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Aviation weather thread

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  • Registered Users Posts: 1,342 ✭✭✭Negative_G


    Carnacalla wrote: »
    Also to note Cork at the moment:
    EICK 091930Z = Cork Airport, 09th Sept, 19:30 hours
    30007KT= Wind 300 degrees 7 knots
    0500= Visibility 500m
    R17/1000U= RVR (Runway visual range) Runway 17 1000m up
    R35/1100U= RVR (Runway visual range) Runway 35 1100m up
    FG VV002= Fog, vertical visibility 200m
    03/03= Temp 3c, Dewpoint 3c
    Q0976= Air pressure 976hpa (Hector Pascals)
    BECMG 3000 BKN003= Trend: Becoming vis 3000m, clouds broken at 300ft.
    In terms of RVR and D, U and C:
    D indicates downward trend.
    U upward trend.
    N no change.

    This may change for example throughout the passage of a warm front.
    From a piloting perspective, the wind speed and the dew point split will aid in discussion for approach planning.

    The time of issue will also help decision making. The above example is at 1930Z (7.30pm), the dew point split is unlikely to increase heading into the night time, generally speaking in our climate at least.
    However if it was in the morning, the dew point split is likely going to increase as the air temperature increases towards its diurnal maximum. This will result in the fog lifting and wind speed increasing, generally speaking.

    Fog is unlikely to cause any delays where you have tightly spaced isobars. On the other hand, an area under the influence of a high pressure with the associated slack pressure gradient may experience issues in the early morning, or all day depending on humidity and dew point split.



    From an Irish aviation point of view, Ireland is particularly complex compared to other areas of Europe.
    The prevailing winds in Ireland generally come from a south westerly to westerly direction. This wind comes in from the Atlantic. Many of the weather systems that develop in the Atlantic happen to be low pressure systems.

    Low pressure systems (also known as depressions) are areas where the pressure is relatively lower than the surrounding area. This results in the air movement on the earths surface moving toward the centre of the depression. As it reaches the centre from all directions it then rises upward toward the sky(imagine a funnel) where it will then move outward from the centre, the opposite of what happens on the surface. It converges at the surfaces and diverges at the top.

    As the air mass moves across the surface it will pick up moisture until it becomes saturated, in other words, it cannot carry any more moisture. As the air mass rises, it becomes cooler as it moves away from the surface. Once the temperature (the actual temperature of the air) and the dew point (the temperature which causes the moisture laden air to freeze, which can vary depending on atmospheric conditions) are the same, this results in cloud formation.

    You then have this moisture laden air which is steadily moving toward Ireland. Land mass is often warmer than the sea, particularly during the summer. As this moisture laden air mass moves toward Ireland the warm convection currents over land cause the moisture laden air mass to rise further into the atmosphere where it becomes colder and colder. The water droplets help in suspension condense (turn from gas to a liquid form) and become heavier until such time as they can no longer be held in suspension, and then fall as rain.

    Thats a very simple view of why ireland receives so much rainfall and weather systems. The weather we experience mostly originates in the Atlantic and our prevailing wind means that Ireland and indeed France, the UK and Iceland often bear the worst as we are the first land mass in its path.
    Of course there are other considerations such as stationary high pressures over mainland europe and greenland which can keep these depressions away from us and then you have to consider the different types of fronts which can form as part of these pressure systems, each bringing their own unique characteristics which are often observable from the ground.

    Weather is a complex subject and getting a grasp of the basics can be difficult, it certainly was for me, but if you have more than a passing interest it can be rewarding. For the most part and in my own opinion, any local forecast more than 48/72 hours should not be relied upon except in the exceptional circumstances of a blocking high for example.

    I have to laugh when I hear of the Donegal postman et al, predicting specific weather three months in advance. Pure codswallop and guess work.


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


    Negative_G wrote: »
    There is already a dedicated weather forum with many very informative posters who post regularly.

    Any adverse weather which which has an impact on airline traffic is already discussed in depth, with links to external sites, in the FR24 & LiveATC threads.

    Yes, I know, but the weather thread gets bogged down in all sorts of side discussions. This is purely for weather affecting flight operations. Maybe the title should be Aviation weather and delays thread.

    For example, at one point on Wednesday I noticed that 53% of all delays in Europe were caused by weather. At the moment it's just 11%. The links above complement the FR24 and LiveATC threads and the thread in general can be a quick reference guide.


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


    EFHK 03-09 –SN
    ESSA 00-05 2000M SN
    ENGM 00-00 –SN
    EPWA 00-08 –SNRA
    EGPH 02-08 300m FG FZFG
    EGLL 00-10 tempo 300’
    London area 16-22 +SHRA 20G30kts
    Paris area 00-06 600m BCFG tempo 200m
    LOWW 00-09 400M FZFG
    LSZH 00-00 tempo -SN
    LIML 03-08 400M FZFG
    LDZA 00-12 300m FG 200’


  • Registered Users Posts: 10,075 ✭✭✭✭smurfjed


    23654464064_bca8525250_o.jpg

    EDIT: added image posted by smurfjed in a later post


  • Registered Users Posts: 1,980 ✭✭✭Growler!!!


