Jump to content
Thunder?
Local
Radar
Pollen

Model output discussion 9th April onwards


Recommended Posts

Spotted a post you think may be an issue? Please help the team by reporting it.
Posted
  • Location: Andover, Hampshire
  • Location: Andover, Hampshire
    1 hour ago, Britneyfan said:

    Everyone is so dramatic on this forum ūüėÖ

    it hasn’t felt particularly cold, strong sun this time of the year changes that, running similar to 2013 here so far, 

    models seem to be chopping and changing at the moment, between some warmer members and cooler members, wouldn’t be surprised to see a big flip mid month onwards, either way, when the sun shines temps of 14 or 15 are perfect! 

    Fingers crossed a big flip.

    If I was saying temps of 10-11 are perfect as we headed into November, I would be hung, drawn and quartered on here - and quite rightly so.

    • Like 6
    Link to comment
    Share on other sites

    Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl
    3 hours ago, stodge said:

    Evening all ūüôā

    Those wanting early summer warmth should avoid the GFS 12Z OP at all costs - plenty of northern blocking and winds often from the north or east.

    The issue of the Russian HP - well, the problem with that is if you keep heights to the west and build heights to the east, guess where the trough ends up? That's the problem with an amplified scenario - if you end up in the wrong place, you can be stuck there for a while.

    It would be curious if, after an exceptionally dry April, we ended up with an exceptionally wet May.

    Mmm the March 12 to April 12 switcharound springs to mind...

    • Like 2
    Link to comment
    Share on other sites

    Posted
  • Location: N.E. Scotland South Side Moray Firth 100m asl
  • Location: N.E. Scotland South Side Moray Firth 100m asl
    3 hours ago, CreweCold said:

    Possible I guess. 

    We seem to be lurching between extremes for extended periods. We seem to be in a period of a very meridional jet which started last summer...we were on the warm side of it for vast swathes then; with thundery outbreaks. We were quite evidently thrust into a low solar pattern last summer, which is why I was gunning for a colder than average winter (or at least a lot colder than the winters that preceded).

    In low solar summers there is generally a (mean) trough located somewhere around the UK. If it sits just west then we get warm and thundery (last year) On the other hand we can see it park directly over the UK like at times between 2007-2012.

    P.S this is some chart for May

    ECM0-192.GIF?27-0

    Lambing Storm  or  Gab of May  ?

    • Like 2
    Link to comment
    Share on other sites

    Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK

    image.thumb.png.031db20faaca6baa784da2fb08240e32.pngimage.thumb.png.02ba3122245f7b953382bf9bc6e8c318.pngimage.thumb.png.0e09f213e2b6f0e8b10f3224effc559d.png

    May....or November? A couple of deep lows heading our way on this mornings ECM. High pressure to the north forcing the jet on a more southerly track straight through the UK.

    • Like 5
    Link to comment
    Share on other sites

    Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

    Just wheeched through the GFS 00Z . . . and it's not a pretty sight; even the post-Day 10 period is hardly cockle-warming:ūü§Ē

    h500slp.png    h850t850eu.png

    h500slp.png    h850t850eu.png

    h500slp.png    h850t850eu.png

    I guess the only encouragement comes from the temperature ensembles, though not from the operational run (which is I think utterly horrendous!ūü•∂) -- but from the burst of scatter that's always been progged for 3-4th May?ūü¶∂

    t850Bedfordshire.png    t2mBedfordshire.png

    Edited by General Cluster
    • Like 8
    Link to comment
    Share on other sites

    Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK

    image.thumb.png.9514fa3c4baac8084bb0abfbdb7faa48.png

    Any worries of a rainfall deficit and the recent very dry spell are likely to be a distant memory for the vast majority after the next 10 days and beyond. Even the very dry E/SE corner getting in on the soaking.

    • Like 3
    Link to comment
    Share on other sites

    Posted
  • Location: bingley,west yorks.81 absl
  • Location: bingley,west yorks.81 absl

    Morning all. Has anybody heard from Tamara lately?.

    I really rate her musings on here as I know a fair few do.

    • Like 5
    • Thanks 1
    Link to comment
    Share on other sites

    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
    1 hour ago, joggs said:

    Morning all. Has anybody heard from Tamara lately?.

    I really rate her musings on here as I know a fair few do.

    Did she not put up a post some time ago that suggested April could be dry and relatively cool?

    • Like 1
    Link to comment
    Share on other sites

    Posted
  • Location: Cleeve, North Somerset
  • Weather Preferences: Continental winters & summers.
  • Location: Cleeve, North Somerset

    h850t850eu.png

    -5s into Scotland and +10s into St Petersburg... sums up the weeble end of being in a meridional pattern. Quite the dome of warmth to the east though, if we eventually had a May easterly... Seems more likely going on recent runs that May will perhaps become more typically mobile with an eventual lift northwards of the jet - here's hoping anyway, and fingers crossed it doesn't take all month to get there!

