Model Output Discussion - Heading Away From Easter

[TonyH]

Do you know what drought actually means? it takes months to reach that and we've had plenty of rain/snow to top up the reserves this year, fields are still flooded here, there is still groundwater flooding in the south east, reservoirs are almost full.

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Various definitions of drought, one is 15 consecutive dry days.

Edited April 3, 2013 by TonyH

[Captain Shortwave]

Yet again the ECM wants to take this low through southern England

Yet again heights building to the north of this low, in this run more favourably to bringing settled weather.

UKMO has also shifted south towards the ECM solution at T144

GFS has the low here

Possible tentative signs of a possible building of high pressure to our north east in around a weeks time perhaps from ECM/UKMO

Edited April 3, 2013 by Captain shortwave

[Severe Siberian icy blast]

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Various definitions of drought, one is 15 consecutive dry days.

We had the wettest summer in 100 years last summer , followed by a very wet autumn , and a winter with lots of snow ,and a hell of a lot of rain again , it's ludicrous that people are even hinting at it , if you go to parts of Africa , and see children with no water and no food , who go many many months without seeing a cloud in the sky, that's a country in drought , it makes me cringe when I read people talking seriously about a drought , when just 2 wks ago we had upto 75ml of rain in 2 days? Get real .

[mushymanrob]

ECM and to an extent GFS hint at a transition to a very much more unsettled regime so, yes, warmer than now but very much more unsettled and snow to higher elevations cannot be ruled out. I can't see a transition to warm, dry, "springlike" (whatever that means) conditions without a period of more unsettled and potentially quite wet weather.

totally agree, it was never going to go from very cold to springlike warmth practically overnight, a spell of unsettled zonal was always going to be the most likely route towards anything warm. and a return to some colder spells is certainly on the cards, its not mild all the way from the weekend onwards.

Pub run seems to have gone a bit mental but I'd still take "zonal rubbish" over cold easterlies and snow showers every time.

interesting fax this morning, gets rid of the 528 dam by saturday, so we should get warmer and (for a time) less windy weather. so a niceish weekend, not warm but feeling much nicer especially for those lucky enough to get any sunshine.

next week is looking changable, wet and windy at times with showers and brighter spells, pretty normal april weather... suits me!

[Purga]

Interesting looking ENS with a big hint at colder conditions returning in FI after the brief warm spell. Note that both the Op and the Control go cold upping the odds.

further strong hints from GFS FI on a norherly regime and Greenland blocking

A brief warm up again

Then the Arctic bites back

Frost and single digit day temps again

Edited April 3, 2013 by Purga

[Gibby]

Hi folks. Here is the morning look at the 00z output from GFS, UKMO, GEM and ECM for today Wednesday April 3rd 2013.

All models continue to display a change in weather type as we move out of this coming weekend and into next week. In the meantime is as you were as far as the weather goes with High pressure to the North and low to the SE with a cold and raw NE flow over England most pronounced in the South where some wintry flurries are possible today and tomorrow. Some good sunny spells are likely elsewhere but with frosts widespread at night. Over the weekend the winds of change will be beginning as a ridge collapses East along with a weakening band of rain and in the north hill snow as it makes it's way slowly East across the UK through Sunday.

GFS then breaks this feature up leaving just cloud and rather cold conditions for Monday but largely dry. However, from Tuesday fronts make better progress into the UK as a deep Atlantic depression makes it's way into the UK along with rain bearing troughs and milder if fresh SW winds. This pattern is then sustained through the rest of next week before it departs East by Friday allowing a cold Northerly feed to bring wintry showers South across the north on Friday. Through FI today the weather remains very changeable with a couple of potentially rather warm days in the South as high pressure crosses the UK and exits towards the East developing a Southerly feed for the UK. This quickly gives way to a Northerly later with wintry showers in the North again which then lasts until the end of the run with renewed night frosts across the UK should it verify.

The GFS Ensemble pack shows the volatility of the operational run not supported in the run at all. Instead most members prefer the option of delivering substantially milder conditions from early next week with some rain at times and winds from a SW quarter.

The Jet Stream shows the flow currently undergoing a change in location as it moves north to a latitude near 50-55deg North of the equator travelling West to east over the UK in a week or so.

