Jet stream weather charts for Es research - chart drawer

Discussion in 'Radio Propagation Questions' started by Jim Bacon g3yla, May 1, 2015.

  1. Sunday 27th August 2017

    A very good start this morning with 10m particularly busy due to a contest lifting activity levels.

    The western side of the UK seems to be favoured at the moment with paths into eastern Europe. The principle trigger appears to be small upper trough moving east across Denmark with areas of falling (red) and rising (blue) contours giving an extra incentive for gravity waves to be generated. This moves farther away to the east, probably allowing stations in eastern Britain to benefit, but it will be just outside the ideal radial rings by the later operating window this evening, so use it while its within range.

    The second area of interest is associated with the broad, but fairly weak segment of westerly jet stream across central France and occupies the whole of the southeastern quadrant of the ideal distance radial ring. This favours paths towards I/IS0 etc.

    Thirdly we still have the sharp upper trough over Portugal, which arrived yesterday, and looks to be a good position with the exit of the southerly portion of jet stream, on its eastern side, to be within the distance rings for paths to the south into EA/CT.

    The Atlantic is doing quite well as the main polar front jet stream migrates east and provides stepping points to get to the States.

    73 de Jim

  2. Monday 28th August 2017

    A strong jet stream is pushing in towards northwestern Britain today with speeds well in excess of 100kt, so Autumn is here! It does give a chance for some paths from southern UK towards TF/OY/OX as the jet stream encounters the Highlands along with rapidly falling contour values, both good omens for generating gravity waves in the atmosphere; you may be able to pick these up by looking for ripples in the cloud patterns on satellite pictures.

    Other points of interest are the northerly jet stream ahead of the upper ridge over the UK and near continent. This northerly jet over Germany is at the right distance to play a role for UK stations and suggests the sector from Scandinavia round through eastern Europe to the Balkans is worth a look today. This jet stream is moving bodily east, so may be out of range later today.

    The upper ridge itself is also a feature which could help with some random Es across the axis of the ridge. Never easy to call, but a good upper ridge can produce widespread openings where jet streams and thunderstorms are noticeable by their absence.

    The other obvious jet stream provider is the small cut-off upper low over Portugal. Whilst this is just on the borders of the ideal radial rings for distance, there may be the occasional option for a maximum range path, say down to ZB2 or EA8.

    The Atlantic has already been mentioned, but of course the extended track of strong winds across the 'pond' could support multi-hop paths to the southern States and Caribbean.

    73 de Jim

  3. Tuesday 29th August 2017

    Clear sunny skies over the near continent with no thunderstorms or jet streams, yet we have some 10m Es. All the paths seem to be crossing the upper ridge, which has sharpened slightly since yesterday. These can be good providers of Es events, either in their own right or due to contribution from wind shear on the edges of the jet streams which surround the ridge. As ridges go, this one looks promising due to its movement eastwards and its sharpness, which can lead to turbulence on the ridge axis. This supports paths from the UK towards the Baltic round to Hungary and Italy.

    Moving northward to the main Atlantic jet stream, now across northern Britain and Scandinavia, which has forecast core speeds in excess of 100kt (shaded yellow). Paths across this from southern UK to OY/TF look possible, as do paths into Scandinavia.

    The small cut-off low over Spain has barely moved, so remains on the edge of our reach, just about making the radial rings to the south and therefore not impossible to see paths to EA/CT/EA8 using the various jet stream segments around the low.

    The Atlantic is still doing well with segments stretching most of the way back to the States. It possibly favours the southern States and Caribbean and perhaps even South America.

    73 de Jim

  4. Wednesday 30th August 2017

    The Es have returned this morning although rather a sketchy appearance, so far as UK operators are concerned.

    The main features on the 300mb upper air forecast charts are connected, in fact this is true of upper air patterns in general since no feature exists in isolation, but is influenced by upstream and downstream events. Anyway, today's top features are the sharp upper trough moving into Britain and the sharp upper ridge being pushed up ahead of it over central Europe.

    Starting with the upper ridge; this is probably behind the paths over Poland and the Balkans due to turbulence on the axis of the ridge where the wind changes direction. This part of the pattern is slow-moving, but unfortunately is outside our ideal distance rings.

