Tuesday August 25 2020 Forecast (7:35AM)

82 Comments

DAYS 1-5 (AUGUST 25-29)

Discussion…

One more hot day with high humidity, which will be sliced into by a cold front moving quickly northwest to southeast across the region during the afternoon. While there may be a few pop up isolated showers and/or thunderstorms ahead of this front, the front itself will also bring a chance of showers and storms, some of which may be locally severe. The front may struggle to produce widespread coverage on the activity, so some locations could be missed entirely by the activity. But don’t count on that – keep an eye out, especially if you have plans to be outside. By tonight, a cooler and drier air mass will be arriving and you’ll notice that on Wednesday with a fresh northwesterly breeze and very low dew points – an autumn preview. But that doesn’t last, as a low pressure disturbance moves rapidly southeastward out of Canada and across New England during Thursday. This day ends up being a tricky forecast as we’ll have a warm front trying to cross the region in advance of the disturbance, and it’s a little uncertain how far eastward that boundary will get. This will be important to determine both high temperatures and the strength of possible thunderstorms that could occur near and just on the warm air side of the boundary, which will push southward again later in the day as the low pressure wave goes by. So there is going to be some fine-tuning to do with that part of the forecast during the next couple of blog updates. By Friday, a weak area of high pressure will be in control and that looks like a decent late summer day. The next wildcard day is Saturday as we have another disturbance to contend with – timing uncertain, and moisture content also uncertain as it may be infused with some tropical moisture from the remnants of Marco & Laura from the Gulf Coast.

Details…

TODAY: Partly sunny. Isolated showers and thunderstorms possible first half of afternoon. Scattered showers and thunderstorms likely second half of afternoon. Any storms, especially later, may be locally strong to severe. Highs 83-90. Dew point middle to upper 60s. Wind SW 5-15 MPH, but locally strong and gusty near any storms.

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

WEDNESDAY: Sun and passing clouds. Highs 72-79. Dew point falling through 40s. 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: Mostly cloudy. Passing showers and a chance of thunderstorms. Highs 70-77. Dew point rising to 50s. Wind SE to variable 5-15 MPH.

THURSDAY NIGHT: Mostly cloudy. Chance of showers and thunderstorms early. Patchy fog. Lows 60-67. Dew point near 60. Wind variable up to 10 MPH but possibly stronger near any storms.

FRIDAY: Partly sunny. Highs 80-87. Dew point near 60. Wind variable 5-15 MPH.

FRIDAY NIGHT: Variably cloudy. Chance of showers. Lows 63-70. Dew point rising through 60s. Wind variable to S 5-15 MPH.

SATURDAY: Variably cloudy. Showers likely. Chance of thunderstorms. Highs 77-84. Dew point middle 60s to near 70. Wind variable to SW 10-20 MPH.

DAYS 6-10 (AUGUST 30 – SEPTEMBER 3)

High pressure moves back in with fair and dry weather August 30 & 31. High pressure shifts offshore and a frontal boundary sets up to the west, probably far enough west for mostly dry weather and a warm-up during the first few days of September.

DAYS 11-15 (SEPTEMBER 4-8)

High pressure offshore strengthens early in the period with above normal temperatures but some risk of a few showers and thunderstorms as well. A frontal boundary in the region may bring the risk for showers during mid period before drier air arrives at the end of the period.

82 thoughts on “Tuesday August 25 2020 Forecast (7:35AM)”

  4. Laura

    GFS

    https://www.tropicaltidbits.com/analysis/models/gfs/2020082506/gfs_mslp_wind_scus_9.png

    CMC

    https://www.tropicaltidbits.com/analysis/models/gem/2020082500/gem_mslp_wind_scus_10.png

    EURO

    https://m3.pivotalweather.com/maps/models/ecmwf_full/2020082500/054/prateptype_cat_ecmwf.us_sc.png

    UKMET

    https://m2.pivotalweather.com/maps/models/ukmet/2020082500/054/sfcwind_mslp.us_sc.png

    HWRF

    https://www.tropicaltidbits.com/analysis/models/hwrf-p/2020082506/hwrf-p_mslp_wind_13L_18.png

    And for laughs and giggles the 3KM NAM (Do not use for Hurricanes!!)

    https://m2.pivotalweather.com/maps/models/nam4km/2020082500/048/sfcwind_mslp.us_sc.png

  5. Thanks TK.

    Taking a look at the SPC outlooks this morning… 3 of the next 5 days with an outlook area over New England/the mid-Atlantic! Thursday has me concerned for a possible significant outbreak, but not confident on it yet especially in terms of the location of the greatest threat.

    1. Does Thursday present a “possible” tornado threat?
      Reading the SPC discussion, although they didn’t say it, but
      I would think that it would be a possibility.

      1. Yes, there is enough directional shear combined with the overall magnitude of shear that tornadoes are possible Thursday. Damaging straight line winds would be the more widespread concern though. SPC has a hatched region in their outlook (mainly over NY/PA) indicating the potential for “significant severe” wind gusts (>65 kts).

