Wednesday September 13 2023 Forecast (7:32AM)

213 Comments

DAYS 1-5 (SEPTEMBER 13-17)

A long-talked about trough and associated frontal system will enter our region from the west today and take until sometime Thursday morning to completely pass across the region. This allows high humidity to continue along with a couple or a few rounds of showers and thunderstorms, generally arranged in broken lines or clusters, the first from late morning too early afternoon, the second later this afternoon to early this evening, and a likely third round in the early morning hours of Thursday over southeastern MA (maybe part of RI) lingering on Cape Cod as late as mid morning Thursday. Any or all of these areas could contain an isolated severe storm or to with the emphasis south of I-90. The perimeters are there for even a storm or two with rotation, so that will be something to keep watch for as well. I also know many are concerned with repeated flooding from today’s and tonight’s activity. While heavier showers/storms can result in some additional/renewed flooding problems, these should be more localized and much shorter-lived than the event that took place Monday. As the front passes, a wind shift to northwest, occurring from west to east, will usher in much drier air, but this progression is not rapid, and it will take until midday Thursday for this new air mass to have reached the entirety of the region. Thursday night will give you that feel of autumn in the air, while it’s still technically summer, the days are waning and it’s only a matter of time. But we haven’t felt much of this yet in the late summer days as we’ve been in such a persistent pattern of higher humidity and frequent rainfall events. Speaking of events, while we’re enjoying a comfortable mid September / late summer day on Friday, we’ll be keeping a close eye on Hurricane Lee, which will be in the process of accelerating northward in the waters between Bermuda and southern New England. The track of this system, as usual, has been the hot topic, but some details need to be remembered. These include Lee’s path over cooler water and its encountering of wind shear, and a slightly slower-than-typical acceleration, all which will contribute to a weakening and an early beginning of the transition from tropical to post tropical system. Transitioning systems also expand in size in terms of their wind field, so this has to be taken into account when developing a forecast for our region. My initial ideas for Lee’s eventual path haven’t really changed that much, nor will they here for this forecast. We see the cyclone wavering along its path due to influences from various weather systems in the western Atlantic and eastern North America. This is typical but maybe a little more apparent due to this particular pattern configuration and Lee’s slightly slower movement. But slower movement is still relative, because the system will be accelerating and expanding as it makes its closest pass to us between Friday night and Saturday afternoon. My best guess is that Lee’s landfall will take place between the eastern tip of Maine and the southern tip of Nova Scotia sometime on Saturday evening. What that means for our region is that we get under the cloud canopy of the storm Friday night into Saturday, and a period of stronger northerly wind (on the storm’s back side), especially for the coastal areas / Cape Cod, where it’s not unreasonable to expect gale-force gusts at this point. Does the rain shield on the western side of the storm make it this far west? Good question. It probably does, to some degree, with the greatest chance of rainfall being on Cape Cod. There will also be a significant amount of dry air in place over our region, which tends to eat away at the western sides of these precipitation areas when the storms are passing by like this one will be. So I’m downplaying the rain chance, based on this, and just focusing on the impacts of cloud cover and wind, and probably the most important of all, for coastal areas – rough surf and rip currents, which have already begun and will continue into the weekend as Lee passes by then moves away. The peak for this will likely be the second half of Friday and a good portion of Saturday, so keep this in mind if you have late-season coastal water or beach plans. Is it too early to call for the potential of stunning sunsets on Friday and/or Saturday during the approach of Lee Friday and the departure of Lee Saturday, allowing the setting sun to sneak under the storms cloud deck? Mark it down – let’s see what happens!

TODAY: Some early sun for eastern areas otherwise generally cloudy. Showers and possible thunderstorms midday on. Any storms can produce downpours and localized flooding. Isolated severe storms are possible mainly south of I-90. Highs 71-78. DP 60s. Wind S 5-15 MPH.

TONIGHT: Cloudy. Showers continue and become most likely in RI and southeastern MA. Areas of fog. Lows 61-68. DP 60+. Wind SW up to 10 MPH.

THURSDAY: Clouds and showers linger in the Cape Cod region for a while in the morning. Otherwise, a sun/cloud mix. Highs 71-78. DP falling 60s to 50s. Wind W 5-15 MPH.

