Sunday August 23 2020 Forecast (1:13AM)

77 Comments

DAYS 1-5 (AUGUST 23-27)

Discussion…

As we roll through the next-to-last weekend of August we’ve seen a return to higher humidity and somewhat more active weather. Showers and thunderstorms developed on Saturday, and while I was expecting mainly isolated afternoon activity, the atmosphere decided it to be more appropriate to produce more scattered to even general activity in some areas, beginning in late morning northwest of Boston with the trend gradually moving south and east through the late afternoon hours. Today’s activity should, in theory, develop a bit later with a focus a little further north, with the majority of the activity expected to occur from mid afternoon to mid evening and north of I-90. But convection can be rather unpredictable, and just outflow boundaries from mere showers can be enough to kick off activity in areas that you expected to remain quiet. So with that in mind, while the focus is north, the chance exists anywhere. The process will repeat again on Monday with a weak frontal boundary still in the area. On Tuesday, a stronger cold front will cross the region from northwest to southeast, providing yet another chance of showers and storms. Will try to pin down the exact timing as we get closer to this event. Tuesday night and Wednesday, a Canadian air mass will arrive with dry and somewhat cooler air, ushered in by a gusty breeze. A warm front will approach the region Thursday with some clouds moving in, but it looks like it will remain dry.

Details…

TODAY: Areas of valley, swamp, and bog fog early morning, otherwise sunshine morning yielding to developing clouds during the afternoon, which will then lead to scattered showers and thunderstorms, activity most likely north of I-90 but possible anywhere. Highs 83-90. Dew point middle 60s. Wind SW to variable 5-15 MPH, can be briefly strong near any storms.

TONIGHT: Variably cloudy. Scattered to isolated showers/thunderstorms. Areas of fog forming. Lows 63-70. Dew point lower to middle 60s. Wind variable up to 10 MPH, but locally stronger winds are possible near any storms.

MONDAY: Variably cloudy. Scattered showers and possible thunderstorms. Highs 78-85. Wind variable 5-15 MPH.

MONDAY NIGHT: Partly cloudy. Patchy fog. Lows 63-70. Dew point lowr to middle 60s. Wind variable 5-15 MPH.

TUESDAY: Partly sunny. One or two passing showers and thunderstorms likely from midday to late afternoon from northwest to southeast. Highs 82-89. Dew point lower to middle 60s. Wind SW 5-15 MPH, higher gusts, may be variable and quite strong near any storms.

TUESDAY NIGHT: Clearing. Lows 55-62. Dew point falling to upper 40s. Wind NW 5-15 MPH, higher gusts.

WEDNESDAY: Sun and passing clouds. Highs 78-85. Dew point upper 40s to lower 50s. Wind NW 10-20 MPH.

WEDNESDAY NIGHT: Clear except patchy ground fog in low elevations. Lows 47-54. Dew point lower to middle 40s. Wind NW diminishing to under 10 MPH.

THURSDAY: Sun/cloud mix. Highs 75-82. Dew point upper 40s to lower 50s. Wind variable 5-15 MPH.

DAYS 6-10 (AUGUST 28 – SEPTEMBER 1)

Higher humidity and a shower/thunderstorm threat exists for August 28-29. Drier, breezy, cooler air follows for August 30 then high pressure builds over and eventually south of the region with fair weather and a warming trend later in the period.

DAYS 11-15 (SEPTEMBER 2-6)

Dry weather and above normal temperatures to start the period, a cold front with a shower threat somewhere mid period, and a cooler/drier end to the period.

77 thoughts on “Sunday August 23 2020 Forecast (1:13AM)”

  1. Good morning and thank you TK.

    Euro has Laura hitting Eastern Texas at 947 mb!! Yikes!

    Very high Cat 3 or low end Cat 4

    1. Just a tad different than NHC’s forecast.

      Also looks like mass media is going to miss getting their historic 2 hurricanes in the Gulf of Mexico at the same time … by TWO DAYS. This is why stories like that should never appear 5 days or more in advance of a “potential”. But they’ll never get it. And you want to know what’s worse? I’m gonna say it anyway. There are a whole host of people that believe it either already happened with these 2 systems or that it is still going to happen, no matter what, because the 5-day forecast a few days ago already said so. Yes, they should know better. But we’ve already seen that educating them does better than pumping out hyped headlines. Yet the practice continues, and words like mine get put into the “unimportant” or “disregard that” file because they are not exciting enough. 😛

  4. Thanks TK!

    Thanks again for providing dew points in your forecasts. I have a suggestion. Can you also provide daily precipitation probabilities as well?

    1. I’ll see what I can do. I’ve never been a fan of pops. I don’t think it had much value in a forecast, but maybe a wording tweak is possible in some instances.

      1. I agree. I always IGNORE those as they are basically useless.

        If you have wording such as chance of showers, that is good enough for me.

        You have a forecast area. What might be a 50% chance in one location, might be practically zero in another.

        You generally say something like favoring North of the pike or favoring SE MA etc.

