Model Output Discussion

[BlueHedgehog074]

Finally read through a lot of bickering posts to find someones view on the GFS 12z without success!!!

Anyway, the gfs 12z shows pressure building to the southeast of the BI after the unsettled blip tomorrow, southern & eastern england should be largely fine and warm for most of next week with southeast england probably sunniest but by contrast, it looks much cloudier in the north and west and a depression out in the atlantic looks like slowly taking control during the second half of next week with cooler and more cyclonic conditions and even the chance of a N'ly in early may with a risk of snow on northern hills, wintry weather keeps fighting back, hopefully during may we will have a widespread warm settled spell eventually.

From the latest model output a Northerly looks like a strong possibility, and is shown on the ECM tonight too, and would deliver wintry showers to the North of the country, with sufficient heights building around Greenland. Would be a shock after this week coming

http://www.wetterzen...n/fsecmeur.html

In the near future, I suspect a few places in the south will reach 20C tomorrow, and the warmer settled theme will continue for a while in the South East, but by mid-week in the North West it will turn cooler and more unsettled, and these conditions will head Eastwards and affect the whole country by next weekend, with temperatures returning to average for most areas.

Agreed. I would say that while the temperatures the GFS are predicting are a little cooler compared to some of the updates a few days ago, 20*C I think could be achieved in some South and Eastern spots. This probably most likely in the afternoon, with some good sunny spells spilling in from the South-West. Certainly still a quite a warm week to come, though.

Some convective potential for tommorrow afternoon, with possible thundery showers for places, and this is helped by the highish levels of CAPE with some Western areas, in my view, seeing the stormiest of the weather with CAPE levels peaking to 700 k/jg. However, the Deep Layer Sheer, looks to be shallow, so the showers probably won't be too strong, but the South-Westerly winds should still help to bring any showers a good distance inland. (I think with the wind coming from more of a Southerly source would probably help to bring in more warm and unstable air from the South).

The UK Met Office also show chances for some showers/thundery rain for places tommorrow, with sunny periods mixed in.

[Thundery wintry showers]

Still pretty high convective potential for tomorrow, but as others have indicated in the convective discussion, probably more the sunshine and showers variety with scattered thunderstorms rather than widespread electrical activity. There will be more showers about on Monday despite high pressure close by, especially in East Anglia according to the GFS precipitation outputs which are normally quite good at 2 days out.

Looking at the further outlook I see low pressure taking charge over the UK as we approach the Bank Holiday weekend. There is considerable disagreement on temperatures, because GFS keeps us in a cyclonic westerly/south-westerly type, albeit probably showery rather than dull and wet for most of the country. In contrast ECMWF continues to go for a northerly but I agree that snowfall looks like it would be limited because the northerly doesn't sustain long enough.

[Eugene]

LOL, arguments over frost in April i see, ummm well i've recorded air frosts and temps just above 0C this past week the countryside i'm sure even colder, i recorded 0C on my car thermometer early yesterday morning before parking and going for a long distance walk and once the sun comes up there are LOADS of insects flying around so the myth frosts kills insects is nonsense and frosts in April nature has got used to them, it seems like it's only a certain one poster who hasn't

Cool to cold mornings warming up quickly when the sun gets to work are one of the best things about spring, much worse is mild nights turning to very mild cloudy days with hardly any temperature difference abit like early the coming week.

Edited April 25, 2010 by Eugene

[Derp Patrol]

LOL, arguments over frost in April i see, ummm well i've recorded air frosts and temps just above 0C this past week the countryside i'm sure even colder, i recorded 0C on my car thermometer early yesterday morning before parking and going for a long distance walk and once the sun comes up there are LOADS of insects flying around so the myth frosts kills insects is nonsense and frosts in April nature has got used to them, it seems like it's only a certain one poster who hasn't

Cool to cold mornings warming up quickly when the sun gets to work are one of the best things about spring, much worse is mild nights turning to very mild cloudy days with hardly any temperature difference abit like early the coming week.

Not everywhere.. we are predicted lows of 8-10C and maxes of 19-23C.. about a 10C change!

[The PIT]

Well away from Scotland and Ireland this week should be fairly settled until later on this week once we got today's showers out of the way. FI shows another Northerly outbreak being possible briefly.

[mushymanrob]

there are LOADS of insects flying around so the myth frosts kills insects is nonsense

so why are there no insects around in winter? :lol:

looking more unsettled in the near future before some kind of northerly manifests next weekend. the 00z gfs is a plausable evolution as it seems to 'run smooth', whilst the ecm has a far more potent northerly/northeasterly. although the general flow in fi is from the northeastern quadrant the uppers on the 00z are only breifly low so id expect 'normal' early may weather...

[Milhouse]

Still fairly strong agreement for things to settle down once again at 216h following a brief cooler, more unsettled spell over the weekend. Well i suppose we have been very lucky with having nice weekends recently.

In the shorter term Wednesday looks the warmest day next week with 22c possible.

