Wednesday August 4 2021 Forecast (9:15AM)

47 Comments

DAYS 1-5 (AUGUST 4-8)

The continuation of the fine-tuning process for the upcoming wet weather event goes on even in the final hours before it arrives. If you recall, our guidance just a few days ago was overwhelmingly in favor of rain-free weather through early Thursday and wet weather later Thursday through Friday. How’s that going to work out? Not well. And this is why I (and other mets) often caution and remind people not to trust guidance so easily beyond just a few days, because many times it will lead you very astray. Here, yet again, we have another in an endless string of examples of this. Anyway, the job now is to focus in on this event, which is now a Wednesday night into Thursday event, and will be on the heavy side for some of the region, but will spare many areas that suffered previous flooding issues. This particular set-up is not part of the same pattern that brought us our wet weather in July. This is a different pattern, drier overall, but still capable of delivering a solid wet weather event. This one will be the result of high pressure building off the US East Coast and pushing a frontal boundary westward into coastal New England during the next couple days, with a passing wave of low pressure the shower activity along that front evolves into a fairly solid area of rainfall that will move south to north through the region tonight into Thursday before exiting during the second half of Thursday. The swath of heaviest rainfall should be somewhere in the I-95 belt and eastward, but that doesn’t mean some briefly heavier rain can’t reach a bit further west than that. It just looks like the areas in southwestern NH that struggled with flooding will miss out on the heaviest, which is good, and that a good portion of still-dry Cape Cod will get in on some decent rain, which is also good, but some areas between that don’t need it end up with some flooding issues, which is not good. The good news is this will be a fairly short-lived event, a matter of hours versus several days and episodes of wet weather. As we get to later this week and the weekend, we’ll be largely rain-free with a warming trend and more humidity. A few diurnal showers and thunderstorms may pop up well inland later Saturday and a few more may develop on Sunday with the help of an approaching weak trough of low pressure, but this won’t be a return to a wet weather pattern, just more typical summertime weather.

TODAY: Filtered sunshine then clouds thicken up again from south to north. Highs 73-80, coolest coastal areas. Dew point ranging from middle 50s north central MA to middle 60s South Coast. Wind SE up to 10 MPH.

TONIGHT: Cloudy. Widespread showers arriving from south to north, heaviest I-95 corridor southeastward with a chance of embedded thunder. Flash flooding may occur in prone areas. Areas of fog forming. Lows 62-69. Dew point in 60s. Wind SE up to 10 MPH.

THURSDAY: Cloudy with numerous showers in the morning, heaviest I-95 belt southeastward, including the slight chance of thunderstorms and areas of fog. Breaking clouds with showers ending from south to north afternoon. Highs 69-76. Dew point in 60s. Wind E to SE 5-15 MPH.

THURSDAY NIGHT: Partly cloudy. Areas of fog. Lows 61-68. Dew point 60s. Wind SE under 10 MPH.

FRIDAY: Partly sunny. Highs 76-83. Dew point 60s. Wind S 5-15 MPH.

FRIDAY NIGHT: Partly cloudy. Patchy fog. Lows 65-72. Dew point 60s. Wind SSW up to 10 MPH.

SATURDAY: Partly cloudy. Isolated afternoon and early evening showers and thunderstorms possible favoring central MA / southwestern NH. Highs 78-85. Dew point 60s. Wind SW 5-15 MPH.

SATURDAY NIGHT: Partly cloudy. patchy fog. Lows 65-72. Dew point 60s. Wind SW up to 10 MPH.

SUNDAY: Partly sunny. Isolated to scattered afternoon and early evening showers and thunderstorms. Highs 80-87. Dew point 60s. Wind SW 5-15 MPH.

DAYS 6-10 (AUGUST 9-13)

Larger scale: High pressure off the US East Coast is an overall warm to hot August pattern but with limited rain chances. Regional scale: high pressure at the surface centered to the north will bring an easterly flow in for August 9 with modified temperatures and slightly less humid air here, then we’ll experience more warmth and humidity after that.

DAYS 11-15 (AUGUST 14-18)

High pressure off the Atlantic Coast but also high pressure in eastern Canada means a boundary between the two may be closer to our region with continued warmth but a better chance of showers and thunderstorms during mid month.

47 thoughts on “Wednesday August 4 2021 Forecast (9:15AM)”

  6. The difference between the 12km & 3km NAM (12z run) on rainfall totals and distribution is pretty remarkable for an event that’s just hours away from starting.

  7. Thanks TK.

    Even if we were going to have the same wet pattern we had in July, the 17.09” (1955) August record would be difficult to get close, let alone beat.

      1. The 1930s (drought) and 1950s (hurricanes & tornadoes) were remarkable decades for weather.

        Yes, Connie & Diane. That record will likely stand for a very very VERY long time.

