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FI Charts (T120+ onwards) Summer/ Autumn 2018 **READ MOD NOTE IN FIRST POST**
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First, I'll start where I finished off from yesterday. The GFS 12z ensembles were an upgrade on the warmth yesterday in FI (they are similar today but the 16th-19th July is quite cool on today's 12z ensembles). They were showing the unsettled spell in terms of temperatures as a blip than a persistent phase with temperatures warming up again after about a week. Precipitation spikes also seemed to lower in FI. But these are just subtle hints more than anything as it's pointless otherwise because of all the uncertainty again.
Now onto today. This is the latest update of Hurricane/Tropical storm Chris. Chris is expected to become a hurricane tomorrow, back to tropical storm status by Friday as it passes by Newfoundland and then become extratropical as it travels over the North Atlantic. The centre of Chris on the latest run of the GFS is expected to be way to the north of Ireland so wind shouldn't be too much of a concern.
The GFS 12z is a changeable westerly flow with rain from time to time and is quite normal Ireland type conditions, nothing overly wet as well as not very dry. Air masses changing different ways with one having warmer than average temperatures and another having average or relatively cool temperatures. The GFS 0z and 06z had a far more unsettled and zonal pattern with unseasonable strong winds along with some quite heavy rain, the 12z seems to have died that down quite a bit but still changeable. These changes from run to run yet again reveal the uncertainty! Giving Thursday's chart (+66 hrs) on this post to show you where Chris is at that stage and watch how it travels up the North Atlantic and combines with the low pressure over Iceland.
UKMO 12z shows everything slack on Sunday 15th and Chris pushing in from the Atlantic.
GFS ensembles are bringing the NAO into negative territory through next week meaning there is signs of the jet stream heading southwards - at least for a time, bringing depressions with it over Ireland. However, the strength of these depressions whether it's the intensity of the rain or the wind is open up to question. GFS 12z suggested light rain over south and eastern regions whilst the north and west would get the bulk of the rain - as you'd expect in a zonal pattern.
I know there will be people throwing their toys out of the pram - there always is some people that do - that Summer is now over, good luck to us next year. I plotted this graph of the daily NAO data for Summer 1976. As you can see, July 1976 had quite a negative NAO index during much of the month in comparison to a positive NAO June and August that year. July 1976 was actually a rather dull and more unsettled month than June and August even though mean temperature wise, it tended to be the warmest month of that Summer.
Basically, plenty more opportunities for more settled weather sometime this Summer and as you've seen, September (even sometimes October) can be an extension to Summer too.
Photography site - https://www.sryanbruenphoto.com/
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hatrickpatrick wrote: »Either Sryan or Meteorite mentioned a few weeks ago that the GFS has a bias for returning to a typical jet stream / Atlantic dominated regime in FI, so that's probably something to bear in mind.
Yep it does but it's persisting in the last few runs. TBH they all can overplay the lows in FI but the range between is rather big at present
Latest GFS 6z:
ECM 0Z:
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hatrickpatrick wrote: »Either Sryan or Meteorite mentioned a few weeks ago that the GFS has a bias for returning to a typical jet stream / Atlantic dominated regime in FI, so that's probably something to bear in mind.
Correct, sometimes it can even give some weird northerly charts. Let me give some historical examples from GFS 0z runs, I have plenty more though.
I'd advise to not go beyond Tuesday 17th July with the model runs for now.
GFS 0z for Friday 22nd June on 10th June 2018
Actual 22nd June chart
GFS 0z for Sunday 24th June on 13th June 2018
Actual 24th June chart
GFS 0z for Wednesday 24th July on 12th July 2013
Actual 24th July chart
GFS 0z for Wednesday 25th June on 14th June 2014
Actual 25th June chart
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Just wrote a big analysis of the latest GFS run, only for Boards to randomly log me out after hitting post and lose the whole thing. :mad:
The 12z looks like a big improvement on the 6z for those who are looking for the settled weather to continue. The low pressure predicted by the 6z for next week has been significantly downgraded.
