Model Output Discussion

[Milhouse]

I'm sure I'm an alternate reality compared to some...

The outlook is good with average temperatures and dry sunny weather for most, except in the east. Night temperatures can be ignored, sure they might be a little below average but not much.

I'm a little concerned that people think there will be a poor outlook based on the charts because this isn't true at all if you want typical British summery weather.

If you compare it to the past 3 summers it certainly wont be typical. There looks to be an awful lot of dry and pleasantly warm weather around for the next week, possibly 2. Comparing that to the endless unsettled conditions that have plagued much of the past 3 summers this month could turn out very nice indeed, despite us not heading for some proper summer heat as yet. Having said that i do like the look of 6z which shows the high sinking south back over us bringing higher temperatures to most parts for a while. I expect it to be a theme played out in future runs but as the 6z shows it brings with it something more unsettled.

http://www.wetterzentrale.de/pics/Rtavn1741.png

http://www.wetterzentrale.de/pics/Rtavn18017.png

[Frosty.]

I'm sure I'm an alternate reality compared to some...

The outlook is good with average temperatures and dry sunny weather for most, except in the east. Night temperatures can be ignored, sure they might be a little below average but not much.

I'm a little concerned that people think there will be a poor outlook based on the charts because this isn't true at all if you want typical British summery weather.

Not sure what you are on about really, are you in a parallel universe?

[BlueHedgehog074]

Quick summary for today:

Quite an active day ahead according to the GFS and Met Office outlook with a chance for storms and showers for England/Wales as a small low from the North sinks southwards:

Eastern areas probably will not see much in the way of showery activity until the late-afternoon and evening, with Steep Lapse rates and CAPE potential transferring South-Eastwards and should help to bubble up convective showers here:

Also:

- showing coolish Dewpoints for areas along with high humidity contributing to the Lapse rates. The unstalibilty in the air not too strong, but could still see some good convection occuring, nevertheless.

As such, I think storms and showers that do make it to (and/or develop) the East/North-East could deliver some heavy downpours; the MLCIN (j/kg) peaking to high levels in Eastern parts. Add to the arrival of the small Low, plus the clash in the wind directions here:

- (another contributing factor which should help with the development of storms/showers), we could see quite an active evening and night for Eastern parts.

No doubt with the high CAPE levels in Western areas, before hand, we could still see some heavy showers and spells of rain, perhaps with the odd rumble of thunder. The Met Office outlook certainly show some great potential for a broad area of England and Wales, with heavy showers from the North-West spreading South-Eastwards.

On the whole, a showery day for England and Wales, especially from the afternoon, onwards, with the weather generally cloudy to the North, but drier.

Edited June 13, 2010 by Rainbow Snow

[Eugene]

A cooler week ahead for central and southeastern parts than last week which felt very muggy indeed on some days esp tuesday and wednesday, very pleasant in any sunshine but chilly under any cloud and early in the morning/late at night, definately the risk of ground frost in sheltered western and northwestern areas away from that chilly northeasterly breeze, in the east less risk of a ground frost due to cloud and a northeasterly wind but it will feel chilly here too, some much lower dewpoints in the coming week than last week with them down to mid single figures in central, western, northwestern parts.

http://www.wetterzentrale.de/pics/MT8_London_ens.png

[damianslaw]

Mid atlantic ridge staying in situ for the foreseeable future, tenatively ridging north eastwards on occasion to bring slightly above average temps and plenty of dry sunny weather, but the upper trough will plague the country dropping south east over the country bringing cooler northerly airstreams - this is a pattern that could easily dominate the rest of the summer, it would bring neither a washout or a heatwave, just very average conditions..., however, under such a set up which are always prone to a more sustained unsettled cyclonic spell as those heights retrogress far enough north westwards, with slow moving low pressure taking up residence, conversely, however, under such a set up we are always equally not that far off a more sustained very warm spell, if those heights ever ridge far enough north and east - its a fine balance, making for rather interesting weather watching, much better than the atlantic steam roller, which thankfully seems to be in permanent hibernation at the moment and long may it continue to do so.

Edited June 13, 2010 by damianslaw

[lukemc]

Hi,

Talking of this so-called "mid atlantic ridge" pattern does anyone have any examples of where it was dominant in previous summers? Was it dominant in the summer of 1993 which was considered to be as dry but cool summer for most? I have also read comparisons to 1988 in particular June was it the dominant pattern that month as it was mainy a dry and sunny month but not much in terms of above average temperatures? Also I have noticed looking at the WZ archives that the major heatwave in 1990 started out with HP to the west was that the case? Would show that this set up can deliver hotter than average tempertures if the HP is in the right position.

Luke

[pyrotech]

The big signal to me is the difference in the last few years and this one with the Jet stream. This year its much less potent and more fragmented at times and keeps trying to move North of the UK.

Not a signal of a heatwave all summer , but potential for a more seasonal normal summer here in the UK.

Rainfall has already been low in last 3 months for some parts of UK and can see this pattern continuing with hose pipe bans in some areas.

GFS has been pretty good in medium term so far and Fi ( 7days +) has as always been very mixed. GFS seems pretty acurate till about 7 days max then it picks and mixes each run.

