Short range model discussion - into 2018

[chrisbell-nottheweatherman]

2 minutes ago, knocker said:

Yes that looks likely Chris  looking at the radar and the high res. Modis for 1130 although the temps are a tad high for snow with 41F at Norwich at 12.

Indeed - by "precipitation" I meant rain or hail, not snow!

[DOdo]

Typical Polar Maritime  - we had a heavy shower of rain, then it snowed for 10 minutes and then it froze, Nightmare getting to work  this morning. My car door was frozen solid,and if that wasnt bad enough I had to tend with  black ice on the roads. 

[knocker]

The cold front and little bent back occlusion are quite close to the east coast on th 12 analysis. The mass of cloud to the west on the 1200 geostationary (courtesy Dundee Receiving Satellite Station) indicating tomorrow's cloud and rain/snow

[knocker]

After a quiet and cold night we arrive at this analysis at 06 tomorrow. A deep low Iceland with associated fronts already impacting western Scotland and Ireland with rain and a wave forming on further fronts west of southern Ireland.

During the next 12 hours the fronts and rain, heavy at times, track south east across the UK accompanied by strong winds in the west, perhaps reaching gale force whilst the wave becomes more organized and nips NE to be over N. Ireland 992mb at 1800.

This will bring more heavy rain, and strong winds, as it tracks across in to the North Sea still deepening, and perhaps snow in the north, Leaving behind in it's wake frequent wintry showers as the cold Pm air, that can be readily seen on the earlier chart, encroaches.

Edited February 9, 2018 by knocker

[knocker]

Just an observation as at the moment as it's outside the range of this thread, but this evening's ecm is indicating some very wild and wet conditions next week with some deep Atlantic lows flying around. Will look a little closer tomorrow as it sure doesn't look like I'll be going anywhere.

Edited February 9, 2018 by knocker

[biggreyface]

1 hour ago, knocker said:

Just an observation as at the moment as it's outside the range of this thread, but this evening's ecm is indicating some very wild and wet conditions next week with some deep Atlantic lows flying around. Will look a little closer tomorrow as it sure doesn't look like I'll be going anywhere.

I hope you won't be going anywhere knocker this thread would fall apart if it wasn't for your input .

I've got to say that it's been a been a good addition to the forum this year .when  the charts that are getting  posted are probably going to happen 95% of the time .

Just a thought that maybe we could  rename this thread (knockers woodshed thread) only joking hope you keep up the good work.?

 

[knocker]

As the witching hour of transition gets closer there is no apparent pattern changes discernable this evening but caution is advised as changes towards the end of the period will not become immediately obvious in this time range.

Perhaps a slight change upstream with the Aleutian ridge stretching further into the Arctic (some disagreement on the alignment)  thus emphasising the general area of high pressure across the Pole, including NE Greenland, connecting to the east European ridge. Thus at the moment we still have the intense Canadian vortex and associated trough stretching south east across southern Greenland towards the UK.

But as mentioned last night the very strong westerly upper flow leaving the eastern seaboard is partly diverted in mid Atlantic NE/N by the ridging into Greenland. So although the current Atlantic profile is ideal for cyclogenesis the direction of travel and how far of the lows is a little problematic. But weather over the UK  unsettled with strong winds on occasions looking the percentage play with temps below average.

But reverting to my opening comments which was related to tonight’s GEFS and EPS means the NOAA 6-10 which is blend of tonight’s outputs does indeed the start of the transition with the Azores ridging in mid Atlantic which initiates the trough disconnection and interrupts the strong westerly upper flow.

 

[knocker]

As we were talking briefly about surface radiation inversions this morning. Not due to radiation, the McGrath surface to 925 mb inversion was 31.3°C (56°F)!!! today This is a February record.