For comparison:
6z:
12z:
And:
6z:
12z:
Low pressure in the Atlantic continuing to be blocked. Heights lower than we've been seeing over Ireland, but still high.
Further out, towards the end of its run, the 12z shows the jet stream finally coming back into play - but the way things have been going, this seems to be getting delayed repeatedly with every model update.
Definitely still incredibly uncertain, but this run is at least an indication that those who don't want a washout aren't quite out of the game just yet. 0 -
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I don't know whether to laugh or cry......hatrickpatrick wrote: »Just wrote a big analysis of the latest GFS run, only for Boards to randomly log me out after hitting post and lose the whole thing. :mad:
The 12z looks like a big improvement on the 6z for those who are looking for the settled weather to continue. The low pressure predicted by the 6z for next week has been significantly downgraded.
For comparison:
6z:
12z:
And:
6z:
12z:
Low pressure in the Atlantic continuing to be blocked. Heights lower than we've been seeing over Ireland, but still high.
Further out, towards the end of its run, the 12z shows the jet stream finally coming back into play - but the way things have been going, this seems to be getting delayed repeatedly with every model update.
Definitely still incredibly uncertain, but this run is at least an indication that those who don't want a washout aren't quite out of the game just yet.0 -
giveitholly wrote: »I don't know whether to laugh or cry......
Well are you on Team Rain or Team Sun?
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What does that mean?
Ending up with a picture like this. Lp off the Iberian Penninsula and LP in Europe. Warm air drawn up over Ireland and Hp building around Ireland and being blocked in. Like a lot of the weather we have been having. Long way off, just has the look of heights and pressure building again at the end of the week. Will need to see more proof
Example of Omega Block from awhile back.
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What does that mean?
An omega block is a blocking area of high pressure that is "sandwiched" in between two areas of low pressure to form the shape of the greek letter, omega. Once established, an omega block can be very difficult to move and last for a couple of weeks though depending on how strong the blocking is. This is one of the two types of blocking that can occur. Omega blocks are most common in Spring but on occasion, they can occur on other seasons and last for multiple months resulting in some quite extreme weather. Summer 1976 was as a result of an Omega block with low pressure up to Greenland and Iceland with a vast area of above average pressure over top of us and low pressure to the east of Europe taking on the omega shape.
These types of blocks tend to give away to easterly winds which in Summer time result in quite hot weather for much of the country away from coasts.
To give a recent example, here's the appearance of an Omega block on a chart back in mid-March 2016 which was quite an extended dry spell then lasting up to nearly two weeks of duration.
The omega block is far away and is not to be taken seriously for now thanks to numerical weather prediction uncertainty (which can be likely due to these tropical depressions and a Pacific trade wind burst).Photography site - https://www.sryanbruenphoto.com/
Weather photo portfolio - https://sryanbruen.myportfolio.com/weather-1
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sryanbruen wrote: »An omega block is a blocking area of high pressure that is "sandwiched" in between two areas of low pressure to form the shape of the greek letter, omega. Once established, an omega block can be very difficult to move and last for a couple of weeks though depending on how strong the blocking is. This is one of the two types of blocking that can occur. Omega blocks are most common in Spring but on occasion, they can occur on other seasons and last for multiple months resulting in some quite extreme weather. Summer 1976 was as a result of an Omega block with low pressure up to Greenland and Iceland with a vast area of above average pressure over top of us and low pressure to the east of Europe taking on the omega shape.
These types of blocks tend to give away to easterly winds which in Summer time result in quite hot weather for much of the country away from coasts.
To give a recent example, here's the appearance of an Omega block on a chart back in mid-March 2016 which was quite an extended dry spell then lasting up to nearly two weeks of duration.
The omega block is far away and is not to be taken seriously for now thanks to numerical weather prediction uncertainty (which can be likely due to these tropical depressions and a Pacific trade wind burst).
