Monday September 4 2023 Forecast (7:11AM)

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DAYS 1-5 (SEPTEMBER 4-8)

It’s still the weekend for many people on this Labor Day 2023, and it will have the feel of summer with high pressure sitting just to the south and east, pumping in very warm and more humid air. This pattern will hold into midweek too as the high doesn’t move much. Coastal areas will end up a little cooler probably all of the next 3 days due to developing sea breezes. A frontal boundary will move toward the region later Thursday into Friday when the shower and thunderstorm chance will increase…

TODAY (LABOR DAY): Mostly sunny. Highs 81-88, falling back to 70s coast. Dew point60+. Wind SW up to 10 MPH with coastal sea breezes developing.

TONIGHT: Mostly clear. Fog patches in lowest elevations. Lows 62-69. Dew point lower to middle 60s. Wind SW under 10 MPH.

TUESDAY: Mostly sunny. Highs 82-89. Dew point middle to upper 60s. Wind SW 5-15 MPH.

TUESDAY NIGHT: Mostly clear. Fog patches in lowest elevations. Lows 63-70. Dew point 60s. Wind SW up to 10 MPH.

WEDNESDAY: Mostly sunny to partly cloudy. Highs 83-90. Dew point 60s. Wind SW 5-15 MPH.

WEDNESDAY NIGHT: Partly cloudy. Patchy fog in lower elevations. Lows 63-70. Dew point 60s. Wind SW up to 10 MPH.

THURSDAY: Partly sunny. Chance of showers/thunderstorms late-day or night. Highs 80-87. Dew point 60s. Wind SW 5-15 MPH.

THURSDAY NIGHT: Variably cloudy. Chance of a shower or thunderstorm. Areas of fog. Lows 63-70. Dew point 60s. Wind SW up to 10 MPH.

FRIDAY: Variably cloudy. Chance of showers and thunderstorms. Highs 78-85. Dew point 60s to 70. Wind SW to variable 5-15 MPH.

DAYS 6-10 (SEPTEMBER 9-13)

The trends have been to slow the frontal boundary down with high pressure offshore and no big push from the west. This means higher humidity and shower/thunderstorm chances can linger during the September 9-10 weekend, maybe even into early the following week. Eventually a push of more settled weather should arrive. Temperatures near to above normal.

DAYS 11-15 (SEPTEMBER 14-18)

Leaning toward high pressure to be the dominant feature with mostly fair weather and near to above normal temperatures during the middle of the month, but we may need to keep an eye on a potential tropical system offshore (or approaching the coast) sometime during this period as well.

83 thoughts on “Monday September 4 2023 Forecast (7:11AM)”

      1. As will I. I’ll have one child and family in the south and appreciate all of your updates. Not to mention it’s just plain interesting to watch its development

  4. Good morning and thank you TK.

    All 3 of the major globals
    have a tropical system approaching or hitting the US.
    Take a look at the 6z gfs for pure entertainment .

    Long way to go A mistimed trough is all that is needed to keep this system off-shore. the models can’t time things 4 days out, let alone 10-14 days.

    So we have something to watch, but nothing to worry about at this point. The only thing I will say is that we are long over due.

    1. Thank you JPD. I know they cannot time but models last night had it around 15th I think. I’d this a ways off then

  8. A tales of 3 models

    0Z GDPS (CMC)

    https://www.pivotalweather.com/model.php?m=gdps&p=sfcwind_mslp&rh=2023090400&fh=240

    0Z Euro

    https://www.pivotalweather.com/model.php?m=ecmwf_full&p=sfcwind_mslp&rh=2023090400&fh=240

    6Z GFS

    https://www.pivotalweather.com/model.php?m=gfs&p=sfcwind_mslp&rh=2023090406&fh=222&r=conus&dpdt=&mc=

    https://www.pivotalweather.com/model.php?m=gfs&p=sfcwind_mslp&rh=2023090406&fh=222&r=conus&dpdt=&mc=

    https://www.pivotalweather.com/model.php?m=gfs&p=sfcwind_mslp&rh=2023090406&fh=222&r=conus&dpdt=&mc=

    Wind gusts

    https://www.instantweathermaps.com/GFS/2023090406/USA_GUSTM_sfc_288.gif

    1. I wonder IF anything could change in the 12 days between now and the depicted landfall above? Not much, I imagine. 🙂 🙂 🙂