UKMO for the start of next week shows a deep low pressure area knocking on the door of Ireland early next week and after a rather chilly start to Monday milder Atlantic winds will steadily make their way in over Tuesday with rain and freshening milder air extending across the UK with rain at times.

GEM is broadly similar with Low pressure reaching the west a day earlier with rain into the SW on Monday. The parent low drifts across the UK through the week with rain at times for all in milder SW winds before a change back towards dry and anticyclonic type weather to end the run with sunny spells and touches of frost by night but nowhere near as cold as currently.

ECM shows a deep depression winding itself up close to the far West over Monday with rain making it's way slowly East through the day. By Tuesday the Low affects all with strong South winds and rain followed by blustery showers. Though milder in the South things look like they could stay rather colder in the North with this cooler air extending back South to end the run as the Low fills and moves away ESE into Europe leaving a weak ridge South over the UK from a Scandinavian High pressure. Frost could return by night late in the week.

In Summary the change to milder conditions is still on the cards this morning. As with all British weather nothing is straightforward and the models show a much weaker first attempt now on Sunday fizzling out as the rather cold air looks like hanging on one more day at least into next week. Thereafter there is good agreement on a more meaningful push of milder and wet conditions in association with a deep Atlantic depression crossing the UK midweek, the exit of which throws up a new set of problems for the models to decipher as ECM refuses to allow pressure to fall out to the NE of Britain. Consequently the Low has nowhere to go but amble slowly ESE filling as it goes and bringing a temporary return of colder conditions with frost at night to end the week. As it stands all models covering the end of next week bring back High pressure conditions and more benign weather but what temperatures will be experienced under this is open for debate today.

[Purga]

Some snow still on the cards for thursday in the south

[Summer Sun]

This mornings GFS ensemble don't look bad at all come mid month

Potential for milder south westerly winds and with the MJO expected to change who knows

[Paul]

If you're pulling up random charts just to highlight a specific weather type based purely on a preference for that weather type and nothing else (like some sort of reasoning why those charts are relevant aside from a preference), then please post into the banter/ramping thread as it's really not model discussion. We've moved several posts of a similar type in there already today.

http://forum.netweat...oans-and-ramps/

[rory o gorman]

If you're pulling up random charts just to highlight a specific weather type based purely on a preference for that weather type and nothing else (like some sort of reasoning why those charts are relevant aside from a preference), then please post into the banter/ramping thread as it's really not model discussion. We've moved several posts of a similar type in there already today.

http://forum.netweat...oans-and-ramps/

hear hear, its rather annoying when people pull hail mary , ens members or random unsupported F.I changes and do full posts on them just to highlight their preference.

Anyway good too see the 06z ensembles returning to near temps from Saturday ,some descent WAA shots and post shortwave instability with a chance of perhaps some descent convection given the step laspes. I will take it over this mundane pattern currently

[A Winter's Tale]

Good afternoon everyone. The chilly but settled theme to our Spring weather for another few days atleast before the anticyclone and cold uppers are pushed out of the way by an area of low pressure moving off the atlantic around the early part of next week. It really has been an exceptionally cold first half to Spring so far, which has in itself has consequences despite how interesting and rather enjoyable it was for some. It's alsio been pretty dry across much of the British Isles since the middle of February, especially in the north west highlands of Scotland where it has been especially dry and the low dew points, lack of precipitation in an easterly wind and plentiful sunshine has resulted in a number of moor fires. Certainly, next week will come as a shock to the system but it should be refreshing to see a change in the weather and for Spring to resum once more. However, as the low pressure system moves across the British Isles (centred just to the north of Scotland), there is a chance of a brief arctic sourced northerly around the middle next week bringing a return to colder conditions for a time, but in a more Spring-like fashion in the form of a toppler. I'd suspect that the northerly flow would clear eastwards away from the British Isles but given the variablility of Spring weather, in theory anything and the unexpected could happen so during this week one thing to look out for is the overall synoptic pattern for the latter part of next week. I suspect that a ridge of high pressure would extend across the British Isles behind the northerly and this may be followed by low pressure strongly influencing our weather or, instead high pressure to our south and east bringing in milder air in the south westerly winds but another feasable option isa return to high pressure being placed to the north, so the nature of this change in conditions and synoptics is far from being determined.

