Forecasting With Gfs, Or Anything Else!

[johnholmes]

hi folks

Now here is something for all of us to have a go at!

Using ONLY the 12Z GFS output each day give your general summary for 1 week, then 2 weeks ahead; just a general idea, windy, wet, warm, hot, cold etc.

Just to set you going here is my attempt out to T+384(16 days)

After the start of next week, never very warm, and occasionally cool, rain at times for most, with winds from north of west, not south!

There you are. if its seems popular we could perhaps have a forecast for a specific time for a specific place.

cheers

John

Edited July 15, 2005 by johnholmes

[J10]

My Go,

Next week looks fairly unsettled especially in Northern Areas, with High Pressure never too far away from the SW. Winds fairly light in the South, but possibly quite windy in the North of Scotland at times, the wind direction normally from the NW.

Rain is possible in NW areas on many days but most of the rain seems to be showery. A more general band of rain seems likely to push across the UK early next week, but after this it looks as if it will be mainly dry in the S, especially in the SE.

Temperatures Around Average for the North, turning warm in the South, especially the south East, but never getting very warm.

There are hints of High Pressure nudging in from the West for next weekend, after this there are hints for the weather to turn unsettled and fairly cool but confidence is very low at the moment.

[pottyprof]

hi john.. great idea!!

im up for this.. FI is very complex and might explain my gripes.. the 0c isotherm is quite low.. ill get back with my thoughts tomorrow.. nice one!! <_<

potty

[Rollo]

Great idea John,this should become popular. It looks to me as though (for the moment) summer is about to leave us and we will go into a much more zonal westerly type with the odd day of northerly winds,some quite windy days in the North can be expected and as usual the best and warmest weather will be the further south one goes. More rainfall generally but not enough for the south where it is needed the most , I would expect this unsettled spell to last into early August.

Edited July 16, 2005 by Rollo

[Candice]

Well, let's have a go. Remaining hot to very hot in the far South and East through to Monday night. The north and west having a bit of a wet and windy spell tho. Then definitely more zonal through Tuesday to Friday. Warming up a tad after that and then hot hot hot in the south but cooler and wetter in the North, towards the end of the period. Thunderstorms in the South/East on Monday pm. Never "cold" as such but cooler than of late and much less humid in the south overall.

Probably a total load of c**p but had a try anyway.

[johnholmes]

hi folks

Thanks to those who have already 'had a go'. Hope fully more will join in. It could do two things.

1) Make people more away of how good GFS is, and also problems it has after about T+120.

2) Increase the understanding all of us have as we share comments about GFS.

My time with GFS is well documented at checks with GFS to T+168. Its showing signs, no more than that, at the moment, of getting more accurate beyond the T+120 mark.

One thing I thought of trying, but I need to wait for Paul to come back, is to have a forecast for, let's say T+168 hours, or beyond, for a particular spot in the UK? Somewhere with accurate weather observations to use as a check. Might be Edinboro', or Belfast, London etc??

regards

John

[Candice]

hi folks

Thanks to those who have already 'had a go'. Hope fully more will join in. It could do two things.

1) Make people more away of how good GFS is, and also problems it has after about T+120.

2) Increase the understanding all of us have as we share comments about GFS.

My time with GFS is well documented at checks with GFS to T+168. Its showing signs, no more than that, at the moment, of getting more accurate beyond the T+120 mark.

One thing I thought of trying, but I need to wait for Paul to come back, is to have a forecast for, let's say T+168 hours, or beyond, for a particular spot in the UK? Somewhere with accurate weather observations to use as a check. Might be Edinboro', or Belfast, London etc??

regards

John

<{POST_SNAPBACK}>

Good idea, I suggested something similar to Paul via the "new ideas" thread

[Adi F]

Next week the north will be under the influence of a low bringing unsettled weather and reduced temperatures and wide spread cloud with periods of rain can be expected. In the south we can expect to see more cloud and some showers but temperatures should stay around average.

The weekend and beyond we seem to be under the influence of a short wave trough bringing slightly cooler temperatures a rain to the whole country.

[Polar Continental]

Ok, so here is my effort, sorry about the length, got a bit carried away. <_<

Sunday July 17th 2005, 14 day forecast. Using GFS 12z

Monday 18th + 24h

The break down begins from fine hot weather we’ve enjoyed over the weekend.

An area of low pressure will move east over Northern Ireland and Scotland bringing cooler weather with a few showers, which may get as far south as northern England and possibly the Midlands by Tuesday 19th. Areas from the midlands south should remain dry, with a little sunshine, though more wind and cooler than of late.