[William of Walworth]

Is my current fear of the High retrogressing westwards around next weekend onwards overly pessimistric and irrational, chaps?

Summer lovers and rain averse types like me could certainly do far worse than have a cool Northerly dominated pattern, and I'm happy with the talk of a very inactive Jet.

My big fear though, and the fear of all Glastonbury goers for the week starting 21st June, is that the High will not end up close enough to the UK to allow continued dry settled weather over the last full week of June.

Most of us would be relaxed about relatively cool June temps so long as dryness persists, but right now I'm far from confident of a 2 week rather than 1 week settled spell upcoming.

Reassurance??

[SP1986]

Reassurance, the GFS and ECM in the realistic timeframe show a settled, sunny and warm picture away from northeastern coasts. The models that we usually ignore are the ones with the northerly and unsavoury weather.

Personally the UKMO is way out and hasn't performed particularly well of late, I'd say the GFS/ECM is the most likely pattern to emerge.

FI being post 168 can also be pretty much ignored.

[William of Walworth]

Thankyou, I'm very finely balanced between optimism and pessimism right now, and I agree there are still some very reasonable signals for the week after next. As you suggest, UKMO may well be overdoing the retrogression, but at this exact time of year I'm rather prone to panicking.

I should wait for JACKONE's next wise words tomorrow.

[Thundery wintry showers]

The outlook in the near term looks dry and sunny for most with near-average days and cool nights- not unusual for a summer anticyclonic/northerly type. In general I don't think Arctic airmasses tend to bring as much cloud over the North Sea as the more stable, modified continental airmasses from the NE. Again, as on many previous runs, cloud is perhaps most likely to be an issue over SE Scotland and NE England, rather than the southeast of the country.

[mushymanrob]

the cool outlook continues this morning, after an improvement this week some sort of northerly is depicted in every run at some stage later on. no sign of any heat, or any proper rain, in these runs.

[BornFromTheVoid]

ECM looking quite chilly for the UK. Northerly airstream by T96 and by T144, sub zero 850s across most of the country. That must be fairly unusual for mid June, no?

Ireland, being closer to the high, manages to keep the warmer uppers (5C and above) within the reliable timeframe, so it should remain warm and generally sunny here.

[Frosty.]

Still a few residual heavy showers around today but nothing like the deluges of yesterday and this week will then become fine with increasing amounts of sunshine and becoming warmer once again into the 70's F for most inland areas but some northeastern coasts will become cooler with some misty low cloud developing as winds become NE'ly. High Pressure should last all week and maybe even into next week too but as time goes on we could see another trough dropping into scandinavia and our high pulling out further into the atlantic which would open the door to cooler and more unsettled weather as the GFS 00z shows in FI.

[Glacier Point]

Longer term, the developing issue looks like being low pressure over mainland Europe leading to some fairly big rainfall totals in the next few weeks. All of this very consistent with the Pacific flow and Atlantic Tripole.

GFS Ensemble mean height anomaly days 10-15:

http://raleighwx.easternuswx.com/models/gfsensemble/00zENS11-15day500mbHeightAnomalyNH.gif

This is very much in tune with where the Global Wind Oscillation and Madden Julien Oscillation are heading over the next 2 weeks - that is stalled somewhat in the low angular momentum (Nina) base state. Hence the notable ridge in the North Pacific and North Atlantic.

[SP1986]

Quite a substantial turnaround in the mid term by the 6z moving in line with the ECM which also showed a sudden change, these signals cannot be ignored. The cool-cold northerly is being shown and this at the timeframe it's being shown is a dead cert now. Not the greatest outlook from being quite a decent outlook only earlier this morning.

The UKMO has really shown how poor it is of recent by reverting back to what the GFS/ECM were showing yesterday, which really does highlight how exceptionally poor the UKMO has been of late as a model.

So the mid-outlook now looking pretty dire for many with cold winds, cool-cold and generally unsettled with showers, some of which may well turn to snow over the highest of northern hills. However before then some pleasant weather for a few days.

[The Northern Ramper]

How far south will these winds penetrate?

[Jezzer]

That latest run is not good for my mood, from positive this morning to glum this afternoon.

Just hoping they bring more positive news later in the week, could really do with the High sticking around rather than retreating to the west

Edited June 14, 2010 by Jezzer

[Thundery wintry showers]

If this northerly does come off, then it's a case of "well done to the ECMWF" as the ECM has regularly shown a northerly at around that timeframe in recent runs, in contrast to UKMO and GFS which built high pressure over.

My general rule of thumb for summer northerlies is that if the airmass source is west of due north and pressure is low, it will probably be bright and showery, but if the source is east of due north it will probably be cloudy and mainly dry. High pressure in close attendance tends to promote dry sunny cool conditions in that setup.

At the moment, looking at those outputs, the showery scenario looks unlikely with the lack of a pronounced low over Scandinavia, so it's a question of how cloudy it gets in the east.

[reef]

Closing this one as its getting a bit long.

New thread here:

http://forum.netweather.tv/topic/62939-model-output-discussion/

Thanks :lol: