Wednesday Forecast

144 Comments

2:08AM

DAYS 1-5 (JULY 6-10)…
After a whole lot of analysis of data during the last 12 hours leading up to the writing of this blog entry, I’ll be making a few adjustments to the forecast overall but with the general idea still the same – heat today, then a boundary nearby with temperatures depending on location of the boundary, and shower/thunderstorm chances depending on timing of disturbances and locations of boundaries, with a greater-than-usual amount of uncertainty for the remainder of the period. The current thinking is that more of the region than not will be on the cooler side of the boundary Thursday and Friday with a risk of showers/thunderstorms both days, but possibly favoring late Thursday as activity is slow to arrive, and then less of a risk for a while on Friday as activity is pushed further to the southwest. This boundary will likely make an attempt to return as a warm front Friday night into Saturday but it is uncertain how far it will get, with the greatest chance of getting into the warm/humid air the further west and south you are. This would end up being the region with the greatest risk of stronger storms. Again, timing and placement being uncertain, there will still be much fine-tuning to do. By Sunday, though the main cold front from the weekend system should be by, enough instability may remain as the trough is slow to pass at upper levels, and this may allow for some additional scattered shower and thunderstorm activity. This is a change from the previous forecast. So, with medium to lower confidence, here is the latest forecast update, but check back for updates!
TODAY: Mostly sunny. Humid then slightly drier. Highs from the middle to upper 80s immediate coast, lower to middle 90s otherwise. Wind light W except sea breezes at shoreline locations.
TONIGHT: Partly cloudy. Lows from the middle 60s to lower 70s. More humid. Wind light variable.
THURSDAY: Mostly cloudy. Isolated to scattered showers/thunderstorms. Highs from the middle to upper 70s eastern coastal areas, upper 70s to middle 80s most other areas except some upper 80s to lower 90s in interior MA, northern RI, and northeastern CT. Wind variable, mainly E to NE up to 10 MPH near eastern coastal areas and mainly SE to S up to 15 MPH elsewhere.
FRIDAY: Variably cloudy. Isolated showers possible. Lows in the 60s. Highs 70s coast, 80s interior.
SATURDAY: Mostly cloudy. Episodes of showers/thunderstorms. Lows in the 60s. Highs in the 70s.
SUNDAY: Partly cloudy. Isolated showers/thunderstorms. Lows in the 60s. Highs from the upper 70s to middle 80s.

DAYS 6-10 (JULY 11-15)…
Dry weather expected July 11-14, starting out with mild/dry weather then trending toward hot/humid. Showers/thunderstorms become more likely at the end of the period.

DAYS 11-15 (JULY 16-20)…
Showers/thunderstorms may be around to start the period followed by drier and warm weather. Heat may try to return later in the period.

144 thoughts on “Wednesday Forecast”

  4. Thank you, TK. The quiet ends for a bit it seems. We have had an amazing stretch. About a months worth of perfect weather.

    1. Hottest day of the year was reserved for the birthday boy . Bring it on triple H please. Saying that I hope the people that don’t do well in this can find some relief like Mrs Old salty .

      1. Not good John. She was already sick just from the humidity
        of yesterday. We are supposed to head to the Cape tomorrow.
        Most likely NOT going to happen. The humidity knocks the crap out of her.

        1. 🙁 This weather literally knocks the crap out of many people 🙁 Let Mrs. JPD know I’m right there with her!

  9. From NWS out of Taunton tomorrow.
    Fat, deep- layer cape
    profiles per soundings and wet-bulb heights down around 8-10 kft,
    looking at signals for large hail. Given inverted-V profiles and
    some mid-level dry air, gusty winds seem plausible. And finally
    there is a heavy rain potential along with nuisance, poor-drainage
    impacts. Will continue to prevail heavy rain wording within the
    forecast.

    1. JJ, just a caution on the EHI values.

      It is derived from a combination of helicity and CAPE. In this particular
      case, helicity is low to moderate at best, while CAPE is extremely high.
      Therefore, in this case, the index is mostly comprised of CAPE.

      If you are thinking tornado, then look at the Significant Tornado Index
      found on SREF and also available at the College of DuPage website.

      http://weather.cod.edu/forecast/

      1. On more thing JJ. FWIW, the 4KM NAM is not nearly as
        robust as the regular NAM, HOWEVER, it shows considerable
        ELEVATED INSTABILITY.

  11. Quick peak at 6z GFS impressive as well for tomorrow. Yesterday the American models were keeping the instability away from Boston area. With this run Boston area gets into the action. Will see what 12z runs say.

  12. Euro is not very bullish at all for tomorrow, while it has the area in a slight chance
    of severe for Saturday. I think it is all too volatile for the Models to get a good handle on it. Let’s see what the 12Z runs show.

    It looks like the 6Z runs want to keep the warm air in up to and North of Boston, thus
    putting most of the area in line for possible severe weather.

    My concern for Saturday is not necessarily getting into the warm sector, but
    being in a very active area of the Warm front with SE surface winds and NW winds higher up. My concern for Saturday is the “Revere” situation.

    Not that tomorrow won’t be interesting, because it likely will be.
    I think that the tornado risk for tomorrow is quite low, but non-zero.

  13. Thank you TK for that great detailed discussion.

    I can tell you one thing, today is starting out HOT with a decent LAND breeze here
    so far. This is one time I am rooting for a robust sea breeze!!!

  15. The ideal situation would be just to get a good soaking without the severe weather.
    This is the first week we have had so far in the warm weather season with multiple thunderstorm chances. Now will see what unfolds.

    1. I like the severe weather, but then that can bring hardship to people if
      they suffer damage. So, I would be very content with a good slug of rain.

      Just garden variety thunderstorms can cause serious problems with
      lightning strikes.

      Actually, what would be best would be tropical off and on showers.

      But, unfortunately, I fear at least some severe weather across the region either tomorrow and/or Saturday.

    1. That is what I was alluding to above. It is starting out HOT!!!!

      IF Logan stays with a land breeze, it will make a serious run at 100.

      btw, looking at flags on top of buildings near my office, it looked like
      a NW wind blowing at about 10-15 mph. A NW wind can bring us our
      hottest weather.

          1. I think Logan will eventually seabreeze, especially once it gets to 90F just inland. Just not enough gradient to overpower the rising heat inland.

            Unfortunately, a light enough seabreeze that I’m not sure it will offer any relief where you live.

            1. Yup, Agree with that assessment. However, the dew point is helping to mitigate it somewhat.

          2. However, it is only 5.8 mph. Kind of open to
            a Sea Breeze. Even so, likely to only cool
            the shore line and a mile or so inland. Likely not
            to reach my house even if it occurs.

            Latest buoy temperature 59.4 degrees, so there
            is PLENTY of cooling potential out there. 😀

            When I was in charge of building HVAC systems and the energy management computer, we used
            to have the output temperature at 55 Degrees to maintain about 72 in the building. SO 59 Degree water out there, should be able to get the
            temperature at Logan down to 77 or 78 degrees.

              1. I was cool. I programmed that
                sucker to produce cooler output
                temperature depending on the temperature and dew point.

                I actually had 3 levels of cooling.

                I would make the office area

                70 in really HHH weather, 72 for in between and 74 for dry comfy weather.

                I controlled all of the valves opening and closing to automatically turn the chillers on and off. It was pretty cool stuff. If it were cool enough outside, I’d turn the chiller off and run with outside air, much like you would do with your vehicle air conditioning and ventilation.

  19. Dave thanks for the link and explanation.
    I agree with you I think there will be parts of the region that see severe weather tomorrow or Friday. The 6z runs of the American models more than enough juice for strong to severe storms. NWS Taunton mentioning large hail tomorrow as one of the threats.

    1. Large hail, I believe is due in part to the ELEVATED INSTABILITY.
      Also, at some level above, it must cool off more than normal.
      Will have to look at some 700mb temperature readings and some soundings.

  20. Thank you, TK. The adjustments in your forecast suggest that the hint we had a couple of days ago of a cool front coming in Thursday will likely come to fruition.

    The rain will be welcome, even though it will come in batches and be stormy at times. I also will not mind some clouds around. We’ve been blessed with a healthy dose of sun in recent months. Having cloudiness adds variety.

    Eastern Massachusetts is parched still. Different story in the western part of the state. It’s not exactly wet – in fact, it’s dry out there, too – but much greener than here. Less `droopiness,’ lawns are less stressed, trees look more vibrant. I noticed this in central Vermont, too, a few weeks ago. It just looked healthier than here. Judging from what we’ve seen of the storms that have crossed our region, I think that the reason for less drought there is that those storms produced some substantial rainfall there before petering out as they approached coastal sections.

    1. Not convinced that the BDF makes it to Boston. I see some signs that
      Boston stays in the warm sector tomorrow. Will be close either way.
      Saturday much more likely Boston stays on the cool side.

      So for tomorrow, I see Boston with Cold front/trough convection while for Saturday I see Boston with Warm front convection.

