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Winter 2019/2020 - General Discussion

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  • Registered Users Posts: 13,469 ✭✭✭✭sryanbruen


    ZX7R wrote: »
    But the reality is that February is traditionly when we would get proper blast of cold / snow.
    2010 event has really changed people's outlooks,it was really a one in a lifetime event

    Replying here because it's off topic to the FI charts thread.

    You're kinda right, kinda not with the first point. Why do I say this? February on average has a slower jet stream with a higher chance of it meandering - this makes it more vulnerable to high latitude blocking although spring and summer months have even more vulnerability.

    However, January is regarded as the month with the highest chance for a severe cold spell. It holds both the only -18C and -19C Ireland has recorded (1979 and 1881) whilst December has a record of -17.5C (2010) though this record was only -14.6C before 2010 and February has a record of -17.8C (1895). March has a record of -17.2C (1947) too.

    November and December 2010 definitely were both one of a kind and unprecedented. Other severe cold spells going down to their level of cold have either not been quite as cold; like 1982 which had an air minimum of -14.6C at lowest (as far as I know) or as long; such as 1978/79 which lasted a few days at most at the end of December and start of January. The last comparable November cold to 2010 was way back in 1919 which held the previous November record low of -11.1C before the -11.5C in 2010. However, this cold was in mid-November 1919 before a mild and wet winter. You could say this deserves to be held in a similar regard to 2010 though because such cold in mid-November in Ireland is extraordinary and that same year, Scotland got down to -23.3C on 14th November. December 2010 was more than 1 degree colder than any December in recorded history for all Irish stations - previous very cold Decembers include but not limited to 1916, 1950, 1976 and 1981. I'd highly doubt we'd see anything quite like these two pair of months again in our lifetime that early in the season. An event like Feb/Mar 2018 Beast from the East (and Storm Emma combined too) is equally extreme and rare to me. Last time that time of the year saw such cold was 1785.

    Only other comparable months to December 2010 in the last century were February 1947 and January 1963 but even these, going by available station data, didn't have the amount of ice days and severe cold (air minimum temps below -10C or -15C) as December 2010. So... late 2010 was most certainly a different ballgame of its own.

    February 1917 didn't have much ice days but the amount of severe frosts and low max with snow lying was very notable. Most places had continuous snow cover lying for the last week of January and first two weeks of February as high pressure proved stubborn following a snowy second half of January.


  • Registered Users Posts: 688 ✭✭✭bazlers


    sryanbruen wrote: »
    Replying here because it's off topic to the FI charts thread.

    You're kinda right, kinda not with the first point. Why do I say this? February on average has a slower jet stream with a higher chance of it meandering - this makes it more vulnerable to high latitude blocking although spring and summer months have even more vulnerability.

    However, January is regarded as the month with the highest chance for a severe cold spell. It holds both the only -18C and -19C Ireland has recorded (1979 and 1881) whilst December has a record of -17.5C (2010) though this record was only -14.6C before 2010 and February has a record of -17.8C (1895). March has a record of -17.2C (1947) too.

    November and December 2010 definitely were both one of a kind and unprecedented. Other severe cold spells going down to their level of cold have either not been quite as cold; like 1982 which had an air minimum of -14.6C at lowest (as far as I know) or as long; such as 1978/79 which lasted a few days at most at the end of December and start of January. The last comparable November cold to 2010 was way back in 1919 which held the previous November record low of -11.1C before the -11.5C in 2010. However, this cold was in mid-November 1919 before a mild and wet winter. You could say this deserves to be held in a similar regard to 2010 though because such cold in mid-November in Ireland is extraordinary and that same year, Scotland got down to -23.3C on 14th November. December 2010 was more than 1 degree colder than any December in recorded history for all Irish stations - previous very cold Decembers include but not limited to 1916, 1950, 1976 and 1981. I'd highly doubt we'd see anything quite like these two pair of months again in our lifetime that early in the season. An event like Feb/Mar 2018 Beast from the East (and Storm Emma combined too) is equally extreme and rare to me. Last time that time of the year saw such cold was 1785.

    Only other comparable months to December 2010 in the last century were February 1947 and January 1963 but even these, going by available station data, didn't have the amount of ice days and severe cold (air minimum temps below -10C or -15C) as December 2010. So... late 2010 was most certainly a different ballgame of its own.

    February 1917 didn't have much ice days but the amount of severe frosts and low max with snow lying was very notable. Most places had continuous snow cover lying for the last week of January and first two weeks of February as high pressure proved stubborn following a snowy second half of January.

