Fools Blizzard and having a rare April snow day. It was great since I knew there was going to be no school I was able to stay up and watch a great NCAA men’s basketball championship game between Arizona and Kentucky. Arizona won a thrilling game in OT led by Miles Simon.
    UGH meter on the NAO a 5 at the moment since it is tough to predict.

    1. I loved that storm. People at work asked me how much we were going to get and I told them 2 feet and I was dead wrong!!! Boston had 25 inches!! Lol

      1. If I remember it was mild a few days prior to that storm system.
        Low Pressure looks to remain over the fish for Saturday as it forms near the Carolina’s. If that could make only
        make the turn up the coast things could get interesting with some cold air in place.

        2. When I was in the corporate world, it was the only storm to ever shut down a corporate office that I was in for 2 days. From that storm, some snowpiles made it to my birthday.

  14. It was inyeresting reading WW post about the MJO going into a different phase. I think we need it at 7 if I am correct.

    1. Hadi,

      I am still not sure on this. I may be totally wrong, but I thought that we
      wanted it negative. Negative means more RAIN in the Western Pacific which then translates to more colder weather here. It is a very technical and confusing concept. Perhaps TK can clarify for us?

  16. Old Salty that Saturday storm over the fish is a watcher and will see what the 12z runs say. I know reading the discussion out of the NWS office from NYC both the 0z EURO and 0z GFS keep it a fish storm.
    We want the PNA to go positive so there is ridging in the west and the NAO to go negative so that could get the trough going in the east sending the cold air down from Canada and creating snow potentials on the east coast. Of course we don’t want it too negative as was the case in the winter of 09-10 when we were robbed of several dumpings of snow the Mid Atlantic received. High pressure is having trouble establishing itself so far over Greenland.

  17. Seems like dry times ahead. I was having a difficult time finding a storm on the 0z EURO this morning, out to 10 days. Quiet southern stream, with a few northern impulses…..this makes some sense given environmental Canada’s temp outlook of a below normal southern US and an above normal northern tier US…..theres simply no temp contrasts for storm development.

    1. Hi Hadi.

      I’d trust TK a lot more than me !!! 🙂

      In this new pattern, there seems to be some repetitive features emerging. One is the split flow jet stream with the cutoff upper low in the southwest and the northern jet near the US/Canadian border. Seems those could be repeating for a while. The SE ridge has been tapered back some and as a result of these things, it doesnt seem to be allowing for either huge temp contrasts or good upper level flow to cause storm development.

  19. Tom,

    I agree with the split pattern overall, but all it takes is a little buckle and you get the battle ground for storm development.

  20. I am still thinking a snowless December, but with the NAO now towards neutral, there is definitely some hope for January. We will probably have our snows on the “back” end (February-March) as opposed to TK’s original thinking on the front end (December-January).

    It certainly remains to be seen if we even get normal snow totals, however. My bet is that we end up well short, unfortunately.

  21. The 12Z GFS shows all sorts of possibilities. Not going to get into it all, but suffice to say chances on 12/21-22, 12/25, 12/28 and 12/29

    This battle ground TK was discussing “may” just percolate something yet.

    We’ll keep watching.

    1. 12/29 would be exactly two months since the pre-Halloween storm.

      It certainly would be ironic if it works out, but I doubt we would be that lucky. 🙂

  22. something different on the latest GFS for sure…nothing great yet but looks like a different set up

    http://mag.ncep.noaa.gov/NCOMAGWEB/appcontroller?page=Image&prevPage=Param&image=..%2FGemPakTier%2FMagGemPakImages%2Fgfs%2F20111213%2F12%2Fgfs_namer_204_850_temp_mslp_precip.gif&fcast=204&imagesurls=&model=GFS&area=NAMER&storm=&areaDesc=North+America+-+US+Canada+and+northern+Mexico&cat=MODEL+GUIDANCE&rname=SFC-LAYER+PARMS&pname=850_temp_mslp_precip&cycle=12%2F13%2F2011+12UTC&imageSize=M&currKey=model&scrollx=0&scrolly=0&prevArea=NAMER&prevImage=yes

  23. The 12z GFS was action packed, also I saw no signs of a warm up in that run.
    It may be a last minute opportunity to get that white Christmas.

    1. Heres hoping….I look just to the east pf Greenland though and get the suggestion the GFS thinks northern latitudes will be closer to blocking later in the month and I just dont trust that reasoning.

        1. Of course neutral is better than Plus 2. When I say not too promising, I mean as opposed to clearly negative, which of course is what we want.

