Model Output Discussions 12z 08/03/17

[Frosty.]

The GEFS 6z mean certainly shows the uk becoming cooler next week compared to how mild it currently is in the south and we can expect sunshine and showers, some heavy and thundery with hail and over high ground in the north, a wintry mix of sleet and snow with nights becoming chilly enough for slight air frosts where skies clear as well as mist / fog patches..looking further ahead indicates increasingly settled conditions as high pressure builds in and as the high gradually migrates to the east for a time, we start to import milder air from the near continent and feeling pleasant in the strengthening late March / early April sunshine, especially further south..high pressure stays largely in control, at least further south which would bode well for the first part of April..and perhaps even further ahead!

Edited March 18, 2017 by Frosty.

[Sky Full]

As Frosty has pointed out the GFS eventually wants to bring in much more Spring like conditions thanks to a UK centred high pressure.

This is 15 days away so plenty of time for modification if not total backtracking but I am hoping that the GFS is on to something here!

[Summer Sun]

UKMO shows it settling down towards next weekend pleasant enough by day if it was sunny but cold overnight with some frosts where skies clear

[Frosty.]

Following a cooler blip for a time next week, the Gfs 12z shows temps recovering to pleasant levels, especially across the south and becoming more settled too with lots of sunshine. Further ahead shows a north / south split with the north more unsettled whereas the south is generally influenced by high pressure, ergo, largely dry and the run ends with HP centred over the south of the uk.

Edited March 18, 2017 by Frosty.

[Frosty.]

A pleasant end to an otherwise changeable Ecm 12z with a band of persistent rain on Monday giving way to brighter but colder, showery conditions from the west later with hail / thunder and cold enough for sleet and snow on northern hills and night frosts returning. Later in the week pressure rises and it becomes largely fine with sunny spells and temps recovering but still a risk of more cloud and a few showers continuing across the south. Next weekend slowly becomes more unsettled from the south west (especially for sunday / monday) but then high pressure returns to end the run. 

Edited March 18, 2017 by Frosty.

[Frosty.]

According to the GEFS 12z mean, high pressure is holding all the aces from later next week through into early April with increasingly pleasant daytime temps, especially further south and in the sunshine but under clearer skies overnight, chilly with slight frosts and mist / fog patches.

Edited March 18, 2017 by Frosty.

[Man With Beard]

This set up reminds me of many from last year - trough splitting just to our SW. It leaves us on a fine line between being close to the centre of the trough (cool/showery) and far enough away to get a dry continental feed.

At this time of the year the continent is still cool so chances of strong warmth unlikely but not impossible - if the draw is from the Mediterranean region, some well above average warmth will be possible - bit like threading a needle to get that one though.

[damianslaw]

After months when trough disruption over the country has failed materialise.. alas the week ahead promises such affair, as is more typical as we head through spring, than winter it seems. A classic trough dropping through the country with a cold northerly behind and then high pressure quickly building in behind heading towards scandi - too late to deliver a snowfest, but it will produce a rather cold feel for many especially the north, with mid single digit maxima at best for the north come the middle of the week and the return of frost.

Longer term signals we may see more of a southerly continental drift, with low pressure/trough action becoming weak and unstuck to our west, uncertain how things might develop thereafter. 

March like September can be a trying month, never concertedly able to dip its toes firmly in the season it heralds, it seems and generally frustrating those who want the remnants of the season gone to dissapear rapidly, for this reason they pale against April and October which have much more 'business' about them, and mark the rapid swifts from the winter state and summer state, March and September are just idle teasers..

[knocker]

Haven't had much of a chance to look very closely at this morning's output but they just seem to confirm what has been indicated recently at that is a quite quick pattern change is likely with the movement of the still quite strong vortex to the Franz Joseph area and associated trough into eastern Europe Certainly signaled by the GEFS

Whether this is partly the reason or not there are some huge differences between the GFS and ecm starting after the unsettled interlude this week which is nailed on I haven't done a detailed analysis of the differences, the GFS is very keen on retrogression of the high cell and the ecm isn't; so have settled for the time being with showing the difference at T240 whilst emphasizing that is the only reason for posting them.