    Where was the -17.2 recorded in March 47?


  • Registered Users Posts: 13,469 ✭✭✭✭sryanbruen


    bazlers wrote: »
    Where was the -17.2 recorded in March 47?

    Markree Castle, Co. Sligo. It holds a few monthly record lows in Ireland including January and all-time, March, April and October. Held the November record too before 2010.


  • Registered Users Posts: 17,819 ✭✭✭✭peasant


    sryanbruen wrote: »
    Markree Castle, Co. Sligo. It holds a few monthly record lows in Ireland including January and all-time, March, April and October. Held the November record too before 2010.

    One thing that should be notable about this is the location...as the crow flies Markree is only about 10 - 12 km from the coast.


  • Registered Users Posts: 22 Allanjjmurphy


    ok.. Its November and its mild.....


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  • Registered Users Posts: 471 ✭✭KingdomRushed


    ok.. Its November and its mild.....

    Temps aren't really exceeding single digits and there is ground frost by night. I wouldn't call it mild!


  • Registered Users Posts: 3,426 ✭✭✭ZX7R


    Part's of whales got some snow from the band of rain that went through this morning.


  • Registered Users Posts: 2,431 ✭✭✭sideswipe


    ZX7R wrote: »
    Part's of whales got some snow from the band of rain that went through this morning.


    They'll be happy with that;)

    Untitled.png


  • Registered Users Posts: 16,533 ✭✭✭✭nacho libre




  • Registered Users Posts: 57 ✭✭cowana


    Kippure this am


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  • Registered Users Posts: 1,008 ✭✭✭icesnowfrost


    Hi guys, is the FI Charts thread started yet?


  • Registered Users Posts: 65 ✭✭freesia1




  • Registered Users Posts: 1,008 ✭✭✭icesnowfrost




  • Registered Users Posts: 6,827 ✭✭✭pauldry


    Markree may only be 10 to 12km from the coast but the hills around Ballisodare and forestry around the Castle mean its in a sheltered hollow. Frequently Collooney is several degrees colder than Sligo town.


  • Registered Users Posts: 598 ✭✭✭Captain Snow


    Been keeping an eye on this for awhile.

    Large amount of cold predicted to flood into western Russia Next week. With HP from Scandinavia forecast to move west and join up with Greenland HP.....could be coming our way early December....

    DWmHNTX.jpg

    As long as the LPs keeping going in the that Direction. We could pull in very cold air.


  • Registered Users Posts: 598 ✭✭✭Captain Snow


    From the Beijing climate centre.

    Looks like snowy Christmas Period on this run. Showing cold to our NE and E. We could be tapping into that cold from Russia or Scandinavia....

    High Pressure Centred out in the Atlantic and ridging North to Greenland.

    RLtFk7s.png

    Colder then average. Pulling in cold NE

    u9d9N6M.png


    Paddy Power is 6/1 for snow on Christmas day Dublin...….lol


  • Registered Users Posts: 688 ✭✭✭bazlers


    Is MT Cranium due to give an update to his winter forecast?
    He might be confident enough in it that he doesn't need to update it either I suppose.


  • Registered Users Posts: 471 ✭✭KingdomRushed


    I have to admit I am becoming very intrigued by what the models are hinting at this last few weeks. While no exceptional cold and snow is forecast in the foreseeable, there is a real trend in the modelling to force northern blocking, scandinavian blocking, greenland and iceland. This trend is unwavering across the model output. Unfortunately it is not yet modelled to draw in any exceptionally cold air, but bear in mind it is only the 15th of November. The jet stream wants to stay south, and low pressure over the iberian peninsula is very much our friend in this scenario. I genuinely see an interesting winter ahead. It feels a different set-up. I mean even this rain we have been experiencing, the thing of note is that it is cold rain, circulating in from east to west often as low pressure systems are diving south east. This has not been the norm in the last several years, at least not to this extent. Something is afoot, and if it does deliver cold it may well be this side of Christmas in my opinion. We have already seen snow from a marginal set up just 2 days ago in the Irish midlands.


  • Registered Users Posts: 32,634 ✭✭✭✭Graces7


    I have seen the difference already this year in how my usual daily life is affected. Always the last winters it has been mild and dry enough days of the week for me to walk the lanes early almost every dayy. This year I have managed one walk in two weeks, . Bitter cold, high winds that make being out unsafe, deluges.
    Because of the situation here weather dictates so much

    Like being in a different country at times.

    I have no technical input just close observation.

    More like, and even more extreme than, my years up in the outer Orkney islands.

