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FI Charts ( T120+ onwards) Spring 2020 **READ MOD NOTE IN FIRST POST**

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Comments

  • Registered Users Posts: 223 ✭✭United road


    Thanks Gonzo for taking the time to post your informed point of view on the weather in the next few weeks, it's much appreciated. Particularly given that a lot of us are stuck at home, the weather has taken on even more importance than usual!!! That, food and alcohol.. although I couldn't possibly comment on the latter. Laughing emoji X 3

    Yes very well said!!
    Personally, you helped lift my spirits with recent posts and the theme being more nice weather
    I must say i hate the rain, love the sun, the only thing I accept from the skies in Ireland is snow.
    Thanks for the updates Gonzo, also acknowledging how well written they are, easy to follow for the untrained such as me


  • Registered Users Posts: 282 ✭✭eon1208


    Gonzo wrote: »
    just one more update for now. The GFS is updated again and we are beginning to lose the unsettled signal and a definite warming trend. From as early as Monday we will see temperatures beginning to lift up and very little in the way of rainfall and possibly temperatures taking off again from next Friday.

    ens_image.php?geoid=64981&var=201&run=12&date=2020-06-04&model=gfs&member=ENS&bw=1

    The ECM is also turning on the heat for next weekend. GEM continues with it's high pressure and very warm uppers second half of next week. It's beginning to look like this unsettled spell could run out of steam much sooner than we thought, but would need to look at what the models are showing over this weekend to be more confident, this could all look very different again by the morning.

    Thank you indeed Gonzo for your informative updates. A quick question please if I may.. How do you read the rainfall data from the ensemble chart. Well done again and please keep the updates coming. They are appreciated.


  • Registered Users Posts: 589 ✭✭✭Monkeynut


    eon1208 wrote: »
    Thank you indeed Gonzo for your informative updates. A quick question please if I may.. How do you read the rainfall data from the ensemble chart. Well done again and please keep the updates coming. They are appreciated.

    I had a quick google and found this. it may help.

    https://www.netweather.tv/secure/cgi-bin/pages/ensembles1.pdf


  • Moderators, Science, Health & Environment Moderators Posts: 16,679 Mod ✭✭✭✭Gonzo


    eon1208 wrote: »
    How do you read the rainfall data from the ensemble chart. Well done again and please keep the updates coming. They are appreciated.

    Basically the coloured spikes you see at the bottom of the graph are rainfall spikes, each coloured spike is from 1 of 20 GFS models. The more coloured spikes you see bunched up in one area the more chances that it will rain, the higher the spikes the heavier the rain might be. If you see no spikes across a section of the graph there won't be much if any rain on those days.

    In the case of today's ensembles you can see a few small spikes at the start, that represents this weekends rainfall, and it doesn't look like much, but there are several spikes bunched together so there is a decent probability of rain this weekend, even if it's not going to be very heavy. Between the 8th and 10th of June there are no coloured spikes so those days look set to be dry in general.

    Between the 10th and 16th of June there are only single spikes in certain areas so only a few of the models of going for rain which looks light to moderate, however there are not many spikes on top of each other so the probability of rain looks rather low.

    Back in February during the deluges these ensembles were covering from beginning to end with loads of rainfall spikes all on top of each other every single day. Some of the spikes were so tall that they were running into the horizontal temperature graphs further up the graph and it became hard to read at times!

    If I want to see more information about how much rain will fall I'll look up the model and look at a precipitation map to see where the rain might fall, for how long and how many mm of rain might fall. Every time the models update the rainfall spikes can change quite a bit from one run to the next so it's not an exact guarantee that rain will fall on any particular day but it gives a good guide to how settled or unsettled the weather will become, at least in the short term.


  • Moderators, Science, Health & Environment Moderators Posts: 16,679 Mod ✭✭✭✭Gonzo


    this mornings charts continues to show the warming trend. After a cold and showery Saturday temperatures start to to recover from as early as Sunday with mid to possibly high teens up to Wednesday and a fairly dry scene away from the west and north-western areas where showers or drizzle can be expected there.