Thanks for that explanation.0 -
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Deleted User wrote: »High pressure equals hot weather
East wind equals hot weather
Blocks equals hot weather
Is that the gist of it?
I'm currently having a look at the Met Office site which tells you how to read synoptic weather charts. Are the charts you guys look at synoptic or are there other types?
If only it was that simple Persepoly - then again if it was that simple, it probably wouldn't be as much fun as it is.
High pressure doesn't necessarily mean hot weather. High pressure doesn't necessarily mean cold weather in Winter either. You can have high pressure and cool temperatures in Summer (just like you can have high pressure and mild temperatures in Winter) but that is an odd combination for this time of year because usually when it's wet, it's cool and when it's dry, it's warm. Sometimes, you can have the high pressure centred just to the west of the country and ridging over Ireland forcing the wind direction (winds go in a clockwise direction around an area of high pressure) to come from a northwesterly or northerly. Summer 1981 was infamous for that kind of pattern. Whether it's hot depends on the wind direction because each wind direction has a different source to where the air is originating from. If it's a southwesterly, it will be rather mild. If it's a southerly with air coming from Iberia, it can get very hot. If it's a southeasterly with air coming from Europe, it can be very warm to hot too but the air is more stable so less in the way of cloud and lower humidity. Easterlies are also very warm in Summer time away from coasts. Different regions are favoured for the warmth by different wind directions like the west is going to be hotter than the east of Ireland during an easterly phase generally for example. Southerlies favour the warmth to be in the south, north and east.
An atmospheric block is a vast area of high pressure basically and where it sits is the driver to how the wind direction is going to face or our weather is going to take place. Let's look at a few case scenarios of historical Summer charts to show you what I mean of looking where the wind is coming from to get an estimate of how cool or warm the weather is when an atmospheric block of high pressure is somewhere over Europe.
Example 1: 27 June 2007. Winds are coming in from the north with air originating from Siberia - see where the isobars go back to and the arrow that I labelled. High pressure is to the west of Ireland and up to Greenland - that's the atmospheric block. Low pressure is over us and to the east over Scandinavia. This is a cool and wet setup.
Example 2: 14 July 1981. Winds are coming in from the northwest as high pressure laid to the southwest of Ireland trying to throw up a ridge but failed to as the northwesterlies were dominant. This day wasn't particularly cool itself but other days were and a lot of cloud with it. Notice how the pressure is average to relatively high though?
Example 3: 30 June 2015. Winds are coming up from the south dragging hot air from Iberia. Temperatures going into the mid 20s for some in the east and in the UK, into the 30s peaking at 37c the next day. Low pressure laid to the west of Ireland with high pressure to the east ridging back into Greenland which was going to be the theme of the Summer after this initial warm snap (sounds weird to say instead of cold snap).
Example 4: 28 June 2018. Winds are coming in from the east. There is an Omega block set up just to the north of us and ridging down to us. The jet stream is way to the north leaving us in very sunny and hot conditions.
A synoptic chart is any type of weather chart that shows atmospheric conditions so yes the charts we all show on here are synoptic charts. Don't let words like "synoptic" confuse you.
Hope you've found this post easy enough to understand and you've gotten some grasp of how to read these charts or how the atmosphere works in patterns like these. It's a lot more complicated than this though and this is just the beginning. However, take it day by day and step by step, we all have to begin somewhere!
Meanwhile, GFS 18z is not really seeing a very unsettled pattern for next week though it shows everything slack. It builds an area of high pressure for a time around the weekend after before low pressure invades from the south and everything goes a bit wonky.Photography site - https://www.sryanbruenphoto.com/
Weather photo portfolio - https://sryanbruen.myportfolio.com/weather-1
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sryanbruen wrote: »Deleted User wrote: »High pressure equals hot weather
East wind equals hot weather
Blocks equals hot weather
Is that the gist of it?
