Model discussion - Warm spell ending as Spring begins

[Frosty.]

Darn it..I was really hoping for this but I guess I will have to make do with what tonight's Gfs 18z shows instead!!!

[MATTWOLVES 3]

5 minutes ago, Frosty. said:

Darn it..I was really hoping for this but I guess I will have to make do with what tonight's Gfs 18z shows instead!!!

You never know frosty, them scenes are possible if we get a strong enough wind!!

[icykev]

Tuesday is still looking like an interesting day by all model accounts. Will probably be the last biting cold spell/day we get until Christmas or next year . Hopefully brings some snow to all that is still searching for it. Don't think it will reach me but cheltenham will be great viewing, unless it intensifies (cyclo something). Sound like the unspoken now remaining cool, snow at times with the chance of thunderstorms and warm sunny spells

Should be an interesting start to the festival❄ 

Edited March 8, 2019 by icykev
looks nasty already

[icykev]

Ok maybe not the last day

[knocker]

The NH 500mb and the Atlantic surface analysis for midnight and the 0500 UK surface chart.

A clear start to the day with quite a widespread frost but cloud and rain from the next frontal system will quite quickly effect the north west and then all western regions, before tracking east across the country during the rest of the day.The heavier rain will be in the north with some snow on the higher ground in Scotland, The rain will clear into the north sea during the evening but but still quite windy in the north with squally showers over Scotland and perhaps N. Ireland.

Saturday a generally unsettled day in a quite fresh north westerly wind with sunshine and showers and a period of more prolonged rain encroaching the south west during the afternoon as another frontal wave tracks east. Some cooler air being introduced from the north west

Over Saturday night and through Sunday the pattern is quite complex with an upper trough residing over the north east Atlantic, including the UK, with a new trough entering the fray in the west. Thus a mryiad of surface systems floating about, some effecting the UK, resulting in  another unsettled day with showers and longer periods of rain, particularly in the north where there could be some snow down to quite low levels in what is a much cooler day.

The showers will continue for a while over Sunday evening but a transient ridge is moving east so a much quieter day on Monday but note that the aforementioned trough in the west has now entered the picture and there is quite an active surface low in mid Atlantic.

The low continues to deepen and track north east and by 1200 Tuesday is 961mb WNW of the Hebrides resulting in strong winds and heavy rain sweeping across the country through Tuesday/Weds with perhaps severe gales in the north with snow over the high ground there, and maybe even a tad lower. The continuous rain will give way to frequent squally showers once the fronts have passed through/

Edited March 8, 2019 by knocker

[Sky Full]

GFS this morning is showing the following conditions for Sunday....

Deep low pressure centred on the UK:

High winds across the south and west:

Bands of rain and showers with some snow mixed in:

  

This seems to be a fairly typical picture for an average UK March.

 

Edited March 8, 2019 by Sky Full

[knocker]

A quick look at the ecm post the short range. By midnight it has the low just west of Denmark as it has tracked north of Scotland and then south east as the subtropical high again surges in the west. Thus the UK in a brisk north westerly

But the surge of the high is just a quick flex as rain from a warm front associated with the low in the Denmark Strait brings rain and more strong winds across the country on Thursday. And over the next 24 hours. as the low tracks east of Iceland, the cold front will duly follow accompanied by another belt of rain

 

Edited March 8, 2019 by knocker

[knocker]

The 0600 WV image. A veil of Cs down here at the moment with some Cu

[Frosty.]

Well..it is the day after tomorrow but it's not the day after tomorrow if that makes sense!!

[Jordan S]

No one seems to of mentioned this but still the possibility of potent storm for some parts this Sunday? Not much support which is very unusual at this late stage Arpege in particular very keen on this storm the GFS seems to be leaning back towards it but other charts aren't aggreing but certainly could cause a few problems if it happens.. 

 

[Summer Sun]

The pennines could see the most snow by the end of Sunday with up to 15cm possible. SW Scotland seeing up to 10cm and some other northern and western locations ranging from 1cm to 8cm

Obviously this time of year any snow doesn't hang around very long unless you get a fairly exceptional set up

Edited March 8, 2019 by Summer Sun

[knocker]

Over the last three days the ext EPS has consolidated it's upstream pattern but it is not as zonal across the Atlantic with the European trough and the subtropical high pressure remaining more engaged and thus the strong westerly upper flow takes on a north westerly slant over the UK and thus the unsettled weather staying on the cool side with temps below average. Albeit the flow does continue to flatten later

Again last night's NOAA not identical but in the same ball park

 

 

[Derecho]

Not a bad 06z IMO, the Atlantic winds down and looking at the NH charts, it becomes pretty clear what that is due to...

 

We get some calmer weather under a chilly NW wind before high pressure ridges in around the Spring equinox to bring some fine weather. I wouldn't mind that! Some places would even see snow next weekend!

Another cold pool heads towards the NW North Atlantic... but by then the Azores high has already made its move, keeping us under a settled pattern.

[MATTWOLVES 3]

Possibly a few cold shots according the 6z operational runs, there will be an ongoing risk of snow in places, I say places has snow can be difficult to pin down to any location! Also around day 9 or 10 we have a potential Nthly bringing a risk of the white stuff to more Eastern and even THE SE areas. The  colder arctic sourced air being picked up by the latest ensembles quite nicely! 