    EFHK 03-09 –SN
    ESSA 00-05 2000M SN
    ENGM 00-00 –SN
    EPWA 00-08 –SNRA
    EGPH 02-08 300m FG FZFG
    EGLL 00-10 tempo 300’
    London area 16-22 +SHRA 20G30kts
    Paris area 00-06 600m BCFG tempo 200m
    LOWW 00-09 400M FZFG
    LSZH 00-00 tempo -SN
    LIML 03-08 400M FZFG
    LDZA 00-12 300m FG 200’

    As I said to Carnacalla, the above means nothing to your average poster on here. You need to provide translations so everyone can learn from it, not just licensed individuals ( on their high horse:D)


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


    Growler!!! wrote: »
    Perhaps pm the mods before launching the thread? That way they can decide before it goes live?

    Jeez, does every other thread that is opened get forensically dissected too?

    As I said, maybe I should have titled it Delays thread, which in most, but not all, cases relates to weather delays. I see no other thread related to delays. The Eurocontrol link above covers all delays, network issues, etc. Relevant to many people here. Most people here will understand metars, etc. They may find this useful.


  • Registered Users Posts: 2,159 ✭✭✭PukkaStukka


    +1 for this thread.

    I like aviation and meteorology, and this thread being a hybrid of the two is something I'd find interesting. There are a number of threads in this forum which I'd have shag all interest in, but hey it's not my place to dictate anything to those with an interest in these threads, nor stand in their way! :)

    Live and let live as they say!


  • Registered Users Posts: 3,001 ✭✭✭Pat Dunne


    EFHK 03-09 –SN
    ESSA 00-05 2000M SN
    ENGM 00-00 –SN
    EPWA 00-08 –SNRA
    EGPH 02-08 300m FG FZFG
    EGLL 00-10 tempo 300’
    London area 16-22 +SHRA 20G30kts
    Paris area 00-06 600m BCFG tempo 200m
    LOWW 00-09 400M FZFG
    LSZH 00-00 tempo -SN
    LIML 03-08 400M FZFG
    LDZA 00-12 300m FG 200’
    I would be interested in acquiring more of an insight to Aviation Meteorology. Perhaps you could you provide a translation, for us who are a less learned :)


  • Registered Users Posts: 18,136 ✭✭✭✭JCX BXC


    Pat Dunne wrote: »
    I would be interested in acquiring more of an insight to Aviation Meteorology. Perhaps you could you provide a translation, for us who are a less learned :)

    Based on what I know, (Which is still fairly little), the four letter codes like EGLL=London Heathrow are airport codes, ICAO codes, (SN= Snow, -SN= Light Snow +Snow= heavy snow) FG=Fog, FZFG=Freezing Fog,


  • Registered Users Posts: 705 ✭✭✭BZ


    Pat Dunne wrote: »
    I would be interested in acquiring more of an insight to Aviation Meteorology. Perhaps you could you provide a translation, for us who are a less learned :)

    Example: LIML 0300z to 0800z 400 metres visibility in freezing fog


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  • Closed Accounts Posts: 1,208 ✭✭✭Long Time Lurker


    Loving this thread. Still learning. This ones helping.


  • Registered Users Posts: 18,136 ✭✭✭✭JCX BXC


    Also to note Cork at the moment:
    EICK 091930Z = Cork Airport, 09th Sept, 19:30 hours
    30007KT= Wind 300 degrees 7 knots
    0500= Visibility 500m
    R17/1000U= RVR (Runway visual range) Runway 17 1000m up
    R35/1100U= RVR (Runway visual range) Runway 35 1100m up
    FG VV002= Fog, vertical visibility 200m
    03/03= Temp 3c, Dewpoint 3c
    Q0976= Air pressure 976hpa (Hector Pascals)
    BECMG 3000 BKN003= Trend: Becoming vis 3000m, clouds broken at 300ft.