    The strong southwesterly jet stream over Britain with core speeds in excess of 100kt is capable of generating strong gravity waves, especially where it intersects with mountain ranges like the Highlands and Norway. However, at present these regions are not generating any Es, but the potential is there.

    The southern leg of this jet stream connects, across France, with the flow around the old cut-off upper low over Spain. There have been some isolated paths across this area and Biscay into Spain, so worth checking this region since the upper air pattern is moving very slowly at the moment. The radial rings look well-filled in most sectors from NE round through SE to S for European QSOs, should Es materialise.

    The Atlantic side of the picture is also well-stocked with jet streams, but placement of the first hop for a multi-hop path suggests that a more southerly route is better placed, towards the Caribbean and South America.

    73 de Jim

  5. Thursday 31st August 2017

    A geomagnetic storm, K=5, is making for an uncertain picture, but the clusters are reporting some activity up to 6m, so all is not lost.

    The main southwesterly jet stream flow from northeast Spain across France into the Low Countries and southern Scandinavia is capable of producing gravity waves and hence turbulence, especially as it crosses mountain ranges. At present, the hot spots are over southern Scandinavia, where a core of >100kt is currently crossing the Norwegian mountains and are located within the ideal radial ring distance markers. This should continue to feature in this zone for the rest of today, so worth beaming towards the northeast to check. It is also worth checking the more southern entrance region of this jet stream over France, which is producing some 10m paths.

    Another feature of today's charts, carried over from yesterday, is a sharp upper ridge over eastern Europe, which continues to provide the odd path across the ridge axis on 6m, but all out of range from the UK.

    The jet stream segment on the other side of the upper trough, which is now pushing into northern Spain may produce some interest over Biscay for paths into Spain later.

    The Atlantic is still well set up with jet stream segments, which may provide stepping stones for paths to the States.

    73 de Jim

  6. Friday 1st September 2017

    Since Sporadic E doesn't know what the date is, I shall continue with the blogs into September, as conditions dictate.

    Today its the same ingredients providing the activity; an active cold front with its associated jet stream across the Low countries, into Denmark and southern Scandinavia is probably behind the Es over the Baltic. This has a strong core of 100kt+ winds moving into Norway and likely to make paths to the Baltic and Scandinavia preferred directions. This region of jets stream activity lies within the ideal distance rings and remains so for the rest of today.

    The upper ridge ahead of this jet stream over eastern Europe still appears to be working for Es and there is another region of activity across this ridge, located over southern Poland and Slovakia. This will remain just out of range, unless part of a multi-hop path towards Ukraine and Black Sea.

    Other parts of the jet stream pattern around the upper trough over Britain are potentially useful and the northwesterly jet stream across Biscay and into Spain may also add to the options for paths to the south into EA/CT, especially later today as the strong flow reaches the Cantabrian Mountains.

    The Atlantic has a good supply of various jet stream segments to keep some interest in multi-hop paths to the States.

    73 de Jim

  7. Saturday 2nd September 2017

    ... and still the season clings on. The European section of the jet stream maps shows an active segment with a core above 100kt and rapidly falling contour values moving across the central Mediterranean and likely to give some very 'un-holiday-like' weather with severe thunderstorms. This means that the key area for generating gravity waves is outside our ideal radial rings for distance, but should give some good options within the Mediterranean area.

    The northern part of the same southwesterly jet stream has pushed well into eastern Europe, northern Scandinavia and Russia with some early paths crossing the Baltic states, also out of reach from the UK.

    The more interesting options involve the northerly jet stream segment on the western side of the upper trough over the continent. This is blowing straight down the country and may well contribute to local Es due to turbulence over the Highlands, Pennines and Snowdonia. This jet stream continues across France and onto the Pyrenees so this bodes well for paths to the south into the central Mediterranean and EA6/IS0/IT9 etc and Spain and Portugal.

    The Atlantic is well stocked again and there should be several options for stepping stones towards the States and Caribbean.

    73 de Jim
  8. Sunday 3rd September 2017

    Plenty of activity on the jet stream charts again and a few Es paths showing on the website.