THURSDAY NIGHT: Clearing. Lows 55-62. DP ~ 50. Wind WNW 5-15 MPH.

FRIDAY: Sun, but clouds increasing later in the day from south to north, especially in eastern areas. Highs 68-75. DP ~ 50. Wind NW 5-15 MPH.

FRIDAY NIGHT: Mostly cloudy. Lows 55-62. DP lower 50s. Wind N 5-15 MPH except 15-25 MPH Cape Cod with higher gusts.

SATURDAY: Mostly cloudy through midday including a chance of rain Cape Cod. Sun may shine more, especially western areas, later in the day. Highs 66-73. DP lower 50s. Wind N 10-20 MPH except 15-30 MPH Cape Cod with higher gusts possible.

SATURDAY NIGHT: Clearing. Lows 50-57. DP falling to 40s. Wind NW 5-15 MPH.

SUNDAY: Mostly sunny. Highs 68-75. DP 40s. Wind NW 5-15 MPH.

DAYS 6-10 (SEPTEMBER 18-22)

Next trough brings a chance of some wet weather early next week, before high pressure returns and brings a stretch of dry weather for several days following, starting slightly cooler and drier then with a warming trend as we hit the last couple days of summer

DAYS 11-15 (SEPTEMBER 23-27)

Autumn arrives with the equinox on September 23. The early days of the new season look fairly quiet with a zonal flow pattern, mostly fair weather, a brief shower threat or two, and temperatures near to slightly above normal.

213 thoughts on “Wednesday September 13 2023 Forecast (7:32AM)”

  1. Thanks TK !

    Looks like some torrents currently in CT.

    Hope they avoid that rte 2 corrider that got hit the other night.

    Hope later on that N Providence to Attleboro areas also get spared and N Andover seems to need a break too.

    1. This should somewhat transition out of its “overnight” mode into something a little less potent this morning-midday. That will take the coverage down somewhat.

  6. Obs on Long Island show S and SE winds and a dp surge back into the low 70s, so unfortunately, a quick return of deep, tropical moisture is coming in for these storms in CT to ingest.

  8. My daughter is flying from DC to Boston Friday night. What is the likelihood this will be relatively seamless? Thanks.

  12. Thank you Tk. This is my go to blog for weather!!

    Also thank you to everyone else who make this blog what it is. We get the best information around.

    I hope all of you who have had a loved one that has been sick gets better soon! You are in my prayers.

    1. What a lovely post. We are blessed to have such a wonderful team. I have been thinking for days that I doubt you could find the level of knowledge and willingness to share anywhere.

    1. Well that is interesting.

      The old ones as far as I am concerned are the
      HWRF and HMON

      The new ones are the HAFS-A and HAFS-B

      It is the HAFS-B that brings Lee closest to us.
      If that one is not performing so well, then perhaps
      Lee WILL, indeed, be more off shore.

      Now I will compare the 6Z runs of the HWRF and the HAFS_B

      HWRF

      https://www.tropicaltidbits.com/analysis/models/?model=hwrf-p&region=13L&pkg=ref&runtime=2023091300&fh=81

      https://www.tropicaltidbits.com/analysis/models/?model=hwrf&region=13L&pkg=ref&runtime=2023091306&fh=87

      HAFS-B

      https://www.tropicaltidbits.com/analysis/models/?model=hafsb-p&region=13L&pkg=mslp_wind&runtime=2023091306&fh=78

      https://www.tropicaltidbits.com/analysis/models/?model=hafsb&region=13L&pkg=ref&runtime=2023091306&fh=87

      So, IF the older one is performing better, it is not as close
      as the newer one, but still packs plenty of impact.

      1. I’ve had the sense…and it is only reading between the lines on my part so could be absolutely wrong….that has been the train of thought for our Mets the past few days …..while making it clear that it ain’t over till Mother Nature sings so prepare for the worst and hope for the best.

  18. https://www.tropicaltidbits.com/sat/satlooper.php?region=13L&product=vis

    I post this because we can see Lee’s eye at 67W Longitude.

    Look due west of the eye to 71W Longitude. Boston is at 71W Longitude. Clouds look like they are ripping pretty good from N to S. I’m thinking gale force N wind gusts extend to 71W already.

    I kind of think 67W is where Lee will be when she reaches our latitude and the wind field will have expanded further than it already is.

