Tuesday Forecast

98 Comments

7:39AM

DAYS 1-5 (FEBRUARY 28-MARCH 4)
A warm front approaches today and passes through overnight tonight with a few patches of light rain possible today and a more solid area of rain and possibly embedded thunderstorms coming through the region during tonight and very early Wednesday morning. Then a break while we’re in the warm sector, possibly setting record high temperatures again, during the day Wednesday. Late-day and especially nighttime showers and thunderstorms are likely as a cold front comes along. Behind this front it’s back to reality on Thursday as it turns windy and much cooler. A disturbance will pass just south of the region Friday with a risk of snow showers and possibly a period of snow in far southern areas. What this will do is drag in even colder air for the first part of the weekend.
TODAY: Mostly cloudy. Slight chance of light rain. Highs 50-57. Wind light SE.
TONIGHT: Cloudy. Periods of rain. Chance of thunderstorms after midnight. Lows 44-52. Wind S 5-15 MPH.
WEDNESDAY: Mostly cloudy with rain and possible thunder very early in eastern MA and southeastern NH then partly to mostly sunny mid morning into afternoon. Mostly cloudy later in the day with a risk of showers and thunderstorms central MA through RI. Highs 55-62 South Coast, 63-70 elsewhere. Wind S to SW 10-20 MPH with higher gusts.
WEDNESDAY NIGHT: Mostly cloudy. Rain showers and thunderstorms likely until around midnight. Lows 50-58. Wind SW 10-20 MPH with higher gusts, shifting to W.
THURSDAY: Partly to mostly sunny. Temperatures fall from the 50s through the 40s. Wind W 15-25 MPH with higher gusts.
FRIDAY: Variably cloudy. Windy. Chance of snow showers. Lows 22-30. Highs 32-40.
SATURDAY: Mostly sunny. Lows 15-22. Highs 28-35.

DAYS 6-10 (MARCH 5-9)
Colder during this period with a couple episodes of rain/ice/snow possible.

DAYS 11-15 (MARCH 10-14)
Temperatures near to below normal. Overall trend looks drier but can’t rule out a storm threat at some point.

98 thoughts on “Tuesday Forecast”

  5. Latest 9Z SREF significant tornado ingredients for tomorrow PM:

    http://www.spc.noaa.gov/exper/sref/gifs/latest/SREF_prob_combined_sigtor__f036.gif

    Tornado parameter

    http://www.spc.noaa.gov/exper/sref/gifs/latest/SREF_SIGTOR_MEDIAN_MXMN__f036.gif

    helicity

    http://www.spc.noaa.gov/exper/sref/gifs/latest/SREF_1KMHEL_SSB_MEDIAN_MXMN__f036.gif

    Not much has changed with these runs. The worst of the parameters STOP
    just East of the NY/MA and NY/CT state lines. Tomorrow is March 1st. Until
    the ocean to the South of us warms significantly, it’s going to be tough to get
    unstable air in Eastern sections due to the marine influence. We’d need a WSW to W
    wind in order for that to happen. Tomorrow looks to be SW wind or so.

    http://www.instantweathermaps.com/NAM-php/showmap-conussfc.php?run=2017022806&time=INSTANT&var=GRDM&hour=039

  8. I don’t know if the NWS is crying WOLF one more time, but some pretty strong
    wording here:

    Convective risk…
    Remnant EML with mid lvl lapse rates reaching 6.5C/km and
    7.0C/km moves over the region by late day tomorrow, allowing the
    overall MU CAPE profiles to reach 500-1000j/kg, TT to reach 50+.
    This could combine with the strengthening LLJ reaching nearly
    60 kt. High shear values expected, with 0-6km shear nearly 50 kt
    and 0-3km helicity values exceeding 200. Therefore, expecting
    another high shear-low CAPE environment late tomorrow, similar
    if not even with higher shear than this past Sat. While a bkn
    convective line is the mode of choice here, SREF supercell
    parameter/sig TOR parameters are high enough to warrant some
    concern given the values mentioned above. Exacerbated by LCLs
    below 1000ft. Therefore, can`t rule out a risk of strong winds
    or even an isolated TOR in any T-storms that develop late in the
    day, however there are mitigating factors.

    re: EML = elevated Mixed Layer

  11. Hello all. Here is a very very interesting link which discusses QLCS tornadoes.
    QLCS = Quasi Linear Convective System
    This applied to the CONWAY tornado Saturday and “could” apply to any convection
    tomorrow as well. The SPC has mentioned this for tomorrow:

