Heat, Humidity, Storms For Some

86 Comments

12:39AM

A large area of high pressure will continue to drift westward over the eastern USA. Here in southern New England we will be on the northeastern side of this ridge, and though it’s a generally hot pattern for most of the region, it does allow for some natural air conditioning via a sea breeze, and this will be possible through midweek, possibly even enhanced a little by a weak back-door cold front coming into some areas today. By later in the week, a more prominent west to southwest wind will limit the ocean cooling to the South Coast and Cape Cod, and while this is ongoing, a trough of low pressure and associated cold front trying to press southeastward out of Canada will provide  energy and focus for a better chance of thunderstorms starting late Thursday but especially Friday and Saturday. The timing of the front is uncertain this far out, so it is difficult to pin-point the coverage and timing of storms. There is some potential for strong to severe storms, regardless. Wording will be vague for now and will be fine-tuned as the potential event draws closer. By late in the weekend, provided the front does not get hung up, we should be treated to somewhat cooler and less humid air.

Updated forecast for southeastern New England (southern NH, eastern MA, and RI)…

TODAY: Mostly to partly sunny. Isolated to scattered showers and thunderstorms possible mainly interior eastern MA, southern NH, and northern RI from mid afternoon to sunset. Highs 90-95 but 80s beaches possibly falling to the upper 70s NH Coast to Cape Cod late. Wind variable to N 5-15 MPH shifting more to the NE from southeastern NH into eastern MA during the afternoon.

TONIGHT: Partly to mostly clear. Lows upper 60s to lower 70s. Wind variable 5-10 MPH.

WEDNESDAY: Mostly to partly sunny. Isolated to scattered afternoon thunderstorms possible, favoring southern NH and interior southeastern MA to northern RI. Highs 90-95 inland areas, 80s beaches. Wind variable 5-15 MPH with coastal sea breezes developing.

THURSDAY: Partly cloudy. Isolated to scattered PM thunderstorms. Low 71. High 92.

FRIDAY: Partly cloudy. Scattered PM and evening thunderstorms. Low 73. High 94.

SATURDAY: Variably cloudy. Scattered showers/thunderstorms. Low 70. High 89.

SUNDAY: Partly cloudy. Low 64. High 82.

MONDAY: Mostly sunny. Low 62. High 84.

86 thoughts on “Heat, Humidity, Storms For Some”

    1. Yes I see that. 3 successive days. Reading between the lines, there doesn’t
      seem to be the same conviction on SPC’s part. I “could” be reading too much
      into it. We’ll just have to wait and see how it plays out.

      Perhaps our area will be spared. Don’t need damaging winds of any kind.

  2. Third day in a row where it will be over 90 so I guess it’s an official heat wave.

    Not sure Logan will get to 90 — sea breeze maybe.

    1. Probably make it before sea breeze really kicks in.

      Tk Mentioned the possibility and looking at this surface map, perhaps coastal
      areas see a BACK DOOR COLD FRONT later today. Will have to watch
      observations this afternoon. That WOULD be nice.

  3. The question is ….. What is the end of month July temp anomaly going to be ….. +3F, 4, 5, 6, 7F. Its around +5F now……

    Ridge must be breaking down just a bit. Sky is mostly cloudy and the wind has picked up significantly out of the north early this morning, this following another blazing sunshine, very warm to hot day by Maritime Standards. Think the cooler 70s are back up here today.

    Have a good day all !

    1. Hi Tom – please send some of those lower 70s this way. In the meantime I hope you and your family are having a wonderful vacation!!! Did you get your sandwich?

  4. Thank you, TK. When you say somewhat drier and less humid air do you mean cooler also?? I like what you have for Sun and Mon – yay!

  6. The storm prediction center continues to have us highlighted which has been consistent now for a few days. I’ll also noticed the threat for severe weather is mentioned in the hazardous weather outlook for SNE for Saturday with damaging winds the main threat. The storm mode and this could change looks to be line form. As I have been saying now for a couple of days the ingredients are in place now we just got to see if everything lines up just right.

