Tuesday November 24 2020 Forecast (8:08AM)

27 Comments

DAYS 1-5 (NOVEMBER 24-28)

Discussion…

On we roll toward the end of November, with Thanksgiving just 2 days away. Today will be the coldest day of this week as high pressure in the Great Lakes delivers an air mass right out of Canada, air that crossed over snow covered ground on its way here. You’ll feel that chill in the air, minus the snow, but with a gusty breeze today. High pressure will slide eastward, its center passing to our north, tonight into early Wednesday. As a warm front approaches Wednesday, we’ll see clouds move in. As previously noted, this warm front is going to be in for a struggle to make much progress into New England Wednesday night into Thursday (Thanksgiving Day) as low pressure moves slowly eastward into the region. While the actual low center will be weakening, its center, or what’s left of it, will move along the frontal boundary, which by the time it gets into the area will become generally stationary. This means that the warm air probably gets into the South Coast and maybe as far north as I-90 but not much further. This sets up the issue of possible icing in north central MA and interior southern NH if precipitation comes in early enough Wednesday evening, and also sets up an interesting temperature forecast for both Wednesday night and Thursday. Thanksgiving Day itself is likely to be overcast through the day, and see periods of rain, especially during the morning and midday hours. Once we get to Thursday night and Friday, the wind will turn more to the north and eventually northwest, and we will dry out as clouds break, but there is still the risk of a passing rain shower as a disturbance crosses the region on Friday. Even Saturday, which looks mainly dry and milder will have the chance of a passing shower as a front passes through later in the day or during the evening.

Details…

TODAY: Sun/cloud mix through midday then mostly sunny rest of afternoon. Highs 38-45. Wind NW 10-20 MPH, gusting around 30 MPH.

TONIGHT: Clear evening. Increasing high clouds overnight. Lows 20-27. Wind NW 5-15 MPH early, shifting to NE and diminishing to under 10 MPH.

WEDNESDAY: Early morning sun and high clouds, then thicker overcast. Slight chance of brief very light snow/mix southern NH and far northern MA late morning or midday. Highs 38-45. Wind NE to E up to 10 MPH.

WEDNESDAY NIGHT: Cloudy. Periods of rain/drizzle developing, with the potential for some icing interior southern NH and north central MA. Lows 31-38 southern NH and north central MA, 38-45 interior central MA to northeastern MA, and 45-52 in areas to the south during the evening. Temperatures may rise slightly overnight. Wind E to SE up to 10 MPH.

THURSDAY (THANKSGIVING): Cloudy. Rain likely in the morning. Chance of a few lingering showers or some drizzle in the afternoon. Highs 40-47 southern NH and northern MA, 48-55 to the south. Wind E to SE around 10 MPH.

THURSDAY NIGHT: Mostly cloudy. A few additional showers possible early. Patchy fog. Lows 37-44. Wind NE to NW up to 10 MPH.

FRIDAY: Partly sunny. Chance of a passing shower. Highs 48-55. Wind NW 5-15 MPH.

FRIDAY NIGHT: Partly cloudy. Lows 37-44. Wind W up to 10 MPH.

SATURDAY: Mostly sunny to partly cloudy. Highs 48-55. Wind W 5-15 MPH.

DAYS 6-10 (NOVEMBER 29 – DECEMBER 3)

I don’t know. Just kidding – killing a bad joke. Working out the timing and looks like high pressure brings a nice day for November 29 to end “Thanksgiving Weekend” before low pressure comes at us from the southwest and brings a beneficial rain event for the last day of November. There remains some uncertainty in how the first few days of December play out with guidance again all over the place. My current thought is that we may need to watch for a low pressure wave to bring additional unsettled weather at the same time we watch the approach of cold air December 1. Dry/colder weather follows that.

DAYS 11-15 (DECEMBER 4-8)

Hints of of what may be some high latitude blocking trying to set up at some point during this period. This would increase the chance of some East Coast storminess while we’re in the battle zone of warm air to the south and east and much colder air to the west and north. Far too soon for details, other than I’m most concerned with the December 6-8 period.

27 thoughts on “Tuesday November 24 2020 Forecast (8:08AM)”

  2. Thank you, TK!

    As an April Fool’s joke, on April 1, 2021, I suggest your forecast for Days 1-5 should be “Anyone’s guess,” Days 6-10 “Who knows,” and Days 11-15 “You’re on your own.”

    1. That’s a good one Joshua! Of course with our luck with what’s been happening these many months now, we get a repeat of April 1, 1997 to deal with. 😀

    2. I love the idea…. but since it’s yours, I might have to let you be the “guest forecaster” that day. 😛

  3. Good morning and thank you TK.
    You have my attention for the 12/6-12/8 time frame.
    I am SURE I will disappointed in the end. Time will tell.