        Whatever works for you is fine with me. 🙂

      2. For one thing, people don’t understand them. Write a forecast that says 50% chance of rain, and ask 10 people what it means. 5 will tell you that you have a 1 in 2 chance of seeing rain that day, and the other 5 will tell you that 50% of the area in the forecast will receive rain.

        That’s why I avoid using them unless I absolutely have to.

  6. Thanks TK!!
    My official forecast is that everyone will see lightning tonight around 8:00. 😉 GO BRUINS!!

  7. Thanks TK.

    Tropical Storm Laura is showcasing spectacular outflow this morning, a true “buzzsaw” appearance. This is indicative of near zero wind shear. Over open waters, I would suspect it would be well on its way to rapid intensification into a major hurricane. Fortunately, it has a major problem in that the center is over land, not water. And it still has to deal with Cuba after Hispaniola. The longer the center stays over land, the less time Laura will have to organize and the better chance that the center gets disrupted. However, we can’t ignore the almost unanimous model consensus for rapid intensification in the Gulf of Mexico. Should its center survive to the Gulf intact, the environment there should be very favorable. I’d treat all model forecasts as conditionally suspect until we know what the storm will look like after interacting with Cuba, but a major hurricane landfall into the Gulf Coast this week is on the table.

    https://weather.cod.edu/satrad/?parms=subregional-Greater_Antilles-13-24-1-100-1&checked=map&colorbar=undefined

    1. Thank you, WxW. I continue to worry about the folks along the coast and even inland with wind and rain. At first I thought it was good that both might not occur at pretty much the same time. But frankly, if there are two and even if second is significantly weaker, this could be beyond devastating on more than one level. Hopefully, evac orders get out early. But then, where do they go?

    1. Too bad the Tuesday front with the nice, cool dry air will be very short lived. It seems we can never string out a solid (3 days) 72 hours worth of Canadian air (more like 1-barely 2 days) but no problem 72-96 hours (3-4 days) worth of the crappy, stuffy HHH air.

      1. We’ve strung together long periods of Canadian air during the summer. We just haven’t had that kind of pattern this summer.
        I remember we had so many Canadian air masses in 2001 that people were actually complaining how chilly it was, even though we had a very fair weather summer.

  11. Tom not weather relates but know you sometimes go to rexhame. There was a shark sighting There. I’m reading Everyone is ordered out of water at Humarock also

    1. I know I might be one of the few but I am extremely happy about the sharks its a sign of an improving ecosystem 🙂

      1. I’m not surprised. There were a ton of seals A few days ago at Brant rock which is just down from rexhame and then Humarock. It’s their home. I have no problem with them

    2. Wow !! No sharks up here on the Saco River. Just occasional small ice chunks that haven’t fully melted out yet. 🙂 🙂

      The water is COLD !!!!!!!

      1. I remember fishing the Saco and also Ellis and it is ankle biting cold not matter what time of Year. Enjoy

  12. As expected the convective activity is further north today. some of these cells have exhibited weak supercell characteristics. There was one in far southern New Hampshire with a little bit of broad very weak rotation. But for the most part these are just pop-up / rain out. a few of them are trying to sustain themselves like the ones in southwestern New Hampshire that probably made use of some topography.

    Earlier some of the short range guidance was carrying this activity into tonight and more recently it has not carried it into tonight but we all know how good the short range guidance has been recently….. Which basically just leaves us to watching the radar.

  13. Well if you believe the 12z GFS most southern New England won’t hit 80 degrees again after August 28th. I don’t …

    Also over the next 2 weeks it brings 4-6″ of rain region wide.

    ECMWF is about 1.0″ of rain over the next 10 days.

    R

    1. Meanwhile the Ensemble mean has most days in the upper 70s after August 28th and a general rainfall of 1-2″ across southern New England over the next 16 days.

      The ECMWF Ensemble mean has a general 1.0-1.5″ of rain over the next 10 days, and temperatures generally in the lower to middle 70s after August 28th.

      At this point, I trust the Ensemble mean a lot more than than operational runs.

      1. Tend to agree with you about enesmble mean ironing out the peaks and valleys. but I don’t think we are done with 80s post August 28th. A shorter duration cool down and then perhaps seasonably warm weather there after?

        Yes I did notice that tropical dissipation. …

    2. Was essentially using my post to point out the wild almost toxic volatile nature of the current op runs and while I like the ensemble means to smooth out the volatility, I don’t love their prognostications either.

      A lot of applied meteorology and correct interpretation of the current synoptic set up in relation to understanding of reasoanble climatology is needed. In other words – “ruh roh, George.”

  15. 12z Euro dissipates Marco before it can make landfall in Louisiana, then weakens Laura to a minimal tropical storm at landfall in southeastern Louisiana early Wednesday morning. Willing to bet you won’t see those maps shared all over Facebook and Twitter this afternoon.

    FWIW, the GFS also dissipates Marco without landfall, but has Laura make landfall as a weak Category 2 in southwestern LA Wednesday night.