    We must be nearing the end of reliable openings now, so if we do see any paths, be prepared for them to be transient. I suppose the key region to examine today is the sharp upper trough heading east across central Europe and the Adriatic; turbulence from this should be able to generate some strong gravity waves, which can propagate up to reach the E region where they can be part of the wind shear mechanism for making Sporadic E. The strong northwesterly jet stream, across eastern France, the Alps and down across Italy into the Adriatic, is the driver for this. It will remain in the southeastern quadrant of our radial distance rings during today, so check for paths to Italy and the Balkans.

    There is another segment of northwesterly jet stream across northern Spain and the Pyrenees and this will extend the directions of interest westwards into Spain and Portugal. This zone may be better later as the region of rapidly rising contours (within the blue lines) moves into Biscay this evening.

    Of course, there are many other areas within Europe where jet streams could trigger some Es, but they are mostly out of reach from the UK.

    Lastly a look at the Atlantic where the next major jet stream is moving out across the Atlantic with speeds well in excess of 100kt, so worth checking out those paths towards the States.

    73 de Jim
  9. Monday 4th September 2017

    Its looking a bit thin on the clusters this morning and although there are plenty of jet streams, like yesterday activity may be hard to find despite plenty of options.

    Just about any direction looks promising in terms of triggers from jet stream activity, including paths across the Atlantic.

    73 de Jim

    PS I shall very soon revert to the out of main season approach of just uploading the charts, rather than preparing a full blog daily. Thanks for joining me this year; I will have an update for you at the RSGB Convention, plus some ideas on future developments for the displays for next season.

  10. Tuesday 5th September 2017

    With so much activity from the sun at the moment I am sure there'll be some other implications, but as it stands there are plenty of jet streams available to generate gravity waves.

    So far, the main centre of activity is over the Balkans where the strong northerly jet and rapidly rising contours is the likely generator of the gravity waves and the western end of this over the Alps is just within the ideal radial rings and should allow access from the UK. Closer to home, over the near continent, a weak upper ridge may provide some paths within reach of the UK towards central Europe.

    There is a fairly strong southwesterly jet stream over the eastern Mediterranean which could explain paths from 4X to the Balkans and may become part of a weak multi-hop-hop path, once the first steps are in place.

    The UK zone is also set up with several jet stream segments to play with and maybe become a source of Es overhead. The other direction of interest is using the smaller westerly jet stream over Biscay and northern Spain to give options to the south.

    Lastly the Atlantic is well set up again to make paths to the States worth checking at times.

    73 de Jim

  11. Wednesday 6th September 2017

    I'm sure there's going to be an end to the season eventually, but for the time being its still worth checking the lower Sporadic E bands like 10m and 6m, not forgetting the role that Es plays on other HF bands at times of soar minimum.

    It is obvious from the jet stream charts that there is no shortage of sources of gravity waves with strong jet streams aplenty! There is a good northwesterly jet stream over the UK at first, so may promote some very short skip to polish off the inter-G squares.

    The forward side of the upper trough over the country, a southwesterly jet over the Low Countries and Denmark has provided some activity on 10m over the Baltic. This is also a region of rapidly falling contour values, which can improve the chances of making gravity waves.

    The other major trough over the eastern Mediterranean is also active this morning with some paths across Italy and the Adriatic where the northwesterly jet stream interacts with the Apennines and Balkan mountain ranges.

    There are many smaller features on the charts which could aid our Es efforts and the best actions may be to follow the regions where jet streams are accompanied by rapidly changing contour values within the blue and red lines.

    The Atlantic is producing a very strong jet stream pointing at the UK and paths across to the northwest and down across the northeastern States could benefit from this.

    73 de Jim
  12. Thursday 7th September 2017

    After yesterday's major solar flare and a K index of 4, things are looking fairly quiet on the bands this morning.

    There is some 10m activity centred over southern Sweden, which is where a small northwesterly flow around the cut off low over the Baltic states is probably being affected by the Norwegian mountains before reaching Sweden. The other 10m paths are associated with the southerly flow over western Russia ahead of the upper low.

    The strong Atlantic jet stream is now pushing into northwest Britain over the Highlands and further developments downrange over France will produce a strong northerly jet stream over the Pyrenees and Cantabrian Mountains. Both these regions could produce some activity if all the other ingredients allow, since the interaction of jet streams and mountain ranges is usually a very good option for Es in the high season, but at the tail end, maybe not such a good prospect.