  9. Hurricane models:

    HWRF model projection at 126 hours or 12Z 9/9

    https://www.tropicaltidbits.com/analysis/models/?model=hwrf-p&region=95L&pkg=mslp_wind&runtime=2023090406&fh=126

    HAFS-A same time

    https://www.tropicaltidbits.com/analysis/models/?model=hafsa-p&region=95L&pkg=mslp_wind&runtime=2023090406&fh=126

    HAFS-B Same time

    https://www.tropicaltidbits.com/analysis/models/?model=hafsb-p&region=95L&pkg=mslp_wind&runtime=2023090406&fh=126

    HMON

    https://www.tropicaltidbits.com/analysis/models/?model=hmon&region=95L&pkg=mslp_wind&runtime=2023090406&fh=126

    From the Hurricane Center

    https://ibb.co/jMFCFwb

  12. The operational GFS is an extreme outlier. The overwhelming majority (>90%) of the ensemble members from the GFS/ECMWF/CMC don’t get the storm within a few hundred miles of f the East Coast, hence my statement above that the threat to Bermuda is larger.

      1. IMO it would be irresponsible not to. My daughter asked me to thank you. She said the hardest part is that you cannot find timeline or any possibilities anywhere. She means for the average person of course. And repeated ….which she has in the past….that this is one of the beauties of WHW. Sources and discussion of possibilities.

        1. Interesting. Thank you.

          I am curious. With most ensemble members taking it off shore, how does the operational run do what it does.

          It will be most interesting to see how this plays out over time.

          1. As I said yesterday, the models cannot handle systems that have not formed yet that well. Thus, ANY solution from them should be taken with a huge grain of salt. The Ensembles tweak the initial conditions and then run, so that is how they can end up different than the operation.

            This is no different than the winter when the models all start forecasting a blizzard, and as soon as the system gets to an area where there is data (i.e. the West Coast), they suddenly change. In this case, the system is in a data void, and is too small/disorganized for the models to have much data to start with. Once it forms, and starts organizing, you’ll get better satellite data being input, data from ships, and eventually recon data, which will help the model’s performance. Right now, it is literally guessing.

  14. Turning our attention away from Fantasyland, there is the potential for a 3-or-4 day heat wave away from the coastline this week. Using data for Lowell, here is the complete list of September heat waves, dating back to 1889:

    September 21-23, 1895
    September 22-24, 1914
    August 27 – September 5, 1953
    September 9-11, 1961
    September 4-7, 1983
    September 8-10, 2002
    September 7-9, 2015

    That’s it. Just 7 in 134 years of records, and only 2 of them lasted more than 3 days.

  17. the model guidance has gotten in rather good agreement with a curve northeast of the NE Caribbean as a rather decent TC. After that, its just a look and see. There is to many questions to say where the storm goes after the 20N latitude mark.

    1. It would seem so. Sigh. 🙁

      At least today there’s a nice sea breeze here in Boston to take some of the edge off.

        1. Hahahahahahaha.

          More sorry for you all in school. And it will give me an opportunity to put the new kestrel outside on the rotating wind mount I got for it so I can get readings.

          1. The one positive to come out of the pandemic.

            New ventilation system for the 2nd floor of the school and with that seemingly came effective central air conditioning.

            Still uncomfortable in the hallways, but nice in the rooms all school day long.

  28. Great weekend weather-wise. I walked the Nashua River Rail Trail from Ayer MA to Nashua NH. Prefer mountain climbing but it was a good trek in good weather!

        1. I’m sure it does a whole lot more than I have figured out

          I’m still in shock. I started with the one at 139ish (which I debated for a few months) and ended with the $329. It made more sense to me to have information sent to my devices. The display on first (3000) is one line only. The 5000 (shown) has three lines on Home Screen which can be customized. It’s an easy scroll down to see other readings.

          The vane made my kestrel was 69. And the tripod 15. So about a 400 total.

          Kestrel got high reviews from the local Mets

    1. THANK YOU!

      Six months often separate summer’s and winter’s “last stand.” Doesn’t mean that we can’t get snow and brief cold in late March and April. Doesn’t mean that we can’t get brief bouts of heat in late September and October. But sustained warmth like we’re getting now is much harder to come by later in the month. Similarly, sustained cold and snow is much harder to come by in late March and April.

  32. To me once we get past the first week and a half of September the heat and humidity don’t have the staying power.

  33. In terms of heat it has not been a hot summer thankfully but when September comes I don’t want to be dealing with heat.

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