    1. “Generally” speaking, a line of storms is not as conducive for tornado development, certainly not the most dangerous ones. A broken line, with
      individual super cells is much more favorable.

      Although the risk for a tornado may be there, the main risk will probably be damaging straight line winds, perhaps even a Derecho.

      In any event, could be a very interesting day on Saturday.

  7. I did not see the word supercell mentioned in the latest discussion from the storm prediction center which is good.
    As you mentioned a line is not a conducive for tornado development. When watching a line of thunderstorms you always look to see if a kink develops in the line for a possible tornado to form.
    It will be interesting what the SREF model has to say as we get closer.

  8. The NWS has mentioned in their update while ago re: Severe threat for Saturday:

    THERE IS A GREATER THREAT OF STRONG TO DAMAGING WINDS
    /INVERTED-V PROFILES WITHIN FORECAST SOUNDINGS

    So I looked it up and found this:

    Environmental temperature and moisture profiles characterized by steep
    lapse rates and decreasing dew point depression with height in the lower
    troposphere, capped by a moist layer in the mid troposphere, are known as
    “inverted V” profiles (Beebe 1955). Convective storms forming in these
    environments frequently produce strong to severe convective wind gusts
    resulting from the evaporative cooling and strong downdraft potential
    associated with such a profile (Bluestein 1994).

    Very interesting. I also read that Hail and Tornadoes are NOT often associated with
    this profile.

    So, I am wondering if anyone really knows what to expect on Saturday??????????

    1. Hopefully nothing. This sox game cant get cancelled and planning on Hampton beach after the game.

      1. John,

        Highly UNLIKELY that there will be nothing.
        Could be as little as a routine thunderstorm with down pours,
        OR, it could be considerably worse. We just don’t know yet.

        What time is the game? If it is an afternoon game starting at 1PM, you may get it in before the action. 😀

  9. I remember a while back Henry Margusity talking about the inverted V and said that represents a wind damage threat. Looking at the discussions and data this morning and were still days away and things could change but there looks to be an elevated risk for damaging winds and a low risk of a tornado assuming everything lines up.

    1. Yes, I agree. That’s how it is beginning to look.

      Still a chance for a tornado, but that won’t be the main threat, or so
      it appears at this point. Still time for parameters to change some from
      that which is currently forecast. It will be interesting to see what the SPC
      lists as a tornado chance, if any, come Saturday. I’m guessing 2% and not
      5%. We shall see.

      1. I agree with 2% chance for tornado right now and anywhere from a 15-30% for wind. With a line you always got
        to keep an eye on for any kinks that develop in the line that could produce a weak tornado.

      1. It could be just that (don’t think so), but if it lasts while, it could still interfere with the game and perhaps even cause cancellation.

        Just too early to know. Have to watch on Saturday.

        For now, plan on the game, but stay tuned for updates.

        Best of luck.

    1. HA HA HA HA HA….. Absolutely HILARIOUS!!!!!!!!!!!!!!!!!!

      Right on Matt. Yup, your correct. TOO HOT FOR THUNDERSTORMS. 😀 😀 😀 😀 😀 😀 😀

  15. From WXedge.com for Saturday.
    Heat sets the state for potential thunderstorms on Saturday. The computer models have slowed down ever so slightly with the approach of a cold front from the northwest. The result will mean another hot start to the day, but some increasing clouds by late-day. The threat of thunderstorms increases by mid-afternoon and the focus shifts towards the severe potential. Although the atmosphere should be relatively unstable with increasing wind shear aloft, the best dynamics and forcings are projected to stay northwest of Connecticut until around or after 00z Sunday. The confidence on any pre-frontal thunderstorms is somewhat low, but the potential appears higher than that of Friday and a few supercells may be able to form. Later forecasts will keep an eye on the situation to see how it evolves

  16. What I find interesting there is the first mention of possibly a few supercells to form. A lot talk has been about a line of forming with the front. You sometimes get these discrete cells to form ahead of the main line. The timing of the front is key in figuring out what type of storms we will be dealing with.