  8. Laura has become a hurricane, and NHC is now forecasting a major Category 3 hurricane landfall near the TX/LA border (though this may shift west a bit). Evacuations are underway in some areas for what is an extremely dangerous and life-threatening situation there.

    1. Thank you as always, WxW. It is indeed a life threatening situation…more than ever….and my heart goes out to everyone in that area. Fortunately, they have had the warning they need. Same for folks in the fire areas of CA….although many there don’t have the benefit of being warned ahead.

  10. Thanks TK
    I just had a good downpour happen with a little bit of a gusty breeze. Will see if this is the appetizer for action later.

    SPC Outlook today
    https://www.spc.noaa.gov/products/outlook/day1otlk.html

    SPC Outlook Thursday. I would expect an upgrade in the circled area to enhanced risk tomorrow.
    https://www.spc.noaa.gov/products/outlook/day3otlk.html

    SPC Outlook for Saturday. It is not often you see New England highlighted for severe weather in the SPC 4-8 day outlook
    https://www.spc.noaa.gov/products/exper/day4-8/#

  12. I got sunshine right now after that brief heavy downpour.
    Quick peak at the SREF for Thursday a lot of SNE in that 15% area which to me indicated an elevated tornado risk. There is a 5% low risk for eastern areas on Thursday. There is an even a 30% risk for parts of Upstate NY and that is the circled area from the SPC. As I said earlier I believe if these trends continue the circled area will be upgraded to an enhanced risk. That circled area a little too close for comfort for my liking as it is not far from me.

  13. I really wasn’t paying attention to this Thursday threat until Ryan Hanrahan tweeted about it last night. Reading the comment from WxWatcher that he is concerned for this possible severe weather event further peaks my interest.

    1. A non-zero threat for sure, but as it appears now, probably
      not enough to warrant a tornado watch. Of course, this could
      easily change. Will be interesting to monitor.

  15. Good morning and thank you TK for your continued great forecasts and discussion. Recommendations on GOOD weather apps for an iphone. Want to avoid the “app trap” so I’m willing to pay as well. Maybe one good free and one good pay app?

      1. Thanks SSK. Are there many ads? I’m looking for one with a variety of maps but also aesthetically pleasing and simple interface.

        1. No adds I believe it has maps , radar etc . I find it helpful late at night working the snow storms having that information as well as here is a big help . It’s free check it out & you can type in many Zipcode

          1. I just checked it out I mean it has a few adds I guess after looking but never caught my eye . It offers a lot of information with excellent color graphics

  16. Ryan Hanrahan with his latest tweet for Thursday thunderstorm potential.
    Our computer models are showing the potential for a higher end severe weather event. Strong deep and low level shear plus unusually steep mid level lapse rates. Worth watching very closely.

  17. Eric Fisher tweet for Thursday thunderstorm potential.
    After a brief break tomorrow, Thursday severe setup also looks potent. With more shear around there’s supercell (rotating storm) potential

  18. All this talk of Thursday severe weather is fine, but nobody is mentioning one possibility….the warm front gets hung up to the south, and we stay cloudy, drizzly, and showery with temps in the 60s and a northeast wind. That is what the GFS is showing. The NAM brings the warm front as far north as the MA/NH border. If the GFS is right, you can kiss the severe potential goodbye for most of us (CT would be a different story).

  19. Greetings from Hampton Beach New Hampshire…

    After I posted this morning I haven’t had much of a chance to look at anything other than the satellite picture for the Northeast.

    But I will add two thoughts…

    1) regarding Thursday’s thunderstorm potential, it’s definitely a real potential, but probably for areas just outside of New England, i.e., New York and Pennsylvania. Not completely ruling out seeing parts of Western or interior southern New England get involved in it but it’s going to highly depend on that warm front. I am having my doubts that that front successfully pushes very far north and east. But the potential is there so it is worth monitoring very closely.

    2) Laura will probably end up stronger than forecast and will probably end up further west than currently forecast but usually NHC makes these adjustments slowly. As much as Marco was a non-factor, Laura will probably be a much bigger factor. in the end, this scenario is nothing like what was being painted all over media last week. Yet this morning when I got up here I overheard a couple of people talking about the two hurricanes in the Gulf of Mexico. This proves my point about people remembering what they hear far too many days in advance being presented like it’s a little bit too likely. That needs to be reeled in. The real focus now should be on Hurricane Laura and its potential and eventual impact.

    1. Excellent commentary. Thank you.

      I know in the Spring, those warm fronts are notorious for
      getting hung up. Do we have a similar scenario now?
      Or does it have a better chance of getting through?

      I know one factor is WNW winds aloft that don’t bode well
      for it getting through.

  20. Looking at the dew point projections from the 12z American models you could see where that warm front is.
    The NAM brings in 65 -70 degree dew points for Thurs pm and the GFS keeps the dew points in the upper 50s to around 60 Worcester Boston areas points north providing a more stable environment which is a thunderstorms kryptonite.

    2. Somewhat surprising having a warm front struggling through this time of year. That is usually a springtime phenomenon.