    A strong deep-layer wind field of southwesterly flow from 50-60 kt
    at 850 mb and increasing with height to 70-100 kt in the midlevels,
    will aid in the potential risk for widespread wind damage associated
    with a squall line and other linearly organized storm clusters.
    Some tornado risk may develop as well with mature linear bands
    (short-lived QLCS variety) or where greater destabilization occurs

    Link:

    http://www.meteor.iastate.edu/~ralliss/qlcsmesovorticies.pdf

  13. I was reading that JPDave. Very interesting. I believe with the severe weather outbreak we had back in February 2016 there was an Elevated Mixed Layer present which produced an overnight severe weather event with all those damaging wind reports.
    I will say this NAM has been consistent with the western parts of CT and MA showing a lot of wind shear. The bullseye on the NAM continues to be northern NJ NYC area.

  14. Visible satellite making me think there’s an opportunity for some sun this afternoon.

    Seeing a few sunny breaks already.

    1. Don’t think so. There is a chance of a thunderstorm tonight from the warm front. The main threat is late tomorrow afternoon into tomorrow evening after we reside in the warm sector most of the day, very much like Saturday, except perhaps a littler earlier in the day. According the NWS there is even MORE
      shear for tomorrow.

      1. Thank you, Dave. I was not sure which round of potential storms this threat would accompany. I appreciate your clearing it up for me.

  17. The threat for the showers and strong to possibly severe storms best chances that west of Worcester is Wed late afternoon and evening. While some good wind shear is present in there one of those low CAPE high shear environments the more impressive wind shear is to our southwest NYC area Northern NJ.

    1. Thank you also, JJ. I don’t like these threats but am somewhat more comfortable when they are during the daylight hours.

  18. Now this would be a good thing should this pan out but I would not let my guard down. Just like the summer if that sun could come out after morning showers that will destabilize the atmosphere. Tweet from meteorologist Ed Vallee.
    Becoming increasingly concerned with AM “contamination” due to showers, limiting PM severe threat across much of NE PA, NY, CT.

    1. I don’t quite understand it but found this definition for helicity

      A property of a moving fluid which represents the potential for helical flow (i.e. flow which follows the pattern of a corkscrew) to evolve. Helicity is proportional to the strength of the flow, the amount of vertical wind shear, and the amount of turning in the flow (i.e. vorticity).

      And CAPE is (really roughly in Vicki terms) the potential energy? If I’m understanding correctly, I believe I understand what the combination could represent.

  20. JPDave I totally agree if the Convective Available Potential Energy was higher we would be a lot of trouble. With that said that link you posted shows there is a lot of wind shear in the atmosphere and as I said yesterday this would be something in the winter to have two severe weather events in the northeast less than week a part.

  24. SAK do you agree with that outlook from SPC? To me the slight risk should be over western parts of CT and MA where the best wind shear is. I was surprised the SPC expanded the slight risk to include all of CT.

  27. I have to remind myself its still winter with the links that are being posted for those potentially strong to severe storms tomorrow afternoon and evening..

  29. SPC Discussion for our area for tomorrow:

    Low-level moisture is expected to gradually increase, especially
    from the Atlantic, with surface dew points of 60-65F from the
    Delmarva region southward, and 50-60F extending northward into
    southern parts of New York and New England. The limited moisture
    will be offset to some extent by an plume of modestly steeper
    mid-level lapse rates spreading over the area, with MUCAPE of
    500-1000 J/kg possible over the area. Strong winds aloft and
    associated vertical shear will enhance storm organization, with
    potential for some rotating updrafts and bowing line segments to
    develop through the night. Damaging wind gusts are expected to be
    primary severe threat, although a tornado cannot be ruled out given
    the large clockwise low-level hodograph structure indicated in

  31. I wrote a quick blog about the record warmth and thunderstorm potential: https://stormhqblog.wordpress.com/2017/02/28/in-like-a-lion/

    SPC does not do a good job forecasting for New England historically. I think the threat for tomorrow is mainly in western New England, especially southwestern New England, but I also think it’s conditional on two things: 1. How much sun we can actually get, 2. Wind direction. #1 is fairly obvious. For #2, if the wind direction is 200 (SSW) or lower, then fugeddaboutit. At that direction, you’re advecting cooler, much more stable, marine air into the region, and that’ll kill anything that forms quickly. If it’s 210 (SW) or better, then we’ve got a shot. Just looking at the raw data for BDL, the NAM has a wind direction of 210-220 tomorrow, and has thunder in the forecast, while the GFS has wind direction around 200, and no thunder.

