Wednesday September 21 2022 Forecast (7:32AM)

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There is a lot of weather to talk about as we wrap up astronomical summer and enter autumn. The autumnal equinox will occur at 9:04 p.m. Thursday, marking the official change of seasons. First, we have leftover low level moisture behind yesterday’s departing low pressure system. We haven’t had a strong advection of drier air into the region behind this system, so the clearing has not been quick to occur. The drizzle is gone though, and the clouds are breaking in some areas as of sunrise, and while many areas start with a grey sky, we’ll end up with intervals of clouds and sun – sun becoming more dominant – as the day goes on, and really a nice final full day of summer. Appropriately, the day we transition from summer to autumn will also be a transition day for our weather. A strong cold front will be moving across the region. I once thought this system would whistle through from northwest to southeast during the early morning hours, but Hurricane Fiona (we’ll get to her shortly) has had enough impact on the pattern already, just enough, to slow the front down by a handful of hours. This means that a lot of the shower activity will take place from Thursday morning to mid afternoon with a slightly slower-moving frontal boundary. But it will push through, and almost as if somebody planned it, we’ll know that a new air mass has arrived – cool air on a gusty northwest wind – as we get to evening and fall officially begins with the occurrence of the equinox. Friday through Sunday will be dry days for us here in the WHW forecast area, with an October-like day for the first full day of autumn on Friday – very dry air, a gusty breeze, and some locations that struggle to make 60. The cool breeze will continue Friday night into Saturday, and that combined with the very dry air will be the reasons that some interior portions of southern New England don’t see their first frost of the season as the temperature probably won’t be able to drop low enough due to wind-mixed air. Anyway the air might just simply be too dry for dew or frost to form. Regardless, if you’re an early riser, get ready for a chilly Saturday morning, even with a bit of “wind chill” in areas that keep the breeze going. We will see a nice temperature recovery back to the 60s that day with sun. Sunday will further warm up, back to 70+ territory for much of the region, although our sun may become filtered to limited in advance of an approaching warm front by later in the day, although it does look rain-free. So our first weekend of autumn does indeed look like quite a nice one. However, if you have plans taking you to the coastline then, even before then (South Coast already today and tomorrow, all areas Friday-Sunday), watch for rough surf and large ocean swells stirred up by Hurricane Fiona. The storm itself, now a major hurricane moving into open waters northeast of the Bahamas, will be taking a track fairly close to by west of Bermuda late Thursday / early Friday. I do believe it will be far enough west to spare that island the worst of the storm, but they will still get a gusty rain event. This is kind of a best-case scenario for Bermuda and the US East Coast for a storm this far west and this strong – moving between the two with minimal and manageable impact. This may not be the case for southeastern Canada, a large portion of which will be whacked by the post-tropical but still-powerful storm with lots of wind, rain, and even some snow over interior areas where it will be just cold enough, while we’re enjoying our nice weekend. Oh how the weather can be vastly different over not-too-great a distance.

TODAY: Clouds break for intervals of clouds and sun – more sun with time. Highs 69-76. Wind NW up to 10 MPH shifting to SW by late in the day.

TONIGHT: Clouds return west to east. Scattered showers arrive west to east overnight but may favor areas north of I-90, especially southern NH. Lows 59-66. Wind SW 5-15 MPH, a few higher gusts especially South Coast.

THURSDAY: Mainly cloudy through mid afternoon with scattered showers early, then numerous to widespread showers and possible embedded thunderstorms, which will then end from west to east by later in the day. Breaking clouds and intervals of sunshine from west to east by late day. Highs 67-74. Wind SW 5-15 MPH with higher gusts, shifting to NW 10-20 MPH with higher gusts by late in the day from west to east across the area.

THURSDAY NIGHT: Partly cloudy early, then clear. Lows 45-52. Wind NW 5-15 MPH, higher gusts.

FRIDAY: Sun and passing clouds. Highs 58-65, coolest in higher elevations. Wind NW 10-20 MPH, higher gusts possible.

FRIDAY NIGHT: Clear. Lows 44-51. Wind NW 5-15 MPH, higher gusts.

SATURDAY: Mostly sunny. Highs 63-70. Wind NW 5-15 MPH.

SATURDAY NIGHT: Clear. Patchy ground fog may form in interior low elevations. Lows 45-52, slightly cooler some interior lower elevations. Wind variable up to 10 MPH.

SUNDAY: Partly sunny. Highs 67-74. Wind SW 5-15 MPH.

DAYS 6-10 (SEPTEMBER 26-30)

More weather changes as we head through the final 5 days of September… Low pressure trough and frontal system moves through September 26 to early September 27 with a shower threat – more details to come later. Generally fair weather and another shot of cool air to follow this system as Canadian high pressure moves in, then a little warmer weather be the end of the period as high pressure shifts to the east of the region.

