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Model output discussion - into July 2020


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For those that discount the impact of tropical systems on forecast models - check this loop out for Friday out.

Ex Fay has been added to the mixing bowl, and as Ant Masiello states, watch how the Icelandic low depth and position keeps changing as the model changes how it resolves the impact of Fay. As it happens, the forecast from today actually has it deepest, which is in part why the weekend forecast has been toned down a notch.

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...Like shoals of fish they are starting to point the other way in midstream...👸 Recent NWP, up to the start of this week, had seemed suspicious the way it had reverted to extrapolating the defaul

Self evidently this is yet more nonsense excessive hyperbole. Ultimately, and it seems ridiculous to have to keep mentioning it on the basis of the weather to come in the days ahead for many -  t

It gets a bit of a "boys own" scrum on here. Computer models being assessed like they are competing engines being road tested for performance.  Temperatures being frantically compared from one compute

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48 minutes ago, mb018538 said:

For those that discount the impact of tropical systems on forecast models - check this loop out for Friday out.

Ex Fay has been added to the mixing bowl, and as Ant Masiello states, watch how the Icelandic low depth and position keeps changing as the model changes how it resolves the impact of Fay. As it happens, the forecast from today actually has it deepest, which is in part why the weekend forecast has been toned down a notch.

ECMWF is pretty disappointing for the next 10 days. Ex Fay added to the Icelandic low will lead to unsettled conditions this weekend. image.thumb.png.4f8ca11c1805bacf858466f0f7942be9.pngimage.thumb.png.7e0295b7f41343e6bbef2259a9e3d7f7.png

Driest and warmest in the south

Thursday and Friday should be dry and warm in most of the UK with the risk of rain becoming restricted to the north west. Temperatures in many areas will be over 21C (70F) and in the south 28C (82F) could be reached. 

Through the weekend cloud and patchy outbreaks of rain steadily push southeastwards. Cooler and showery conditions follow into northern areas but there is uncertainty about the timing. 

Early next week week it should be generally dry and settled weather as high pressure builds from the southwest again. Later on the the risk of showery rain increases. Plenty of Rain to look forward to on Saturday. 

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Edited by NApplewhite
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I give up on this summer! I'm off to Rhodes for a week of blue skies and hot sunshine in August!  June and July has been dire and August looking no better! image.thumb.png.4e5362776007fc89427b366f9c67774e.pngLook at the position of the high - cool NW winds off the Atlantic according to the CFS model.  September looking average at best. image.thumb.png.456e986be78e15d0917df674f0a54013.pngimage.thumb.png.3ef170987a46164270d0d68b78879b69.pngimage.thumb.png.c3435db9ff89a536f35bf8d562b13905.png November looks very wet and windy. 

Edited by NApplewhite
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Pressure looks OK until day 8, when a clear downward trend starts to emerge. Too early to say if this a dip into a more widely unsettled spell, or just a temporary blip. The Met OFfice update over recent days - today included - is this:

'Towards the end of the period (around 27th July), more settled conditions are likely to develop, across many parts. Spells of wetter and windier weather are possible across northern and western areas at times'

Tuesday 28 Jul - Tuesday 11 Aug - Although confidence remains low throughout this period it is likely that settled conditions will persist across many areas towards the end of July.

Clearly favouring more settled weather, though i'm not entirely convinced just yet looking at the output. That said - The ECM AAM forecast is finally expected to pick up from very low levels towards the end of the month. The models could perhaps respond to this in the coming days and start showing a better solution for the UK. 

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3 minutes ago, mb018538 said:

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Pressure looks OK until day 8, when a clear downward trend starts to emerge. Too early to say if this a dip into a more widely unsettled spell, or just a temporary blip. The Met OFfice update over recent days - today included - is this:

'Towards the end of the period (around 27th July), more settled conditions are likely to develop, across many parts. Spells of wetter and windier weather are possible across northern and western areas at times'

Tuesday 28 Jul - Tuesday 11 Aug - Although confidence remains low throughout this period it is likely that settled conditions will persist across many areas towards the end of July.