Edited March 8, 2019 by Mattwolves

[Frosty.]

Love the new upgrade..

To me the 6z operational looks better than the 00z in terms of wintry potential..anyone agree?

[MATTWOLVES 3]

1 minute ago, Frosty. said:

Love the new upgrade..

To me the 6z operational looks better than the 00z in terms of wintry potential..anyone agree?

Yes frosty, the upgrade is sweet, and th 6z brings wintry potential to more areas overall

[Frosty.]

2 minutes ago, Mattwolves said:

Yes frosty, the upgrade is sweet, and th 6z brings wintry potential to more areas overall

Actually I misspoke, the 00z in deep FI was far more wintry but the short to medium term looks better 

[MATTWOLVES 3]

2 minutes ago, Frosty. said:

Actually I misspoke, the 00z in deep FI was far more wintry but the short to medium term looks better 

Lol, I just went along with you, because I hadn't even viewed the 0z today, thanks for clearing that up though.

[icykev]

2 hours ago, knocker said:

Over the last three days the ext EPS has consolidated it's upstream pattern but it is not as zonal across the Atlantic with the European trough and the subtropical high pressure remaining more engaged and thus the strong westerly upper flow takes on a north westerly slant over the UK and thus the unsettled weather staying on the cool side with temps below average. Albeit the flow does continue to flatten later

Again last night's NOAA not identical but in the same ball park

 

 

Do not really understand these charts knocker. What do the blue purple red and green lines actually represent as there is no key and still learning when it comes to the NAO, let alone these charts. Any difference between nao and noaa? Just interested because snow risk on netweather says boom on the 23rd. Way out still though as always

[Summer Sun]

Short term the pennines still look to be best placed for some heavier snow possibly close to 4 inches by Sunday evening

Beyond this period we don't see much snow away from the higher ground and Scotland

 

 

[MATTWOLVES 3]

5 minutes ago, Summer Sun said:

Short term the pennines still look to be best placed for some heavier snow possibly close to 4 inches by Sunday evening

Beyond this period we don't see much snow away from the higher ground and Scotland

 

 

I would just love to see what these charts showed for the 2 or 3inch of snow that fell in the Dublin area on Sunday just gone!! My guess is.... Nothing!! If snow  crops up at short notice like it will inevitably do, these precipitation charts won't help one bit! 

[winterof79]

Sunday looking interesting for Derbyshire northward and NI

[MATTWOLVES 3]

8 minutes ago, winterof79 said:

Sunday looking interesting for Derbyshire northward and NI

 

 

 

Can we get this snowline a little further SW winterof79! Go on just a few miles! Still, I expect a few places are gonna end up being caught out.

Edited March 8, 2019 by Mattwolves

[stodge]

Afternoon all :)

I'm struck by the unremitting strength of the Canadian PV in the output this morning. Signs of the PV lobe draining away or moving to Siberia seem to have been erased in the form of a strengthening in the Canada/Greenland area (perhaps due to some faint Wave 1 warming from the Eurasian side which would trigger such a consolidation).

The problem for the trough diving down into Europe is a small cut-off LP in mid-Atlantic which forces the Azores HP to ridge further east back across Iberia and France so the LP can't dig too far SE. There's also (as per Exeter) a signal for rising pressure later in the month (the GFS 00Z OP rises pressure from the NW which would be interesting) with the more likely option rising that pressure from the SW so warmer, drier and more settled as we head toward month end (again, as you'd expect).

With the 10HPA temperature of the PV declining only slowly, it looks currently as though the PV will slowly dissipate by end April so nothing too dramatic.

[knocker]

1 hour ago, icykev said:

Do not really understand these charts knocker. What do the blue purple red and green lines actually represent as there is no key and still learning when it comes to the NAO, let alone these charts. Any difference between nao and noaa? Just interested because snow risk on netweather says boom on the 23rd. Way out still though as always

Firstly - the black lines on NH charts and the green lines on the NOAA are lines of equal potential height ( known as isohypse or contour lines) and are used to draw charts at different levels above the surface.which can be useful for many reasons but not the least for easily identifying troughs and ridges. A brief explanation here along with the rest of the isopleths

https://www.weather.gov/source/zhu/ZHU_Training_Page/definitions/isopleths/isopleths.htm

Secondly - The blue and red colouring on the NH charts indicates areas where the meteorological element under consideration (temp, pressure, etc) is lower or higher when compared to climatology over a specific period in the past for the time of year The NOAA charts are essentially the same but instead of colouring areas they use blue and red contour lines

The basic idea is to try and get an idea of what the long wave pattern will be in the medium term. It's quite important to try to nail this down because the det runs will be operating within this framework and from which the every day detail will evolve

They should not be used to determine detail, apart from very generally, but used in conjunction with the det runs (not every six hour production) as a check as to whether they are operating within the suggested parameters as the time scale increases

John Holmes is far better at interpreting these charts than myself, and has done for many years, and, in his opinion used correctly with the det, runs, it's as good as way as any of attempting to nail down the evolving pattern in the medium term. And that's good enough for me.

 

 

Edited March 8, 2019 by knocker