Edited February 9, 2018 by knocker

[knocker]

The band of rain (perhaps some snow on high ground in the north) associated with the frontal system expected today is currently lying south west Scotland, N. Ireland, NW England, Wales and the south west whilst there is a widespread frost to the east. And the wave expected later is currently getting organized away the south west. During the day the band of patchy rain will move SE with clearer weather behind but by 1600 the wave has arrived over N. Ireland  bringing more heavy rain in the north and snow on the higher ground in Scotland and the north of England

The wave continues to deepen as it tracks into the North sea whilst the front tracks SE bringing more patchy rain in England and Wales. The rain more persistent  in the north and much of it could be of snow over the higher ground in Scotland and the north of England and accompanied by high winds, perhaps gale force, across N. Wales and the central belt of England. Once the low has moved further east the UK will be in cold north westerly airstream with frequent wintry showers of just about everything concentrated in Scotland and western coastal areas.

The showery and cold north westerly continues overnight but by 1200 Monday the wind has backed westerly as a front associated with another deep low is approaching from the west  Over the next 12 hours the low deepens to 960mb and tracks north over Iceland at Tuesday 00 whilst the front brings rain, snow in the north, and strong winds to the UK

The front clears by 1200 on Tuesday but during it's travels it develops a wave which  impacts the north and could well bring a fair amount of snow to Scotland and the north of England, particularly on the high ground.

Stepping back a little now to get a quick overview, there is a complex cold  upper trough dominating the Atlantic with a strong thermal gradient and thus an ideal breeding ground for some very active cyclogenesis and this is what we get. At Wednesday 00 there is a very deep low in mid Atlantic with the warm front SW Ireland to Cornwall.

Twelve hours later the low has deepened to 947mb south of Iceland and the front has brought rain, snow in the north, and gales to the UK

 

 

Edited February 10, 2018 by knocker

[knocker]

Some spot charts from the ecm essentially in support of the above post

[knocker]

An update on today. Quite heavy rain later with snow in Scotland and high ground in the north of England and strong winds across Wales and the southern half of England.

And need to keep a storm watch, and possible snow watch, next week as the Atlantic depressions gear up

The westerly influence is reflected in the precipitation distribution

[johnholmes]

Yes, a windy unsettled and rather cold spell over the next few days looks pretty much certain.

Thanks for the regular updates k, nice to get away from the, at times, rather frantic and personal atmosphere, in the main thread.

[chrisbell-nottheweatherman]

47 minutes ago, johnholmes said:

Yes, a windy unsettled and rather cold spell over the next few days looks pretty much certain.

Thanks for the regular updates k, nice to get away from the, at times, rather frantic and personal atmosphere, in the main thread.

I rarely bother with that thread now, John - even after extending my "Ignore" list, there's still an annoying amount of over-reaction and ramping (both cold and mild) in there.

Just a quick question for John, Malcolm or anyone else who might be able to shed some light on the matter, might I ask what the High pressure centre off the west coast of Ireland in the following output is indicating?  Thanks.

[johnholmes]

yES i NOTICED THAT cHRIS. i DON'T USE THOSE CHARTS SO K MAY BE ABLE TO GIVE YOU A BETTER ANSWER THAN ME. i DID WONDER IF IT IS SOME WAY OF INDICATING WHERE THE LOWEST VALUE IS, OR IS IT TO SHOW WHERE THE MAXIMUM RAINFALL IS BEING SHOWN. iN HONESTY i DON'T REALLY KNOW!

Oh heck please excuse the capitals, hit the wrong key as I started.

Edited February 10, 2018 by johnholmes

[knocker]

I've no idea Chris but I think it has something to do with two centres as it appears on a number of charts, like here for example

The midday geostationary showing the developing low west of Ireland. Image courtesy Dundee Satellite Receiving Station

 

[knocker]

The 1200 analysis

Edited February 10, 2018 by knocker

[knocker]

Once the rain and some snow in the north has moved away to the east it will be quite wintry in it's wake with frequent wintry showers of Rain, hail and snow in the strong W/NW wind, perhaps gale force in Wales and the north. This is also pretty much the picture tomorrow with ice another feature after a cold morning.

Edited February 10, 2018 by knocker

[chrisbell-nottheweatherman]

3 hours ago, knocker said:

I've no idea Chris but I think it has something to do with two centres as it appears on a number of charts, like here for example

The midday geostationary showing the developing low west of Ireland. Image courtesy Dundee Satellite Receiving Station

 

Had both been labelled "L" I'd have understood it - what confused me was that, to me, "H indicated an anticyclone.