Clearly favouring more settled weather, though i'm not entirely convinced just yet looking at the output. That said - The ECM AAM forecast is finally expected to pick up from very low levels towards the end of the month. The models could perhaps respond to this in the coming days and start showing a better solution for the UK. 

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Yes, that's my reading too, mb. I have just checked the raw data from GFS for the week ahead too – and that looks pretty darned decent away from the NW. Sometimes this forum can appear misleading but I think much of it is that members read the models (quite understandably) with their location in mind. The NW/SE split is a common animal but can cause much consternation and confusion! 

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1 minute ago, Downpour said:

Yes, that's my reading too, mb. I have just checked the raw data from GFS for the week ahead too – and that looks pretty darned decent away from the NW. Sometimes this forum can appear misleading but I think much of it is that members read the models (quite understandably) with their location in mind. The NW/SE split is a common animal but can cause much consternation and confusion! 

It may feel decent if the sun is out but statistically it is poor. Leeds is not that far north in this regard and it seems London is on its own with regards to any 'decent' July weather.

Regarding the model output the next question to be resolved with regards to Atlantic strength are two lows which exit Newfoundland at days 5-8. Euro has these weaker and thus gets a bit more of a amplification while the GFS has these stronger.

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2 minutes ago, summer blizzard said:

 Leeds is not that far north in this regard

 

 

 

I thought Leeds was up near the Arctic Circle if I was honest 🤣

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30 minutes ago, Alderc said:

I thought Leeds was up near the Arctic Circle if I was honest 🤣

Very different climate to London certainly – not the Arctic Circle but not far off!! 

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1 hour ago, mb018538 said:

For those that discount the impact of tropical systems on forecast models - check this loop out for Friday out.

Ex Fay has been added to the mixing bowl, and as Ant Masiello states, watch how the Icelandic low depth and position keeps changing as the model changes how it resolves the impact of Fay. As it happens, the forecast from today actually has it deepest, which is in part why the weekend forecast has been toned down a notch.

You would think these ex hurricanes coming into the mix would produce beneficial outcomes occasionally. All weather being chaotic to some extent, you’d think it would possibly sweep away poor weather just once in a while. Always seems to result in the toning down of a better outcome.

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1 hour ago, Northwest NI said:

You would think these ex hurricanes coming into the mix would produce beneficial outcomes occasionally. All weather being chaotic to some extent, you’d think it would possibly sweep away poor weather just once in a while. Always seems to result in the toning down of a better outcome.

Talking of Tropical systems, while what remains of what was once Tropical Storm Cristina is now in the Central Pacific, meteorologists are monitoring a new tropical depression in the East Pacific this week.

A broad area of low pressure moving off the southern coast of Mexico over the warm waters of the East Pacific Ocean developed into Tropical Depression Six-E on Monday afternoon with maximum sustained winds of 35 mph.

While this depression is expected to become more organized through the beginning of the week, there is one thing that will keep it from rapidly strengthening.

- this system is expected to encounter vertical wind shear, or the change in direction and speed of wind at increasing heights in the atmosphere. As a result, depression may be slow to gain strength over the next couple of days as the system moves away from any major landmass.

If the system continues to strengthen, it could become a named tropical storm by midweek.

The next system to reach tropical storm status, which is a system with maximum sustained winds of at least 39 mph, in the East Pacific Basin would be given the name Douglas. 

Meanwhile, what remains of former Tropical Storm Cristina continues to spin farther west and has moved into the Central Pacific Basin.

Cristina weakened as it moved over cooler waters late Sunday night and was designated as a post-tropical cyclone, or remnant low, by the National Hurricane Center. Cristina initially formed late last Monday night.