    Temperatures begin to take off again from Wednesday with high teens to low 20's right up to the end of FI on both the ECM and GFS. For now this look like we may get a prolonged spell of warmer than average temperatures with temperatures in the 18 to 25C range for much of the time. The GEM has backed off slightly from it's very settled and high pressure dominated pattern it has had for the past few days. I still think a few more days of model watching is needed before we can be certain that we are heading into a very warm pattern once again from as early as mid week.


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  • Moderators, Science, Health & Environment Moderators Posts: 16,679 Mod ✭✭✭✭Gonzo


    What a difference a few hours makes when it comes to model watching. Over the past few days were models were beginning to show a return to warm and settled conditions after tomorrow with the possibilities of some very warm weather after next wednesday. However yesterday the GEM changed it's tune and so did the UKMO with an unsettled spell mid week next week. This was later joined by the ECM last night with all 3 models going for a somewhat unsettled scene with dryer interludes inbetween. The GFS stuck to its guns with lots of high pressure and plenty of warm weather up to this mornings run.

    GFS has just updated again and it is all change. Like a thief who sneaks in the backdoor to rob everything the GFS has now completely flipped and sneaks the Atlantic in through the backdoor from Iceland and goes to town with a very wet, cool and unsettled scene for the next two weeks with no end in sight to the unsettled conditions.

    We start off with an improving scene after this weekends cold snap with a dry and settled scene on Monday and Tuesday, however from Wednesday this breaks down very quickly.

    The Azores high is stopped in it's tracks as a low moves down through the UK and Ireland delivering wet and cool conditions.

    GFSOPEU06_105_1.png

    Low pressure dives in from the Atlantic from Greenland with bands of rain or showers along with cool temperatures from next weekend.

    GFSOPEU06_162_1.png

    This low deepens and sets up shop just off our west coast delivering bands of rain and strong winds, temperatures begin to struggle in the low to mid teens.

    GFSOPEU06_192_1.png

    The low goes nowhere fast and continues to pivot on itself over just to our west, bringing a conveyer belts of rain or showers up over Ireland along with cool and windy conditions.

    GFSOPEU06_228_1.png

    We finish at +360 hours and yep the low is still on our doorstep with bands of rain or showers and temperatures struggling.

    GFSOPEU06_384_1.png

    For June it doesn't get much worse than this.

    The latest ensemble run begins the unsettled spell from this Wednesday and the rainfall spikes are back in action properly from next weekend.

    ens_image.php?geoid=64981&var=201&run=6&date=2020-06-06&model=gfs&member=ENS&bw=1

    We are clearly losing the dry and settled signal here very quickly with many of the members going for lots of rain and average to slightly cooler than average temperatures.

    show_diagrams.php?model=gfs&lid=ENS&var=201&bw=1&geoid=64956

    by the end of the run the GFS is going for 30 to 90mm of rain over the next 2 weeks.

    240-777UK.GIF?06-6

    Temperatures struggling too in the 9 to 16C range much of the time

    150-580UK.GIF?06-6

    With so many model changes recently you have to wonder has the GFS just gone crazy on this sudden change to cool and wet conditions. The Atlantic has been nowhere to be seen for weeks and all of a sudden it is back full steam ahead at least for Ireland and western UK. I really hope this is wrong and we see a flip back to the dryer and settled scene.


  • Registered Users Posts: 16,553 ✭✭✭✭nacho libre


    Gonzo wrote: »
    What a difference a few hours makes when it comes to model watching. Over the past few days were models were beginning to show a return to warm and settled conditions after tomorrow with the possibilities of some very warm weather after next wednesday. However yesterday the GEM changed it's tune and so did the UKMO with an unsettled spell mid week next week. This was later joined by the ECM last night with all 3 models going for a somewhat unsettled scene with dryer interludes inbetween. The GFS stuck to its guns with lots of high pressure and plenty of warm weather up to this mornings run.

    GFS has just updated again and it is all change. Like a thief who sneaks in the backdoor to rob everything the GFS has now completely flipped and sneaks the Atlantic in through the backdoor from Iceland and goes to town with a very wet, cool and unsettled scene for the next two weeks with no end in sight to the unsettled conditions.