    1. Model consensus goes from a little more than 69 W out to about 66 West and everything in between.
      67 is as good a guess as any. I really don’t know.

      Ask me after the 12Z suit. 🙂

    1. That’s headed for me. No real wind here but pitch black and thundering with torrents of rain coming down. Up over an inch in the last 45 min. and a flash flood warning in effect.

  25. I know we don’t use the NAMS for tropical systems, but since
    it will be Extra Tropical up here, what the bleep…..

    But I looked anyway. FWIW, not a whole lot of difference betwen 6Z run and 12Z run. A tad closer, but about the same impact which is not much.

    For fund here they are

    6Z

    https://www.pivotalweather.com/model.php?rh=2023091306&fh=78&dpdt=&mc=&r=conus&p=ref1km_ptype&m=nam

    12Z

    https://www.pivotalweather.com/model.php?rh=2023091312&fh=72&dpdt=&mc=&r=conus&p=ref1km_ptype&m=nam

  29. That was quite the deluge we just received here in Coventry. Brightening up now but we received 1.57″ in the rain gauge in about an hour with more to come later.

    Up to 5.34″ now since Friday. Pales in comparison to what the Attleboro and Leominster areas have received but still a crapload of rain, especially coming off the 20″+ we got in July and August!

  30. The whole max wind forecasts nearing our latitude, while technically correct, are so misleading to the transition to an extra tropical system.

    With that said, I think one can see that slight, slight time just pass 60 hrs, where the max wind either briefly stops weakening or even strengthens ever so slightly.

    That’s a sign of when Lee will receive some jet stream energy and that’s why the pressure holds steady at/around 960-965 mb from east of the Carolinas to SE of Nantucket.

    Its weakening in the sense of a hurricane, but its maintaining or even strengthening slightly as a mid latitude cyclone.

    I really dislike the messaging of the max winds in this unique case. How many folks will look at the max winds decreasing and think, “eh, no big deal”.

    2. You are so correct.

      That is a pretty intense storm at our latitude, even IF
      it might be Extra-Tropical, a Nasty N’oreaster!!!

  32. Lee super ensemble blend map (EPS/GEFS, CMC, and UKMET).

    Some really good analysis and a breakdown of the timing/impacts from Michael in his thread that goes with this map as well.

    Michael Page
    @MichaelPageWx
    2h

    Wednesday 8 AM | The questions about #Lee impacts are coming in fast and furious. Please read along in this thread to find the latest analysis, and what you should prepare for.

    https://x.com/MichaelPageWx/status/1701941200939348413?s=20

  44. Thanks, TK.

    Very dark here and starting to rain. No thunder or lightning or winds – yet. We will end up as a tropical forest, with this stuff going on. Expect to see monkeys swinging from our trees out back soon! 🙂

  46. Flash flood warning just issued for us. We can’t take anymore rain. Keep your fingers crossed this moves through quickly. Thinking of those in the Lemonister area too.

      1. Yikes. It is varying intensity right now. I can’t get a good radar view though, since Taunton has it set to something that shows my area with little precip. It was great on Monday.

    2. Went by us quickly but shifted so we didn’t get the brunt. Ended up with 0.20. For once I’m praying for a Charlie hole over you,North

    3. Hoping and praying that these storms start picking up speed – prayers for you and your family and everyone where you are and for those in Leominster area too.

  49. Interesting from the NHC Update:

    “It should again be noted that the 34- and 50-kt wind speed
    probabilities beyond 36 hours in the text and graphical products are likely underestimating the risk of those winds occurring. This is because the forecast wind field of Lee is considerably larger than average compared to the wind field used to derive the wind speed probability product.”

    These are the wind speed probability graphics they are referring to:

    https://www.nhc.noaa.gov/refresh/graphics_at3+shtml/144019.shtml?tswind120#wcontents

    https://www.nhc.noaa.gov/refresh/graphics_at3+shtml/144019.shtml?50wind120#wcontents

  50. Dave, I often have us showing no precip when the Taunton radar is set to certain setting they use, since we are not that far away. On Monday obit was great. Any suggestions?

    1. I would look at a composite radar map. The My Radar app on my phone shows complete precip coverage over your area. Looks like the back edge of the heavy rain is approaching PVD right now. Raining hard there but fortunately moving quickly.