    We shall see but agreeing with thee
    I have to admit I am becoming very intrigued by what the models are hinting at this last few weeks. While no exceptional cold and snow is forecast in the foreseeable, there is a real trend in the modelling to force northern blocking, scandinavian blocking, greenland and iceland. This trend is unwavering across the model output. Unfortunately it is not yet modelled to draw in any exceptionally cold air, but bear in mind it is only the 15th of November. The jet stream wants to stay south, and low pressure over the iberian peninsula is very much our friend in this scenario. I genuinely see an interesting winter ahead. It feels a different set-up. I mean even this rain we have been experiencing, the thing of note is that it is cold rain, circulating in from east to west often as low pressure systems are diving south east. This has not been the norm in the last several years, at least not to this extent. Something is afoot, and if it does deliver cold it may well be this side of Christmas in my opinion. We have already seen snow from a marginal set up just 2 days ago in the Irish midlands.


  • Moderators, Science, Health & Environment Moderators Posts: 16,668 Mod ✭✭✭✭Gonzo


    In my area this autumn has been exceptional in terms of rainfall, one of the wettest autumn's in my lifetime and yesterday I spent the whole day digging trying to get rid of surface water from the garden and the driveway. Our road is still partially flooded, it's been in this state for the past week or more. It's certainly been cold too, although no snow here and very little frost so far this season. The UK is also experiencing exceptional levels of flooding too with over 300 flood warnings yesterday.

    The milder trend is still showing up on this mornings charts, however it's beginning to look temporary with temperatures possibly sliding below average once again into the first week of December, after a brief warm up in the final week of November. We may see a trend to something much colder in December, we shall wait and see.


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  • Registered Users Posts: 6,013 ✭✭✭Elmer Blooker


    I have to admit I am becoming very intrigued by what the models are hinting at this last few weeks. While no exceptional cold and snow is forecast in the foreseeable, there is a real trend in the modelling to force northern blocking, scandinavian blocking, greenland and iceland.
    I've been thinking the same lately as the current set up is very similar to December 1978 ....


  • Registered Users Posts: 13,469 ✭✭✭✭sryanbruen


    November 2019 500mb height anomaly reanalysis up to 12th vs November 2002 & 1995 reanalysed (two similar QBO years to 2019). Some big similarities including Aleutian High stretching down to the western United States and trough over Canada. There is evidence of some above average heights close to or over Greenland in both charts but obviously the signal was way stronger in Novembers 2002 and 1995.

    Trough in Novembers 2002 and 1995 was centred further westwards allowing a milder push of southwest to southerly winds. This meant that whilst both were very wet much like November 2019 so far, they were also quite significantly milder.

    The November 2019 pattern is actually what I had in mind for this winter.

    WZbHGs2.jpgiR7ZPnU.png

    For clarity, both winters 2002/03 and 1995/96 featured easterly episodes at one point or another but 1995/96 was far colder than 2002/03 with the latter being a near miss winter for Ireland although eastern Europe had a bitterly cold and snowy season. 1995/96 was an on and off cold winter with wintry episodes each month from December to April and even May had well below average temperatures. First three weeks of January were notably mild and damp though.

    The stratosphere remains a very confusing but intriguing picture with a weakening initially coming out of this record breaking strong Polar Vortex but what happens thereafter? GFS operational run is keen on a strengthening again and is a huge outlier in its ensemble even as soon as days 3 or 4. GEFS meanwhile show the SPV just further weakening. Remember that the GFS operational run was the one that forecast this strong SPV event first before anything else. ECM has backed away from its strengthening after the initial weakening too going by the latest available update at the University of Berlin and keeps it at a fairly stable weak level throughout the rest of its run.

    Keep up to date with the latest stratospheric news in the stratosphere watch thread here as well as read my first post if you want to know how the stratosphere influences the weather.


  • Registered Users Posts: 191 ✭✭weetiepie


    bazlers wrote: »
    Is MT Cranium due to give an update to his winter forecast?
    He might be confident enough in it that he doesn't need to update it either I suppose.

    Could you point me in the direction of his 2019/20 winter forecast please?


  • Registered Users Posts: 13,469 ✭✭✭✭sryanbruen


    weetiepie wrote: »
    Could you point me in the direction of his 2019/20 winter forecast please?

    Here.
    This is what I have come up with after the usual process. The mid-November update might be more than just a tweak this time, I could see this going several different ways as there are some unusual synoptics in various regions of the hemisphere. But the emphasis in my research study was on high-energy events. I don't think low pressure areas this winter will be fooling around, they are going to be packed with energy and moisture compared to some winters. Possibly 2013-14 is somewhat of an analogue, although I would say, shifted a bit south of that onslaught of storms. This is copied from my post on Net-weather which explains a Britain and Ireland focus in the wording.