DAYS 11-15 (OCTOBER 1-5)

There is a fair amount of uncertainty in the forecast for the early days of October. A tropical wave approaching the southern windward islands, typical for this time of year, is getting more organized and has a good chance of becoming the next tropical storm (eventually possible / probable hurricane). I don’t often mention names too far in advance because of uncertainty, but we already have TS Gaston in the open Atlantic, and with no other systems of concern at the moment the disturbance heading for the Caribbean would likely end up with the name Hermine, so let’s assume for a moment that this is what happens. Again, noting that model guidance for tropical systems is to be taken with grains of salt due to their limited performance ability with such systems, the medium range models are in agreement at this time that this new system would move through the Caribbean and be in a much better position to impact at least the southeastern US (not sure where yet – too soon to know) eventually. After that the guidance takes the remains (or weakened version of the system) at least part way up the US East Coast as a significant rain system. Again it’s too soon to sound like I’m grabbing onto any details – we’re really just talking models at this point. But at this time of year you monitor. In our case, we monitor for any typical issues a storm like that might bring, but also monitor somewhat in hopes that moisture from a system like this could help us majorly reduce our still-ongoing drought. So as you can see there is a lot to consider in the medium range, and while we never should jump to conclusions we must be aware of all of the possibilities. These will be kept track of as always, and refined and fine-tuned as we get closer to this period of time. For now, I’d lean toward dry weather to start October, a milder spell, and then the chance of rain at some point, pending future movement of that tropical system and any mid latitude disturbance that may approach the region too.

35 thoughts on “Wednesday September 21 2022 Forecast (7:32AM)”

  3. TK, thank you for covering a wide range of changing weather.

    To add to it, the tropics are picking up. Gaston formed in the mid-Atlantic; Hermine is the next one up which seems likely to form and maybe work its way to the Caribbean; followed by more bouncing off the African coast; followed by who knows what.

    https://www.nhc.noaa.gov/

  8. The 6z GFS says pay attention to what happens with Fiona and some jet stream energy near Cape Breton Saturday, because on a smaller, less intense scale, it does the same thing over the eastern US with the next possible tropical system.

    1. https://www.pivotalweather.com/model.php?rh=2022092106&fh=240

      hr 240, 987 mb over the southeast

      https://www.pivotalweather.com/model.php?p=500wh&rh=2022092106&fh=240

      hr 240, can see that jet stream energy around the Great Lakes, separated from the decaying tropical cyclone in the southeast

      https://www.pivotalweather.com/model.php?p=prateptype_cat&rh=2022092106&fh=258

      18 hrs later, 978 mb over PA

      https://www.pivotalweather.com/model.php?p=500wh&rh=2022092106&fh=258

      the 2 pieces of energy have phased with much lower heights and a closed low.

      We’ll have to look and see if this trend continues in the hrs and days ahead.

  11. Thank you, TK.

    Someone asked about snow up in Newfoundland. Well, there will be some wet snow in Labrador (places like Labrador City) and as temps dip below 32F some of it might stick ever so briefly. In any case, as usual, Labrador City will have some God-awful weather around the equinox. September/early October up there is often rainy and in the 40s and maybe low 50s, with lows in the 30s. This year is no exception. https://weather.gc.ca/city/pages/nl-20_metric_e.html

  13. https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G16&sector=car&band=GEOCOLOR&length=24

    Looking at this tropical wave along the northern coast of South America (at a very low latitude) …… can see the broad circulation in the low clouds. Low clouds moving south to north along part of the South American coast. The low clouds in the islands are moving generally east to west and the low clouds on the leading edge are moving northeast to southwest.

  14. A while ago, SAK remarked about one of the runs that had a landfalling cyclone over Long Island at the same time as the kickoff of this Sunday’s Pats-Ravens game. In that scenario, assuming the kicking team were kicking towards the lighthouse at Gillette, the opening kickoff may have ended up in Walpole or Sharon! 🙂

    Have fun at the game, SAK!

    That brings to mind this sports and weather story:

    Today is the 84th anniversary of the Hurricane of ’38 and the Boston Bees (our NL team before the Braves) played a doubleheader that day against the St. Louis Cards. Game 2 continued until the outfield fence blew down and an infield popup ended in the right field stands.

    https://sabr.org/gamesproj/game/september-21-1938-storm-of-the-century-hits-bostons-braves-field/

    I read the chapter about the 1938 Hurricane in Eric Fisher’s and was shocked to find out that hardly anyone knew of the approaching story. I think Eric wrote that the Weather Bureau had even taken the wording of the approaching out of the forecast and life, that day, went on as normal. I was so saddened to read about the school children who were swept away in their school bus on the way home and the driver who tried to save them.