    1. Which model do you favor for the wind direction?

      24-36 hours is certainly in the NAM wheelhouse.

      I guess we’ll know tomorrow.

      1. Asking which model is better for a 10-degree difference in wind direction 24-36 hours in advance is like asking if I prefer the model that has a high of 63 on Wednesday or the one that has 62. You can’t just resolve differences like that until the last minute, no matter how critical a small change can be.

        1. As stupid as it might seem to you, I thought you still could have preferred one over the other, like “possibly” the higher resolution of the NAMS ie the 3KM and the 4KM as opposed to the lower resolution GFS. I don’t think it was such a far fetched question.

  33. My take on tomorrow’s severe threat for our region: conditionally, the risk exists for storms capable of producing damaging winds and a quick tornado or two, especially in western New England. However, as was something alluded to in the NWS discussion last night, there’s a good possibility that most of the action ends up south, and to a lesser extent north, of SNE. Much of the short range guidance reflects this. There will be some nowcasting involved tomorrow, I’m not super concerned but we’ll have to watch it. The fact that we’re talking legitimately about this for the second time in a week though, that’s impressive.

  34. This tweet to me says it all from Ryan Hanrahan for tomorrow.
    A lot of questions surrounding tomorrow’s severe weather threat. Low/medium impact for now until we know more.

    To me this screams NOWCASTING!!!

  35. True!
    Right now if I had to guess I would say a couple severe warned storms western parts of SNE. The best chance for the more widespread severe weather and isolated tornado NYC area Northern NJ down to Mid Atlantic.

    1. JJ take a look at the 18Z Cape.

      There isn’t much but during the evening tomorrow, “some” CAPE makes
      it all the way to boston.

      1. I just noticed that on the Cod Site. Some of that wind shear makes it about the Worcester area after 8pm but less than western parts of CT and MA. Those wind shear values for those areas as well as the NYC area and northern NJ are down some from the 12z NAM run so hopefully that trend continues.

  37. FWIW, the 18Z NAM and the latest 19Z RAP both have surface winds (10m) tomorrow
    afternoon at roughly due SW or 225 degrees. Placing my ruler on the screen the wind
    barbs from the map “appear” to split the difference between horizontal (270 deg) and vertical (180 deg). 90 deg difference divided by 2 =45 deg added to 180 yields
    225. Of course these maps are not perfect, but that should provide a “rough”
    idea of what these models think. Other models may provide different results.

      2. hope it doesn’t happen. Give me a big one or none at all. I’m in full spring mode. Didn’t help either that I was in dallas last week and it got into the 80’s.

  42. I’m not superstitious really, but maybe Springfield area should take note. Their tornado in 2011 was on the first day of the month, on a Wednesday, and took place the night of a concert my son was involved in at Woburn High School.

    Tomorrow, Wednesday the 1st, is the date of the trivia concert at Woburn High School that my son is participating in…

    2. I’ve never thought of you as superstitious. I suspect there is a different word that could be used but cannot come think of it quickly. Either way…..oh boy.

      This timing is late evening? Is that around this time of night? After dark?

  43. Sad day at umass today. Someone committed suicide. Person took a drop from the 3 floor to the under level lounge at the campus center. the sound of the body hitting the table and floor about 3 tables down from where My friends and I were sitting. It sounded like a gun shot lets just say it did not look good. The floor at which he jumped has a conference/lounge area which has tvs, games, tables etc. Today a faculty meeting was going on there, so my friends and I decided to go down to the lower level lounge area . I only wonder if we were up there if he would of joined in our goofing off instead of jumping. the Person did hang up there a bit.

    1. Very sad, indeed. I am familiar with the area you describe as we had an all
      day function there a few years ago.

  45. As for percentages tomorrow here in SNE from SPC here is what I am thinking
    Tornado 2%
    Wind 15 %
    Hail 5%
    I think NYC area south to D.C. 5% tornado chance.

    1. Generally agree and it is a guess on our part, but I am thinking
      10% in the moderate area, 5% in the slight
      And 2% in the marginal.

      When will we see the 1st posting on this?

  47. The updated look from SPC will come in between 1am -2am tomorrow next update between 7:30am – 8:30am then another one 10:30am -11:30am

  48. Quick peak 0z NAM on Cod Site greatest helicity super cell composite values western parts of CT and MA. NAM picking up on some helicity super cell in Boston area during overnight tomorrow.

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