Edited April 25, 2010 by Milhouse

[Frosty.]

Good model agreement that next weekend will be much cooler and unsettled with a brief N'ly which soon topples as a ridge cuts it off before it really becomes established but with the main centre of the high to the west, we may end up with a rather cloudy NW'ly rPm flow. This coming week looks warm and fine in the south & east of england but becoming breezier and cloudy in NW Britain with some rain at times and cooler, this cooler more changeable/unsettled weather will then extend to the rest of the uk by late in the week as the high to the southeast gradually gets pushed away.

[phil nw.]

Good model agreement that next weekend will be much cooler and unsettled with a brief N'ly which soon topples as a ridge cuts it off before it really becomes established but with the main centre of the high to the west, we may end up with a rather cloudy NW'ly rPm flow. This coming week looks warm and fine in the south & east of england but becoming breezier and cloudy in NW Britain with some rain at times and cooler, this cooler more changeable/unsettled weather will then extend to the rest of the uk by late in the week as the high to the southeast gradually gets pushed away.

A good summary there Frosty and it looks pretty dry for the South East quadrant for the next 3-4 days with High pressure never far away from there.

Some differences going into next weekend with ECM making more of the cooler incursion with a more active trough of Low pressure crossing the country.

[cooling climate]

Snow showers next Sunday into Monday for eastern England the east Midlands and

the southeast according to the GFS 06 run. Of course it will change (probably showing

blizzards by tomorrow).

[Thundery wintry showers]

The outlook to Wednesday looks pretty much nailed on- showery today and tomorrow (less so tomorrow than today) and then Tuesday and Wednesday reverts to the NW-SE split with dry, warm, sunny weather for East Anglia and the southeast, cloudy and wet over Scotland, Ireland and NW England and dry and cloudy in intervening areas.

The northerly has been delayed a bit- it was at T+168 a couple of days ago and still is, so I'm not totally convinced about it. Sleet and snow showers would be pretty widespread at around T+168 if the GFS came off, with minima near freezing, maxima of 7-8C during the day and 850hPa temperatures of -8C.

[TonyH]

The northerly has been delayed a bit- it was at T+168 a couple of days ago and still is, so I'm not totally convinced about it. Sleet and snow showers would be pretty widespread at around T+168 if the GFS came off, with minima near freezing, maxima of 7-8C during the day and 850hPa temperatures of -8C.

Yes, but with sunny spells in early May maxima unlikely to be below 10c at lowest England and Wales at least.

[Thundery wintry showers]

Perhaps in the southern third of England, but on the 6th May 1997 maxima of 7-8C were pretty widespread across Scotland and northern England, and also 7.5C max at Norwich Weather Centre. The 11th May 1995 had similarly low maxima in Scotland and north-east England despite some sunshine in between the showers.

It's also notable that a fairly half-hearted northerly around 7-9 May 2005, which produced snow only over high ground, also produced maxima of 10-12C across lowland northern England.

[reef]

Perhaps in the southern third of England, but on the 6th May 1997 maxima of 7-8C were pretty widespread across Scotland and northern England, and also 7.5C max at Norwich Weather Centre. The 11th May 1995 had similarly low maxima in Scotland and north-east England despite some sunshine in between the showers.

It's also notable that a fairly half-hearted northerly around 7-9 May 2005, which produced snow only over high ground, also produced maxima of 10-12C across lowland northern England.

Indeed, some notable low May maxima here:

6th May 1997: 8.3C

7th May 1997: 9.7C

8th May 1997: 8.7C

17th May 1995 also managed a max of only 6.7C! Lets not forget that as recently as the last week in May in 2007 there were sub-10C maxima in parts of the south-east. Its very much possible to get low maxima in rather modest setups at that time of the year.

The northerly shown on the GFS 6z would be of the bright and showery variety, so plenty of sunshine, however the temperature would drop massively during those wintry showers, so maxima would struggle unless theres a long dry period during the afternoon.

As Ian mentions though, its still outside of the reliable timeframe and the ECM has a similar outcome, but from a quite different setup.

[danm]

Surely after experiencing the warmth and sunshine over the past week you guys don't want cold weather to return?! Roll on summer. I'm looking forward to 23c on Wednesday and plenty of warm sunshine. Cold and snow is for winter.

[Frosty.]

A good summary there Frosty and it looks pretty dry for the South East quadrant for the next 3-4 days with High pressure never far away from there.

Some differences going into next weekend with ECM making more of the cooler incursion with a more active trough of Low pressure crossing the country.

Thanks phil,

I notice the GFS 12z also shows a brief cold N'ly blast coinciding with next weekend but the further outlook looks more promising with high pressure building in across much of the uk, the jet looks like it could be pushed further north eventually, most of this coming week still looking good for SE Britain, becoming more unsettled everywhere later.

[frostyjoe]

Perhaps in the southern third of England, but on the 6th May 1997 maxima of 7-8C were pretty widespread across Scotland and northern England, and also 7.5C max at Norwich Weather Centre. The 11th May 1995 had similarly low maxima in Scotland and north-east England despite some sunshine in between the showers.