      We shall see.

  21. TK has quite a talent for analyzing the weather conditions.

    12Z NAM really depicts the BDF tomorrow and has Boston with an EAST wind.
    GINORMOUS CAPE Values West and Southwest of the City.

    1. We’ll be in Carver (southwest of Plymouth) in Myles Standish forest. I get the feeling we may see some storms tomorrow.

    2. But then, the front appears to move Northward and Boston gets more into the big CAPE area.

  22. I will say this. The SREF is NOT bullish on severe weather here either for tomorrow
    or Saturday.

    1. It’s a crapshoot of sorts regarding whether we’ll get severe storms, sort of like predicting what we’ll get out of Sox pitchers. I do think that from Thursday through Saturday we get some rain and some moderate storms as well, also in the Boston area.

      1. Good descriptor.

        We shall see.

        Not impressed. 4KM NAM keeps East wind in at Boston
        All day tomorrow.

        On the simulated Radar, it doesn’t show much action at all.
        Just a cell here and there.

        I wish the HRRR were in range. The experimental version
        is stopping at 18 or 23 hours and isn’t going out far enough.

  24. Friday NAM wants to keep instability in CT and RI and Saturday no instability for Boston area.

  25. 88F at Logan at 11am, light SW wind.

    I think we have a seabreeze, a very light one, in Marshfield. Hasn’t dropped the temp much though, it’s blazing away.

    1. Thanks Tom. Didn’t have a chance to look.

      6.9 mph. “Might” Be just enough to avoid the sea breeze.

      btw, the dew point is 59, which is an absolute BLESSING!!!!

      Wind North at Beverley and CALM at Plymouth, so it does “appear” to be
      setting up for a Sea Breeze. I had better happen soon, or the damage will have been done.

  26. While writing my forecasts last night, I had pretty much the same things written in the discussion that accompanies them – the potential for a 25-degree swing in temps based on where the front sets up. I’m not going to quibble with your forecast for the next few days for that reason (my forecasts varied a bit, but not much). The bigger difference in our forecasts is for Saturday. I went warmer and more humid once again. I think the front lifts back north as a wave of low pressure rides along it. I had middle to upper 80s for most of southern New England with showers and thunderstorms as the front comes through.

    Yes, this is different from what the models are showing, but if the models were really that good there’d be no need for meteorologists, would there?

    2. With the 500 as far north as it looks like it will be in may start to tip the scales to the warmer side as well…

  27. 12z GFS less CAPE than the 12z NAM for tomorrow but still decent with 1,000 – 1,500 CAPE
    LI’s look to be in that -4 to -6 range.

  28. 12Z GSF not impressive at all regarding instability parameters for tomorrow.
    Rather wimpy, however, it shows a fair amount of qpf, generally .4 to .6 inch
    across the area.

    1. Yup, same ole same ole. They tease and then don’t deliver.
      In spite of all of that, tomorrow and Saturday, we “should” receive
      some much needed rain. Let us hope anyway.

    1. Down to 84 here. Just stepped outside and was surprised it felt cooler than it had at 9:00ish

        1. Sutton. Humarock is not till next two weeks. Sorry.

          Let me check my weather station. I got that from Wunder since I’m at the computer working.

  34. Impressive warm airmass ….. Falmouth, Hyannis and a couple other Cape locations at 86F at noon time.

    FWIW ….. The GFS certainly keeps projecting in the very long range one of those southern New England sizzlers, where a piece of the western and southwestern heat wave breaks off, travels up into the Great Lakes and then dives east-southeastward across the northeast for a day.

    The GFS has been doing this for a while in the extended, but I have a feeling given the drought, our proximity to the climatologically warmest part of the year and a continued transition to a weak la Nina, that one of these projections sometime in mid to late July is going to happen, and we’ll end up with a day similar to July 22nd or 23rd of 2011, when I believe Logan hit 103F.

  35. At 1PM Logan has gone to SouthEast wind at 9.2 mph.

    At my house at the same hour, we had a rather stiff WSW wind, so Go Figure.

      1. 3PM Logan is at 87 with SE wind at 8+ Mph.
        Marshfield 90 with East wind.

        Plymouth, 91 with NorthWest wind.

        Beverely, 3 miles inland is 91 with a SW wind.

        Blue Hill is 89, BUT with a SW wind gusting to 17 mph.
        Very strange indeed. Logan has a climate of it’s own. 😀 😀 😀

        1. Very impressive temps with an ocean component to the light breeze. And the shallow top layer of ocean has gone from 59F this morning to 68F, 16 NM out in Boston harbor.

