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Cumulonimbus Tower

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Posts posted by Cumulonimbus Tower

    Model Output Discussion

    in Forecast Model Discussion

    Posted · Edited by ned

    Well at least this evenings ECM and NOGAPS show that there is a cold way out of next weeks set up. Whether it is just a blip or a new trend remains to be seen.

    In the later frames of the ECM it almost seems like the west based pattern has become so west base we become under the influance of the Scandi trough while the low pressure progged over us drifts out to the mid atlantic not really bothering us.... If you know what i mean....

    Model Output Discussion

    in Forecast Model Discussion

    Posted

    No excitement from the 12z output so far. The ensembles show nothing mild but nothing particularly cold either! The UKMO is looking very frustrating with the low keeping the cold uppers at bay!

    Let's see what the ECM will bring...

    Karyo

    NOGAPS seems to go off to somewhere interesting longer term... I'm backing the ECM to follow that :drinks:

    Model Output Discussion:

    in Forecast Model Discussion

    Posted

    Maybe members should in fact consider a pattern in the model output....

    Last nights 18z GFS went the same way as tonights. With the ECM and UKMET following it, only for it to strengthen the whole set up over the course of today in favour of the cold option, and the other two big players to do the same in their later output. So we are back to square one.... I bet the ECM and MET have the high ove rus tomorrow morning with lotws of toys out of prams etc, only for everything to be back on track by 8 pm tomorrow eve!

    Model Output Discussion:

    in Forecast Model Discussion

    Posted

    Here's the 12z GEM at +144

    gem-0-144.png

    Nuff said.

    I have seen much worse for cold at this time of year over many of the last 20 years or so. You don't have a long southerly fetch and heights are rising over Greenland instead of the core of the polar vortex centred there driving the weather. I don't see a block as such on todays charts either, just a cold Scandinavian trough which keeps throwing cold air westwards as the shortwaves track across us (weakening every time, from what they start out as on the models) We have a nice covering of snow now and expect more tomorrow so i can live with a week or two of this sort of a pattern :drinks:

    Model Chat And Moods

    in Forecast Model Discussion

    Posted · Edited by ned

    On the subject of the models, if thats ok, i wonder how resolved the coming week actually is looking at the way the GEM seems to want to go this evening. Could there still be the odd twist to the saga?

    ECM looks to want to "slide one under" early doors too :)

    Model Output Discussion:

    in Forecast Model Discussion

    Posted

    UKMO>> GFS>>

    The ukmo and gfs very different at +120 with the gfs shoving much more jet energy south.

    The ecm seems about the middle ground between these 2 charts,so anything still possible.

    Yup, the GFS is being very bullish with regards to the cold not going anywhere fast with only a brief 24h less cold spell and very cold easterly by next Frifday as it slides any Atlantic influence under the block. 156h is a thing of beauty to me :)

    Model Chat And Moods

    in Forecast Model Discussion

    Posted

    Have to say that more than half of me is very uncomfortable with the long range ensemble mean guidance on offer today.

    For sure, GFS and GEM ensemble means are very bullish about a significant blocking structure centred over norther Siberia / Barents Sea to migrate eastwards towards Greenland.

    Day 10 ensemble mean height anomalies depict about as strong a positive height anomaly as you could get at that range:

    http://raleighwx.easternuswx.com/models/gfsensemble/00zGFSEnsembles500mbHeightAnomalyNH240.gif

    http://raleighwx.easternuswx.com/models/cmcensemble/00zGGEMEnsembles500mbHeightAnomalyNH240.gif

    For days 11-15, again solid cross model ensemble mean guidance:

    http://raleighwx.easternuswx.com/models/gfsensemble/00zENS11-15day500mbHeightAnomalyNH.gif

    http://raleighwx.easternuswx.com/models/cmcensemble/00zCMCENS11-15day500mbHeightAnomalyNH.gif

    This may well be related to modelling of downwelling zonal wind anomalies from the jump in stratospheric temperatures and disruption of the polar vortex going on.

    However, the Global Wind Oscillation composites, which are my main confidence-weakener, depict a likely evolution of the Scandinavina trough being more resiliant than modelled (this discussed several days ago and still there t120-144) towards a mean mid Atlantic ridge. Phase space composites for the more likely evolutions all suggest more energy going poleward than the model suites are programming.