Temperatures in the range 17c in the north to 21c to 23c in the South east, winds moderate, though fresh north westerly in the north.

Wednesday 20th 66h +

The Azores high looks extending its influence in to Ireland and the far southwest of England, so dry with some warm sunshine here. England and Wales will be mostly dry with some sunny spells, possibly a few light showers. The low will gradually move north east towards Scandinavia, but Scotland will still be close enough to affected by cooler and showery north to north west winds. Temps an range of 17 in the north, 21c to 22c over the Midlands and 23c-24 over the southwest and southeast.

Thursday 21st 84h+

The high to the southwest will move northeast to be centred over Southern Ireland, so Ireland, Wales and most England will be dry with warm sunshine, only the far east of Scotland and England will be cooler with cloud and a few showers.

Friday 22nd, Saturday 23rd 108h +

The main high pressure cell looks like being sucked up towards Iceland and Greenland, but pressure looks like staying fairly high over the UK around 1015 to 1030 mb. So conditions should remain fair and dry with sunshine and little wind, temperatures in the range 20c to 21c over Northern Ireland and Scotland to 23c or 24c over the south of England.

Sunday 24th- Tuesday 26th 156h +

Moving in to FI, the charts suggest most of the UK will be in something of a col, so winds will be slack over most areas. Fair conditions should prevail, with possibly some showers in the afternoons, temps in the range 21c to 22c over Ireland and Scotland, warmer over England and Wales, 23c to 24c. Pressure around 1010mb to 1015mb during this period.

Wednesday 27th – Sunday 31st July +228h - +324h.

Well in to FI, Another area of low pressure takes an almost identical path as Monday 18th July. So showery and average temperatures for a time over most areas. Saturday 30th looks to be settled with warm sunshine as a ridge of high pressure extend from the Azores through to Norwegian Sea.

Regards

Paul

[summer blizzard]

Here is my attempt.

This weekend will be cool and cloudy for most parts however it will be wet in the east, main wind direction will be northerly and temperatures will range from 15C in the north and 23C in the south.

Next week will be dry for most parts due to the Azores High ridging in from the south west however the north of Scotland will be mostly cloudy and will turn wet towards the end of the week, main wind direction will be north westerly and temperatures will range from 20C in the north and 30C in the south.

The following weekend will see high pressure move over the British Isles and most places will be dry and sunny with temperatures ranging from 22C in the north and 32C, the wind direction will be variable.

The following week will again be dry and mostly sunny however it will be fairly cool with temperatures ranging from 15C to 25C due to the Greenland High absorbing the Azores ridge, main wind direction will be northerly.

All in all, it looks as though summer is returning for August.

Edited July 29, 2005 by summer blizzard

[summer blizzard]

Here is my next attempt.

This weekend will be cool and cloudy for most parts however it will be wet in the east, main wind direction will be northerly and temperatures will range from 12C in the north and 22C in the south.

Next week will be dry for most parts due to the Azores High ridging in from the south west however the north of Scotland will be mostly cloudy and will turn wet towards the end of the week, main wind direction will be north westerly and temperatures will range from 14C in the north and 24C in the south.

The following weekend will be unsettled with the winds changing from westerly on saturday to northerly on sunday, temperatures will range from 16C to 22C.

The following week will be mostly dry with sunny spells however it will become unsettled towards the end of the week, rather cool with temperatures ranging from 13C in the north to 23C in the south, main wind direction will be north westerly.

All in all, it will be mostly dry but rather cool, no heatwave in the forseable future.

[chilly milly]

Well nice to see the Azores high trying to ridge in next week, however from next Sunday it looks like the whole event backtracks due to the low pressure encroaching down the ne.

Looks like we will be lucky to hit 20C next weekend.

[summer blizzard]

Yep, at least if we are in a cool meridonal pattern then the Greenland High is there which will encourage cold pooling.

[summer blizzard]

Here is my next attempt.

Next week will be dry for most parts due to the Azores High ridging in from the south west however it will turn wet towards the end of the week, main wind direction will be north westerly and temperatures will range from 14C in the north and 24C in the south.

The following weekend will be fairly unsettled however it will remain dry in the south, the main wind direction will again be north westerly, temperatures will range from 12C to 22C.

The following week will start unsettled however it will become dryer towards the end of the week, temperatures will range from 12C in the north to 22C in the south, main wind direction will be northerly.

The following weekend will be warm, dry and sunny with high pressure centred over the British Isles, main wind direction will be variable and temperatures will range from 24C in the south to 14C in the north.

All in all, it will be mostly dry but rather cool, no heatwave in the forseable future.