    We start off with an improving scene after this weekends cold snap with a dry and settled scene on Monday and Tuesday, however from Wednesday this breaks down very quickly.

    The Azores high is stopped in it's tracks as a low moves down through the UK and Ireland delivering wet and cool conditions.

    GFSOPEU06_105_1.png

    Low pressure dives in from the Atlantic from Greenland with bands of rain or showers along with cool temperatures from next weekend.

    GFSOPEU06_162_1.png

    This low deepens and sets up shop just off our west coast delivering bands of rain and strong winds, temperatures begin to struggle in the low to mid teens.

    GFSOPEU06_192_1.png

    The low goes nowhere fast and continues to pivot on itself over just to our west, bringing a conveyer belts of rain or showers up over Ireland along with cool and windy conditions.

    GFSOPEU06_228_1.png

    We finish at +360 hours and yep the low is still on our doorstep with bands of rain or showers and temperatures struggling.

    GFSOPEU06_384_1.png

    For June it doesn't get much worse than this.

    The latest ensemble run begins the unsettled spell from this Wednesday and the rainfall spikes are back in action properly from next weekend.

    ens_image.php?geoid=64981&var=201&run=6&date=2020-06-06&model=gfs&member=ENS&bw=1

    We are clearly losing the dry and settled signal here very quickly with many of the members going for lots of rain and average to slightly cooler than average temperatures.

    show_diagrams.php?model=gfs&lid=ENS&var=201&bw=1&geoid=64956

    by the end of the run the GFS is going for 30 to 90mm of rain over the next 2 weeks.

    240-777UK.GIF?06-6

    Temperatures struggling too in the 9 to 16C range much of the time

    150-580UK.GIF?06-6

    With so many model changes recently you have to wonder has the GFS just gone crazy on this sudden change to cool and wet conditions. The Atlantic has been nowhere to be seen for weeks and all of a sudden it is back full steam ahead at least for Ireland and western UK. I really hope this is wrong and we see a flip back to the dryer and settled scene.

    The UKMO seems to be something similar. If the ECM says something different this evening, you might get your wish, gonzo.

    Otherwise i think the discussion around drought conditions could be a distant memory soon enough.


  • Registered Users Posts: 282 ✭✭eon1208


    Thank you Gonzo.. Can you tell me the meaning behind the colour coded scale line at the bottom of each of the charts and what do the numbers represent. Are the the pressures up in the atmosphere I just presume. Also the minus figures dotted around the charts. Many regards..


  • Moderators, Science, Health & Environment Moderators Posts: 16,679 Mod ✭✭✭✭Gonzo


    eon1208 wrote: »
    Thank you Gonzo.. Can you tell me the meaning behind the colour coded scale line at the bottom of each of the charts and what do the numbers represent. Are the the pressures up in the atmosphere I just presume. Also the minus figures dotted around the charts. Many regards..

    The chart represents 20 different runs from the GFS models. The scale on the left is upper air temperature from -20 to +25 @850hpa.

    The horizonal coloured lines half way up the chart are the upper air temperature predictions by the models and the spikey lines at the bottom are rainfall predictions.

    The horizonal scale is the time period with the left edge of the graph today's date and the far right of the graph 14 days away, then we have all the days in between.

    The more rainfall spikes we see at the bottom, the more propability of rain, the higher the spikes, the higher the rainfall totals. If we see very few spikes or none at all over a few days there is a fair chance those days will be dry.

    The average upper air temperature for us at this time of the year is about +5C @850hpa. Today our upper air temperature is around -2C which is 7 degrees below average, so that is why today feels so cold with daytime temperatures hovering around the 9 to 12C mark.

    Normal uppers of +5 can get us to 15 to 20C daytime ground temperatures depending on sunshine etc. Later next week our uppers will get to around 7 or 8C which would get us daytime temperatures of high teens to low 20s.