    Whether the evolution of blocking highs to the north-east are enough to shunt the jet equatorward is open to doubt given the unreliability of the modelling of the polar field. Therefore, some question marks for me beyond t168 and I would not be suprised to see the persistence of the core high pressure being west and north-west of the UK. That's still likely to deliver a cold 10-14 days but potentially not as severe as some model solutions of late.

    A lot will depend here on how the developing ridge over the Arctic behaves and whether stratospheric propagation takes place within the medium to longer time frames.

    Much respect for sticking to your guns over this one GP. I shall be following developments with interest :lol:

    General Model Output Discussion:

    in Spring Weather Discussion

    Posted

    The ECM is shaping up nicely isn't it. Looks like FI will be very good too - just need pressure to start rising to the north and a decent shot at an E'ly looks likely on this run.

    There seems to be quite a consensus from both the ECM and GEM at around 144 of sending less energy into the northern arm of the jet. I would think this bodes well for any cold spell.

    Model Output Discussion

    in Forecast Model Discussion

    Posted · Edited by ned

    Unfortunately theres quite a large difference in terms of the complexity of the pattern. The shortwave thrown off the main trough could become a real pain,

    I was really looking at the 12z ECM compared with the 00 ECM and commenting that they were similar evolutions. The 12z aint much worse than the 00 imo. I can only view the 12z GEM out to 144h but to me the difference is basically the block further west which might actually bode well in the long run.

    Model Output Discussion

    in Forecast Model Discussion

    Posted

    Well the ecm 12z is a flop as far as an E'ly next week is concerned so i'm afraid the model confusion begins again with several still onboard but the ecm going for a swim.

    ECM 12z looks very much like its 00z to me. Nothing much has changed then except for one or two of the cannon fodder models coming on board :oops:

    Cold Spell Discussion

    in Spring Weather Discussion

    Posted

    Can't open your first two links so not sure where youe sweet spot is, but what i will say is that the most recent NAE and METO precip charts have shunted the precip further north east by about 50-100 miles... If this happened again on the 00z then Bradford council wouldn't be too far off the mark :oops:

    Cold Spell Discussion

    in Spring Weather Discussion

    Posted

    Whilst i fully accept that the snow risk for tonight and tomorrow has all but gone For My Back Yard and this is backed up by the latest message to Lancashire NHS workers today -

    Subject: Snow risk Wednesday - Met Office update

    "24 hours on and the prospects for any disruptive snow across the region

    tomorrow have diminshed to virtually zero with the weather system

    responsible now expected to stall further west than originally

    predicted, before sliding away SE'wards. Yesterday's Advisory update had

    restricted the threat to Cheshire but the latest forecast, whilst still

    hinting at a little patchy rain/sleet/wet snow possibly getting into

    Western Cheshire and even parts of Merseyside at the back end of tonight

    and into tomorrow morning, is playing down the risk even further with no

    accumulations now expected in these areas. Hence it should be business

    as usual across the NW tomorrow with most areas staying dry altogether.

    Still on for a good swathe of rain to cross all areas during Thursday

    evening and Thursday night.

    Will update you only if the forecast changes markedly,"

    What i don't get is why Bradford Met Council are this evening out throwing grit around on the roads like confetti at a film stars wedding and on who's say so? Surly they would be better off saving it for early next week :lol:

    General Model Output Discussion

    in Spring Weather Discussion

    Posted

    Well, the ECM looks like it fancies a trip down the undercutting route this evening as opposed to squashing the block from the North West as was this mornings output. A very good sign IMHO. Tomorrow morning may well show tha a quick return to something colder is very much on the cards. I for one hope so anyway. I'm sick of these +1 temps already. Time to turn the heating off.... :)

    Today's Weather And General Chat

    in Weather reports

    Posted · Edited by ned

    Didn't relly know where to post this but please feel free to moveit....

    Has anyone noticed the streamer coming south west from just to the south of Oslo on todays visible satellite pictures? I have been trying to work out if it is a natural phenomenon such as cold air pouting out of a frigid valley onto the warmer sea or volcanic activity or something manmade such as a fire. Anyway, it is quite puzzling and any thoughts on this would be welcomed.

    Cheers

    Ned

    EDIT there is a good view of it here - http://www.sat24.com/scan

    Cold Spell Discussion

    in Spring Weather Discussion

    Posted

    hope it does stay northerly, seems we could be in the firing line if it continues on its current course.

    Well it would have to do a 75 degree turn and head SSW to make landfall over East Anglia looking at the first of the precip coming into view over the North Sea ATM :)

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