Thursday Forecast

56 Comments

7:32AM

DAYS 1-5 (MAY 14-18)

And just like that, the outlook is not quite the same. It almost caught me, and somewhat did, but there were suspicions yesterday, and as they day went on and today arrived they became larger, and the classic “spring thing” will be taking place. How big of an impact it has here is still somewhat unknown. What is the “classic spring thing”? If you ask most meteorologists who have more than 1 seasons of forecasting experience in spring in New England, they will think of either the ocean’s influence on temperature (locally), or the atmosphere’s tendency to do things that are not quite west-to-east (regionally). Both will be the case before the end of this 5 day period, and we’ll continue the story in the 6-10 day period below. But before we get there, let’s rewind to today, a nice day overall, definitely less windy and much milder than the last 2 days have been, but you’ll start to see an increase in high and mid level cloudiness as the day goes on, and this is the atmosphere’s response to increasing warmth and humidity aloft. That is a warm front approaching, and the front will get into the area, but may not completely get through it. I’m still concerned that the front may never fully make it beyond northeastern MA and southeastern NH Friday, while a good portion of the region gets into the warm sector between that warm front and an approaching cold front. So that sets up a tricky forecast for Friday, yup, the day-2 forecast, for both temperature and weather, when areas to the northeast, say Hampton Beach NH for example, could be stuck in the 50s while the suburbs southwest of Boston are pushing into the 70s. In addition, after we get through some warm frontal rainfall initially from tonight into the early hours of Friday, we’ll then have to watch for the development of showers and thunderstorms as the cold front approaches. Areas that get into the warm air stand the greatest chance of seeing the strongest storms, with a few possibly becoming severe. The greatest chance of this in the WHW forecast area would be northeastern CT, northwestern RI, and adjacent south central MA. Closer to the South Coast, a wind off the water would limit this chance, and the lack of deeper warm air would do the same in areas to the north and east of the higher risk area. So this will be something to watch – updated again on tomorrow morning’s blog post and of course when any new ideas can be shared in the comments section. Beyond that, it looks like before the “typical spring thing” happens, we’ll have a fairly decent weekend: fair weather Saturday, coolest on the coast, then increasing clouds Sunday ahead of the next low pressure system, but rainfall may hold off at least until Sunday evening, and possibly until Monday. What takes place on Monday is likely to be different than what I had been touting in previous blog posts. I’d been optimistic that what we would have been dealing with is one low pressure system coming along in the jet stream, giving us its wet weather late Sunday to early Monday, then moving along. But it’s not that simple. An area of showers and thunderstorms coming out of the Bahamas is going to enter an area off the US Southeast Coast that is favorable for early tropical development, not really purely tropical, but a hybrid type system, or potential subtropical storm, and just enough of a dip in the jet stream carrying our system in from the west will draw this system northward. When this happens, the upper level steering currents can see a low pressure area that becomes separated from the jet stream, so it doesn’t just move along and depart. It hangs around, maybe moving westward for a while or doing a loop. This process will be just getting underway Monday, which now looks wet, breezy, and chilly.

TODAY: Partly sunny. Highs 63-70 except 55-62 South Coast. Wind SW 5-15 MPH.

TONIGHT: Cloudy. A period of rain likely. Lows 48-55. Wind SE 5-15 MPH.

FRIDAY: Mostly cloudy to partly sunny. Showers and thunderstorms likely from mid afternoon on, some possibly strong, favoring interior southern MA, northern RI, and northeastern CT. Highs 55-62 South Coast, NH Seacoast, northeastern MA, 62-69 interior southeastern NH, Merrimack Valley, and remainder of southern NH and far eastern MA, 70-77 interior southern MA, northern RI, and northeastern CT. Wind SE 5-15 MPH coastal NH and northeastern MA, SW 10-20 MPH with higher gusts elsewhere.

