Friday July 31 2020 Forecast

64 Comments

7:14AM

DAYS 1-5 ( JULY 31 – AUGUST 4)

We have a hurricane to talk about, but we will get to that. First, and the more immediate future, we will have a wet start to the day today along the South Coast. This is something that we have been keeping an eye on for several days. The cause is the front that went through yesterday sitting in that region while a week wave of low pressure rides along it and tropical moisture is lifted over the frontal boundary. As you head north where to cross Southeastern New England the weather is drier and eventually clearer as the cloud line sits near the Massachusetts New Hampshire border early this morning. We will see a drying trend along the south coast and a clearing trend for the entire region as the day goes along today. An area of high pressure will provide a very nice day for the first of August on Saturday. If there is one caveat it is that sea breezes forming along all coastal areas may have enough moisture to interact with closer to the south Coast that a couple of isolated showers may develop during the afternoon. This would be the exception, not the rule. By Sunday, low pressure passing northwest of the region will drag a warm front into southeastern New England, increasing the cloud cover and eventually the risk of some shower activity. Humidity will also be on the rise at this time. by Monday, we should be into a warm and muggy air mass with just a risk of a few showers and thunderstorms. During this time we will be awaiting our fate regarding the track of Hurricane Isaias. As has been mentioned previously, subtle changes in a storm’s track can have a significant impact on a storm’s intensity. and a track a little further away from mountainous influence and over very warm water has allowed this system to gain intensity a little more quickly, something it will continue to do as it moves through the Bahamas. The best guess on the track of the system currently is that the center will stay offshore of Florida and Georgia, and South Carolina, and either just offshore or clipping the North Carolina coast over the coming few days as it moves along. That brings us to Tuesday. That will be the day that this system has its most significant impact on our region. The details of that impact will depend on the track of the system, and obviously its intensity. A track over the region would most likely produce a greater wind impact than a rainfall impact, although the rainfall impact would still be significant. A track just to the southeast of the region would likely produce a greater rainfall impact than a wind impact, although wind would still be a factor. a slightly sharper turn to the northeast would lessen the impact of both of these. It is simply too soon to tell exactly what will happen.

TODAY: An overcast and showery start South Coast, with lots of clouds elsewhere except mostly clear north central MA through southern NH. Midday and afternoon showers ending with thinning clouds South Coast, and increasing sunshine elsewhere. Less humid. Highs 78-85. Wind N 5-15 MPH.

TONIGHT: Mostly clear. Lows 58-65. Wind N to variable up to 10 MPH.

SATURDAY: Mostly sunny to partly cloudy. Slight risk of isolated showers in southern RI and eastern CT during the afternoon. Highs 80-87. Wind variable up to 10 MPH with sea breezes.

SATURDAY NIGHT: Clear. Lows 61-68. Wind variable under 10 MPH.

SUNDAY: Increasing clouds. Risk of afternoon showers. More humid. Highs 78-85, coolest coastal areas. Wind SE up to 10 MPH.

SUNDAY NIGHT: Variably cloudy. Risk of showers. Humid. Lows 65-72. Wind S up to 10 MPH.

MONDAY: Partly sunny. Risk of showers and thunderstorms. Humid. Highs 83-90, cooler South Coast. Wind S-SW 5-15 MPH.

MONDAY NIGHT: Mostly cloudy. Chance of showers. Humid. Lows 65-72. Wind variable 5-15 MPH.

TUESDAY: Cloudy. Widespread showers or rain likely. Chance of thunderstorms. Humid. Highs 72-79. Wind variable 10-30 MPH, possibly stronger.

DAYS 6-10 (AUGUST 5-9)

Assuming the timing of Isaias remains as expected we should have improved weather by the beginning of this period, with mostly fair and drier conditions into mid period, followed by an increase in humidity and a risk of showers and thunderstorms later in the period.

DAYS 11-15 (AUGUST 10-14)

Current indications continue to show a weak westerly flow aloft and at the surface a potential battle between high pressure in Canada and high pressure off the US East Coast. This type of pattern can produce episodes of showers and thunderstorms but still plenty of rain-free hours as well.

64 thoughts on “Friday July 31 2020 Forecast”

  5. Thank you TK and SAK!
    Looking forward to everyone’s thoughts as things evolve with this potential event during the next few days.

  8. Good muggy morning. Thank you, TK.

    Will you be incorporating a trampoline impact section on your forecast 😉

    1. Interesting….

      …Northeast…
      Organized convection will again be possible in association with the
      northeastward-moving cyclone on Sunday, as moderate low/mid-level
      flow and rich low-level moisture overspread portions of the
      Northeast. Considerable uncertainty remains regarding how this
      scenario will evolve, but supercells and/or organized bowing
      segments will be possible, with an attendant risk of locally
      damaging wind. Some tornado potential will also be present in the
      vicinity of the retreating surface warm front as it moves northward
      through the day. Some portion of this region may require an upgrade
      once details come into better focus.

