Model Output Discussions 12z 08/03/17

[Summer Sun]

It looks like Tuesday could well be the coldest day as winds come down from the arctic Wednesday and Thursday remain chilly but the cold northerlies get cut off as pressure rises from the west

[Weather Boy]

10 hours ago, MP-R said:

Of course worth remembering that when we had these Synoptics in January there was something of a wishbone effect across the country. I'm expecting some decent convection out of these charts.

Yes, it looks to me like those not close to the coast are likely to see precipitation remaining low.  Having in my location having had a pathetic 2.1 mm in the last 28 days, that doesn't look like changing too radically.

I am mystified as to why the west is show with all the snowfall, or at least precipitation.  Maybe I am being too simplistic, but the LP is of course to the east not the west, so why the lowing snow in Worcs and Gloucs, for example?  I would expect north Norfolk to be the more obvious candidate.

[ANYWEATHER]

Evening all , Ecm dilutes the cold a little but certainly a Thunder storm chart for the uk this time next week.....

[Summer Sun]

UKMO extended shows the colder flow of air getting cut off at t168 as the high edges in further from the west

[ANYWEATHER]

Hello Folks ...an extremely cold air mass from the gfs this time next week and its still sticking to its guns , What weather can we expect??? Everything but the Kitchen sink , well perhaps we might get that if we have a small tornado....

[snowray]

2 hours ago, ANYWEATHER said:

Hello Folks ...an extremely cold air mass from the gfs this time next week and its still sticking to its guns , What weather can we expect??? Everything but the Kitchen sink , well perhaps we might get that if we have a small tornado....

That chart is about as cold as it gets for late April I would think.

12z runs shortened the cold spell, 18z has extended it again slightly into Thursday with HP staying slightly further west.

Some snow showers and more organised bands of snow/sleet showing up almost anywhere.

Edited April 20, 2017 by snowray

[Cheshire Freeze]

Post cold shot, there are some stunning synoptics emerging through FI (if it was winter). All looks a bit familiar with N blocking taking hold as we head into May, with the jet pushed well south

[Summer Sun]

UKMO follows on from last nights t168 by cutting off the colder winds from Thursday

Given the lighter winds and strong sunshine now temperatures would be starting to recover by day with quite a pleasant feel

[legritter]

morning gang ,not posted lately but i am lurking and reading ,very interesting charts and a big thanks to all regular posters who keep this forum buzzing ,lets hope someof us get to see some white stuff ,cheers gang

[Summer Sun]

After a chilly period next week temperatures begin to rise just in time for the bank holiday weekend especially so for the south and south west

Edited April 21, 2017 by Summer Sun

[MP-R]

15 hours ago, Weather Boy said:

Yes, it looks to me like those not close to the coast are likely to see precipitation remaining low.  Having in my location having had a pathetic 2.1 mm in the last 28 days, that doesn't look like changing too radically.

I am mystified as to why the west is show with all the snowfall, or at least precipitation.  Maybe I am being too simplistic, but the LP is of course to the east not the west, so why the lowing snow in Worcs and Gloucs, for example?  I would expect north Norfolk to be the more obvious candidate.

I would imagine a trough in the flow enhancing shower activity perhaps. Similar to plume events when the most instability is out west but the thunderstorms head northwards to the east.

[Summer Sun]

Spring returns slowly but surely

[weirpig]

Just  for fun   because it really is outlandish   but the GFS  shows prolonged snow and wintry showers covering large swathes of the country   Yeah right.

[knocker]

Looking at this morning's anomalies and last nights NOAA the only thing one can say with any conviction is that we looking at a pattern change next week with the demise of the amplified meridional pattern and the unwanted colder spell.

Upstream not too bad with the twin lobes Franz Joseph and N. Canada with associated trough Scandinavia and the negatively tilted one orientated into the Atlantic. It could well be the handling of these troughs that is causing the disagreement downstream Although no strong anomalies NOAA and the GEFs are attempting to build a ridge in close proximity to the UK whilst the EPS is making much more of the Atlantic trough. The latter evolution would tend towards more unsettled zonal weather than indicated by the other two. Hopefully this wil quickly get sorted and the det runs start to agree. indications are that temps would still be little below average but rising.