FRIDAY NIGHT: Mostly cloudy evening with showers and possible thunderstorms, especially RI and southeastern MA. Gradual clearing overnight. Lows 48-55. Wind shifting to NW 10-20 MPH, diminishing overnight.

SATURDAY: Mostly sunny. Highs 56-63 coast, 64-71 interior. Wind SE 5-15 MPH

SATURDAY NIGHT: Mostly clear. Patchy valley fog. Lows 43-50. Wind S under 10 MPH.

SUNDAY: Increasing clouds. Highs 55-60 coast, 60-65 interior. Wind SE up to 10 MPH.

SUNDAY NIGHT: Cloudy. Chance of rain. Lows 45-52. Wind E 5-15 MPH, higher gusts coastal areas.

MONDAY: Overcast. Periods of rain/drizzle. Areas of fog. Temperatures steady 45-52. Wind E-NE 10-20 MPH, higher gusts coastal areas.

DAYS 6-10 (MAY 19-23)

This 5-day period’s weather largely depends on the movement and behavior of a broad area of low pressure just to the south of the region. Current idea is for cool/wet/breezy conditions to start, then lots of clouds and occasional drizzle/showers hanging on for a couple more days before low pressure is then replaced by a southerly air flow, warmer temperatures and higher humidity with additional showers as one of the remaining lows approaches as a trough from the west later in the period, with finally some clearing possible by the very end of the period. This complex evolution idea will probably change so monitor future updates.

DAYS 11-15 (MAY 24-28)

Watching for high pressure in eastern Canada which may put a boundary between cool Canadian air and much warmer air to the south nearby. Tricky forecast in here, but leaning toward more unsettled days than fair ones.

56 thoughts on “Thursday Forecast”

    1. If Friday goes according to many past Springs, the warm front will
      NEVER make it through Boston. We shall see.

      For Friday, SPC has the entire marginal area in a 2% chance of tornado and that did include Boston. I highly doubt that Boston would really be in that risk
      area. Highest risk in that yellow slight area, imho.

  6. Thank you, TK

    The greatest chance of this in the WHW forecast area would be northeastern CT, northwestern RI, and adjacent south central MA. . Do we know any folks here that live in that area 😉

    1. Duh, I think Sutton fits the bill as well as Coventry, Ct and perhaps ahhh
      Southbridge??????????????????????????????????????????????????????

  7. Thanks TK
    I liked the outlook area yesterday from the SPC where it had the marginal risk yesterday.
    I disagree expanding the marginal risk to areas near and at the coast as this time of year more often than not the thunderstorm activity weakens on approach as a marine influence is a thunderstorms kryptonite. I agree where they have the slight risk. Will see around 130pm today when this outlook gets updated.
    Tweet from Ryan Hanrahan showing the HREF model which is QUITE BULLISH for tomorrow.
    https://twitter.com/ryanhanrahan/status/1260913286633132033

  8. Friday will be classic contrast day with lots of bust potential temp and sunshine wise.

    As TK so aptly wrote – Lesson in eastern New England March 15 to June 15. Hint of a backdoor front – there will be a backdoor front! I think it gets a bit further south Friday than TK, but it is going to cool eastern NE significantly both Friday and Saturday with highs being acheived in the late mornings.

    The other bust is with highs to the west, probably just to the west of the WHW forecast area. The airmass to our south on Friday will be hot and humid. NYC could be 85 with dew points in the 60s. With enough sunshine (and I think there will be) I can see temps in CT and Western Mass valleys making run into the 80s. If this happens then the convection in these areas will likley lead to some warning level storms in the late afternoon.

    Saturday, the northeast wind turn may impact eastern MA further south and west with cooler temperatures. But again out in the western valleys with full mixing possible temps may be underforecast by 3-5 degrees.

    As for next week. This is what I meant when I wrote a few days back with my usually sarcastic quip what is a modelologist to do next week when he needs a meteorologist?