    • Like 3
    Link to comment
    Share on other sites

    Posted
  • Location: bingley,west yorks.81 absl
  • Location: bingley,west yorks.81 absl
    4 minutes ago, Timmytour said:

    Did she not put up a post some time ago that suggested April could be dry and relatively cool?

    I must have missed that. Cheers.

    Link to comment
    Share on other sites

    Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK
    1 hour ago, joggs said:

    Morning all. Has anybody heard from Tamara lately?.

    I really rate her musings on here as I know a fair few do.

    @Tamara tends to hibernate in the winter season. I know she moved to Portugal (very lucky!) last year too so that may explain some quietness. Hopefully she will provide some excellent analysis through late spring and summer as usual. I love reading the posts, as do many others.

    • Like 3
    • Thanks 1
    Link to comment
    Share on other sites

    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
    50 minutes ago, joggs said:

    I must have missed that. Cheers.

    I did too. But I'm sure she would have covered it. She usually covers all bases :)

    Link to comment
    Share on other sites

    Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.
    1 hour ago, Timmytour said:

    I did too. But I'm sure she would have covered it. She usually covers all bases ūüôā

    And so do today's GEFS 06Z temperature ensembles:ūüėĀ

    t850Bedfordshire.png    t2mBedfordshire.png

    • Like 6
    • Thanks 1
    Link to comment
    Share on other sites

    Posted
  • Location: Cardiff
  • Weather Preferences: Warm and sunny!
  • Location: Cardiff

    Painfully slow crawl towards average temperatures for Cardiff.  Still some signs of a big warm up later next month (it will surely have to arrive at some point!).

    28_04_2021.png

    • Like 7
    Link to comment
    Share on other sites

    Posted
  • Location: King‚Äôs Lynn, Norfolk.
  • Weather Preferences: Hot and Thundery, Cold and Snowy
  • Location: King‚Äôs Lynn, Norfolk.

    What an odd April it’s been. Very dry, almost devoid of the traditional blustery April showers, but also very cool. 

    I’m glad these Synoptics have taken place now and over the last few weeks, as time is on our side for the start of some heat opportunities, and hopefully some juicy plumes to start showing up as we head through May. My theory is that hopefully due to such a cold start, the atmosphere in our immediate area has not had the ingredients to heat up sufficiently, and therefore when we get some heat imports, we could see better opportunities in terms of CAPE due to a cooler atmosphere aloft. 

    Also to add, the soil has remained dry, so we should get a better response and return of heat at the surface if we get some warm uppers in place. 

    We shall see! 

    Edited by East_England_Stormchaser91
    • Like 6
    Link to comment
    Share on other sites

    Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

    Okay, I know it's Day 10, but after what seems like weeks of unbroken, if freezing cold, sunshine, there are signs of something somewhat less-cold come early-mid May:ūü§Ē

    h500slp.png    h850t850eu.png

    And, by gad, do we need some rain!ūüĎć

    And, hopefully, we'll get it? And . . . I might even need to clean my Zak-O-Vision specs!ūü§ď

    h500slp.png    h850t850eu.png

    Edited by General Cluster
    • Like 4
    Link to comment
    Share on other sites

    Posted
  • Location: Kirkheaton, Huddersfield
  • Weather Preferences: Sunny days and balmy evenings.
  • Location: Kirkheaton, Huddersfield
    31 minutes ago, Tamara said:

    Boa tardeūüôā

    Its a synoptically intriguing Spring-time situation with the atmospheric circulation, 'c/o tropical and extra tropical wind-flow cycles, still clearly 'remembering' the patterns of mid to late winter; at the same time as seasonal wavelengths in tandem with what *looks* like a standard fading away of the stratospheric vortex start their make their imprint over the weeks to come. However confidence in this needs to further gain traction in the weeks to come.

    What is meant by 'remembering' in this context? There are known periodicity timeline recurrences with tropical and extra tropical cycles and when these both combine to produce strong wind-flow signals (high amplitude forcing) they often have a profound amplification response globally - and especially when the winter-time stratospheric feedbacks have been highly unstable as they have been over the winter of 20/21. 

    The feedbacks of these tropospheric and stratospheric forcing elements can produce a 'shockwave' response within the broad-scale patterns lasting through extended  intra-seasonal timescales  That has been very much the case in this first quarter of 2021.. Awareness of these cyclical responses can be very useful in terms of anticipating amplification potential - even though it cannot be possible, at distance, to pinpoint more geographical areas in terms of pattern/weather detail. Its very much the case of whether the significantly unstable relationship between the stratosphere and troposphere can evolve through a more seamlessly benign final warming process and then couple with the encouraging adjustment of the rossby standing wave further east within the tropics to reduce retrogressive shifts in blocking and which retain cool air advection process risks - at least for more Northern parts of Europe.