    The following is a preliminary long-range forecast for winter 2019-20, If it seems necessary, I will amend or update this forecast in mid-November.

    This appears likely to be a season where high energy weather events will be grappling with a fairly robust supply of colder air at high latitudes.

    Britain and Ireland can expect a very unsettled winter with frequent low pressure systems steered by a strong jet stream running a little south of its average position.

    This favours a split north-south outcome where the south is often on the milder side of the storm track getting strong southwest winds and rain, while the north is more open to snow, ice and easterly winds.

    The north-south divide may be enhanced by the likely appearance of strong blocking highs over eastern Scandinavia and western Russia. I don't think these are going to dominate the circulation but they will come into conflict with the zonal regime at times, forcing it to dive southeast around 5-10W and into France and the western Mediterranean. This may be another winter of heavy Alpine snowfalls and frequent severe cold spells in Germany and possibly Belgium and Netherlands into northeast France.

    Battleground conditions seem likely at times across southeast England into Wales and central to northern Ireland. Frequent snow events may occur in northern and even central England, and southern Scotland, also Northern Ireland and some adjacent parts of the Republic of Ireland.

    Some heavy precipitation is likely in this scenario, heavy rain in most cases in southern England, especially the southwest, and the southern third of Ireland (Munster and south Leinster).

    A set-up like this may not remain steady-state, but could fluctuate north-south bringing the milder conditions further north at times, while setting the battleground further south at other times. However, the tendency will be for temperatures to average closer to normal or above in the southwest, and below normal in Scotland.

    This pattern could evolve into a colder February or even March if the strong jet stream loses energy, then the blocking may be able to assert more control.

    North America can expect a rather harsh winter in general, with severe cold waves at times, colliding with an active storm track from Texas northeast towards Virginia and southeastern New England. There could therefore be heavier than average snowfalls in the Ohio Valley, Midwest, and inland Mid-Atlantic to northeastern states. A pattern like this would not rule out one or two coastal blizzards in the mix. The west will be dominated by persistent cold high pressure trapped in valleys, and coastal areas will have a fairly average winter with a lot of rain, low cloud and moderate southeast winds. Snow on western mountains will be generally a bit above average but might be twice normal in the southern Rockies and northern Arizona around Flagstaff. Drought will break during the winter for California.

    This may also be one of those winters where extreme cold moves south from Siberia into China, Korea and Japan.


  • Registered Users Posts: 191 ✭✭weetiepie


    sryanbruen wrote: »
    Here.

    Many thanks!




  • I have to admit I am becoming very intrigued by what the models are hinting at this last few weeks. While no exceptional cold and snow is forecast in the foreseeable, there is a real trend in the modelling to force northern blocking, scandinavian blocking, greenland and iceland. This trend is unwavering across the model output. Unfortunately it is not yet modelled to draw in any exceptionally cold air, but bear in mind it is only the 15th of November. The jet stream wants to stay south, and low pressure over the iberian peninsula is very much our friend in this scenario. I genuinely see an interesting winter ahead. It feels a different set-up. I mean even this rain we have been experiencing, the thing of note is that it is cold rain, circulating in from east to west often as low pressure systems are diving south east. This has not been the norm in the last several years, at least not to this extent. Something is afoot, and if it does deliver cold it may well be this side of Christmas in my opinion. We have already seen snow from a marginal set up just 2 days ago in the Irish midlands.

    Steady on, if Kermit reads this he'll trip over himself to start a 'Snow Roller-Coaster' thread.


  • Banned (with Prison Access) Posts: 8 NK76


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    Home » Global weather » You are reading »*Stratosphere warming watch* A powerful new warming phase is building for early December. Stratospheric temperatures likely to raise over 30°C above normal, affecting the already weakened vortex!By Andrej Flis | Global weather | 17 November 2019
    -spread the word-



    The polar vortex is slowly but steadily losing its power. While the pressure waves are “attacking” the polar vortex, a new temperature wave is building for early December, that should prolong the weakening of the vortex, and perhaps push it even further beyond the point of return for a while, later in December.

    In the past days, we wrote updates on the weakening of the stratospheric polar vortex, and the likely collapse in December. Currently, the polar vortex is under a wave-2 pattern attack, which is slowly receding, making way for a wave-1 pattern to take over. The number of the wave tells us how many “highs” are pressing against the polar vortex (low). On the images below (weatheriscool.com) we can see the current ongoing wave-1/2 pattern weakening the polar vortex. We can see the brief warming phase-1 by the 24th.