    So in summary, paths to Scandinavia look worthwhile on 10m and perhaps 6m?, otherwise the next best option is south towards Spain or southeast to Italy and the Balkans. As a long shot, the Atlantic jet stream extends the full width of the ocean and may offer points along its length where multi hops can be supported.

    73 de Jim

  13. Friday 8th September 2017

    It seems that the only activity showing at the moment is due to the small upper trough over the central Mediterranean. This region is moving east, but it does have some areas of rapidly falling and rising contours within the red and blue lines. There are also areas of thunderstorms predicted and observed on the satellite images this morning. This means that there are good reasons to expect some strong gravity wave generation in this region and hence Es. So far the principle paths cross Italy and the Adriatic and will be out of reach from the UK as a first hop.

    The rest of the jet stream pattern is still dominated by the main polar front jet across the Atlantic and down into the trough over Britain, before turning back as a southwesterly over the near continent.

    I suppose the main focus within reach of UK is to the south across the fast jet stream blowing in across the Channel and northern France. This will be ideally placed for paths into southern France and Spain. It is also possible that later today paths to the southeast into eastern Europe will be able to use the southwesterly portion of the jet stream over the near continent.

    Obviously, the Atlantic remains in good shape with several regions of strong jet stream flow, any of which could contribute to paths across to the States.

    73 de Jim

  14. Saturday 9th September 2017

    The recent solar activity continues to play havoc with the ionosphere, but there have been some very nice auroras from 10m up to 2m, so plenty to distract us!

    The Es season is slowly winding down now and seems to struggle to get to 6m. So far this morning 10m has revealed some activity across central and eastern Europe. These appear to be across the strong southerly jet stream on the forward side of the upper trough over the North Sea. This is barely moving so should remain within the ideal radial ring distances through the rest of the day. The broad spread of this southerly jet stream gives options from northeast round through east to south.

    The other and probably strongest prospect is the very strong northwesterly jet stream over Ireland and moving down into Biscay and Spain. This could be beneficial for paths from the UK and hopefully may extend up to 6m later today.

    73 de Jim
  15. Sunday 10th September 2017

    The strength has returned to the Atlantic jet streams and this carries forward into Europe. This offers several good quality regions where the turbulence might develop gravity waves and hence Es, when these gravity waves propagate up to the E region and interact with the background winds/tides and long-lived meteor ions there. This gravity wave generation by the weather is particularly effective when the jet stream is strong (shaded yellow/orange) and when rapid changes in contour values on the jet stream maps occur. These regions are bounded by red and blue lines. Other potential generators of gravity waves, based on observations over the years, are upper air ridge patterns and thunderstorms (orange blobs), but these appear to be orders of magnitude less productive than jet stream generated turbulence.

    All of this allows an estimate to be made, from the upper air charts shown below, as to where Es are more likely. However, it is widely known that there is a seasonal component to this propagation mode. Many things may contribute to this;
    1) it may be due to diurnal and seasonal changes in the background solar radiation, since there is a solar peak around midday in the magnitude of the foEs.
    2) it may be due to seasonal changes in the background tidal winds in the E region, which give us the two operating 'windows' in the morning and evening.
    3) perhaps the upper winds in the stratosphere through which these gravity waves must propagate to reach the E region play a role, since they change over to become slack or weak easterly during the May to Aug main Es season. (they've now gone back to westerly)
    4) not an exhaustive list, since there are many other parameters involved like meteors and K index etc, which also probably have some impact

    So, although the charts may show plenty of strong jet stream activity, it is not necessarily a period of unbounded joy for Sporadic E, since whatever the main seasonal controls are, they do seem to be bringing an end to the season now. There can, of course be some Es outside the main season, but I feel its time to cease the blogs for this year, although I will continue to upload the maps. Thanks you for your company this year and hope you can return in 2018.

    I shall be making several changes to the way the data is presented over the next few months with some exciting new graphical formats which will generate automatic probabilities of the directions which are most favourable. This will make the information available earlier each day, which is always a good thing. As some of you may already be aware, the jet stream charts are also available on another website, and this will be where the new layout will be first developed. It also contains useful near real time graphs of foF2 and foEs data.

    73 de Jim
  16. Tuesday 12th September 2017

  17. Wednesday 13th September 2017

  18. Thursday 14th September 2017

  19. Friday 15th September 2017

  20. Saturday 16th September 2017


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