  12. Air is still comfy up here with DP in upper 50s. Much higher DP’s to the south eventually to advect up here.

    Another gorgeous solar halo in parts of the region this morning. 🙂

      1. It’s like I’ve been awakened
        Every rule I had you breakin’
        It’s the risk that I’m taking
        I ain’t never gonna shut you out!

        (No I didn’t really try to sing that… haha gotta save my vocal ability for the second F&S single that is due out in about 1 month.) 🙂

          1. Yup! How original! 😉
            We can stylize it several ways: F&S, F and S, F+S, Effenesce, or Effin’ Ess. 😉

            The only song we have completed and released online so far is that instrumental electronic piece called “MayDay” on 5-1-2020.

  14. Not sure how to interpret your comment about total rain and distribution given my lack of models and lack of knowledge. Where are you expecting the biggest amounts?

    1. I-95 corridor southeastward, I like 1 to 3 inches with the majority of the locations in the lower half of that range.

      I’m not buying some of the model forecasts of 3-5 inches of rain as far west as the I-95 to I-495 area.

  15. I finally turned ac back on. Whatever allergies are out there broke me.

    Also, for anyone who enjoys feeding birds as much as I do, there is an update on the disease and on feeders

    I spoke to wild birds unlimited in Franklin. They have been very helpful.

    Cornell believes the problem may be from pesticides people used to kill the Cicadas and not the fungus that occurs naturally on the Cicada.

    Audubon and mass wildlife are still recommending keeping feeders down pit of an abundance of caution. Frankly, my birds have a better variety of natural food than I can give them so I don’t mind. I will put my hummingbird feeder back….see above for my reason to remove them.

    1. Ignore see above. I posted this on a few FB pages discussing what to do and forgot to take that part done

  17. Oopsie. To avoid embarrassing anybody, I am not going to name a source but I saw a forecast today in which they showed the 12km NAM’s “futurecast radar” and the 3km NAM’s total rainfall and explained them to both be what was expected. They are SO vastly different, they can’t both verify.

  18. HRRR trend is to paint the heaviest in the I-95 belt but hold back on some of the astronomical totals we have seen from the 3km NAM and the ECMWF.

  19. Big time back-off on rain totals and a shift somewhat east with the 12z ECMWF, into the realm of reality IMO.

  20. Light to moderate rain now, south coast, just west of Buzzards Bay entrance.

    I’m actually ok with this weather. This is our one summer, no electricity camping adventure and the cooler weather is greatly appreciated ! It’s let us settle in comfortably.

    Ocean still plenty mild !

  21. What do the new forecast rain totals look like for metro west? Is 1-2 inches still the most likely? Crazy gyrations right up to the last minute.

    1. It’s not really crazy gyrations as much as varying model runs.
      We get too hung up on specific numbers of model runs which don’t mean a whole lot until we are sure a particular model or set of models is keyed in and somewhat accurate.

      All along I’ve pretty much stayed with the same idea and I’m not going to change it at this point either. Total rain 1-3 inches in the I-95 belt eastward. Less to the west with a significant drop off over a short distance. A couple place in the I-495 belt north of I-90 may go over 1 inch but I think most will come in under. I-495 to the south of I-90, especially toward the southeast end of the highway, will be in the heavier rain band.

  23. Overcast but lovely evening. 69 and 62 DP but a coolish breeze. I finally put one of my wind chimes out. I’ve been stalling so I didnt disturb neighbors. But the sound is soft and lovely

  24. JPD. Not sure if you’d go this far to rush but this is just one of a couple of really nice catches in a pond in northbridge. I can get more info and permission to send other photos I can’t crop people out of If you are interested.

    https://imgur.com/a/swX9b7x

  25. Is it my imagination or is the rain petering out a bit? Channel 5 has forecast light rain/showers until 2AM and radar doesn’t look too scary. I realize things haven’t really come together yet but a few hours ago it seemed more was forecast at this time.

    I don’t want to commit the sin of calling the game in the first quarter but wanted to tap into the WHW network.

  27. I think there was a bit more hype on this event (by news anchors more than any meteorologists) and therefore the mass mentality of “hey where’s all the rain?” kicked in this evening. I received numerous messages asking me where all the rain was and heard people talking about it where I was.

    Most of the rain from this event falls during the first 12 hours of Thursday, the heaviest of which will be in the I-95 belt southeastward (as I have had in the forecast for a couple days now), with 1-3 inches in the max area, favoring the LOWER end of the range for most.

  28. We came to the one spot getting hit. These red echos coming in just west of New Bedford are something else. Intense rain and some very brief gusty winds.

Comments are closed.