I'm currently having a look at the Met Office site which tells you how to read synoptic weather charts. Are the charts you guys look at synoptic or are there other types?
If only it was that simple Persepoly - then again if it was that simple, it probably wouldn't be as much fun as it is.
High pressure doesn't necessarily mean hot weather. High pressure doesn't necessarily mean cold weather in Winter either. You can have high pressure and cool temperatures in Summer (just like you can have high pressure and mild temperatures in Winter) but that is an odd combination for this time of year because usually when it's wet, it's cool and when it's dry, it's warm. Sometimes, you can have the high pressure centred just to the west of the country and ridging over Ireland forcing the wind direction (winds go in a clockwise direction around an area of high pressure) to come from a northwesterly or northerly. Summer 1981 was infamous for that kind of pattern. Whether it's hot depends on the wind direction because each wind direction has a different source to where the air is originating from. If it's a southwesterly, it will be rather mild. If it's a southerly with air coming from Iberia, it can get very hot. If it's a southeasterly with air coming from Europe, it can be very warm to hot too but the air is more stable so less in the way of cloud and lower humidity. Easterlies are also very warm in Summer time away from coasts. Different regions are favoured for the warmth by different wind directions like the west is going to be hotter than the east of Ireland during an easterly phase generally for example. Southerlies favour the warmth to be in the south, north and east.
An atmospheric block is a vast area of high pressure basically and where it sits is the driver to how the wind direction is going to face or our weather is going to take place. Let's look at a few case scenarios of historical Summer charts to show you what I mean of looking where the wind is coming from to get an estimate of how cool or warm the weather is when an atmospheric block of high pressure is somewhere over Europe.
Example 1: 27 June 2007. Winds are coming in from the north with air originating from Siberia - see where the isobars go back to and the arrow that I labelled. High pressure is to the west of Ireland and up to Greenland - that's the atmospheric block. Low pressure is over us and to the east over Scandinavia. This is a cool and wet setup.
Example 2: 14 July 1981. Winds are coming in from the northwest as high pressure laid to the southwest of Ireland trying to throw up a ridge but failed to as the northwesterlies were dominant. This day wasn't particularly cool itself but other days were and a lot of cloud with it. Notice how the pressure is average to relatively high though?
Example 3: 30 June 2015. Winds are coming up from the south dragging hot air from Iberia. Temperatures going into the mid 20s for some in the east and in the UK, into the 30s peaking at 37c the next day. Low pressure laid to the west of Ireland with high pressure to the east ridging back into Greenland which was going to be the theme of the Summer after this initial warm snap (sounds weird to say instead of cold snap).
Example 4: 28 June 2018. Winds are coming in from the east. There is an Omega block set up just to the north of us and ridging down to us. The jet stream is way to the north leaving us in very sunny and hot conditions.
A synoptic chart is any type of weather chart shows atmospheric conditions so yes the charts we all show on here are synoptic charts. Don't let words like "synoptic" confuse you.
Hope you've found this post easy enough to understand and you've gotten some grasp of how to read these charts or how the atmosphere works in patterns like these. It's a lot more complicated than this though and this is just the beginning. However, take it day by day and step by step, we all have to begin somewhere!
Meanwhile, GFS 18z is not really seeing a very unsettled pattern for next week though it shows everything slack. It builds an area of high pressure for a time around the weekend after before low pressure invades from the south and everything goes a bit wonky.
Sryan. I often wondered what do the words in "FI" stand for when you are describing the charts.0 -
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That would go down nicely as an 11th anniversary to the rainstorm of 20/21 July 2007.
Those are the kinds of charts where it would rain for several weeks with little break.
As we've seen from this whole Chris thing though, it can all change very easily. The ECM just the other day was building an Omega block for around those dates.
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Met Eireann forecast is suggesting the 0z saying a return to more changeable weather is probable....?
Yep their forecast ends withFurther trend: A gradual transition to a more changeable or mixed weather pattern than of late is probable, with all parts seeing some spells of sunshine but rain or showers at times too with an Atlantic regime resuming.
