Model Discussion - 10th March Onwards

[johnholmes]

After an unsettled weekend ECM shows high pressure to begins to dominated once again

http://www.jp2webdes...o.uk/ds/ecm.htm

well it would would'nt it you little hp chappie?

gawd knows what you will do when the synoptic set up shows low after low and no sign of a high within 1,000km of the Uk but enjoy it while you can Gavin old chap.

[Geordiesnow]

I think its clear too see that any Atlantic influence won't be particularly strong in a wind sence but slow moving weather fronts will lead to quite a bit of rainfall in one area one would of thought, whether it will be in the areas that is needed is uncertain at this stage however.

The jetstream don't look particuarly strong so another Azores high ridge could happen as the models are indicating, difference this time, if any high pressure does come in, then its coming over cool air so at least it might be more sunnier than this high is proven to be - makes you learn that some weather set ups are not as they appear to be in terms of the actual weather.

[johnholmes]

sorry not from net Wx but this GFS chart shows the current anticipated rainfall totals by the start of next week, the 'rainy' period(!) before HP takes over again?

yet again the areas needing rainfall seeing not much - IF the GFS version is correct and there seems little reason to doubt its probably got the totals as high as seem likely.

[lorenzo]

CFS has not been too shabby this winter at all. Looking ahead there is not much to glean from either forecast at present..

With the evolution of long staying pattern being a clear trend over the last couple of years it would appear that any set trend that is established is neither quick to break down nor quick to change. Pity the cold of Europe never sneaked as far West as we all hoped.

Strat thread is worth a look re Spring and Summer pattern as is technical thread some interesting thoughts and lead in analysis happening there.

Am glad you are enjoying the HP Gav - hoping for a 'cleaner' high some time soon..

[johnholmes]

as so often happens the 00z issue of the chart I showed above for cumulative rainfall, courtesy of Wx Online has changed on the 00z GFS run.

Indications, as per Met O Fax chart for 96 and 120 hours of a wave developing on the cold front. This creates higher totals over the south and south east than shown on the 12z from yesterday.

[karyo]

CFS has not been too shabby this winter at all.

Agreed! I think the CFS deserves a lot more credit than it gets in this thread!

It seems that in temrs of temperatures, we can expect a more average April and a warm May. http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/images3/euT2mMon.gif

I never look more than 2 months ahead.

Karyo

[MP-R]

GFS 00Z continues the theme of an unsettled weekend and windy start to the next week before quickly becoming dry and settled for most by midweek. Then, it shows a change to more unsettled again for the final week of March after a brief spell of southeasterlies. So, a bit more variation on this run but still not a great deal of rain certain after this weekend.

[phil nw.]

The current High has been quite cloudy for many,certainly here in the midlands we have had only brief breaks in the afternoons.

It does look like we have a good chance of more sunshine tomorrow as the high retreats south east pulling in some clearer continental air before the approaching Atlantic trough brings a more unsettled spell from Friday.

http://cdn.nwstatic.co.uk/metoimages/20120314/00/met.72.png

Difficult to say how much rain will fall over this period but looking at last nights T120hrs.fax a shortwave development shown over the south east may well bring more than first thought.

http://www.meteociel.fr/ukmo/fax/fax120s.gif

Into next week and although pressure rises from the south it does look breezy and cooler in quite a strong westerly flow with the north especially still prone to more unsettled conditions for a couple more days before things really settle down again.

http://cdn.nwstatic.co.uk/ecmimages/20120314/00/ecm500.144.png

So a more changeable and cooler few days to come after tomorrow.

[Summer Sun]

GFS 00z this morning once again shows high pressure to re-build quickly again next week after an unsettled weekend, once the HP does build it lasts to 360h, at 384h it shows low pressure moving in but that it way to far out to even worry about

http://www.null/ds/gfs.htm

ECM

Unsettled and wet for some this weekend, before high pressure begins to build ECM doesn't send it over all of the UK as quickly as GFS but it get's there, by Thursday for all of the UK, parts of the south see the HP building as early as Monday, once the HP builds it lasts for all of ECM's run

http://www.null/ds/ecm.htm

UKMO

High pressure build's quickly next week after an unsettled weekend

http://www.null/ds/ukmo.htm

[Summer Sun]

Weekend Rain Fall

So this weekend will see rain for just about everyone

Saturday

Sunday

So as we can see many parts of Yorkshire and the North east could miss out on the rain, but thankfully the drought hit south and east should get some much needed rain

[phil nw.]