  10. Thank you, SAK……odd, I do not see a trampoline impact rating there either.

    I went back on whw and read the blog on July 4, 2014. Fun comments as well as interesting information TK, I do enjoy being able to go back and read

  12. SPC mentioning areas where they could upgrade for Sunday. Looking at the 12z NAM and the SREF it looks like PA, NJ, and NY would be the areas.

  13. 12z NAM clips western parts of CT with parameters favorable for thunderstorm development Sunday but the best parameters just west of CT in the Hudson River Valley of NY. Close call at this point. Eastern areas of SNE look to be sitting out on this one.
    This tweet from John Homenuk goes with the 12z NAM
    Sunday’s severe weather setup in the Mid Atlantic/New England deserves some attention. Ample kinematic support w/ an approaching mid level perturbation & weak EML. Plenty of instability and ample moisture. All severe hazards would be possible should this regime come to fruition.

  15. 12Z GFS wants to bring Isaias through our area,
    but taking an inland route most of the way.

    Plenty of rain, but wind impacts would be minimal, imho.

  16. Thanks TK.

    Isaias struggling significantly with both dry air and shear. I stand by my initial thoughts – it’s unlikely to become a powerful hurricane, or to be a significant threat to the US. In fact, it’s possible it already achieved peak intensity last night, though it may continue to flirt with low end hurricane strength for another day or two.

    We may be about to dodge a pretty major bullet too. It’s not a bad upper air pattern at all in terms of what you need to get a New England hurricane strike. And it is increasingly likely that moisture from the storm will affect us. However, the fact that it is expected to weaken as opposed to strengthen in the Bahamas due to shear is rather unusual. Many storms blow up in intensity there, whether they affect us or not. This one will not.

  17. WxWatcher things might get interesting down your way in terms of thunderstorms for Sunday.

    1. I sort of suspect the best severe chances will be west of me, maybe more towards central PA and NY, but definitely watching! Haven’t had a whole lot of time to give it a close look but there are some severe weather positives for sure.

  18. Looking at the 12z American model runs the best severe parameters are just west of me in the Hudson River Valley of NY. It is close for my area. At the moment I expect when I wake up tomorrow morning and click on the SPC website some part of the marginal risk will be upgraded to a slight risk.

  19. I laughed When Cindy on Ch 5 news tried to pronounce Isaias and then finally just said “the hurricane.” I gave up trying to Pronounce a bit ago.

    1. Mrs. Fantastic had an uncle named Isaías. They all called him “Uncle Easy.” So maybe Cindy can call our storm “Hurricane Easy.”

      1. Love it. She just had a commercial blurb and said it. I’m practicing. I actually like the sound

        Eee—sigh—eee—us

        I think.

          2. Yay. This is awesome. Thank you.

            I meant to also tell you that my cousin who is a retired middle school principal said she decided to learn a new language during this time. She is using Duolingo for Spanish.

  20. TK, our favorite anchor on BZ radio just said, you can get a walk in during the morning but the afternoon will go downhill quickly and the weekend is looking very unsettled.

    1. Which afternoon? today? tomorrow? Sunday?
      the 12th of never? You can’t make up this shit!

  21. Most of the 12Z runs want to take the big easy on an inland route
    with far less rain along coastal areas and the jackpots well
    inland. Of course, there are a few days to go to zero in
    on that track. Also pretty obvious (for now anyway) that
    this thing will NOT be a hurricane when/if it gets up here.

    1. There’s been a tropical depression lingering just off the coast of Africa for a couple of days now. NHC has so far resisted classifying it, but it’s garnered a bit of attention on Twitter and the like. It should dissipate within a day or two.

      1. Yeah i know it should dissipate soon but i am wondering the NHC resistance to classifying it, what is their reasoning.

  25. For anyone familiar with Boston, this is the start of the muddy river. This stream comes out of Ward Pond which is fed
    by Jamaica Pond. The water is so clean, then gets so
    dirty yucky muddy. This shot is barely in Jamaica Plain, mere
    stone throw from Brookline.

    https://imgur.com/a/mZSXS6A

    1. Yes. I haven’t had much time to look very closely at that, hence the generic hit on my blog, thinking it may be more west of my forecast area anyway. I’ll re-evaluate tonight.

  28. So question I should know answer to but don’t seem to be able to find in my memory banks. Which direction does TD wind come from? I do know it switches as eye passes. And guess what this relates to 🙂 🙂 🙂

  29. Recon found a pressure of 985mb. Peak flight-level wind of 63 knots so far. Surface winds mostly 50-55 knots, except for one questionable 76-knot wind. Definitely an eye on radar. Shear relaxing. All signs point to a period of intensification. The questions are 1. Will it? 2. If so, how quickly?

  31. Nearly every NWS office east of the Mississippi River will be launching balloons 4 times a day to get more upper-air data into models to help with the forecasts for Isaias.

      1. Haha. Thanks. I’m not sure any more what is good news or just not liking what is reported so didn’t dare comment. So then yay. Thanks, North

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