Edited March 19, 2017 by knocker

[Sky Full]

Thursday, Friday and Saturday nights next week could bring widespread frosts according to the GFS this morning:

  

Gardeners beware - 

[knocker]

If we run the EPS 6-10 anomaly forward into the ext period we have a strengthening  of the Franz Joseph lobe and associated east European trough but also a retention of the Canada/Greenland lobe with Atlantic trough.This is in conjunction with a weakening of the HP in the north west Europe theatre and a movement east whilst simultaneously also weakening the trough to the south. Thus a fairly weak W/SW upper flow sets in. The Main difference at this stage between this and the GEFs would appear to be the orientation of the vortex lobes and associated troughs. To me it has the feel of a return to the old Atlantic Azores's/trough interplay but with perhaps the Azores being a tad more influential but I wouldn't like to bet Sidney's nuts on it.

Edited March 19, 2017 by knocker

[Frosty.]

The Ecm 00z has certainly upgraded the cold during the week ahead with some very cold frosty nights on the way and I wouldn't be surprised to see some snow around until high pressure takes over later in the week.

Edited March 19, 2017 by Frosty.

[Polar Maritime]

Yes Frosty, This mornings GFS also showing colder -11c uppers over the majority of Scotland Thursday. Lets see what the 6z pulls out the hat..

 

 

[johnholmes]

Well the anomaly charts have for several days now shown quite marked differences, ECMWF-GFS showing one thing and NOAA another, see below. It will be interesting through this next week and into the following weekend to check which has the upper air pattern more correct.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

 

[Frosty.]

9 minutes ago, Polar Maritime said:

Yes Frosty, This mornings GFS also showing colder -11c uppers over the majority of Scotland Thursday. Lets see what the 6z pulls out the hat..

 

 

Yes PM I get more interested when sub -10 T850's are involved..cold upgrades for a change!

[Sky Full]

A brisk northerly airflow in place by Thursday next week:

Followed by high pressure centrally positioned above the UK by Saturday.  Settled but still on the cold side.

[Summer Sun]

UKMO 850's for later in the week

[The PIT]

I suspect when the high settles over us we are going to get a good range of temps from day to night. So cold nights followed by warm days. It's going to be interesting too see what range of temps we get.

[summer blizzard]

Modelling pretty confident now that the Atlantic effort will be dismissed and high pressure rebuilds by day 5.

[Winter Cold]

Taking a look at the 6z GEFS then:

Bit of a chilly week to come, this is for South Yorkshire. Temps around 5 or 6c and frosty at night. Can see they then start to recover through next weekend a little and probably back into double figures towards the end of the month. You can see the large temp ranges PIT talks about above with perhaps low teens by day but still a chance of cold nights.

Can see here on the 850s chart why next week will be chilly, a mean of -5 this coming week with a recovery thereafter

A very strong signal, in fact full agreement of a strong pressure rise into next weekend so hopefully a pleasant weekend to come next weekend. It may not last though with the mean trending down a little through week 2. April showers perhaps to start the new month?

Shown nicely in the precipitation graph above with a dry up after next week through the final week of March in conjunction with the pressure rise and then an uptick again towards the end.

[Eugene]

Interesting week to come with colder more brighter conditions with night frost and the risk of wintry showers taking over before a chilly easterly for midlands/south next weekend with more cloud cover, nice change from this mild dross with temps not varying much between day & night.

[knocker]

Could well be a quite unpleasant day in England and Wales on Thursday before the weekend improvement.

Edited March 19, 2017 by knocker

[Summer Sun]

Continued hints from UKMO that it will settle down next weekend pleasant enough by day but some frosty nights in the north the south may be less frosty with more of an easterly breeze here bringing the risk of some rain

Edited March 19, 2017 by Summer Sun

[Frosty.]

Let's jump to the good part, the Ecm 12z shows high pressure centred over the uk in six days time.

[Methuselah]

1 minute ago, Frosty. said:

Let's jump to the good part, the Ecm 12z shows high pressure centred over the uk in six days time.

Let us pray?