In the meantime, let's focus on the weather during the coming days. In the sunshine, temperatures this afternoon could be as high as 9C, especially in more western areas, whilst under cloud cover in the south east it may only be 4C, typically across the British Isles maximum values should be 6 to 8C. Skies should be clear across many areas this evening away from the south east of England and eastern parts of Scotland. Temperatures should also drop making for a chilly evening. Overnight, there could be a few passing snow flurries in south east England, a little bit of light rain for Shetland and possibly some mist and fog patches in highland Scotland. Another cold April night with lows of -2 to 2C in many areas, and even lower values in rural areas.

Initially a cold start to Thursday morning but temperatures should begin to rise after sunrise - values of 2 to 5C should still feel chilly. Sunshine and unspoilt blue skies in a number of regions, especially away from eastern counties where there should be some passing clouds. Possibly further snow flurries for the far south east. Into the afternoon and some clouds may build up across some areas, but generally speaking most of the cloud cover should be across southern England and north eastern Scotland. Temperatures should rise to 5 to 8C in many areas, a bit lower than that under cloud cover. Clear skies may not be as widespread on Thursday night but many areas should at least have some clear intervals, less clouds for the south west, west Wales and NI, some cloud cover for eastern Scotland, a few mist and fog patches too before dawn. Another cold, frosty night with lows of -1 and 1C in urban areas.

Medium-level cloud cover may be present across many areas on Friday with sunshine perhaps more likely in southern areas and more overcast in northern Scotland with a threat of some precipitation. Another cold April day with highs of just 5 to 8C. Another dry, cold and frosty night to come with lows typically -2 to 0C, clear skies for many, especially in southern and eastern areas whilst in northern Scotland, there could be a risk of some light and patchy snow.

Saturday could see temperature a degree or two higher with typical values of 7 to 9C, coldest in northern Scotland where it may still be rather cloudy and for Ireland it could also be cloudier. Some sunshine is possible for western and central Scotland and especially across Wales and the southern half of England, for some inland areas during the afternoon there could be a few passing clouds. A cold night to follow but not as cold, with the lowest values in eastern areas with temperatures close to freezing. A cloudy night for northern and western areas, further east there may be clear intervals.

There may not be much sunshine for Sunday, instead medium level cloud cover for most and a little bit of patchy light rain and drizzle for parts of highland Scotland. Maximum temperatures of 7 to 9C which is still below average. Temperatures overnight should be above freezing with cloud cover for most.

Next week a change is on the cards, but as I said earlier it is very early days with regards to the nature of the weather and synoptics that may follow. For a Spring month, I don't mind whether cold or mild, showery or settled April weather prevails, but a good deal of sunshine would be paramount and for the weather to exhibit the truly variable and dynamic qualities of this time of year. With an entire two thirds of a month yet to be mapped out synoptically, and how last month showed how nobody expected such a month, then I'm inclined to think that April 2013 could unfold and every different ways. This month may even end on a warm note.

Edited April 3, 2013 by A Winter's Tale

[Zenarcher]

For the rest of the week staying clear and sunny for most although wintry showers may occur over Southern England and the Highlands of Scotland. Over the weekend turning more cloudier but mostly remaining dry although some showers over the Scottish highlands are likely. For the wind a strong breeze from the North East across England but elsewhere calm. Over the weekend the wind is expected to be calm for the whole UK. Not too much of a change in temperatures for the rest of the week, still staying mostly cold.

A quick look into the start of next week suggests a change a strong low pressure system is expected to enter the Atlantic and slowly weaken and make it's way over to the UK.

Out of the 3 main models the ECM and UKMO are looking similar but the GFS isn't here's a comparison of the GFS and ECM,

GFS has things more flat and the low eventually leads to the North of the UK bringing a unsettled spell with it. The ECM and UKMO send it in a SE direction as the low weakens it ends up either to the South of the UK or over Northern England. Either way it looks like a change is on the way next week.

Edited April 3, 2013 by weathermaster

[phil nw.]

Will be closing this thread shortly and opening a new one in time for the 12z model runs.

[phil nw.]

OK then folks locking this now -new thread now open here