  23. 12z ECMWF only gets the warm front up to about the Mass Pike. It has a high of 80 in Norwood and 68 in Bedford (also 68 at Logan. The North Shore and NH Seacoast stay in the lower 60s. Lower 90s into central/western CT.

  24. SAK thank you for posting that about the 12z EURO. I am paying attention to this potential on Thursday living in western CT.

  25. 39 days this year of 90 or higher at BDL is the most in a year breaking the old record of 38 set in 1983.

      1. Well, you have to consider the model there. 🙂 🙂 🙂

        I think something in the range of 945 to 960 mb is more
        reasonable, but one never knows, That gulf is almost
        a boiling cauldron.

  29. Was a watch warranted today? I know things can change, but
    so far this thing is certainly NOT wowing me by any way shape or manner.

  31. Fall has begun in Northwestern Europe, as a deepening Atlantic low – named Francis – is barreling across the British Isles and into the low countries. The low itself will be located on a Northern Ireland to Scotland to Norway trajectory. This is a very typical trajectory for autumn and winter storms. Not conducive to snow, unless in the high elevations of Scotland. Nor big rain producers, generally. Lots of spitting and light rain. But, definitely wind producers. Hence, the use of the word “storm,” which Europeans and British tend to only utilize in reference to lows that produce lots of wind. Francis is considered run-of-the-mill, though a bit unusual in August. But, as the map embedded in this link will tell you, run-of-the-mill wind there would not be considered run-of-the-mill here. It’ll be a howling strong gale at the coast, and even up to 20-25 miles inland in the Netherlands. https://nos.nl/artikel/2345397-storm-francis-op-komst-windstoten-tot-100-kilometer-per-uur.html

  32. I wonder if they will really pop as conditions get closer
    to Eastern MA OR will it be a bust? Time will tell.

    I see some subtle signs things are about to get active.
    We shall see.

  33. The NAM is on crack right now. Some brains bigger than mine need to figure out its lack of current synoptic recognition which is where all it’s 12-84 problems are stemming from or you will have modelogists posting 48″ snowfall maps on social media in November.

  34. We just had a couple strong wind gusts here in Andover. Maybe mid 30s or so. No rain but dark clouds. It looks like the storms just north of gusted out as you can see the line ripple to the south of those storms. We had a west wind then switched to north even North east during that ripple. Super cool!

  35. Hang in there in southern New England.

    The NW wind is invigorating and busy behind the front and the humidity has plummeted. The airmass changed quickly post fropa.

  36. I spoke to Macs brother. Please keep all of CA in your prayers. I tried to take as many notes as I could. Scott77, I had your family in mind AND in my prayers also. My notes are rough but I think readable …

    There are 4000 fires at this time. Some 200-300 acres. There are 3 complexes that total 1-2mm acres…. bigger than state of RI

    Nearest to BIL is 25 miles at 1000 acres. Wine country has one of huge complex with with Another in Monterey. Winds are from N, E, S with No westerly winds. So air quality horrific

    Of the 3 complexes one is 29% contained, another 13% and the third is 8%. Over 50% gives CalFire some comfort

    These areLightning driven fires. Not strong wind althiugh tonight is breezier than it has been. Sept and oct (their traditional fire months) are wind driven diablo or Santa Ana winds (yes they are supposed to call Diablo but many call santa Anna) with 35-45 more winds and gusts to 75 or 80

    To put this in perspective and truthfully I’m not sure how you can envision this…..at the worst, these fires burn a football field per second growth. Mother Nature is in charge

    Also these fires bring on the arsonists. Let’s pray it does not

      1. I am. Thank you though. Macs brother said they check that and EPA air now And another I missed multiple times during the day.

      2. They have all packed and ready to go along with possible routes. 80 and 5 have fires close. They may head east to SF. That is in orange while they are in red so they may not be able to get fresh air. Just an awful situation

          1. Thanks for sharing all those notes Vicki. My brother commented how bad the air quality was as he struggles with asthma. He is not too far from the airport so South of the city.

          2. Vicki, thanks for posting this. I will pray too.
            My close friend has family farther south; in other years they have spent much time packed and ready to go, but haven’t had to evacuate. Their preteen would lose sleep because of seeing the glow of fires out his bedroom window — it truly is awful.

        1. My wife is from Lancaster, CA. Much of her family is in CA. So far, they have been spared. I wish all the best to everyone dealing with this horrible situation.

    2. Praying for CA. A close friend out there knows people who have lost homes. Thankfully my friend is not in immediate danger but there has been interruption to daily life.

      1. I’ve always treasured that publication (TOFA) for its classic set-up and wealth of info.

  38. 1-1 after 1.
    2-2 after 2.
    3-3 after 3.

    Who will be the OT hero? Will we have a 2-0 series lead for the B’s or will it be knotted at 1? I’d love to see Brad Marchand pot the winner. They play again tomorrow.

    Cooler/drier air flowing in here now. Not rushing it. It’s gradual, but you can feel it now. Dew point should be near 40 by late afternoon Wednesday. And then we get to see it climb back to near 60 by Thursday evening and possibly as high as 70 by Saturday, only to crash back to near 50 by next Monday. Lots of changes ahead as we head toward the end of August!

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