[knocker]

Not a huge surprise but the anomalies do not agree this evening so not too much waffle and just to note that it’s part of the rich tapestry of the current evolution.

In fact the overall NH pattern is in fact in pretty good agreement with the vortex lobe over Siberia, the Aleutian and east European ridges and positive anomalies over the Arctic and the intense vortex lobe over N. Canada.

But it’s the Atlantic arena that’s causing the problem and the handling of the trough associated with the latter and amplification of the Azores high, if indeed there is any.

The GEFS is all for ridging in mid Atlantic and severing the trough whilst the ecm emphatically is not. In fact the EPS continues to bequite keen on dropping the trough into mid Atlantic later. NOAA leans to the EPS.

Until this is sorted the det runs are certainly going to struggle with the detail so I would imagine the sales of Diazepam have yet to peak. I will venture that temps will remain below average and it will continue unsettled.

 

Edited February 10, 2018 by knocker

[knocker]

Today and tonight

The low and fronts associated with yesterdays bad weather have scooted away east leaving the UK in a a strong, unstable, north westerly airstream. This will mean frequent wintry showers of rain, sleet and in particular snow in N. Ireland and western Scotland. The showers will initially be confined to these areas plus Wales and the western coasts of England but increasingly further inland as the day progresses and the snow showers may well slip further south as well. Some reasonable accumulations could occur. There is always the chance of more persistent precipitation with the odd trough embedded in the flow. The showery activity will continue overnight, but perhaps more confined to northern areas with the wind backing a tad, but with ice an added danger Monday morning with a widespread frost. Feeling very cold in the strong wind

Monday another day of sunshine and showers, these confined to the west, but not feeling as cold as the wind abates. But by 12 a deep low 971mb is south of Iceland with associated fronts lying N/S west of Ireland and by Tuesday 00 they have tracked east to be over Ireland backing the surface wind over the UK to a strong south westerly accompanied by a band of rain. This is probably going to be another marginal affair with snow on the higher ground to the north.

The band of rain/sleet/snow clears to the east by 1800 Tuesday leaving the UK in a transitional weak ridge with showers in the west but there is an occlusion out at 20W associated with a deep depression 954mb south east of Greenland that is poised to move track east, which it duly does, and by 1800 Wednesday has brought more rain and strong winds to the UK. At the moment it would appear unlikely to bring snow apart from perhaps on high ground in Scotland.

Once cleared the UK is back in and unstable westerly with frequent wintry showers in the NW once more. The Atlantic is dominated by the cold upper trough but changes are afoot with the Bermuda high pressure beginning to amplify and surge north in the western Atlantic but there we must leave it. This is of course according to the gfs.

Having had a quick glance at the ecm for the purposes of this thread no significant difference to the gfs. I say no more.

 

.

Edited February 11, 2018 by knocker

[knocker]

Terrific Modis high res. image for 1130 (courtesy Dundee Satellite Receiving Station) showing the low in the North Sea and the showery regime to the west and the surface analysis for the same time

[Polar Maritime]

Yes lovely image that Knocker, A true PM flow.

Edited February 11, 2018 by Polar Maritime

[knocker]

Indeed PM and a broader view on the 1200 geostationary.

[knocker]

There is a snow and ice warning in operation for Scotland tonight and tomorrow morning so perhaps the showers indicated will stretch further inland. Ice may well be a concern elsewhere as well as temps drop below freezing in many areas. And to the west the next front is on it's way

 

Edited February 11, 2018 by knocker

[knocker]

Further to the above the occlusion is over Ireland by Tuesday 00 a belt of rain/sleet/snow is lying down England, Scotland Wales having cleared N. Ireland. This is another marginal scenario vis snow but certainly quite possible in northern areas particularly on high ground.

Wind on 24 hours and 1200 Wednesday has a very deep depression south of Iceland with the associated fronts bringing strong winds and rain to all parts of the UK but quite likely sleet and snow preceding the occlusion in places. Firming up on the detail of  possibly tomorrow.

 

 

Edited February 11, 2018 by knocker