            1. North, I found out how to do it. Click on the layers button on the bottom of the screen. In the layers screen, at the top, you can select your type of radar (I usually use “Classic” or sometimes “Hidef” because it shows ptype) At the top there is a little right arrow next to the type of map…if you press that it opens a screen where you can toggle on the animation slider that controls the speed and pausing of the radar loop.

  51. Do we do this all over again next week? The Euro says yes. Model forecast for NEXT Friday looks identical to THIS Friday. Same map, different hurricane.

    Ryan Maue
    @RyanMaue
    3h

    Amazing how potential Major Hurricane Nigel — in the ECMWF model — posts up to the same spot as Lee 7-days apart just west of Bermuda.

    Repeating weather patterns in the tropics: serial hurricanes.

    https://x.com/RyanMaue/status/1701955650987724822?s=20

  52. Could the Almanac get something right for once??? That is the same time period they are calling for a hurricane threat on the Atlantic seaboard.

  53. Hoping that North and others are spared of heavy rains. It’s raining moderately to heavily in Boston. I got soaked AGAIN on a grocery run. It’s hard to avoid rain when it’s an almost daily occurrence.

    I am concerned about the Euro projection for Lee. Should this occur we could get more rain and of course wind. We’ll see.

    I’m not at all convinced we’re out of this pattern. A 36 hour break here and there doesn’t qualify.

    I think the remainder of the month will be relatively soggy and humid.

    2. It’s raining at those same rates here in Dorchester as well, Joshua. I hope Saturday isn’t going to be yet another washout. Last Saturday’s BC football game had a storm delay late but was eventually played to its conclusion. This Saturday could be much more problematic should Lee get real close to SNE. This big game against Florida State here might end up being postponed altogether. I have been really looking forward to it all week. Sigh.

  54. There are some misleading headlines pertaining to Benadryl. Specifically, they’re referring to Benadryl as a product that will be pulled from the shelves. This ONLY applies to the nasal decongestant kind called Benadryl Allergy Plus Congestion, which contains phenylephrine. The over-the-counter Benadryl antihistamine, containing diphenhydramine, is NOT being pulled from the pharmacy. Wrote about this for Forbes: https://www.forbes.com/sites/joshuacohen/2023/09/13/the-antihistamine-benadryl-isnt-being-removed-in-the-us-from-pharmacies-as-an-otc-product/?sh=212d194d6d61

    1. According to CBS news those medications are the same as a placebo. That was the exact word by host Nora O’ Donnell.

      Thanks Joshua.

    2. Which begs the question, what the hell data were they looking at to initially approve the drug?? I think there was such a push at the time to come up with an alternative to the meth derivative they would have approved anything.

  56. From Ryan Hanrahan

    For eastern Massachusetts the strongest winds should stay offshore but any wobble west could bring in a period of damaging winds so it’s worth watching closely

    1. I’m Getting SICK of the back and forth. MAKE UP YOUR MIND ALREADY!!!!!
      Good things it is not an impending snow event, else I’d be going nuts!!!!!

  60. Complete deluge here again…up to 2.46″ on the day. Still raining.

    North – see my response to you above :re the My Radar app

    1. Thanks much better. I figured out how to slow it down to a much more manageable speed. Still can’t figure out the stop completely.p though.

  62. Hi all .. I have a very short break between shifts today and taking my mom to visit cemetery as it’s the anniversary of my dad’s passing (8 years). Vicki I saw your message on my notifications when I expand them – thank you. 🙂 I’m passing that along to mom and family.

    I should in theory have a working messenger by tomorrow (Friday at the latest).

    Otherwise quick update on weather ideas. Really unchanged from this morning’s discussion. Euro Lee track takes him right in my target zone. Fringe effects here but waves/surf not to be underestimated and potential wind gusts from expanding cyclone. At least no direct hit and astronomical rainfall on the table for our area – we certainly don’t need that.

    Current situation: So far not too bad – minor issues with flooding but nothing like Monday. Threat window is open for another 12 hours or so, so hoping for the least impact possible.

    Take care all. I’ll check in again asap. 🙂

  63. Just finished watching FIELD OF DREAMS again.
    I forgot what a wonderful movie that was. Pure fantasy to be sure, but excellent just the same. The whole cast was outstanding!

