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Thanks for the heads up guys,alway an interesting read in here although i don't get most of it lol

interestingly...

the jma has had to upgrade there graph from -30hpa to -20hpa because of the second warming that exceeds the -30hpa chart and would be interesting to see how the -10hpa will look like tomorrow

pole30_nh.gifpole10_nh.gif

i know these are outdated 18th feb but you can see the signifcance of the zonal mean temps rise and zonal mean winds drop off at 10hpa(bottom right)

tlat_t10_nh.giftlat_u10_nh.gif

 

 

Edited by Allseasons-si

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I haven't been keeping up as attention naturally turns to the trop response, but I notice the double dip has now become a triple dip.

u10serie.png

 

Daily 10hpa 60N zonal wind records being smashed one after another.

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4 minutes ago, Yarmy said:

I haven't been keeping up as attention naturally turns to the trop response, but I notice the double dip has now become a triple dip.

u10serie.png

 

Daily 10hpa 60N zonal wind records being smashed one after another.

Does this suggest trophospherically that we will continue to see a weaker jet stream, and thus a less active Atlantic?

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1 minute ago, Paul_1978 said:

Does this suggest trophospherically that we will continue to see a weaker jet stream, and thus a less active Atlantic?

I'll leave that to the Strat gurus, but you would think so. It's certainly in line with the MetO 16-30 day outlook as of yesterday (easterly winds, significant snow likely, etc).

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Judah Cohen‏ on Twitter "Polar Vortex currently over western Canada is predicted to make its way to a more favored location over Northern Asia by end of next week, will help open the door for the return of colder air into the Eastern US."

 

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9 hours ago, Summer Sun said:

Judah Cohen‏ on Twitter "Polar Vortex currently over western Canada is predicted to make its way to a more favored location over Northern Asia by end of next week, will help open the door for the return of colder air into the Eastern US."

 

That looks like it would open the doors to a Nly over the UK. 

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 Hi Guys...

Have not posted on here before.

Was wondering  if the current  change in the outlook for the UK could be strat or globally originated.

It looks to as if a wave from the tropics has moved north and eastwards from the US. (flux?)

As it approached the UK it looks as if it is running out of steam,and just resulted in at sitting around the UK or even might well get pushed back westward again by the northern  east to west jetstream? ...

Could that explain what the models have seen? 

Is there any evidence for the above?

MIA 

Edited by Midlands Ice Age

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Lovely animation of the PV falling apart:

Apologies if double posting.

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On 24/02/2018 at 13:15, Interitus said:

It reached 2.5c in the end, pretty toasty for up there http://www.ogimet.com/cgi-bin/gsynres?ind=04312&lang=en&decoded=yes&ndays=2&ano=2018&mes=02&day=26&hora=12

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Eventually tracked down the Nord data for the AWS and previous station from DMI back to 1961, and though rarely above freezing, February 'warmth' is not totally unusual. The original tweet appears to have used the wikipedia value of 23°F taken in turn from weatherbase for a very short record period (8 years).

Previous temperatures from the old station include -0.4°C from 9/2/1976 and -1.5°C from 6/2/1963 - dates which unsurprisingly saw cold at lower latitudes.

The AWS also reached -1.5°C on 19/2/2007.

Apologies for sidetracking this thread, but stats and data need some perspective!

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Looks like the mean zonal wind at 10mb 60°N will have returned westerly today, around 3 m/s for both GFS and GEOS

17 day reversal, quite prolonged but less than some other years (consecutive days - some years have other reversal days also)

24/02/84 - 40 days

24/01/09 - 28 days

23/01/87 - 22 days

06/01/13 - 22 days

26/02/99 - 21 days

21/01/06 - 19 days

 

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Pity this thread has gone dead would be interested in what the strat is doing right now

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2 hours ago, The PIT said:

Pity this thread has gone dead would be interested in what the strat is doing right now

Agreed!

Looking at the 30hpa level it still looks rather interesting. In about 10 days time what's left of the vortex is expected to transfer to Siberia with a vague high pressure ridge further west. 

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1 hour ago, karyo said:

Agreed!

Looking at the 30hpa level it still looks rather interesting. In about 10 days time what's left of the vortex is expected to transfer to Siberia with a vague high pressure ridge further west. 

I think it’s already there having departed Canada some time ago. there is a hang back into w Canada that will come back west to east  now that the reverse flow has dropped out. as you say, post day 10 we will be left with an Asian vortex which presumably relates to the extended prediction of sceuro trough with higher heights able to establish to our wnw 

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As far as I can see this historic SSW is in fact (slowly migrating into) the final warming. I don't see any significant restoration happening coming weeks.

The stratospherical reverse flow has dropped but is still very neutral. I am asking myself what this dynamically quiet context will mean for the coming weeks and spring. Lingering LP's and shallow HP's don't sound good to me, and don't produce much trop-strat effects.

Do we have comparing years? 

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GEFS forecasts for the Zonal Mean Zonal Wind at 10hPa show the strat vortex with a limited recovery following the SSW, but always remaining weaker than the long term average. The vortex is now further weakening, trending back to negative (reversal) by the end of the forecast period. The chart from Hannah E. Attard shows the forecast at 65N and the longer term average (climatology) for final warming dates. Clearly we are well within the time-frame, suggesting the vortex looks to be in terminal decline for this season. The second chart from http://weatheriscool.com/index.php/stratospheric-forecast-zonal-mean-u-wind-60n-10hpa-gefs/ at 60N shows the last 4 GEFS 0z runs with this morning's run (5th March) the most bullish about the zonal winds going negative again around 21st March.

5a9cfbbbb0fe0_StratHAttard10hPaZMZW2017-2018Season.thumb.gif.67e35838296db0fef225ac804afe769b.gif5a9cfbcb060f1_StratGEFS10hPaZMZW03Oct-21Mar2018.thumb.gif.8b54bb6c68b9b326c13b477f8c124d25.gif

Looking at the forecasts for geopotential heights anomaly at 10hPa, 50hPa and 100hPa and comparing with this morning's GFS 500hPa forecast shows reasonable coupling between stratosphere and troposphere. This shows the main lobe of the strat vortex staying on the Siberia side and as Blue posted above resulting in an "extended prediction of sceuro trough". Not much changing over the forecast period to 12th March.

T0 5th March - 10hPa, 50hPa and 100hPa. Source: http://www.atmos.albany.edu/student/hattard/realtime/nh_strat/nh_stanom.php

10_nh_stanom_1.png50_nh_stanom_1.png100_nh_stanom_1.png

500hPa gfsnh-0-6.png?0?0

 

T180 12th March - 10hPa, 50hPa and 100hPa.

10_nh_stanom_31.png50_nh_stanom_31.png100_nh_stanom_31.png

500hPa gfsnh-0-180.png?0?0

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If anyone's still bothered would they like to have a think about what this;

DXnM6zfW0AIlxO_.jpg

from the recent GFS run might mean for us?

Michael Ventrice tweeted;

"My goodness... over a +5 standard deviation rise in N. Hemisphere averaged atmospheric angular momentum is predicted via the GFS in the medium range. This will have a big impact on the Pacific Jet and downstream America weather."

So with the PV winding down for the year just what should we expect such a shove on the Jet to achieve? Could it be it makes it right over the Pole and reconnects back in the Pacific leaving us suddenly on the summer side of it and Africa spewing its guts over us?

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Will keep an eye on the gefs as the 00z run had another technical ssw in just under two weeks time 

showing on the gfs op 12z too. Displacement to Siberia. 

with downwellings still due from February’s event, could be some interesting patterns in store for Easter 

Edited by bluearmy

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