Cristina became a strong tropical storm with sustained winds of 70 mph last Thursday through Friday

What remains of Cristina will not pose a direct threat to any land, but forecasters will continue to monitor the potential for impacts to the Hawaiian Islands late this week. I'm wondering what the science is around this type of tropical activity in the East Pacific on the jet stream (there is a heat dome developing over the Mid - West, Western United States) driving the Jetstream over Canada. Could this exit over the North Atlantic and increase the power of the jetstream over the next week or two? I'm interested to find out the meteorologists/scientific perspective and the impact on UK weather conditions downstream. image.thumb.png.be5910ee947a425de7303b83db36e135.pngimage.thumb.png.610949e4dcb9895694197ff5cc8d4305.pngimage.thumb.png.f7cf8af996cefe9823b6e5b28efcf823.pngimage.thumb.png.919fe9ce27628debe70aa6f2d4c3be50.png I've attached the latest 700 HPA wind forecasts and a snapshot of the 850s. image.thumb.png.ede8bb7042d45a65d8e1c6ea3663f93c.pngimage.thumb.png.ad384726fc7fcb60aa8a10693c23218a.pngimage.thumb.png.a87724a49b5aafd01e4a28fd947304ab.pngimage.thumb.png.ad614919456bcb835adb1ec3240b6e1f.pngimage.thumb.png.d34f1e9dc84c1bd4be6cca0186f62e27.pngimage.thumb.png.b3870d9886ba3074cc92a9167ba82d26.pngimage.thumb.png.f41d662fc0fd6b72b32a6adb9337f3e5.pngimage.thumb.png.434f738c4b2382e69218856e6b95cf68.pngimage.thumb.png.b4d0ea2d32747a346a2dbe69ca785b0e.png

 

 

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7 minutes ago, NApplewhite said:

Talking of Tropical systems, while what remains of what was once Tropical Storm Cristina is now in the Central Pacific, meteorologists are monitoring a new tropical depression in the East Pacific this week.

A broad area of low pressure moving off the southern coast of Mexico over the warm waters of the East Pacific Ocean developed into Tropical Depression Six-E on Monday afternoon with maximum sustained winds of 35 mph.

While this depression is expected to become more organized through the beginning of the week, there is one thing that will keep it from rapidly strengthening.

- this system is expected to encounter vertical wind shear, or the change in direction and speed of wind at increasing heights in the atmosphere. As a result, depression may be slow to gain strength over the next couple of days as the system moves away from any major landmass.

If the system continues to strengthen, it could become a named tropical storm by midweek.

The next system to reach tropical storm status, which is a system with maximum sustained winds of at least 39 mph, in the East Pacific Basin would be given the name Douglas. 

Meanwhile, what remains of former Tropical Storm Cristina continues to spin farther west and has moved into the Central Pacific Basin.

Cristina weakened as it moved over cooler waters late Sunday night and was designated as a post-tropical cyclone, or remnant low, by the National Hurricane Center. Cristina initially formed late last Monday night.

Cristina became a strong tropical storm with sustained winds of 70 mph last Thursday through Friday

What remains of Cristina will not pose a direct threat to any land, but forecasters will continue to monitor the potential for impacts to the Hawaiian Islands late this week. I'm wondering what the science is around this type of tropical activity in the East Pacific on the jet stream (there is a heat dome developing over the Mid - West, Western United States) driving the Jetstream over Canada. Could this exit over the North Atlantic and increase the power of the jetstream over the next week or two? I'm interested to find out the meteorologists/scientific perspective and the impact on UK weather conditions downstream. image.thumb.png.be5910ee947a425de7303b83db36e135.pngimage.thumb.png.610949e4dcb9895694197ff5cc8d4305.pngimage.thumb.png.f7cf8af996cefe9823b6e5b28efcf823.pngimage.thumb.png.919fe9ce27628debe70aa6f2d4c3be50.png I've attached the latest 700 HPA wind forecasts and a snapshot of the 850s. image.thumb.png.ede8bb7042d45a65d8e1c6ea3663f93c.pngimage.thumb.png.ad384726fc7fcb60aa8a10693c23218a.pngimage.thumb.png.a87724a49b5aafd01e4a28fd947304ab.pngimage.thumb.png.ad614919456bcb835adb1ec3240b6e1f.pngimage.thumb.png.d34f1e9dc84c1bd4be6cca0186f62e27.pngimage.thumb.png.b3870d9886ba3074cc92a9167ba82d26.pngimage.thumb.png.f41d662fc0fd6b72b32a6adb9337f3e5.pngimage.thumb.png.434f738c4b2382e69218856e6b95cf68.pngimage.thumb.png.b4d0ea2d32747a346a2dbe69ca785b0e.png

 

 

Lovely low pressure over the UK at +300 according to GFS!! 