    1. I wouldn’t set hopes high there. It’s really just the idea that the pattern shifts a little more toward one that can create one or two East Coast lows. That does not automatically translate to “snowstorm for Boston”. We’ll have to evaluate the details as we get closer to that time frame. But there’s a bit of a blocking & amplified pattern signal showing up that we need to pay attention to.

        1. That would depend on one’s point of view and expectations. 🙂 For example, I just take it as it comes. If it’s snowy, it’s snowy. If it isn’t it isn’t. We’re always going to have a variety of weather here. Loving all types definitely helps my weather-related mindset be content all the time. 🙂

  4. No snow until after 12/2 please after that it can do whatever . It would be nice to get a snowstorm in December & be home for it .

      1. Thanks. They beat you for a change. Amazing though how Nantucket got off with so little. Yesterday was probably the wettest “day” in some time.

  6. If you want to jump on the 00z ECMWF our drought will be almost eradicated with 4-6″ of during the forecast period. Most of which falls 11/30-12/2 time frame. Not my forecast but it goes to show you the wild variations in the middle range as the 00z GFS is about 1-2″ in that time frame.

    I do think we have a pretty good shot of colder than average with the potential for multiple accumulating snow events in the 12/5-12/25 time range. In my opinion that is the best chance for a slightly retreated ridge and weaker PV allowing for an intrusion of colder with a simultaneous active sagging jet.

    January maybe slightly above average temperature and below normal precip. February transitions to well above normal temperature and below normal precip.

    Where I disagree with TK (I know its rare) is March. I know there is thinking out there that a LA Nina can lead to weakening of the PV in later winter season, allowing a drift southward, but I don’t see it. Normal La Nina’s find the north Pacific colder, not this year. It running way above average and I don’t believe that is going to show significant breakdown in a timely manner. Most climatic patterns I can identify in the last 18 months have taken longer to break down than historical analogs say that they should, even if breakdown is delayed just by a few weeks, that’s all it takes to move SNE further into climatology that becomes even more hostile for snow events. The +NAO / + AO pattern will endure on in our slow to evolve pattern. Similarly, I believe the SE Ridge won’t weaken in March, but rather show some signs of strengthening. I combine this with a more regional persistence of pattern, as we transition into meteorological spring, a local ocean presence that won’t get too cool, I can’t go for an aggressive cold and snow pattern in March for SNE.

    I write the above with the asterisk of TK is a much better seasonal forecaster than I am, but I figured I would share my thoughts and will certainly return to take my flogging if I am wrong.

    1. I was going to say I’d love to hear WxW’s thoughts as well, but he already answered that bell before I rang it. 😉

      Well, you did notice that I make the remark that my March forecast is a huge gamble. So be it. 😉

  7. Thanks TK.

    My brief seasonal forecast thoughts (posted under the Winter Outlook) basically line right up with TK and JMA. The first 2-3 weeks of December are worth watching closely. January-February should be a trend towards the classic La Nina pattern. And March is more of a tossup, I lean the same way as JMA in the La Nina pattern holding through that month as well, but certainly can’t rule out something like what TK has discussed.

    The day 8-14 pattern looks absolutely bizarre. It is completely and 100% counter to what you’d expect in a La Nina. Indications of a rex block developing. The sort of “instigator” storm around 11/30/12/1, which may be quite significant, definitely looks more wet than white though even on that I’m not 100% sold. But behind it, the first week of December looks ripe for a more wintry event (not necessarily a big one).

  9. From Judah Cohen
    GFS ensembles growing even more confident in a #snowstorm for the Northeastern US in early December, especially in the interior. #WinterIsComing

    1. The only negative aspect of early December snows is that they melt away by the time Christmas Eve/Day arrives. Even if it’s a lot, all we’re left with is bare ground and maybe piles in parking lots at best.

  11. https://imgur.com/gallery/mUHVkx0 First week of December does look interesting, with that strong PNA and weakening AO but I am not sure if that really means winter weather for our area. With that said I am wondering what this strong PNA will do to the AO come second half of December.

  12. Matt this might answer your question about the strong PNA.
    Tweet from Meteorologist MJVentrice
    The upcoming North Pacific pattern (+PNA state) is also evolving in a way that could promote upward wave flux towards the stratosphere, displacing the Stratospheric Polar Vortex off its axis during the latter half December.

      1. It means it becomes unstable. “Plunging southward” may not quite be an apt description. More like wobbling around like a loose belt that came off its wheel and would result in an immediate trip to the mechanic. 😉

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