              1. It sure felt that way to me out there. Dew point back down to
                59 again, thankfully.

                I am NOT impressed about tomorrow and/or Saturday. Perhaps something will change and there will be a big surprise, but I’m not counting on it.

                I just hope we get some rain and now I am even questioning that.

                I truly am a PESSIMIST!!!

                1. Even though it’s the warm season, the setup at hr 72 and hr 96 looks like a cool to cold season setup, with a Great Lakes runner almost redeveloping overhead. Does the EURO forecast rain amounts around the Saturday timeframe for Boston ?

  37. Logan reports 90F at 3pm (it had hit it earlier before the weak seabreeze) with a busier SW wind

    If that keeps up, perhaps a shot at 95F by 4pm as some inland locations are close to that value.

    1. I was just going to post that.

      Partly Cloudy
      90.0 °F
      Last Updated: Jul 6 2016, 2:54 pm EDT
      Wed, 06 Jul 2016 14:54:00 -0400
      Weather: Partly Cloudy
      Temperature: 90.0 °F (32.2 °C)
      Dewpoint: 61.0 °F (16.1 °C)
      Relative Humidity: 38 %
      Heat Index: 90 F (32 C)
      Wind: from the Southwest at 15.0 gusting to 19.6 MPH (13 gusting to 17 KT)

      That is quite a shift to go from a SE sea breeze to a SW wind gusting to 20 mph. Amazing. Yes, the SW wind will transport heat from the city (streets and sidewalks and brick and cement buildings) over to the sensor site.

      High temp may be 5 or 5:30 and not 4PM. We shall see.

      Just spoke with my wife, it’s 91 at my house in JP.

  38. Tom, to answer your question, the Euro was NOT showing much precip for Saturday.
    Let me look again and perhaps share a chart.

    Here is the Euro 24 hour precip grid values for Saturday. I presume it is 8PM
    Friday evening through 7:59 PM saturday evening.

    http://imgur.com/dH6YSJf

    It shows most of the precip NORTH of the MA pike, and most in NNE.

  39. Sutton is 91 even. I checked Wunder and surrounding stations are all around that give or take a couple. One Northbridge wunder reports 94.5.

    DP is 66 (wunder) and wind SW gusting to 8 mph (also wunder)

  40. Here at the Storm HQ World Headquarters Compound, the current temperature is 93.4 and we have a PST (Pool Surface Temperature) of 83. Unfortunately, outdoor activities have ceased for the day as it’s time to head for the office. Based on climatology, the temperature inside the office should be around 71 when I arrive somewhere around 6pm, and 80 when I leave around 2am (the building’s AC shuts off at 8pm).

    If anything catches my attention with regards to the next few days, I’ll see if I have time to share my insights. I can already tell that when I get in I’ll be monitoring severe storms in Tennessee and Georgia, since we have radio station customers in those locations. (Speaking on the radio in Cookeville, Tennessee or Gainesville, Georgia and NOT letting my Boston accent come out to play isn’t the easiest thing in the world).

    1. Can we listen in? Do those radio stations stream audio on their websites?

      If so, please provide url and broadcast times. Many thanks

      1. Unfortunately, I never get any notice of when I’m doing severe updates. When a watch or warning goes up, the station may call and ask for, but sometimes they don’t. The only stations I know for sure that I’m on every evening are:

        WVMC-FM, Mansfield, OH (After 7pm) http://wvmc.vaststream.com/ (Christian Radio)

        KETR-FM, Commerce, TX (After 9pm) http://ketr.org/#stream/0 (NPR)

        WVMP-FM, Roanoke, VA (After 10pm) (Adult Album Alternative) http://wvmp.tunegenie.com/#listenlive

        Also, all-day Saturday you can hear my forecasts on WXEX, Classic Rock 92.1FM on the Seacoast of NH and York County, Maine. http://streamdb6web.securenetsystems.net/v5/WXEX

  42. So far as of 17Z, 18Z NAM REALLY keeping instability suppressed to WELL southWest
    of the Boston area. Waiting to see if it moves NE or not. 😀

      1. Nope, 18Z is closest pass of CAPE to Boston, then retreats towards
        the SW again.

        Waiting on the other sites to check out elevated instability.

        This is so close, that Boston is well within the margin of error
        on this thing. We shall see.

  44. My concern as a forecaster for tomorrow would not be severe weather, as that looks very unlikely, but rather localized excessive rainfall, which multiple pieces of the short range guidance are showing. Storms, if they develop, are likely to be slow moving.

