Model Output Discussion 01/09/17

[Frosty.]

The Ecm 12z shows a gradually improving picture by next weekend as winds become lighter and pressure rises across the uk and that process continues into the following week as the azores high ridges in strongly across the uk with increasingly fine pleasantly warm days and sunny spells with chilly nights bringing a risk of mist / fog patches forming as you would expect as we head further into autumn.

Edited September 10, 2017 by Frosty.

[ANYWEATHER]

Evening All and hope you had a great weekend!   general concencus on a week away is very uncertain  ,just watch this space....Hurricane Jose will make it difficult  for forecast models...

Edited September 10, 2017 by ANYWEATHER

[knocker]

Without going into detail suffice it to say that, although they still differ to some extent, last night's NOAA, GEFs and EPS anomalies all indicate a few days when the Azores high pressure becomes more influential and thus a more settled period of weather before our trusted friend the trough in the Iceland area reasserts itself. Ergo a return to a westerly upper flow and changeable conditions which at best will result in a N/S split.

Back to the present and today the low over Scotland witl drift slowly E/NE leaving the UK in a blustery north westerly with many squally showers, possible of thunder and hail, with more prolonged rain in the north east of Scotland. As the low moves away a ridge will build from the south west overnight with the showers dying out. But this is merely the calm before the storm.

Tuesday evening sees the next depression winging in from the WNW on a very strong WNW 500mb flow and is over Ireland 988mb by 1800. It continues to deepen as it tracks quickly across northern England and, apart from the rain, it will generate some very strong winds, possible severe gale, for a time across Wales and the Midlands Tuesday night. Needs watching.

The low continues on it's journey east and thus thus the SW wind veers to a cool northerly over the UK and decreases as the Azores amplifies to the west and nudges east. Thus a more settles spell for the UK but the high tilts on it's axis which is away to the south west and allows systems to sneak around the top as the upstream energy batter on the beck door and this is where we came in so an ideal place to leave  it.

[mb018538]

Nice to see the jet displaced north - even if it is only for a brief respite. Not sure how long this 'settled' spell will last for either!

[knocker]

The ecm is broadly speaking on the same page as the gfs. At T168 it does attempt to split the ridge with a strong high cell established to the north  This would appear to be no bad thing as it facilitates the warding off of the Atlantic with an extensive ridge building north east. A somewhat flimsy pattern and one or two slight adjustments would make quite a difference.

 

[summer blizzard]

The build of pressure to the east appears to be the lagged result of a surge of westerlies around Indonesia recently. Unfortunately for those hoping it will yield fruit later in the month i strongly suspect that a cooler, more westerly pattern will return based on the fact that we are about to see an exceptionally strong surge of easterlies in the Pacific.

[gottolovethisweather]

I've been lurking on and off for quite a while throughout my busier past few months work-wise, and I thought I'd rear my ugly head once again. Pants second-half to summer really but the rain was much-needed in farmer's fields and for a few other industries, despite it washing out a lot of the wildlife such as butterflies and the like. Autumn has kicked in early, check the local trees and shrubbery near you, tells you all you need to know I guess. Intrigued by Damianslaw's (I think it t'was him) post about the possibilities of this being a bit of a different autumn to what we get normally. My gut feeling makes me believe we will get the usual drier slot just beyond mid-month possibly stretching into late September, especially decent towards the South and South West, but far from dry and often unpleasant for those up North though with plenty of depressions with drenching rains and gales at times. Early season frosts in any drier slots are likely too, I'd say, in what will continue to be a rather chilly flow (when compared to average) for most, pleasant in any sunshine though, of course. October and November will be quite stormy months, I'd suggest, with wintry interludes (sleet, hail, mountain snow) occasionally edging south at times, while brief ridges will often make you think of a certain Crowded House tune, Four Seasons In One Day when any sunshine and drier interludes chase the showers and rainbands away.

 

Best Wishes all.

gottolovethisweather

 

Edited September 11, 2017 by gottolovethisweather

[knocker]

A brief overview of the outlook. A continuation of the unsettled weather this week before over the weekend and the beginning of next week some amplification occurs in the eastern At;antic with the Azores high pressure surging N then NE whilst the trough is relegated  to the south east of the UK. Thus a short period of more settled weather before the amplification withers and the low pressure and associated trough over Greenland once more becomes more influential with a westerly upper flow. Not disaster time as the Atlantic is not particular anomalous and the southern half of the UK probably not be that bad under this scenario

A much quieter day today with showers mainly confined to the west before the next low arrives en route to the north of England and the North Sea bringing a fair amount of rain to the north and, more to the point, some very strong winds to northern areas of England and Wales for a time overnight with gusts in the region of 70mph. The winds dying down tomorrow morning and a return to a showery regime.

For the rest of the week with the low pressure to the east and the Azores surging to the west the UK is under a cool showery northerly with perhaps the odd longer period of rain tracking south in the circulation before on Saturday the high pressure ridges more north east bringing drier more settled weather to the UK albeit the temps no great shakes. Perhaps interesting to note the impact on the jet stream caused by the amplification and also how short lived this is.

From this point the usual battle ensues between the upstream generated energy and the trough to the NW and the Azores which the latter loses.and a quick return to cool unsettled weather ensues.

[knocker]

Some interest next weekend. The ecm has a shallow low forming in the western Channel during Saturday which initiates a fair amount of showery precipitation in the south of the UK and France and some quite cool air into the latter over the weekend.Thereafter some brief ridging before the next fronts arrive over N. Ireland by 00 Wednesday.