    1. Your last paragraph is important. Why? In this day of “I-wanna-be-a-weatherman-so-let-me-play-one-online” (and I don’t mean the enthusiasts like we have here that actually try to learn about models and forecasting etc by asking questions), it’s so easy for people to lump everyone in together and trash the professionals. I’m not here to cry “poor us”, but it is hard to be a professional in the field when the information is so available, and there are also so many people willing to put out knowingly hyped or even downright false information for the thrill of being the “news breaker”, even if it means that news may be nearly completely fiction. What’s very important is that we do indeed have a great advantage over what people had back then. There were great forecasters around in the 1930s, despite the science being in its relative infancy and before the explosion of technology to come. They could not have hoped to get everything right, and even knowing there was a big storm out there, they really could only go on relatively very few reports – the few ships that were out there that managed to get word to the people who needed to hear it, so they could warn the rest of the people who needed to hear it. You think about that, then, versus now, when we can look at a storm from every angle, above, below, inside, outside, this side, that side, constantly, and after the information is processed by the professionals and reports prepared, the public warning is instantaneous. We have a responsibility as professionals to do our best with that, and the public has kind of an unspoken responsibility to be aware of what they are hearing and from what source it comes. But still with all the problems that exist, we’re worlds away today from where we were then. We’re very fortunate, when it comes down to it.

      1. Based on this and the story I just posted is why I absolutely agree with 7 day forecasts. The Mets make it clear that they are not accurate. If people chose not to listen, that is their problem It takes time to prepare and responsible folks will use the time wisely.

        1. Guidelines. Yes. The industry demands it. Ratings. Etc. We all know the story. But too many folks out there still lock into that single temperature on day 7. When will they learn? 🙂 Probably never. 😉

    2. My mom repeated the fact that they had no clue many times. It is why she and her mom took the trolly from Belmont to Cambridge and then the subway to Boston for the day. I’ve said before that when they returned to Harvard square trolleys had been shut down. They began to walk still not being completely aware of the severity. By the time they reached the area of my auburn cemetery, wires and trees were coming down around them. A taxi driver from Belmont drove by, recognized them, and drove them home. He may well have saved their lives

      But you may recall my recent story of Carol in 1954. There was very little if any warning then. What there was was vague.

  15. Again today I don’t have a lot of time to stare at weather maps – working on a project with my mom (who is doing great – her eye is back to normal).

    I did glance quickly at 12z GFS & ECMWF and kind of glanced at GEM.

    Not anything I’d change in my outlook posted above, but I have noticed that all 3 of those models today, with regard to what will likely be a hurricane by name of Hermine, they are kind of all over the place with track, as expected, but with the general idea that somewhere in the southeastern US can be impacted. The overall trend on this set of guidance is a slower evolution, and while some of these models had rainfall associated with the system up here as early as September 30, today they are up to several days later than this. Again though, don’t hang any hats on these. It’s just an example of the uncertainty in the guidance that will be around for quite a while, regarding this system. You know, the usual. 🙂

  16. CPC solid below normal temps for 6-10, recovering to near normal 8-14. I have no argument with this outlook.

    Precip forecast is a bit less clear cut, hinging sooner on what Thursday’s front produces, in several days on what the unsettled weather early next week is capable of, and down the road any possibility of moisture connected to future tropical systems.

    1. Are you still looking for half an inch or less tomorrow? It seems like a couple of the tv guys started higher (some over an inch though that may have been locally heavy areas) and are now below a half inch. Thanks.

  17. And NOW the sun comes out for today. I was expecting a generally “sunny” afternoon, not a mostly cloudy one. Oh well. 🙁

    1. It wasn’t mostly cloudy all afternoon where I was. 🙂 Turned partly to mostly sunny from 4PM on. Today was a great day. The sun doesn’t have to be shining all day for it to be a nice day. We had comfortable air, a gentle breeze – great day for the final full day of summer. 🙂

  18. My wife and I went to Hampton Beach today for the last full day of the summer. We were there from 11 am to 2 pm. It was a great day for walking on the beach.

    The sky was very interesting. There were a lot of low gray clouds, but the air was very clear. There was a clear blue area of sky above the horizon of the ocean. The clear spot extended about 10 degrees above the horizon and never really changed in the three hours that we were there.

    2. I love that beach. I go up there every month of the year for my feet-in-the-water. So I never say bye to it for the season anymore. 🙂 But I’m there a heck of a lot in the summer.. 😉

  19. Don’t count on the system near South America becoming Hermine. The wave just moving off the coast of Africa may develop first. If that happens, then the one near South America would be Ian, if it develops.

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