    1. The EPS ensembles are all of the darn place from southern Texas to Louisiana I feel we will have to wait and see what it does tonight and tomorrow before knowing anything about its intentions in the GOM as well as what Marco does. Low shear, Deep heat content, building ridge and retreating trough all point to a stronger system. Maybe you or anyone else can explain to me how Laura strengthen while over Hispaniola which have some of the highest peaks in the Caribbean i think it has to do with the convection occurring over the ocean and moving up against the topography but this system has been a jumper as I like to call it.

    2. Ok, crack of lightning almost overhead, scared a mourning dove hanging out on the peak of the roof, and sent me inside ((reluctantly – I love the wind in the trees…)

  20. Really dark here in Back Bay. No rain yet, but a couple of rather distant rumbles of thunder. I do hope it rains.

  25. Several hours ago when the sun was out, it felt like the atmosphere was unstable. The cloud formation to the west indicated that. Wasn’t sure if this would translate into rain, wind, and thunder here in the city. But, it has, thankfully. Darker now than it was 15 minutes ago. In terms of how dark it is outside it looks like a day in mid to late November at 5pm.

    1. Street lights are on. That’s how dark it is.

      Raining fairly hard. Not a drought-buster, but at least it’s something more than what we got yesterday.

  27. Pea -sized hail at Logan and 0.52″ in just 14 minutes.

    KBOS 232111Z 05007G25KT 330V090 3/4SM R04R/1800V3500FT +TSGRRA BR FEW019 SCT049CB BKN060 19/17 A3006 RMK AO2 PK WND 33037/2057 LTG DSNT NE AND W RAB2057GRB10 CONS LTGICCCCA OHD TS OHD MOV E GR LESS THAN 1/4 P0052 T01940172

    1. Rain tapering off a bit, but a very decent drink of water for a parched landscape. Also, several loud rounds of lightning and thunder moments ago.

  28. I have been missing out on the thunderstorm action this weekend. Maybe Tuesday will be the day I could get some action my way.

  29. Quite an outbreak of severe weather unfolding over SNE right now. Have not really been paying attention but one look at the radar definitely yielded a “wow.” Radar estimating 2″ diameter hail near Norwood at the moment. Worcester gusted to 54 kt.

  30. Reading the text with some of these severe thunderstorm warnings wind damage has or is currently happened.

    Any thoughts on Tuesday strong to severe thunderstorm potential?

  31. Was standing out in my driveway watching the storms come in from the north. Lots of chaotic motion in the clouds, moving from any and all directions. Watched a downdraft right overhead. The clouds were moving straight down. Could feel the temperatures instantly drop about 5 degrees. Steady rain has started now, and there’s suddenly a lot less lightning.

  32. 0.00 rain here (and for the weekend) but the lightning from the straight line storms just to our south and east was fun to sit in the Adirondack chair and watch.

  33. Storms are training in my area of Westwood. Serious amount of water continues to fall from the sky.

    2. There is some serious outflow today and for about the 5th time this summer. While it has been a generally dry summer, these severe storm rain events have been more numerous and less predictable than in past years.

      A winter where it only snows 3 times but the 3 times it does are 20″ events….

  34. FINALLY getting some much needed rainfall. Moderate to sometimes heavy with more back building. There is a Davis weather station that I monitor that is reporting 4.78” out of west Brookfield. They’ve had storms train over them for the last 2 1/2 hours. I’ll take every last drop.

  35. Up to 0.74 inch and still counting. It has been thundering for
    3 1/2 hours. Amazing. Of course most of it was more distant, but
    really nice hearing it. 🙂 My lawn and shrubs are going Ahh…….

  36. As I sat here earlier in the afternoon I was watching the early pop-ups and trying to figure out what to do about chasing, if anything. Some good stuff went up in southern NH, but those cells didn’t have any real staying power. Eventually a more serious cluster went up in southwestern NH and made its way into north central MA. This one got my attention, and I started to watch its evolution, advising a few fellow chasers based on my best ideas about it. We all know that trying to forecast convection on the fly is pretty difficult to do with any real accuracy, so I just try to give people at least a general idea of how I think it will go. Anyway, about 3:45PM I got this “feeling” about Wakefield, and told a colleague my plan was to chase very locally, and drive to Lake Quannapowitt in Wakefield for what I figured would be a good development along the line that was already heading for the North Shore. Did that ever work out, from a chasing standpoint. Ended up experiencing the heaviest cell of the lot including 2 hail cores and 2 episodes of wind between 45 & 55 MPH along with torrential rain and a good deal of lightning. I got lucky that I stopped where I did as just beyond the limit of visibility some pretty extensive tree damage was occurring along a good stretch of Main Street adjacent to Lake Q, as well as across Wakefield Common. About 50% of the trees were damaged, and about 20% of them were destroyed, or at least damaged significantly enough that they will have to be removed. Among these was my favorite Weeping Willow that sat along the edge of the lake. I acquired some good video that I have uploaded to my FB page if you are friends with me there. I also posted about 20 photos of the damage. I will post some of them here tomorrow. Enjoyed quite the lightning show for a few hours after the storms had pushed on to the south from the elevated convection behind the line, and additional development that occurred to the west later. This yielded one more good photo at sunset that I will also post later. Quite the day & evening…

Comments are closed.