Medium term guidance indicate quite dry anticyclonic conditions after the upcoming unsettled period.

The mean hts and anomolity forecasts and the MJO forecasts all indicate a mid atlantic trough and high pressure over or just to just east of the UK.

http://www.cpc.ncep....y/814day.03.gif

http://www.meteo.psu...WF_0z/test8.gif

http://www.cpc.ncep....splume_full.gif

http://raleighwx.americanwx.com/MJO/MarchPhase6500mb.gif

All in pretty good agreement at the moment-so the odds on this dry period continuing in second half to March with some spring sunshine,especially if the High situates just east of the UK which would draw in some dry continental air.

Edited March 14, 2012 by phil n.warks.

[Thundery wintry showers]

After two anticyclones in a row that have produced more cloud than expected I am not too hopeful about sunshine amounts from the next bout of high pressure. The preceding airmass will be a tropical maritime one, so we can expect a fair amount of moisture to precede the arrival of the high pressure (a polar maritime incursion followed by a rapid build of pressure is a much "safer" route to a clear anticyclone). After the high pushes up from the south everything will depend on where the high sets up- many model runs are showing the high on top of the British Isles rather than to the east.

However it will be a bit later in the season, meaning that the slightly-stronger sun will be more able to send surface temperatures high enough to enable the break-up of the cloud sheet.

Re. the unsettled weekend, Saturday will probably see very little rain for most parts as the day's frontal system will weaken considerably as it heads SE across the country, but Sunday's system will be rather more potent. The secondary low may also bring hill snow and a bit of sleet to low levels across parts of the Midlands and/or northern England, depending on the percise track of the low. The outputs do suggest some rain for SE areas but also imply that it may be short-lived, so probably not much of a relief from the drought.

[shedhead]

This weekends set up look pretty similar to the one that brought some decent rain to the east and southeast earlier this month. As ever at this range the devil lies in the detail, but 20mm+ certainly looks on the cards for some as the secondary low tracks NE'wards from the Channel.

[Scorcher]

However it will be a bit later in the season, meaning that the slightly-stronger sun will be more able to send surface temperatures high enough to enable the break-up of the cloud sheet.

This is a crucial point I think. We're still in the first half of March at the moment and we're heading into the period when the sun's strength rapidly increases. By next week the sun will be stronger than it was in the hot spell of late September/early October 2011.

[summer blizzard]

Model outputs very consistent again, cold blip followed by more high pressure.

As an aside, sunshine totals in Leeds are pretty exceptional for the first half of March.

[johnholmes]

As usual the successive runs from GFS are changing the totals and area affected by the rain on Sunday

[summersnow]

Model outputs very consistent again, cold blip followed by more high pressure.

As an aside, sunshine totals in Leeds are pretty exceptional for the first half of March.

Yes, my thoughts exactly! I have been very impressed with how consistent the models have been, GFS in particular - even well into FI. Perhaps indicative of a very persistent default regime, that even now doesn't show much sign of changing!

[Cheese Rice]

As an aside, sunshine totals in Leeds are pretty exceptional for the first half of March.

Indeed, what appeared to be a rather cloudy high has turned out to be a very sunny spell of weather here.

The sat image highlights a regular feature occurring whereby east of the pennines is seeing cloud breaking readily.

Perhaps due to the slack flow the hill tops are cutting into cloud.

The current output suggests much the same with the second high bringing a slack southerly flow. I would say NE England/Yorkshire best positioned for some length spells of sunshine.