  • Registered Users Posts: 282 ✭✭eon1208


    Thank you very much Gonzo. I meant also the figures on the bottom of each of the GFS charts you have up for the different days ahead. They are all around 500 or so.
    Gonzo wrote: »
    The chart represents 20 different runs from the GFS models. The scale on the left is upper air temperature from -20 to +25 @850hpa.

    The horizonal coloured lines half way up the chart are the upper air temperature predictions by the models and the spikey lines at the bottom are rainfall predictions.

    The horizonal scale is the time period with the left edge of the graph today's date and the far right of the graph 14 days away, then we have all the days in between.

    The more rainfall spikes we see at the bottom, the more propability of rain, the higher the spikes, the higher the rainfall totals. If we see very few spikes or none at all over a few days there is a fair chance those days will be dry.

    The average upper air temperature for us at this time of the year is about +5C @850hpa. Today our upper air temperature is around -2C which is 7 degrees below average, so that is why today feels so cold with daytime temperatures hovering around the 9 to 12C mark.

    Normal uppers of +5 can get us to 15 to 20C daytime ground temperatures depending on sunshine etc. Later next week our uppers will get to around 7 or 8C which would get us daytime temperatures of high teens to low 20s.


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  • Registered Users Posts: 282 ✭✭eon1208


    Thank you very much Gonzo. I meant also the figures on the bottom of each of the GFS data operational charts you have up for the different days ahead. They are all around 500 or so with a possible variation up to 600. I wonder about these..
    Gonzo wrote: »
    The chart represents 20 different runs from the GFS models. The scale on the left is upper air temperature from -20 to +25 @850hpa.

    The horizonal coloured lines half way up the chart are the upper air temperature predictions by the models and the spikey lines at the bottom are rainfall predictions.

    The horizonal scale is the time period with the left edge of the graph today's date and the far right of the graph 14 days away, then we have all the days in between.

    The more rainfall spikes we see at the bottom, the more propability of rain, the higher the spikes, the higher the rainfall totals. If we see very few spikes or none at all over a few days there is a fair chance those days will be dry.

    The average upper air temperature for us at this time of the year is about +5C @850hpa. Today our upper air temperature is around -2C which is 7 degrees below average, so that is why today feels so cold with daytime temperatures hovering around the 9 to 12C mark.

    Normal uppers of +5 can get us to 15 to 20C daytime ground temperatures depending on sunshine etc. Later next week our uppers will get to around 7 or 8C which would get us daytime temperatures of high teens to low 20s.


  • Registered Users Posts: 6,836 ✭✭✭pauldry


    Latest GFS rolling out slightly drier and normal temperatures again. Most rain to the South. But night time GFS usually the drier for some reason.

    Tomorrow low will be further North once more


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    eon1208 wrote: »
    Thank you very much Gonzo. I meant also the figures on the bottom of each of the GFS data operational charts you have up for the different days ahead. They are all around 500 or so with a possible variation up to 600. I wonder about these..

    Those are the height of the 500 hPa level, in decametres (tens of metres). So 500 means 5000 metres. The white lines are surface isobars. By looking at both parameters you can get a better picture of what's going on through the depth of the atmosphere and what's likely to happen next.


  • Registered Users Posts: 282 ✭✭eon1208


    Thanks Gaoth Laidir.. I'm thinking the lower the 500 Mb height the colder the air and vice
    versa.
    Those are the height of the 500 hPa level, in decametres (tens of metres). So 500 means 5000 metres. The white lines are surface isobars. By looking at both parameters you can get a better picture of what's going on through the depth of the atmosphere and what's likely to happen next.


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    eon1208 wrote: »
    Thanks Gaoth Laidir.. I'm thinking the lower the 500 Mb height the colder the air and vice
    versa.

    Yes, the lower the heights the colder the air, though that may not be reflected at the surface. Low heights are upper lows/troughs and high heights are upper highs/ridges. There are d8fferent combinations of links between these and surface conditions but in general, for our region, low heights mean more unsettled conditions and high heights more settled.