  65. Not sure what it means yet, BUT the 18Z NAM is coming in a bit farther North and EAST then the 12Z run at the same time.
    We shall see and NOT that the NAM deals with Tropicals very well, but so far it has BEEN in line with all of the others.

  66. Not done with rain for today just yet. There’s one last batch stretching from Fitchburg to Worcester south, moving eastbound.

  67. Some one was asking about when watches would go up.

    Here is an excerpt from the 2 PM advisory.

    Interests in the northeastern United States and Atlantic Canada
    should monitor the progress of Lee. Watches will likely be
    required for a portion of these areas later today or tonight.

  68. Interesting cell on the Eastern CT/western RU border.

    I don’t think it’s a couplet, but it’s got some interesting reds and greens on dopplar.

  69. From the NHC 2PM advisory, Lee will be a low end
    cat 1 near out latitude:

    FORECAST VALID 16/1200Z 41.1N 67.2W
    MAX WIND 70 KT…GUSTS 85 KT.
    50 KT…130NE 130SE 100SW 130NW.
    34 KT…250NE 250SE 210SW 220NW.

    70 knots = 80 mph.

    1. Thanks. Just came here to post. We are at barn in Sutton center. Don’t think that cell is headed this way. ??

  75. For Vicki, from NWS, here is the tentative path

    * This dangerous storm will be near…
    Johnston, Smithfield, Scituate, Glocester, and Foster around 415
    PM EDT.
    Cranston and Burrillville around 420 PM EDT.
    North Smithfield around 425 PM EDT.

    1. And yes, should be on the lookout in Lincoln, RI.
      By then it would have been going for some time. Not likely to maintain for that length of time, BUT needs to be watched
      in case it hippity hops along, being on the ground sometimes, then disappearing, only to come back again.

        1. There’s a little notch in the precip and that’s where it is. It’s not on the southwest most side of the rain echoes. I don’t think.

  79. At least on weather.us dopplar, it’s entered an area that has radar clutter so it’s more difficult to see the couplet.

    But I sure don’t like that notch in the precip where I think the couplet is.

  80. Oops, now this tornado warned storm has decided to track
    NE, instead of East. This would clearly place Lincoln back in the
    track.

  85. On that 18z NAM …. No doubt it’s east.

    But even in its eastern solution, the window from hr 66 to 75, there’s a slight bending back and it doesn’t move very great. About 12-18 hrs to cross from SE of Nantucket to landfall up in Nova Scotia.

    With that wind field. Oh, our ocean is going to be insane.

  86. The area that just got is getting hit by the tornado warned storm, there’s another torrential rain maker developing behind it and yet another out by willimantic CT

  88. with all the ground clutter on radar, it is virtually impossible to see a couplet, if it is there. storms look nasty.

  90. Not 100% sure in terms of a debris signature, but velocity data is highly suggestive of a tornado touchdown on the north side of North Attleboro.

    1. I just missed it within a mile or two max on the ground or in the air. Too close for comfort and just another thing to raise the stress level this week.

    1. Very wise. I will do the same. I have ice packs freezing for cooler, batteries checked, power packs checked, and a loaf of what to do in the next few days.

  103. For those of you in the torrential rain and tornado threat zones, be safe.

    Unbelievable. Another day and more of this crap.

    Seriously, between the very frequent deluges, periodic tornadoes and constant humidity it’s been one helluva ride this summer, and I don’t mean that in a positive way.

  105. North met on 5…don’t know her name…said hook she saw in north Attleboro area for first warned area was strongest she’d ever seen.

  109. Another inch plus today. When does it stop. Pump going on much more frequently again. Just when I thought we were making progress. This is pretty high stress along with the tornado warnings too! Tell Mother Nature I’ve had enough :).

  110. After 8 am tomorrow, Boston’s highest projected dew point I could find in the next 10 days is 59F.

    And many days have 40s dew points.

    This rather incredibly intense and long stretch of September humidity leading to a lot of flooding headaches for many, is in its waning hours.

      1. Yes, indeed.

        This will relegate any fronts to manageable showers and reasonable precip amounts.

        Now, we just need Lee to stay at where the 12z and 18z models have her and we’d likely avoid any big rains with that too.

    1. I’d say kudos to you and Dave also. I know you were not not sure there was a couplet but that is because it was in its infancy.

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