Which based on 0z in isolation is a fair call but I suspect 12z may paint a different picture and that line could disappear later
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Major divergence between the 12z GFS and ECM for next weekend:
High pressure on the GFS:
Low pressure on the ECM:
So essentially there's agreement that next week will be messy, but major disagreement as to how that'll play out going into next weekend. Still holding out for a nice day on Saturday the 21st
Will be interesting to see how the 18z GFS goes, and even more so whether tonight's 0z runs continue to disagree with eachother or if one starts to move towards the other.0 -
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ECM looks unsettled at the end of the run. Possibly get plenty of rain if this came off , thunderstorms possible. Almost like a cut off Low.
Don't know if it will look like that come the weekend but I think in general the models are showing quite possible that area of LP drift near us or over us towards the weekend.
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12z ECM another improvement for next weekend:
12z GFS still showing low pressure areas loitering to our north and south:
Pretty massive divergence between the two at the moment. FI has really become FI again, unlike most of June when FI was somewhat accurate for most of the month across all of the models.
EDIT: I think that depression near Iceland on the ECM is ex-hurricane Beryl. Could the divergence be related to uncertainty as to whether its remnant will redevelop off the US coast? NHC is backing away from redevelopment, but until yesterday they were giving it a 50% chance.0 -
Trough could produce rain around Thurs/ Fri over the country .
Good chance of showers the weekend coming going by present charts although the last two runs showing heights building more and squeezing out the area of LP.
The end of the ECM run finishing up with warm humid SW'ly as heights build again with a ridge extending over Ireland, possibly short lived.
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FI to me currently is beyond 72 hours thanks to the uncertainty so that's why I haven't bothered with NWP for the past few days. Since you brought the above up, I guess I'll post my thoughts on the bigger picture of those charts.
GFS shows contrasting temperatures over Greenland and us by +192 hrs which would most certainly lead to a more powerful jet stream. However, what's holding this back is the potential conjoined blocks of high pressure from the Azores, over us and Russia to form another Omega block. But this is more of a cherrypick than anything with these particular charts the 12z run generated today because the high over Russia looks weak in comparison to the jet stream caused by the temperature contrast. Not to mention, the model shows relatively high pressure over Greenland at that time frame which to me suggests the Azores High retrogressing and this in turn would force the jet stream to be pushed southwards either just to the north of us but close enough to bring unsettled weather, over top of us or to the south of us.
I don't know what to think of the UKMO at +144 hrs, everything is just so "weak" and uneventful.
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sryanbruen wrote: »FI to me currently is beyond 72 hours thanks to the uncertainty so that's why I haven't bothered with NWP for the past few days. Since you brought the above up, I guess I'll post my thoughts on the bigger picture of those charts.
I posted to try and stir up some debate on this particular thread Really because I'm very keen to hear expert opinion, given how serious any prolongment of the current drought will be. 0 -
ECM seems to be similar to the GFS.
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Well well well, what do we have here?
GFS 0z builds a ridge for the latter part of next weekend into early next week before the Atlantic tries to invade in against a block of high pressure over Scandinavia. The low pressure cannot get much further eastwards than the north and west and as a result, they just get pushed northwards. Looks fairly warm.
GFS 06z squeezes out the low pressure on Friday/Saturday then a little ridge (like the 0z) builds in bringing warmer and drier conditions again for a time before a return to westerlies but at the very end, high pressure builds over us again.
ECM builds a ridge of high pressure bringing more very warm air (see the 850hPa and thickness charts below) then everything becomes slack but staying warm at the end of its run. Over three consecutive runs or so now that this has been shown by the model.
ECM clusters have all gone to the warm or hot scenario but unlike Summer so far, this high looks further eastwards with low pressure in the Atlantic. This would mean that we would have some very hot days developing for some especially in the UK and if the low invades from the Atlantic after these hot interludes, we might start thinking about thunderstorms.
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