    1. Sounds very reasonable. BUT, we shall see how much rain falls.
      I wish the HRRR would go far enough out.

      The 18Z 4KM NAM noses HIGH CAPE into Boston at the 20Z hour with
      major convection on Boston’s door step.

      Note this dew point line, most likely aligned with the BDF.

      Here is the MUCAPE (most unstable Cape) at 20Z

      Notice that it is into Boston

      http://climate.cod.edu/data/forecast/NAM4KM/18/NE/NAM4KMNE_con_mucape_026.png

      Note this dew point line, most likely aligned with the BDF.

      http://climate.cod.edu/data/forecast/NAM4KM/18/NE/NAM4KMNE_sfc_dewp_026.png

      1. HILARIOUS as per usual.

        EVEN though MUCAPE is high, The Sim Reflectivity shows
        all MAJOR cells to the West DYING OUT as it approaches
        the BDF. NOTHING or virtually NOTHING makes it to Boston.

        Now this is one run and an 18Z run, but it is a very high resolution model, 4km NAM

      2. Dewpoint map is nice !! Maybe a bit too high on inland dewpoints but I get the idea of what it’s trying to show.

    1. Ouch! I wouldn’t want to be in it’s path.
      Any land in it’s path? What poor island gets blasted?

      1. Nothing in its path and per the NHC track forecast, will weaken to a depression well east of Hawaii.

  46. In case you can’t tell, I’ve had it for today. I am cooked.

    Long 4 day weekend for me starting in a few minutes. 😀 😀 😀 😀

      2. And having said that, it feels like the number should be much higher, given the very warm days lately. I am somewhat surprised that July 4th didn’t get to 90F as wonderful a day that was.

        1. While we haven’t had high heat, we haven’t had raw, chilly days either. June 11th was the last day Logan had a high under 70F, which I think is remarkable, considering how easy it is to have one. (Have low clouds and a NE wind and its struggling to get to 65F)

          Ironically, Saturday may well be a candidate for Logan or some coastal area further north and east to stay under 70F.

  49. Whatever futurecast model Harvey is using (maybe the ARW?) shows an active afternoon for parts of the area tomorrow. Again, heavy downpours and localized flash flooding the major threat. I think north and west of 95 and perhaps more out towards 495 will be the best bet.

    1. I have noticed that those futurecast models don’t accurately predict thunderstorms very well. Too often it looks like Boston is going to get slammed and the next day the storms either go poof or end up in a totally different location. They seem to do a much better job with typical run-of-the-mill east coast storms, for instance. Even then, they can sometimes be somewhat frustrating, but it is all we (the general public) have to go by.

      1. The thunderstorms are definitely more difficult because they’re so localized, plus they’ve yet to form. Much easier to track and predict an already developed ocean storm that will affect the whole region.

        As far as I know though, most of the futurecast models aren’t unique; each forecaster has their preference but I’ve seen the HRRR, hi-res NAM, ARW, and probably some others all used. The only enigma is the RPM, which is proprietary by WSI, but I think some stations use it as well.

  50. Tom posted about Blas in the East Pacific basin earlier. Luckily that strong storm will not harm anyone and will begin spinning down pretty soon. On the other side of the world, Taiwan will not be so lucky. An extremely powerful super typhoon (“Nepartak”) is barreling towards the island and will make landfall tomorrow. We can only hope proper preparations have been made. They’ll have had plenty of lead time, so that is one good thing at least.

    http://www.ssd.noaa.gov/PS/TROP/floaters/02W/imagery/avn_lalo-animated.gif

  52. Humarock Wunder says 79 there

    73.9 (my station) Sutton and 66 DP (Wunder)

    First time I have had AC on past dark but jist turned off.

    JPD how is Mrs OS ?

    2. My central air system died today after we had two power outages in our town late this afternoon ugh!

      2. Yikes. Can’t remember where you are. Son in law manages a heating and AC business in Wellesley. Good luck. Does sound like possible power surge

  53. Anyone know how to get rid of the womder app that slides out of the right side of the iPad. Drives me absolutely nuts. If I’m typing and hit too far right, it appears and I cannot type until I get it to go away.

  55. I would not want to have to predict Logan’s afternoon temp today.

    82F, 72F, 60 something ????

        1. 🙂 🙂

          It can’t be much more than 60F, there’s a light to steady NE wind and we are socked in with low clouds and some fog. Just seems one of those days where perhaps within a few miles of the ocean, it struggles to warm much at all.

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