    Global atmospheric angular momentum has mirrored the dynamic nature of the atmospheric response to amplitude cycles of the intra-seasonal MJO cycles. A convectively coupled kelvin wave  (CCKW) within the tropics has added westerly wind-flow inertia propagation between the tropics and extra tropics c/o torque responses and the atmosphere has accordingly 'remembered' the similar passage across the Pacific Ocean that occured in February and simulated a further blocking response-  (the one in the first half of February augmented  through the fall-out of the January SSW effects within the troposphere and the strongest downwelling tranches of -ve zonal wind anomalies.

    CCKW: image.thumb.png.cfabe48ccb2b92d8679e1a3f031e2234.png   As reflected on the MJO RMM track and forecast  image.thumb.png.9408cdeb74804d5caf47b358cfd3ac57.png.

    = upward movement back to average levels in globally averaged AAM. Notice the much more profound effects c/o the greatest stratospheric/tropospheric instability in Feb image.thumb.png.c4a203f8f391b1865e5c225e4e97d4cb.png

    As the CCKW completes its tropical cycle, and the high frequency signal returns to the Indian Ocean - then this is the signal for a return of greater easterly inertia within the atmospheric circulation and angular momentum tendency easing back again accordingly.  Interestingly, this forcing acts to retrogress the troublesome blocking signatures at mid and higher latitudes sitting to the NW - and in the  short medium term invites a supressed jet stream across more northern parts of europe but also cuts of the ingress southward of polar originated airstreams and restrict them further north than seen for quite some time.  Whether advancing low pressure systems can stall sufficiently and allow warm air advection processes as far west as the UK is debateable, at least to begin with. But it is the first step required to shift the paradigm of blocking away from cold air advection for NW and central Europe. 

    Further south,  across many SW parts of Europe a downstream ridge response settling the weather down after recent showers and thunderstorms.

    For late Spring/summer interest much depends on continued active tropical>extra tropical forcing at the same time as seasonal wavelength changes act on demise of the seasonal vortex to set a more traditional summer pattern response. If this response is non dynamic, and if tropical convection shows signs of continued trend to want to push convergence (and associated westerly wind inertia) further east across the western/central Pacific, then its conceivable a less Nina like standing wave could lead to greater downstream amplification. rather than innate Atlantic blocking (the latter being La Nina-esque) 

    What is key for summer prospects, mainly for Northern Europe including the UK, is that  the relationship between the troposphere and stratosphere is a benign one to assure such ridging at mid latitudes (Western Europe into Scandinavia) - and not persistence of further retrogressing blocks across higher latitudes.  Further south across europe into the Mediterranean ,the implications are more surrounding dryness/wetness and whether more extreme heatwaves are likely relative to usual warm/hot temperature regimes. At least as measured /compared by UK standards.

    Latest indications based on tropical>extra tropical forcing adjusting to a less Nina-esque default ,suggest that a more stable mid latitude pattern can still emerge and produce the welcome warm-up that many parts of NW (inc UK) and central Europe are looking forward to with restrictions looking to ease hopefully for the summer. However (there usually is one), May is that pivotal month in the same way as November and into December is in terms of gauging propagated rossby wave extra tropical forcing from the tropics vs seasonal wavelength changes. Time¬†will tell how quickly the atmosphere will be willing to start to evolve away from and to 'forget' the imprinted highly robust dynamics of the stratospheric/tropospheric relationship in the fist quarter of 2021. That is an answer that I expect professional analysts will not have a good answer to at this stage, let alone me or any other interested parties of laypeopleūüôā

    Thanks Tamara. I enjoyed reading this and for once I actually get it! Cheers ūü•ā

    • Like 7
    • Thanks 1
    Link to comment
    Share on other sites

    Posted
  • Location: East Ham, London
  • Location: East Ham, London

    Evening all ūüôā

    Not all the 12Z output is available but it looks as though, after a very unsettled and wet week next week, tentative signs of rising heights to the south and south east and a pushing of the jet back north. GFS OP in far FI looks much better for those wanting settled warmer conditions but we're a long way from that at this time.

    The key will be to see this trend down to T+240 (around May 8th) and then to the reliable.

    • Like 2
    Link to comment
    Share on other sites

    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
    4 hours ago, General Cluster said:

    And so do today's GEFS 06Z temperature ensembles:ūüėĀ

    t850Bedfordshire.png    t2mBedfordshire.png

    My technical reading of this is that we can expect a warm up (in the sense it will be of any significance) around the 17th May.

    This is based on the assumption we will be allowed back inside the pubs on that date and that's just how the weather Gods roll :)

    • Like 4
    Link to comment
    Share on other sites

    Guest
    This topic is now closed to further replies.
     Share

    • Recently Browsing   0 members

      No registered users viewing this page.

    √ó
    √ó
    • Create New...