    1. JJ,

      At this point, I think almost anything could happen, including super cells
      the day before the front. We could even see severe weather Both Friday and Saturday. I’m just sitting and waiting and watching. 😀

      1. It’s not out of the question that Friday’s threat is greater than Saturday’s.

        1. Interesting TK.

          There has been so much hype about this threat, makes me wonder IF it doesn’t just go poof. 😀

          1. It does seem when there is a lot of talk about severe weather the outbreak is
            not as bad but when there is little talk of severe weather that’s when it seems we get it.

  17. Anyone EVER see this before??????????

    PORTLAND 12 NM Southeast of Portland,ME
    (44007) 43.531N 70.144W
    Last Updated: Jul 16 2013, 12:50 pm EST
    Tue, 16 Jul 2013 12:50:00 -0500
    Temperature: 77.9 °F (25.5 °C)
    MSL Pressure: 1019.2 mb
    Water Temperature: 71.2 °F (21.8 °C)
    Wave Height: 0.3 m (0.98 ft)
    Dominant Period: 7 sec
    Average Period: 5.6 sec

  18. The one thing a lot of us are going to look forward to is a little bit of break from the heat and humidity early next week. Its going to see what unfolds as we transition out of this hot and humid airmass to a more comfortable one.

    1. Works for me. Even my family who loves this weather – again where did I go wrong 😉 – wants it gone.

      Mid 80s. Lower DPs. Perfect.

        1. A few days are fine with some breaks and then even some more but constant is just tough on the system.

  20. Boston hit 93 today. 3 in a row. Another heat wave as Hadi pointed out much earlier and
    13 days of 90 or better for the year, I do believe and Counting……

    Todd G. only indicated Strong storms for Saturday. That is all. 😀

    2. Its hard to ignore the SPC highlighting our area for the 4th straight day with a 30% chance or greater of severe weather.
      Even strong storms could produce some gusty winds and even some small hail.

  22. I saw a report today that Sandy was a once in 700 year storm. That is, Her direct left turn had an average probability of happening only once in every 700 yrs

  24. Tk, I have an unexpected couple days off next week. We were offered a condo up Hampton beach free of charge. There is like a whole crew that rent the same houses up there the same week every year. I’m heading up after the sox game Saturday night and staying till Tuesday night. How’s it looking for Sun, Mon and Tuesday as I’m hoping for beach weather. If you can take a look I would appreciate it. I probably won’t go if say Monday and Tuesday are not beach days. Take care Tk.

    1. I think you’ll have some fine beach weather. You just may be dealing with thunderstorms on Saturday evening. Sunday would be an issue ONLY if the front hangs up enough.

      1. That was fast, thanks. Also hoping my son and I will get to enjoy our first sox/ Yankee game rain free. Boy I’m asking a lot of mother nature this weekend. Thanks tk. How have you been feeling.

        1. I try to check the blog as often as I can but sometimes it takes a while before I get to it. 🙂

          Today, I’m able to check more frequently. 🙂

          I am feeling OK, but still dealing with a flare up of my auto immune condition. It’s a slow process with medication tweaks to get it back in remission while trying to avoid steroids, which will be a last resort. Been through this battle several times since 1994 and I will win it again. 🙂

      2. Same for south shore I assume?? Tx TK

        John have fun. We will watch the area with both you and tom gone 🙂

        1. Sounds good Vicki. This was really unexpected and to good to pass up. My wife and I will come back Tuesday night and he will stay as the fishing trip is at crack of dawn Wednesday. My wife will head back up Wednesday afternoon and they will both come back Thursday.

    1. This explains how a tornado can still from without significant change in wind direction with height as long as there is significant change in wind speed with height.

      I’m hoping TK can add to this for our educational purposes. 😀

  27. Thanks for the link Old Salty. Now it sort of makes sense to me what that meteorology student was saying on WXedge yesterday. I hope he and others post more articles as we get closer to the end of the week.