    Z_temp_10hpa_018-1
    Z_temp_10hpa_156-1
    The 16-day ensemble forecast shows the strength of the polar night jet, weakening over time, taking a brief break around November 22nd. After that period, it starts to weaken again. The operational GFS model does not show a significant reduction of the stratospheric jet stream power. But that is perhaps weakening in disguise, due to the pressure waves contracting/compacting the polar vortex, causing a sharper pressure gradient around the latitude circle where the speed of the strato-jet stream is measured (60N). So while we see a steady strength of the strato-jet stream, it can then suddenly drop or even reverse, as the vortex is losing the battle versus the pressure/temperature waves.

    latest_u1060_ens-1-1
    By November 22nd, the wave 2 pattern will weaken. We will see a shift into a more wave-1 pattern look, where we have one dominant “high” pressing onto the polar vortex. By November 29th, a new warming phase-2 will start over Asia. It is forecast to escalate very fast, emerging much stronger than the previous phase. We forecasted additional warming phases, one week ago. The wave 1 pattern will strengthen, combined with the sharp rise in temperatures over Asia, and will slowly but steadily “eat” the vortex around its edges. Instead of a strengthening vortex, we will see a weakening vortex, which is not common for this time of year. A wave-2 pattern should slowly start to emerge again.

    Z_temp_10hpa_276-1
    Z_temp_10hpa_378-1
    The warming in the stratosphere usually comes from the top down. Energy from the lower levels near the ground, is deflected upwards and reaches the top of the stratosphere. It is then amplified, releasing the themral energy, warming the upper stratospheric layers and slowly propagating downwards, embedding and weakening the polar vortex in the process. We can see on the images below, that temperatures higher in the stratosphere are actually forecast to be in the positive values, which is way above normal! 1mb level is around 45km altitude, while 5mb level is around 34km altitude.

    NH_TMP_1mb_384
    NH_TMP_5mb_384



    The temperatures at the 10mb level (~30km altitude) are forecast to rise from -55°C to -10°C. That temperature at this level is over 30°C above the 30-year average!

    Temperature_isobaric_in_fsdf-1
    GFSOPNH12_384_42



    What is driving these waves? The answer is perhaps not as simple as the question. But we can simplify by saying that the main energy comes from below. A dynamical weather pattern and strong pressure differences in the troposphere where our weather is. That can send waves of energy up into the stratosphere. We can see an example of a dynamic weather pattern on the two graphics below. They show the day-10 pressure anomaly forecast from EMCWF.

    gfs-ens_mslpa_nhem_53
    gfs-ens_z500a_nhem_53-1
    The latest monthly forecast from ECMWF shows strong positive anomalies for December/January. Instead of a cold and deep vortex, it actually hints at a weaker and warmer stratospheric circulation. That is a strong sign of a collapsed polar vortex, and high probability of a sudden stratospheric warming event by the end of the year.

    ec4
    ec2
    What all this means for our weather? Well, a collapsed vortex always greatly increases the chances for winter weather towards Europe and CONUS. A lot depends on how the existing pressure pattern looks, while the effects from the stratosphere come crashing down on us. In some cases, the effects can be partially “deflected” and we don’t feel much of a change in our daily weather. But in most cases, the effects can have a major influence on the distribution of weather systems across the hemisphere. The graphical example below shows the average temperature anomaly 0-30 days after a major warming event. We can see the main cooling effects are across Eurasia and the United States.

    dsad
    We will keep you updated on any important further development, as this situation is just starting to unfold, with many weeks of monitoring and observing ahead!

    But while you wait for more updates, make sure to check out the latest long-range winter forecasts, from various models around the world:





    Copyright © 2019. Severe Weather Europe
    Severe Weather Europe


  • Moderators, Business & Finance Moderators, Recreation & Hobbies Moderators Posts: 24,623 Mod ✭✭✭✭Loughc


    weetiepie wrote: »
    Could you point me in the direction of his 2019/20 winter forecast please?

    Warm and Wet.

    You're welcome :)


  • Registered Users Posts: 2,431 ✭✭✭sideswipe


    Loughc wrote: »
    Mine and Wet.

    You're welcome :)

    yyfuwwp7qt101.jpg


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  • Registered Users Posts: 510 ✭✭✭gerrybhoy


    Loughc wrote: »
    Mine and Wet.

    You're welcome :)
    tenor.gif?itemid=14660916


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