    Take the the model forecasts with a grain of salt and real forecasts will change a lot in the coming days, but generally the further east you are the worse it could be and by Tuesday afternoon or Wednesday morning the sensibale weather impacts in the 75 miles as a crow flies from Amherst to Newton could vary widely.

  9. Thanks JMA for your thoughts as I live in western CT and there looks to be a shot at a locally strong or severe thunderstorm late tomorrow afternoon.

  10. Thanks TK!
    Hmmm Vicki that rings a bell. I may know a few 😉
    Every time severe weather with some elevated helicity parameters are forecast this time of year,it always brings me back to 6/1/11, Even though this is not forecasted for tomorrow, it’s just always in the back of my mind.

    1. AS it should be. How close did that Springfiled tornado come to you?
      Could not have missed by too much.

    2. Terrifying day to be sure and you were in the thick of it, SC. I’d sure like for that not to happen again. Seriously, though, as cool as it has been, it seems to me wind is the real story.

  11. The 12z NAM is slow with the front and it is west of SNE at 8pm. The later the timing may bring down the threat of strong to severe storms tomorrow across interior SNE.

  12. Thanks TK, excellent read this morning!

    Some updated thoughts on tomorrow’s severe potential: I largely concur with JMA. The forecast environment is looking a little more impressive to me. However, the timing also looks slower as JJ mentioned. Best chance for severe storms is going to be well to the west, and I think the SPC outlook captures this well. But in those areas, the CAPE/shear overlap is quite good. Wind profiles are definitely more supportive of a squall line than discrete convection, so damaging winds will by far be the greatest threat. But an embedded tornado or two and some hail will be possible as well. That line probably won’t make it into the urban corridor until after dark, and it will be weakening as it does so both from loss of daytime heating and the air mass further east being more stable to begin with.

  13. 12z HRRR that goes out 36 hours looks to feature some discrete cells across northern CT interior parts of MA late tomorrow afternoon before a line of storms enters from the northwest around 8pm. The HRRv4 has no discrete cells and wants to bring a line of thunderstorms around 6pm.

    1. The HRRRv4 definitely looks interesting, because if the timing is faster like that then the severe threat would be greater further east. I wouldn’t put too much stock in the “regular” HRRR at this point. I believe the HRRR is due to be upgraded this month, so the v4 will become operational and the old one will no longer be run.

  14. Not sure if this was posted or not here but found this on twitter on the 30 year new avg comparisons to the old 30 year avg. split up by month
    https://twitter.com/Climatologist49/status/1260396770418257921/photo/1

    https://twitter.com/Climatologist49/status/1260400682089082880/photo/1
    avg from January through April. Most of the world is rising especially across Eurasia. Mean while in the USA , the south and west, increasing, northern tier is neutral to even below avg. I am guessing because of increasing -AO winters but also shifting temperature regimes in the late winter/spring.

    I honestly can not wait to see how the Summer/Fall is which I believe there will be pretty much no blue/neutral areas and be a sea of red.

  16. JpDave that tornado was a little too close for comfort, it missed my house by about 800 feet or so through the woods behind my house. I was not home at the time but the neighbor said he could hear it.

    1. Terrifying. Mac and I met friends from Southbridge for lunch a few years after 2011 and you could still see the scars on the land.

  18. 2 observations with the 12z NAM and 12z GFS

    1) On Friday, Logan and the north shore may be their warmest up to about 10 or 11am, then, likely a back door front cools the afternoon off. The models suggest a possible warmup again Fri night ahead of the cold front (Coming from the west), but we know from experience, once the heavier marine layer comes in, its hard to move back out.

    2) the projected pressures on the sub-tropical system keep getting lower and lower with each cycle run.

    1. Down to 986 mb ….

      Interesting, as each 12 hrs past with the models, the upper level low seems to be projected to being in a position that CAN capture this think and keep it closer to the coast.

      Stay tuned ……. (its 2020, and if it can go wrong, it will)

      1. Even if the system stays a handful of hundred of miles offshore, the confluent flow at 500 mb in SE Canada is going to create surface high pressure in SE Canada.