Looking further ahea, again no agreement with NOAA tending to be the odd one out although that is possibly down to the longer time period but they are all on the same page, The Atlantic trough takes centre stage but with significant postive anomalies to the north and east of the UK the upper flow backs south west and temps edge above normal. NOAA has gentle westerly upper flow. Actually on reflection GEFS isn't hugely different to NOAA, it's the EPS that pushes the trough further east.

 

Edited April 21, 2017 by knocker

[stodge]

Afternoon all

Just a brief thought or two from me. The 06Z GEFS is all about northern blocking in FI, whether that's to the NW (OP) or NE (Control).

The main scenarios seem to be either:

1) Heights to the NW or NE are close enough to influence the UK and keep us in a mainly dry pattern with winds from the north or east.

2) If the heights develop too far to the north, the gap exists for the trough to take over which is in effect a combination of the Atlantic trough and the cut off Baltic trough migrating back SW. In that scenario, we turn much more unsettled with rain and showers.

Both options are on the table and it's a toss up for me which one wins out. The next Bank Holiday could either be dry, cool and fine or a warmer washout and all places in between.

[Frosty.]

Really potent Arctic blast by late April standards early / midweek according to the Gfs 6z with snow just about anywhere and some very sharp damaging frosts, especially over the snow fields on higher ground. 

I'm looking forward to it!

Edited April 21, 2017 by Frosty.

[Methuselah]

Reminds me of the back-end of April 1989; not only was it darned cold, it was followed by a very fine summer...So I'm hoping on knocker's analysis coming off, as a warm-up will be very welcome!

[Frosty.]

11 minutes ago, Ed Stone said:

Reminds me of the back-end of April 1989; not only was it darned cold

I've waited 6 months for a decent Northerly..better late than never I say

Nice looking Ecm 00z ensemble mean next tues / wed

Edited April 21, 2017 by Frosty.

[knocker]

4 minutes ago, Ed Stone said:

Reminds me of the back-end of April 1989; not only was it darned cold, it was followed by a very fine summer...So I'm hoping on knocker's analysis coming off, as a warm-up will be very welcome!

Well the cmc is cooking with gas Pete And the anomaly is not a million miles away from the others.

[rain_shadow]

20 minutes ago, Frosty. said:

Really potent Arctic blast by late April standards early / midweek according to the Gfs 6z with snow just about anywhere and some very sharp damaging frosts, especially over the snow fields on higher ground. 

I'm looking forward to it!

I think it will be "diluted" by the time. For this week, hards frosts were predicted last week: did not have any. I am certainly not looking forward to damaging frosts together with all the horticulture and landscape industry, and I am not even talking about my flowering fruit trees in the garden.

Edited April 21, 2017 by rain_shadow

[lassie23]

1 hour ago, rain_shadow said:

I think it will be "diluted" by the time. For this week, hards frosts were predicted last week: did not have any. I am certainly not looking forward to damaging frosts together with all the horticulture and landscape industry, and I am not even talking about my flowering fruit trees in the garden.

It always gets watered down, every cold spell did in the winter. I think snow will be limited to northern regions only.

[I remember Atlantic 252]

58 minutes ago, lassie23 said:

It always gets watered down, every cold spell did in the winter. I think snow will be limited to northern regions only.

very realistic post, know that'll happen, so my favourite charts on here posted earlier by SS

[weirpig]

1 hour ago, lassie23 said:

It always gets watered down, every cold spell did in the winter. I think snow will be limited to northern regions only.

Yep. Cold rain I would have thought. However the more North the better chance 

[Frosty.]

Nice looking potent Arctic blast on the Gem 12z which prolongs the cold spell to thursday and there is an increasing risk of wintry ppn and some of us will see snow, especially on hills and with sharp damaging frosts and icy patches..a  taste of winter in late April. Better late than never eh coldies

Edited April 21, 2017 by Frosty.

[Chris.R]

If I see a flake of snow this week i'll eat my Macbook.  27 months and counting.