Edited March 14, 2012 by Cheese Rice

[Summer Sun]

The UK becomes very settled from early next week according to ECM tonight, the key is if we can get a sunny high instead of a cloudy high with sunny spells for some like this one

http://www.jp2webdes...o.uk/ds/ecm.htm

Although the weekend will be wet for some the question is how much rain will fall

The ensembles show clearly tonight that the 17th to 19th will see the most of the rain

The rain charts back this up

Still raining by 18:00

00:00 see's it still raining in the drought areas, possible snow for high ground in wales

06:00 still raining, snow risk increases slightly

12:00

Rain clear's by 21:00

So this weekend does have potential for some decent rain fall, but the question is how much will fall

[coldwinter]

The ECM doesn't look that sunny, at least to start with, i just hope that we can get a sunny high instead of this dreary grey dribble.

Ryan.

[Zenarcher]

Firstly all models show up to this weekend we will get slightly more unsettled as high pressure moves away and rain is likely to move across England and to some areas who really need it.

Just a quick summary on 12z runs for what they are showing for the start of next week.

GFS - High pressure is shown rising across Britain and even up over Northern area's then later the Atlantic weather comes rushing in over the top but staying settled in the South.

UKMO - Brings high pressure back but not really as far North as the GFS.

ECM - Remains consistent to what it was showing on the 00z run although some adjustments to the low pressure systems going near Greenland and Iceland but its current output seems to have good agreement with the other 2 models. It also shows high pressure building over the UK more similar to the UKMO and then going past 168 hours like how it done on its 00z run high pressure goes all over the UK even up North as some energy goes underneath. I would say its showing better charts than the GFS in FI mainly because we want energy to go under and not over. Also its kinda rare to see the ECM show something very similar to its earlier 216 to 240 hour chart.

Edited March 14, 2012 by weathermaster

[damianslaw]

Short term - becoming unsettled for all as the current high slips away to the SE allowing atlantic frontal systems to move across the country.It is a very messy tricky set up to forecast - amounts of rainfall will depend on the position and strength of fronts. Southern parts could see some decent amounts, whereas NE parts will probably remain quite dry. Becoming much cooler in the north as sub 528 dam air makes inroads across scotland and n england during Sunday. I suspect maxima this weekend will be very supressed under cloud and rain, 6's and 7's maxima at best, reminds me of the weekend before last when many failed to see maxima higher than 5 degrees.

Next week - westerly/southwesterly flow at first but strong azores high will ridge NE by mid week settling over the country. Western parts look like seeing a continuation of the very cloudy conditions, but hard to say whether eastern parts will see much sunshine. High pressure overhead at this time of year often means cloudy dull weather especially if it has been drawn up from the SW thanks to the saturated air -which promotes cloud and moisture. Its much better if high pressure can ridge NE and E and pull in continental air - the high looks like setting up shop in the exact position it is in now , and an extra week on what make much difference in terms of sun strength.

So a shortlived unsettled spell this weekend, much like first weekend of March then its back to what we have been used to since mid Feb - more dry probably very cloudy mild weather.. can't say I'm enthused with the prospects of yet another dry cloudy week with no weather to talk about. I can't remember the last time there was a stiff breeze.. what an exceptionally quiet still period we have been locked in, even when it has rained since the New Year it has seldom been accompanied by strong winds.

[KTtom]

Good agreement of a return to settled conditions after this weekends unsettled spell. Next week looks like it will be a cloudy high with SW'erly winds and a return to misty drizzly conditions especially for us in the west, however both GFS (above) and ECM move the core of the high to the north and introduce easterly winds, which although we loose the warmth should ensure some sunshine.

[johnholmes]

The position of the high, spoorted by the 500mb anomaly charts, somewhere north/east of the Uk will mean PROBABLYcloud for eastern areas and more in the way of sunshine for areas west of the main high ground. It is unlikely we will have the detail though to be able to pinpoint areas of cloud until very close to the actual time frame, much as the past week.

It does appear that little if any rain is likely, after the weekend, for most parts of the UK.

Edited March 15, 2012 by johnholmes

[summer blizzard]

Next week looks much the same as this week to me although with cooler air underneath the high.

I suspect the east coast may see lingering cloud but central and western areas will probably see sunshine.

All in all, a fantastic March output for some and pretty pleasing for me. (Leeds will get sun all day if winds are S of E, cloud if winds are N of E).