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1 hour ago, Northwest NI said:

You would think these ex hurricanes coming into the mix would produce beneficial outcomes occasionally. All weather being chaotic to some extent, you’d think it would possibly sweep away poor weather just once in a while. Always seems to result in the toning down of a better outcome.

Weren't Hurricane Irene and Katia in 2011 thought to have had influence in our unusually hot September that year?  Was a long time ago so forgive me if I am under the wrong impression.

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GFS ensembles much the same as the ECM this morning - a slight trend to lowering pressure towards the latter stages of next week. Too far away to be certain yet.

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Next week looks good across most of England and Wales on the EC46, plenty of fine conditions on offer. Towards next weekend conditions trend a tad more unsettled with Low pressure to the North having more influence... Worth noting again, the flow is mainly Wstly so never overly warm, but respectable in a any sunnier moments as you would expect at this time of the year. Beyond that we keep with this general ebb and flow of the Azores High through August, with the best of the conditions always further South, with more of a risk of unsettled conditions at times towards the NW. This signal persists on the EC46 for some time now... The flow never hot or building a strong ridge in a favourable position to promote very warm or Hot conditions in. At this stage August appears to be on a similar level to July with periods of settled warmer conditions mixed with alternating cooler less settled conditions... Again always best the further South one is. Typical Summertime affair really. But as it stands the EC46 remains stubborn in its overall trends moving forward... 

But much better next week looks a good call at present. 

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Now this would be something for the south if it verified 🙈

12_348_2mtmpmax.thumb.png.f355ae0f0420f5ef8103e4da68041e12.png   gens-12-1-312.thumb.png.541001ae6cac0719e246b4bf8e2d645e.png   gens-12-0-336.thumb.png.c21c49c546bff3122b52a311c6d8b538.png

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27 minutes ago, Zak M said:

Now this would be something if it verified 🙈

12_348_2mtmpmax.thumb.png.f355ae0f0420f5ef8103e4da68041e12.png   gens-12-1-312.thumb.png.541001ae6cac0719e246b4bf8e2d645e.png   gens-12-0-336.thumb.png.c21c49c546bff3122b52a311c6d8b538.png

That’s what Scottish Meteorological Independence looks like lol. 

A similar thing happened in 2005.

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3 hours ago, Northwest NI said:

You would think these ex hurricanes coming into the mix would produce beneficial outcomes occasionally. All weather being chaotic to some extent, you’d think it would possibly sweep away poor weather just once in a while. Always seems to result in the toning down of a better outcome.

A toning down as you describe it is, I would venture to say, because the input of quite enormous amounts of energy and moisture have a big impact on all the models short or long range because so far modellers have yet to work out how to deal with these elements. Thus the weather is almost always fairly mobile as a result leading to less settled weather?

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2 hours ago, NApplewhite said:

Lovely low pressure over the UK at +300 according to GFS!! 

Is it necessary to repeat the whole of the previous post, why not give the number of the post then your very short comment?

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2 hours ago, mb018538 said:

image.thumb.png.da5e900e72895a94f2df7ebf74644149.png

GFS ensembles much the same as the ECM this morning - a slight trend to lowering pressure towards the latter stages of next week. Too far away to be certain yet.

EPS goes fully to town soon after d10. Very westerly.

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Lets remember when posting images of high pressure nosing in from the south west its doesn't always turn out great.....

Today 15Z 500mb chart with the 15.55 Radar. Model output is showing further opportunities for repeats such as this....

 

GFSOPEU06_9_1Ugh.png

1555 1407.PNG

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2 minutes ago, Alderc said:

Lets remember when posting images of high pressure nosing in from the south west its doesn't always turn out great.....

Today 15Z 500mb chart with the 15.55 Radar. Model output is showing further opportunities for repeats such as this....

 

GFSOPEU06_9_1Ugh.png

1555 1407.PNG

Surprised how warm it is here. Just been out to the postbox expecting a chill but it's rather warm. Sun now popping in and out. Pleasant. 

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