It's also notable that a fairly half-hearted northerly around 7-9 May 2005, which produced snow only over high ground, also produced maxima of 10-12C across lowland northern England.

no we had single firgures here for the past two weeks and we had around 6c max here last week and in scotland parts had 3c maxes the other day!!? when are we going to get rid of this cloud though im sick of it i want sunshine and 25c!

[Ben_Cambs]

Indeed, some notable low May maxima here:

6th May 1997: 8.3C

7th May 1997: 9.7C

8th May 1997: 8.7C

17th May 1995 also managed a max of only 6.7C! Lets not forget that as recently as the last week in May in 2007 there were sub-10C maxima in parts of the south-east. Its very much possible to get low maxima in rather modest setups at that time of the year.

The northerly shown on the GFS 6z would be of the bright and showery variety, so plenty of sunshine, however the temperature would drop massively during those wintry showers, so maxima would struggle unless theres a long dry period during the afternoon.

As Ian mentions though, its still outside of the reliable timeframe and the ECM has a similar outcome, but from a quite different setup.

I remember the Bank Holiday weekend in May 2007 very well too, on the 28th May 2007 a max of only 7.2C was recorded in Cambridge, it wasnt helped by the fact that LP was anchored just to the SE of the UK, and many places saw in excess of 36 hours rainfall in the south, 52mm was recorded here on that day, which is very impressive considering Cambridgeshire's geological position in the UK, being the countries driest county

The models continue to show the theme that HP will stick to the SE of the UK, favouring the driest and warmest conditions here, with unsettled weather affecting the NW by mid-week and then the HP sinks south-eastwards, allowing a more unsettled airflow from the North west to take hold, then the risk of a Northerly as heights build towards Greenland.

Edited April 25, 2010 by Snowman0697

[rmc1987]

Surely after experiencing the warmth and sunshine over the past week you guys don't want cold weather to return?! Roll on summer. I'm looking forward to 23c on Wednesday and plenty of warm sunshine. Cold and snow is for winter.

No more cold! It would be nice if 23c materialised on Wednesday. It was lovely yesterday but today has been quite dissapointing! Not looking forward to the cooler spell after. And after the long winter and generally slow starting poor spring a decent summer would be great! Lost my confidence in that after the last 3 years though lol.

[Snowyowl9]

Looking a slightly better chance of something more thundery next week to what today gave with warmer upper air.

http://wzkarten.de/pics/brack2.gif

As for no more cold well it probably won`t become cold in the south looking at the latest 12z

But cold can still come in May,and even June.

[Milhouse]

Some quite mild nights coming up this week which should mean the daytime warmth hangs on longer into the evening. Mins in double figures for most on Wednesday night.

http://www.wetterzentrale.de/pics/Rtavn8417.png

[damianslaw]

Strong agreement that this week will see quite a bit of variety, starting off on a dry mild note tomorrow, turning unsettled in the NW on Tuesday whilst at the same becoming even milder in the SE and staying dry, warmth will peak in the SE on Wednesday, low 20's for many in SE Eng I suspect, but at the same time it will turn quite wet for the north, thereafer a gradual cool down as see a westerly and then north westerly flow by Friday.

The Bank Holiday weekend at this strange is unlikely to be a washout, probably showery to start especially in the north but turning dry, temps near average away from the north so hopefully plenty of sunny spells, no sign of the atlantic firing into gear, all very typical synoptics for the time of year, very average seasonal outlook I have to say.

[TonyH]

Indeed, some notable low May maxima here:

6th May 1997: 8.3C

7th May 1997: 9.7C

8th May 1997: 8.7C

17th May 1995 also managed a max of only 6.7C! Lets not forget that as recently as the last week in May in 2007 there were sub-10C maxima in parts of the south-east. Its very much possible to get low maxima in rather modest setups at that time of the year.

The northerly shown on the GFS 6z would be of the bright and showery variety, so plenty of sunshine, however the temperature would drop massively during those wintry showers, so maxima would struggle unless theres a long dry period during the afternoon.

I do realise that sub 10c maxima have occurred in May before, even in the south, I meant that I dont think it will happen next week given the sunshine.

[DaBrigg]

Some reasonable weather on the cards for the foreseeable future.

No monsoons, no washouts, with high pressure staying close by.

Temperatures will be up and down, and it may not stay completely settled all the time, but it could be a lot worse.

Had some thunder here today, which is always welcome!

Edited April 25, 2010 by DaBrigg

[mushymanrob]

this weeks precipitaion looks to be pretty low for the southern half of the country, might get some of thursdays cold front and maybe showers on fri-sat but both the gfs and ecm suggest high pressure being dominant which will continue the dry theme (albeit cold for a couple of days) into may....

im concerned.... on a personal basis i need some rain, not too much, i dont want a drought... i fear though that summer will follow the past three with a dry spring breaking and a summer washout taking over.