  • Moderators, Science, Health & Environment Moderators Posts: 16,679 Mod ✭✭✭✭Gonzo


    eon1208 wrote: »
    Thanks Gaoth Laidir.. I'm thinking the lower the 500 Mb height the colder the air and vice
    versa.

    the way I look at it is, if you see green areas with black outlines those generally is where the jetstream has some affect. The orange and red values usually indicate higher pressure. The greens and blues generally show lower pressure.The Azores high and other areas of high pressure are usually orange to red colours.


  • Moderators, Science, Health & Environment Moderators Posts: 16,679 Mod ✭✭✭✭Gonzo


    This mornings GFS still showing a mostly mixed scene from Wednesday with showers and it will become warmer generally. No real signs of weather settling down with plenty of large rainfall spikes over the coming few weeks, so expect some bands of rain at times or heavy showers. There will be the odd dry day too most likely. The coming week will see temperatures slowly recover towards the high teens and low 20's possible from next weekend.

    I think for now the idea of building the azores high over us and linking up with high pressure over Scandinavia is put to bed for the time being, we will have areas of low pressure near or close to us most of the time. The GFS tries to build the ridge again at the very end of the run but that is so far out it's not reliable.


  • Moderators, Science, Health & Environment Moderators Posts: 16,679 Mod ✭✭✭✭Gonzo


    GFS now going for a big lift up in the temperatures from this Friday lasting till the following Wednesday or Thursday. This warmth will also have some showers possibly thundery associated with it so it may not be completely dry.

    ens_image.php?geoid=64981&var=201&run=18&date=2020-06-07&model=gfs&member=ENS&bw=1

    After the low pushes through on Wednesday we swing the winds into the east from Thursday and temperatures begin to climb fairly quickly from Friday.

    GFSOPEU18_144_1.png

    On Saturday we get temperatures into the low 20's away from the east coast.

    GFSOPUK18_144_5.png

    By Monday we push temperatures into the low to mid 20's, staying cooler along eastern and southern coasts.

    GFSOPUK18_189_5.png

    Tuesday stays very warm, low to mid 20's possible

    GFSOPUK18_213_5.png

    most northern areas look set to be dry during this spell with showers possible across the south.

    After Wednesday we stay in an easterly flow but things cool down a bit, but still remaining warmish in the high teens. We end the run with the Azores high having another go at trying to influence our weather, however low pressure diving south could pose a problem to that.


  • Registered Users Posts: 2,651 ✭✭✭US2


    Not following the weather long but we seem to get more easterly weather in may and june than any other time. Is this true and if so thsts the reason ?


  • Moderators, Science, Health & Environment Moderators Posts: 16,679 Mod ✭✭✭✭Gonzo


    US2 wrote: »
    Not following the weather long but we seem to get more easterly weather in may and june than any other time. Is this true and if so thsts the reason ?

    yep generally May is the most easterly month. Sometimes June can be easterly but not always. One of the main reasons why we build easterlies easier in May and sometimes June is because the Polar Vortex usually dies around then which weakens the jet stream during the late Spring and early Summer. With a weaker jet stream the westerlies generally aren't powered up as much and winds have a higher going into the east. The polar vortex usually starts powering up for the winter from August and as it does so it's powers up the westerlies, meaning an easterly will have a much tougher time trying to fight the westerlies

    The hurricane season also starts around June into July most years and depending on how active the hurricane season is, this can also affect our weather and this can also power up the westerlies as summer goes on.

    Perhaps these are also reasons why the majority of our August's are rubbish. August usually is a very westerly dominated month with bands of rain sweeping in from the west regularly throughout the month.


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  • Registered Users Posts: 2,651 ✭✭✭US2


    Thank you. Makes sense when you explain it like that.


  • Closed Accounts Posts: 145 ✭✭Seven Septs


    Gonzo wrote: »
    yep generally May is the most easterly month. Sometimes June can be easterly but not always. One of the main reasons why we build easterlies easier in May and sometimes June is because the Polar Vortex usually dies around then which weakens the jet stream during the late Spring and early Summer. With a weaker jet stream the westerlies generally aren't powered up as much and winds have a higher going into the east. The polar vortex usually starts powering up for the winter from August and as it does so it's powers up the westerlies, meaning an easterly will have a much tougher time trying to fight the westerlies

    The hurricane season also starts around June into July most years and depending on how active the hurricane season is, this can also affect our weather and this can also power up the westerlies as summer goes on.