  25. Coastal, you make a good point, but then again, I am a pretty negative person, so
    that one is tough for me. I’m trying.

    Hey, did you see the snow dance link I posted last night?

    1. Yes I did, is that you playing? I love the sound of an acoustical guitar. I have several myself but never really learned.

      That’s a great song to play during a snow day.

  28. I was hoping there with the Saturday system with a low forming off the coast it could some how come close enough to at least gives us a little snow to put us in the holiday spirit.

  29. I forgot to wish everyone a happy Santa Lucia day. It is the longest night celebration in Sweden which, according to the old calendar, was Dec 13. We celebrate in our house since my husband spent his first 8 years in Sweden. Sometimes we do it up big and other times – like tonight – we will have a quiet celebration with a few Swedish dishes.

  30. some hope from the NWS…

    NEXT WEEK…
    MAIN FOCUS IN THE EXTENDED IS ON TUESDAY…THE ECMWF IS SHOWING
    ANOTHER LOW PRESSURE SYSTEM WORKING ITS WAY ACROSS THE AREA. THIS
    MAY BRING SOME SNOW FOR SOUTHERN NEW ENGLAND. SINCE THIS IS SO FAR
    OUT AND MODELS HAVE A TENDENCY TO CHANGE…CONFIDENCE IS QUIET LOW
    AND WILL KEEP THE FORECAST AT A SLIGHT CHANCE.– End Changed Discussion —

      1. I’m sorry, the panel I wanted didn’t come out. Please just click
        down below to advance it to the end to view the panel in question for Tuesday 12/20.

    1. This is an added comment to the above:

      Alex Sosnowski · Top Commenter · Works at AccuWeather
      It’s Euro/GFS compromise and based on persistence this fall. We will adjust as nec. as time draws closer.

      1. TWC take on next week’s storm. What a difference!!!!
        I can’t believe that professional meteorologists would have
        such differing opinions on a potential storm system. I could see differences on where rain/snow will set up etc., but wholesale
        differences like this?? WOW!

        Let the DEBATE begin.

        1. Would be helpful IF I posted it!!!!!!!!!

          A new storm system is set to make its mark across the central United States on Tuesday and Wednesday but very little of that mark will be colored white.

          Our new storm that is ejecting out of the Southwest will have moisture to work with. The Gulf of Mexico will “open up”; injecting the central United States with low-level moisture.

          But we’re missing one key ingredient – a full column of fresh, Arctic air stretching from the surface to the upper levels of the atmosphere. Without it, there is no snow to be had!

          Instead, we are left with a “warm” December storm system; full of occasional heavy rain and even some embedded thunderstorms!

          Yes, there is some wintry precipitation in the storm’s initial phases, but it’s not of the white variety; it’ll take the shape of sleet (ice pellets) and freezing rain. We’ll have to wait until late Wednesday or Thursday to finally squeeze out some accumulating snow.

  33. wednesday: partly sunny highs in the upper 30s to low40s
    wednesday night: increasing clouds chance of rain and snow showers late.
    thursday:cloudy rain showers with a possible mix of snow/sleet andfreezing rain durring the morning . highs in the mid to upper40s
    thursday night cloudy with showers lows in the upper30s to low40s.
    friday becoming sunny highs in the midto upper40s dropping in the afternoon.
    friday night: clear lows in the mid20s
    saturday through sunday sunny and cool highs in the mid 30s
    monday and tuesday partly sunny highs in the upper30s to low40s.
    the next 2 weeks look similar in nature. as of now.
    also the extened gfs is showing a break down of the southeast ridge around christmas that will at least allow storms to be to the south of us instead of beeing inside runners.which i think is better since it means the cooler air will stay around with almost no chance for the warmth of the eastern and southern parts of the storm which carries the warmer air.. It also shows it possibly staying that way.Good news for ski areas . Also the greenland high might be getting stronger as well we will have to see. this would be good for everyone .besides for the snow haters

  34. The southeast ridge has to breakdown and high pressure is needed over Greenland to get any big snow events here. Until then don’t expect blockbuster snow events.

    1. i never said anything about a blockbuster storm. i am saying if the gfs and some of the other long range models vertify the southeast ridge will break down and that the greenland high/block might get stonger

  35. I know that but the current setup we are in does not favor blockbuster snowstorms.
    We need what we had for that six week stretch last year and I don’t see indications right now of that pattern returning.

  36. I see at least a small shift in the overall pattern starting to take shape, painfully slow but we are getting there.

  37. I hope it gets there and when it does it locks in like the mild pattern we experienced for several weeks after the Pre Halloween Noreaster.

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