        If you have a 1025mb high and a 990 mb low not a great distance apart, there’s going to good a good wind event between the 2 and southern areas of New England may not be far away from that wind event.

  19. Parent-teacher conferences, by phone, next 2 hours.

    This should be interesting 🙂 🙂 🙂

    1. Good luck, amigo.
      I have been contacting families today, too.
      After today, there are 24 “school days” left of this nightmare.

    1. Makes me so very sad to see the loss of these old mills. Thank you for the photos. Sure was nasty

  21. How long is a typical “remote learning” day?

    Is “attendance” actually taken?

    I would say that this generation is living in the worst times EVER in the history of this planet. They will have a lot to tell their descendants to say the least.

    1. Yeah, you’re right. I thought my stories about being out of school for three straight weeks because of the Blizzard of ’78 were impressive. Those stories are now out the window!

      Maybe Tom can help me here, but, I seem to remember we are supposed to engage our students with work for 3-4 hours a day. Because we have had three phases since March 12, the guidelines have changed a lot. But I think that’s the amount of work. That’s what I have been doing. I put up work on the kids’ Google Classroom account for Monday morning and they are expected to have the work completed by Friday afternoon.

      Many of my students are taking their AP exams this week (my class is not one of them), so I have backed off on my expectations and assignments. I want them concentrating on their APs.

      If the work isn’t done by Friday, I do allow “late work” without penalty. The kids are getting credit or no credit for work assigned. They will receive credit or no credit for the Q4 work on their final report card. I believe that will also be their final grade for the course as well.

      There is no “attendance” per se. I will know if they are working when they electronically turn their assignments in within Google Classroom. Although many teachers are using Zoom, etc., I refuse to. I have done one-on-one tutoring with Google Hangout and have “taught” by recording lessons using Flipgrid and posting the links to the videos to Google Classroom.

      I answer questions via email and will only do so between 9 am- 3 pm. I heard that many of my colleagues are going crazy because they feel like they need to be engaged with their students 24/7. As I mentioned before, the teenagers sleep in late and do their assignments in the afternoon and evening. I rise early and do my work in the morning.

      1. Thanks CF. This “remote learning” seems very complicated. Hope you and your students can go back to classrooms in the fall.

      1. Guessing …. may get a tornado watch for a small part of the western or west-central part of southern New England at some point tomorrow.

  26. My Weekly blog post is now a Bi-Weekly blog post. Been debating starting a Weekend Outlook for a while, just been waiting for decent weather. Started it today. It includes plenty of details about tomorrow.

    https://stormhq.blog/2020/05/14/weekend-outlook-may-14-18-2020/

    As usual, I think SPC is over-thinking it up here. They never seem to realize that what works in most parts of the nation for severe weather just does not work in eastern New England most of the time.

    I’ll likely have another blog post tomorrow about the tropical/subtropical system.

    3. Thanks for putting that their. I made one post when I got home and then was pulled away from the blog for several hours, only to return just now. I love the idea of the weekend outlook.

  27. Warmer and more sun and less wet than the NWS forecast calls for tomorow. If storms time sync with max heating I do believe some could reach warning criteria, but that does not mean rotation reaching the ground….just had a friend say I hear we are getting tornados tomorrow….they read it on face book.

    Also – Tom right on – both Friday and Saturday Boston north has highs achieved in late morning.

    72 with a dew point of 18 here. So dry but lovely.

    1. But if it’s on Facebook it HAS to be true! Just like YouTube! Right?! 😉

  29. For those who watch jeopardy….what a finish. I won’t give it away in case anyone has it recorded.

  30. If I understand the 00z NAM correctly and read Eric Fisher’s latest tweets, the activity tomorrow would be later into the evening now for areas northwest of Worcester.

    Perhaps that lessens the instability a little, but I hope it doesn’t put severe weather in darkness in play out there.

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