    Perhaps these are also reasons why the majority of our August's are rubbish. August usually is a very westerly dominated month with bands of rain sweeping in from the west regularly throughout the month.

    Interesting post Gonzo. Especially regarding August in recent times. However August pre the wet summers between 2007-2012 was a decent month. August 2003, 2002, 1995, 1990, 1991, 1984, 1983, 1976, 1979 were very good summer months.

    August 2006, 2005, 2004, 2000, 1999, 1994 etc were all reasonable summer months.

    It's really since 2007 that these poor Augusts kicked in.


  • Banned (with Prison Access) Posts: 3,829 ✭✭✭Cork Boy 53


    Interesting post Gonzo. Especially regarding August in recent times. However August pre the wet summers between 2007-2012 was a decent month. August 2003, 2002, 1995, 1990, 1991, 1984, 1983, 1976, 1979 were very good summer months.

    August 2006, 2005, 2004, 2000, 1999, 1994 etc were all reasonable summer months.

    It's really since 2007 that these poor Augusts kicked in.

    August 1979 wasn`t a particularly good month as I recall. The Fastnet storm happened then for one thing and the rest of the month was no great shakes.


  • Moderators, Science, Health & Environment Moderators Posts: 16,679 Mod ✭✭✭✭Gonzo


    latest GFS changes things again slightly, there are so many changes it's difficult to keep up, perhaps it's best to wait till the models settle down. For what their worth the latest GFS is not good news for those wanting plenty of rain over the next 2 weeks. We still have a slightly unsettled outlook but no real widespread rain, mostly showers and those will be very much hit and miss depending on location and tracking of showers. From Saturday temperatures generally stay in the high teens to low 20's so it will certainly feel warm and muggy at times as humidity rises.


  • Closed Accounts Posts: 145 ✭✭Seven Septs


    August 1979 wasn`t a particularly good month as I recall. The Fastnet storm happened then for one thing and the rest of the month was no great shakes.

    Beautiful weather around the Mountbatten killing.

    It's just one August. My point being August wasn't westerly dominated and the end of summer until the mid 2000s. As Gonzo said Augusts like 2014, 2015 etc were cool and westerly.


  • Banned (with Prison Access) Posts: 3,829 ✭✭✭Cork Boy 53


    Beautiful weather around the Mountbatten killing.

    It's just one August. My point being August wasn't westerly dominated and the end of summer until the mid 2000s. As Gonzo said Augusts like 2014, 2015 etc were cool and westerly.

    1f I recall correctly there were a string of entire summers at the end of the 1970s/beginning of the 1980s that were also westerly domimated.


  • Closed Accounts Posts: 145 ✭✭Seven Septs


    1f I recall correctly there were a string of entire summers at the end of the 1970s/beginning of the 1980s that were also westerly domimated.

    I just recall from around 1979 on. Yes 1980, 1985, 1986 was really cold and wet.


  • Registered Users Posts: 3,840 ✭✭✭Dickie10


    what was August 2018 like? i remember it being a terrible wet thursday at galway races around the 1st august. and fields began to green up and growth was good around late august that year


  • Closed Accounts Posts: 145 ✭✭Seven Septs


    Dickie10 wrote: »
    what was August 2018 like? i remember it being a terrible wet thursday at galway races around the 1st august. and fields began to green up and growth was good around late august that year

    Average enough, dull. The west wet the east stayed fairly dry. An anticlimactic end to a great June and most of July.

    As you say Dickie, the grass started to grow. The drought eased.


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  • Banned (with Prison Access) Posts: 3,829 ✭✭✭Cork Boy 53


    I just recall from around 1979 on. Yes 1980, 1985, 1986 was really cold and wet.

    I certainly remember 1985 as being an almost complete washout summer but was compensated to some extent by a warm dry September. Summer 1986 was similar though not as bad overall as the previous year.


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