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


    From Eurocontrol
    CB activity:
    Ocnl CB act (top FL 260) :
    EISN/DW, EGTT
    Occasional Cumulonimbus with tops to FL260 (26,000 ft) in Shannon, Dublin and London FIRs.
    STRONG WIND:
    EGLL/KK/LC/GW/SS/BB/CC: 0000-1500 G 25-30 KT
    LFPG/PO: 0000-1300 G 35 KT
    EBBR: 0000-1500 G 28 KT
    EHAM:0300-1200 G 30 KT
    LPPR: 0000-1200 G 42 KT
    LEPA: 0400-1300 G 37 KT
    LEMD: 0300-2400 G 43 KT
    e.g. Heathrow, Gatwick, London City, Luton, Stansted, Birmingham, Manchester. Midnight to 3 pm Sunday, wind gusting 25-30 kt.
    LFPG=CDG, EBBR=Brussels, EHAM=Amsterdam, LPPR=Porto, LEPA=Majorca, LEMD=Madrid.
    Depending on direction, winds could cause crosswind issues, especially if runways are wet.
    LOW VISIBILITY/SN/ICING:
    LIMC/L/E/F/PZ/PO: 0000-0700 400m FG
    LOWW: 0900-1800 700m FG vv 001
    LSZH: 0000-0800 1200m PRFG
    EDDM: 0300-0900 1200m BCFG
    EDDT: 0200-1000 800m FZFG
    EPWA: 1000-1800 2000m SN


  • Moderators, Motoring & Transport Moderators Posts: 9,744 Mod ✭✭✭✭Tenger


    It's for the mods to decide. If this is a waste of time then close the thread and let's be done with it.
    Let see how it goes. While we do have a weather forum this thread doesn't overlap hugely with other threads here (FR24 perhaps)
    If this particular topic invites discussion then good. If it becomes 1-2 members posting weather reports each day then it will be locked.


  • Registered Users Posts: 6,533 ✭✭✭kub


    OP well done i think this is a great idea for a thread, for example if anyone was planning on flying in Europe over the next few days they would have an idea of the weather where they are heading too and this may help with plans and indeed issues with connections etc.


  • Registered Users Posts: 7,466 ✭✭✭highlydebased


    Excellent idea OP.


  • Registered Users Posts: 1,342 ✭✭✭Negative_G


    Seeing as this thread is going to persist, for the time being at least, it may be prudent to edit the first post and include an explanation including what charts signify, an explanation of what an ATIS is as well as what TAF and METAR's are and the frequency of their issuing. Likewise with explaining sig weather charts and the symbols you may encounter on these.

    An EASA abbreviation decoder will greatly help peoples understanding.

    The jeppesen intro section gives good nuggets of information but is probably a bit too in depth for most. Older versions of this are available online for free.

    In my own experience most people don't understand what is to be expected with warm fronts, cold fronts, occlusions, isobars, trough lines, jet streams and pressure systems amongst everything else other than they appear as lines on the RTE weather amongst all the rain.

    I would agree that if this is going to become a copy and paste of METARs with little or know explanation, it is a pointless exercise.

    EDIT: As most weather discussion increases around significant weather an explanation of what a SIGMET is and how to break it down would also be beneficial.


  • Registered Users Posts: 1,342 ✭✭✭Negative_G


    Carnacalla wrote: »
    Also to note Cork at the moment:
    EICK 091930Z = Cork Airport, 09th Sept, 19:30 hours
    30007KT= Wind 300 degrees 7 knots
    0500= Visibility 500m
    R17/1000U= RVR (Runway visual range) Runway 17 1000m up
    R35/1100U= RVR (Runway visual range) Runway 35 1100m up
    FG VV002= Fog, vertical visibility 200m
    03/03= Temp 3c, Dewpoint 3c
    Q0976= Air pressure 976hpa (Hector Pascals)
    BECMG 3000 BKN003= Trend: Becoming vis 3000m, clouds broken at 300ft.

    In terms of RVR and D, U and C:

    D indicates downward trend.
    U upward trend.
    N no change.

    This may change for example throughout the passage of a warm front.

    From a piloting perspective, the wind speed and the dew point split will aid in discussion for approach planning.

    The time of issue will also help decision making. The above example is at 1930Z (7.30pm), the dew point split is unlikely to increase heading into the night time, generally speaking in our climate at least.

    However if it was in the morning, the dew point split is likely going to increase as the air temperature increases towards its diurnal maximum. This will result in the fog lifting and wind speed increasing, generally speaking.

    Fog is unlikely to cause any delays where you have tightly spaced isobars. On the other hand, an area under the influence of a high pressure with the associated slack pressure gradient may experience issues in the early morning, or all day depending on humidity and dew point split.


  • Registered Users Posts: 341 ✭✭lfc200


    Negative_G wrote: »
    In terms of RVR and D, U and C:

    D indicates downward trend.
    U upward trend.
    N no change.

    This may change for example throughout the passage of a warm front.

    From a piloting perspective, the wind speed and the dew point split will aid in discussion for approach planning.

    The time of issue will also help decision making. The above example is at 1930Z (7.30pm), the dew point split is unlikely to increase heading into the night time, generally speaking in our climate at least.

    However if it was in the morning, the dew point split is likely going to increase as the air temperature increases towards its diurnal maximum. This will result in the fog lifting and wind speed increasing, generally speaking.