    1. No Problem JJ. I found it fascinating. I, for one, sure learned something.

      I think tornadoes are More likely with the change in direction, but it’s nice
      to know they can still form if the change in wind speed is enough. As long as that helicity measurement is high enough.

  30. 18Z GFS surface capes for 21Z on Saturday:

    http://www.instantweathermaps.com/GFS-php/showmap-natlsfc.php?run=2013071618&time=INSTANT&var=CAPE&hour=099

    Lifted Index for 21Z Saturday: WOW!!!!!

    http://www.instantweathermaps.com/GFS-php/showmap-natlsfc.php?run=2013071618&time=INSTANT&var=LFTX&hour=099

    Double WOW!! I’ve NEVER seem them that low. IF I read this correctly, it is
    -6 to -8 across our area.

    I’ll have to keep watching these maps. This is incredible!!

    Sure looks like there will be severe weather.

    Scary even.

    1. Those are pretty impressive lift indexes. The highest I remember seeing were the day of the Springfield tornado
      when they were -8 to -10 that day.

      1. Got to watch this situation carefully and see what future model runs have to say. Its a good thing its Tuesday night
        and not Friday night because if this was Friday night with those lift index’s I would be very concerned.

        1. Amen to that. As we get closer the SREF has ALL of the parameters, including CAPE, Lifted index, and Helicity, not to mention the special significant tornado index.

          We’re almost in range now as it goes out to 87 hours.

          Those lifted index numbers really shocked me.
          I WISH we could see them from the Euro.

          Hey Hadi, you out there. Does your version of the Euro
          have those maps?

          1. I believe the normal lift index when we have the threat of severe weather here is between -2 and -5.
            When I saw the map you posted Old Salty with those lift index’s -8 -9 I said wow. Will see what the next model
            runs show.

            1. INDEED!!!! Absolutely Frightful numbers!
              SCARY!!!

              I wish we could see those numbers from the Euro. Would there be corroboration?

              NAM is getting into range as well.

              I’m going to have a busy day at work tomorrow. Hope I can squeeze in some model watching!

  31. Jim Cantore was going over the severe threat earlier this evening.
    You were talking about helicity and if I remember correctly I believe the day of the Springfield tornado the helicity values were between 150-300.

  32. Well here it is from the Weather Channel, the latest TORCON forecast for Saturday 7/20.

    Saturday, July 20

    Severe thunderstorms with damaging winds in OH, southeast MI, eastern IN, northern KY, WY, northern VA, northern MD, northern DE, PA, central and nrorthern NJ, NY, CT, RI, MA, VT, NH, and ME. TOR:CON – 3

    The day of the Springfield tornado it was 3-4.

    Hmmmm

    No definitive answers just yet. Tons of speculation, but clearly something is up.
    Let’s hope for the best.

    1. Further Speculation.

      Re: Torcon

      Multiply the value by 10 to get your chance of a tornado within 50 miles of a location. For example, a TOR:CON index of 6 means there’s a 60% chance of a tornado within 50 miles of a location

      So for our area, 30% chance of a tornado within 50 miles of a location.

      From SPC, they use within 25 miles of a location, reducing the percentage
      significantly. Not sure of the exact conversion, but a 3-4 torcon translated to a 5% chance from SPC.

      So we “could” see a 5% chance from SPC on Saturday.

  33. It was 5% chance the storm prediction center had the day of the Springfield tornado along with only a slight risk of severe weather that day.

  35. TK I was going to ask that question as we got closer to Saturday if this setup is similar to that of July 10, 1989. What ingredients
    do you see right now that are similar to that day?

    1. Some of the early instability forecasts are similar and the PRIMARY one is the direction of upper level flow, likely to be WNW or NW, prime for big severe in southern New England.

        1. NW flow is a major ingredient in New England tornado outbreaks. Will this be an outbreak? Too early to tell. Parameters allow supercells, if they verify.

  36. Rainy for a short while here today, with the sun shining bright all the while. LOVE that! 😀 Loved how it cooled down later in the evening. My AC is still on though for my poor kitties!

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