[mb018538]

On 09/09/2017 at 08:33, mb018538 said:

Already a strong jet streak piling out of the USA again, this high pressure isn't going to last long....soon be flattened out and windy again. No Indian summer on the way.

I was worried about this settled spell on Saturday...now it looks yet again that it's going to amount to nothing more than a flimsy temporary ridge before it all heads south again. Suppose we were due an unsettled autumn, this could well be it.

[Polar Maritime]

Cold enough tonight into tomorrow for a covering of several cm's over the highest peaks in the highlands, As a chilly N/Wly takes hold.

The winds will be the main feature tomorrow, With gusts possibly touching 70mph in places, As shown by Net-Wx SR in house model.

Edited September 12, 2017 by Polar Maritime

[Chris.R]

Looks like tonight's low has been designated Aileen, The first name storm of the autumn. Didn't even know they've come up with a new list yet. I'm sure the first of this years tropical cyclones had a name like that as well. 

Edited September 12, 2017 by Chris.R

[ACCOUNT DELETED]

GFS 6z looks a big disappointment atm the high is just too far west by Friday and Saturday and as a result, it's keeping the heavy / thundery showers around instead of it becoming more settled, what's worse, the high is already retreating back SW before it even reaches us  

can't upload charts as I'm in a low 3G coverage area. 

[Man With Beard]

The models have had real trouble picking the Euro trough this summer at long range. Another example for early next week - a seemingly HP dominated scene becoming progressively a euro trough between D10 and D5.

[Frosty.]

The Gfs 6z eventually becomes very anticyclonic..mists and mellow fruitfulness springs to mind, that would be a lovely spell.

Edited September 12, 2017 by Frosty.

[mb018538]

I wouldn't count on it Frosty....we've been showed long stretches of high pressure domination in FI since the middle of July, and not one has come off! Let's hope for once we can get just a few quiet and settled days...

[ItNeverSnowsInWindsor]

GFS 6z is a massive outlier in terms of precipitation and temperatures from the 19th to the 27th. Expecting it to stay mostly changeable throughout the period. Lets see which way the GFS 12z goes.

 

 

[knocker]

An interesting aspect of the 06 is at T132 it develops a little low in the circulation of the trough in the west Atlantic which doesn't come to much as it engages the jet and tracks towards Scotland but the next one that follows in it's footsteps develops quite nicely on the 150kt jet and explosive cyclogenesis occurs as it tracks just north east of the Hebrides  Obviously nothing to be concerned about at the  moment but it's always worth keeping an eye on future runs when it starts picking these sort of developments. The problem is that Jose may just be influencing things in that neck of the woods.

Edited September 12, 2017 by knocker

[Frosty.]

49 minutes ago, mb018538 said:

I wouldn't count on it Frosty....we've been showed long stretches of high pressure domination in FI since the middle of July, and not one has come off! Let's hope for once we can get just a few quiet and settled days...

I'm not counting on it, just saying it would be nice that's all :- )

[phil nw.]

As tonight's low Aileen passes across the UK and east towards Denmark it produces quite a cool down for many parts of Europe over the next few days as a Northerly wind on it's rear flank digs south into the continent.

Low teens in the early afternoon quite well south into C.Europe by day 3.

Quite a change for many down there i would imagine with any real heat confined to the Costas by then by the looks.Quite an early cool down this year from that Euro trough,more of an October feel perhaps.

[knocker]

Enter Jose stage left

 

Edited September 12, 2017 by knocker

[ANYWEATHER]

Evening All ,A very Turbulent outlook in the days ahead from the 12z suite from gfs and ecm  so expect a rollercoaster ride! Then on to the next few hours a very strong jet stream approaching 200 mph racing towards southern Britain giving very strong winds , while northern England and southern Scotland receive some very heavy rain. So North heavy rain and south high winds , its only the far north of Scotland which will enjoy benign conditions for a change

[ANYWEATHER]

16 hours ago, mb018538 said:

I wouldn't count on it Frosty....we've been showed long stretches of high pressure domination in FI since the middle of July, and not one has come off! Let's hope for once we can get just a few quiet and settled days...

Really cant understand some people banging on about high pressure in the days ahead and the models show something so different.

Edited September 13, 2017 by Polar Maritime

[knocker]

Indications from last night's anomalies of a brief return to a pattern we have seen before this year. That is the Azores high pressure surging north and connecting to the east European ridge whilst relegating the trough to the south east of the UK. With much of the upper flow diverted NE the UK, for a time, is in a slack pressure area, with perhaps the possibility of inclement weather from the south. I say brief because the Greenland trough tracks east and normal service of unsettled weather from the west is quite quickly resumed

At midnight Aileen was over NW England and moving quickly east to be over the southern Baltic 24 hours later. Thus the overnight strong winds will abate apart from the east coast for while. But violent storm F11 for a while in the North Sea. So today will see the SW wind veering north west with squally showers, some thundery with hail, in many areas particularly in the W/NW.

The end of the week sees surface wind continue to veer northerly and a continuation of blustery showers as the Azores ridge nudges east and by 12z Saturday it is stretching NE of Scotland with a shallow low moving slowly SW into the North Sea.which may bring a longer period of rain to the south east for a time.

From here the Azores HP exerts it's influence and the usual battle ensues between this and the upstream energy pushing east with systems either running around the top or through the ridge. The gfs this morning has the Azores hanging in there, apart from in the north, but I wouldn't bet the bank on it

So all in all quite a mixed bag with the rest of the week generally cool and unsettled then a marked improvement next week for most becoming more settled with temps possible even a tad above average. Well that's the theory anyway

 

[knocker]

The ecm in pretty good agreement with the gfs for the weekend