    Fog is unlikely to cause any delays where you have tightly spaced isobars. On the other hand, an area under the influence of a high pressure with the associated slack pressure gradient may experience issues in the early morning, or all day depending on humidity and dew point split.

    Thanks Negative_G, really interesting snippets of info there!


  • Registered Users Posts: 1,342 ✭✭✭Negative_G


    lfc200 wrote: »
    Thanks Negative_G, really interesting snippets of info there!

    No problem, if you want me to elaborate further I'll do my best to answer as best I can.

    While predictable to a degree, the weather is far from an exact science in reality and does not often follow what the experts or textbooks might say. That's not to say that there isn't merit in the study that has been done but it is important to note that it can be incredibly difficult to predict accurately.

    From an Irish aviation point of view, Ireland is particularly complex compared to other areas of Europe.

    The prevailing winds in Ireland generally come from a south westerly to westerly direction. This wind comes in from the Atlantic. Many of the weather systems that develop in the Atlantic happen to be low pressure systems.

    Low pressure systems (also known as depressions) are areas where the pressure is relatively lower than the surrounding area. This results in the air movement on the earths surface moving toward the centre of the depression. As it reaches the centre from all directions it then rises upward toward the sky(imagine a funnel) where it will then move outward from the centre, the opposite of what happens on the surface. It converges at the surfaces and diverges at the top.

    As the air mass moves across the surface it will pick up moisture until it becomes saturated, in other words, it cannot carry any more moisture. As the air mass rises, it becomes cooler as it moves away from the surface. Once the temperature (the actual temperature of the air) and the dew point (the temperature which causes the moisture laden air to freeze, which can vary depending on atmospheric conditions) are the same, this results in cloud formation.

    You then have this moisture laden air which is steadily moving toward Ireland. Land mass is often warmer than the sea, particularly during the summer. As this moisture laden air mass moves toward Ireland the warm convection currents over land cause the moisture laden air mass to rise further into the atmosphere where it becomes colder and colder. The water droplets help in suspension condense (turn from gas to a liquid form) and become heavier until such time as they can no longer be held in suspension, and then fall as rain.

    Thats a very simple view of why ireland receives so much rainfall and weather systems. The weather we experience mostly originates in the Atlantic and our prevailing wind means that Ireland and indeed France, the UK and Iceland often bear the worst as we are the first land mass in its path.

    Of course there are other considerations such as stationary high pressures over mainland europe and greenland which can keep these depressions away from us and then you have to consider the different types of fronts which can form as part of these pressure systems, each bringing their own unique characteristics which are often observable from the ground.

    Weather is a complex subject and getting a grasp of the basics can be difficult, it certainly was for me, but if you have more than a passing interest it can be rewarding.

    For the most part and in my own opinion, any local forecast more than 48/72 hours should not be relied upon except in the exceptional circumstances of a blocking high for example.

    I have to laugh when I hear of the Donegal postman et al, predicting specific weather three months in advance. Pure codswallop and guess work.


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


    I've updated the op with more info to help with deciphering the info provided.


  • Registered Users Posts: 10,075 ✭✭✭✭smurfjed


    23654464064_bca8525250_o.jpg

    This should help with the decoding.


  • Registered Users Posts: 18,136 ✭✭✭✭JCX BXC


    Wouldn't mind an ole +TSSNGR tbh.


  • Registered Users Posts: 7,466 ✭✭✭highlydebased


    SHRAGS is probably my favourite one- showers of rain and small hail


  • Registered Users Posts: 10,075 ✭✭✭✭smurfjed


    My favourite is CAVOK!


  • Registered Users Posts: 18,136 ✭✭✭✭JCX BXC


    smurfjed wrote: »
    My favourite is CAVOK!

    Ah but thats boring!


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


    Carnacalla wrote: »
    Ah but thats boring!

    Not if you're a PPL waiting months for flyable weather!


  • Registered Users Posts: 18,136 ✭✭✭✭JCX BXC


    Not if you're a PPL waiting months for flyable weather!

    BFS is currently CAVOK, go there.


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


    Plenty of SIGMETs (blue) issued for Iberia (Icing, Turbulence) and Italy (Turbulence).

    Porto not the nicest TAF. Heavy thunderstorms this evening, with crosswinds gusting to 45 knots. Windshear already reported on all runways.

    Link to map here. Select Layers to overlay satellite, winds, etc.

    374373.png


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  • Registered Users Posts: 18,136 ✭✭✭✭JCX BXC


    Porto not the nicest TAF. Heavy thunderstorms this evening, with crosswinds gusting to 45 knots. Windshear already reported on all runways.

    The 19:30 AMD TAF only gives wind gusts up to 25kts with no thunderstorms.


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