Jump to content
Will it snow? 7 day forecast Weather Radar Will it be cold?
Snow?
Local
Radar
Cold?

lamppost watcher

Members
 View Profile  See their activity

  • Posts

    65

  • Joined

  • Last visited

 Content Type 

Posts posted by lamppost watcher

    Model output discussion - The run up to Christmas

    in Forecast Model Discussion

    Posted

    7 minutes ago, Weathizard said:

    Shall we all just be happy clappy and pretend that the 850’s are cold enough for widespread laying snow?

    I think for the majority at the moment the 850’s are not cold enough, nobody is trying to be annoying by saying that it’s just the truth.

    It also depends what some people define as snow because I define snow as snowing AND laying, not Snowing and melting.

    My point is that we get it! The 850s might not be great but that's not the only factor. I haven't seen anyone posting that there will be widespread snow like 2010

    • Like 3

    Winter 2020/21 - Moans, Ramps & Chat

    in Spring Weather Discussion

    Posted · Edited by lamppost watcher
    typo

    3 minutes ago, Polaris said:

    Chasing something that never materialises is your own preference. Good luck with that 

    I’ve seen T240 once in 10 years = 2010 

    If it always happened then it'd be no fun. Bit like if it was Christmas everyday. I'm no expert but this looks on track to me t144

    Screenshot_20201218-183847_Meteociel.jpg

    Winter 2020/21 - Moans, Ramps & Chat

    in Spring Weather Discussion

    Posted

    1 minute ago, Polaris said:

    Get a grip it’s always a 10 day chart, hence why we are here on 18th December basking extremely mild conditions despite the GFS and ECM throwing a dice 12 days ago 

    But of course, let’s be quiet to let the dreamers dream and the MOD posters chase rainbows 

    Not always...I've seen a few over the years tick down from T240 to t0 and its the reason I'm in the chase. The best thing ever!

    Model output discussion - Closing in on Christmas

    in Forecast Model Discussion

    Posted

    3 hours ago, northwestsnow said:

    Thanks Nick..

    Lots for the pros to watch!

    Certainly a festive Christmas would be welcomed by many of us here.

    Fingers crossed.

    Please does anyone have the odds for a white Christmas to hand? Certainly Glasgow Aberdeen are in the game...

    I got 8-1 last week for Cardiff. Chucked a fiver on it even though the odds should be more like 50-1 as I don't remember it ever snowing here on the actual day

    • Like 2

    Model Output Discussion - Colder spell ending, what's to follow?

    in Forecast Model Discussion

    Posted

    3 minutes ago, Scott Ingham said:

    Tbh its more negative than it is positive. It states she doesn't agree with Catacol about us staying in an atmospheric nino state as tropical convection would have to move further east and increase as seasonal wavelengths change deeper into winter but as it currently stands we're in the game. Just adding a lot of caution to assume things carry on as well as they are as we still need the dice to fall right 

     

    Screenshot_20201208-231904_Firefox.jpg

    • Popular Post
    • Popular Post

    Model Output Discussion - Colder spell ending, what's to follow?

    in Forecast Model Discussion

    Posted

    22 minutes ago, Tamara said:

    This analysis is geared towards fitting a bias preference into a diagnostic framework which doesn't exist to support singular ice sculptured solutions.

    No theory (in the true sense of the word) has been turned on its head in respect of La Nina. What has happened, as has occurred in some previous late autumns and early winter, is that a relatively active intra-seasonal high frequency tropical signal has created a rossby wave feedback that has resulted in a higher amplified downstream tropospheric pattern than would be seen in a more typical -ve frictional/mountain torque regime that represents a La Nina feedback. However, that doesn't on its own mean anything for the weeks and months to come - especially when pivotal wavelength changes will couple the NAO and AO much more closely, one way or the other, as deeper winter arrives in a few weeks

    Intrinsic coupling of the Annular Mode heading into deeper winter requires more exacting forcing than seen so far - and, with a w/QBO likely to influence, once again, the most important layers of atmosphere through the winter the chances increase that a more organised westerly gyre takes over once present intra-seasonal factors diminish and the tropics cease propagating rossby wave eddies poleward to sustain the imbalance between the pole and the mid latitude. .

    So, in this way, the tropospheric/stratospheric relationship can quickly can become much more stable (i.e through a much more stable GSDM relationship to the oceanic base state) This comes about by less eastward propagation of tropical forcing and greater additions of easterly wind inertia to re-configure the upstream pattern and send greater polar jet energy further downstream. This, in the absence of a top-down forcing to loop that polar jet, rather than across the mid latitudes, instead around the arctic and sustain and/or intensify an unstable profile across the polar field.

    At present, while there is indication that the African/Indian Ocean low frequency standing wave present for quite some time through the summer and into the autumn is relocating/propagating east towards the Maritimes, much more evidence is required to see whether a more specific tropical convergence can set up even further east into the western/central Pacific. This, essentially, leading to a more east based La Nina pattern. Much as happened for example  in 2017/18. This cycle meant that a more unstable GSDM profile persisted into the New Year and which ultimately led to the SSW in February 2018. At present, there is no clear indication, either way, what is going to happen - and angular momentum trends during the remainder of December will be pivotal in this respect.

    From my point of view at 39N, where I will be residing in the next couple of weeks, it is immaterial in terms of any high impact cold weather repercussions this winter - but for those looking for winter wonderlands at latitudes further north - its always worth being aware that there is never any x+y= equation when it comes to fitting given diagnostic parameters to weather patterns

    It is necessary to look at periodicity of high frequency tropical signals (the recurrence timeline) and not assume that the tropical cycle behaves like a time-clock which replicates the same on its subsequent 'mini ENSO cycle' within the next circa 30 days.  These periodicity timelines extend up to circa 60 to 90 day  lengths. Unlike a winter such as 2017/18 the likely persistence of a westerly QBO gyre at the most important levels of the atmosphere means that the tropospheric/stratospheric relationship is going to be also be dependant on solar assistance to de-couple ( ramifications for Brewer Dobson Circulation transport between the tropical and polar stratosphere). Equally, in tandem with US and Asian torque mechanisms getting in on the act to trigger poleward momentum transport  - but then as the complexities of even the last two winters have shown where contravailing forces have mitigated the propagation of these poleward eddies, staring at stratospheric forecasts at *insert time-period* does not not inextricably make it snow even if they move forward in time.

    Sometimes the best posts are from the ones who convert their vast knowledge into layman terms so the average enthusiast can at least have a chance of understanding what the heck knows is going on

    • Like 17
    • Thanks 1
×
×
  • Create New...