Short range model discussion - into 2018

[knocker]

Obviously the detail will vary but the ecm on the same page as the GFS so just some spot charts.

[knocker]

A complex midday analysis to say the least but the high res. Modis at 1330 (courtesy Dundee Satellite Receiving Station) does highlight some of the features such as the low near southern Ireland , a line of showers to the south west currently affecting here after a very fine morning, and the frontal cloud over the NW Midlands. Plus the cloud associated with the low(s) over Europe also affecting the south east. The 1300 chart is an indication on how far north the warmer air has reached and some fog around.

[phil nw.]

Latest fax from the 12z UK model at T48rs shows how well established the less cold conditions will be with the 528 contour line expected to be pushed to the north of the UK by that time..

The cyclonic pattern having mixed out the deep cold leaving us all in a broadly similar setup.

GFS charts showing the pressure/precipitation forecasts at mid day for the next 3 days 

     

Underlining a slow moving almost stationary picture of a complex area of low pressure over and extending towards the south west with signs of further secondary developments heading this way.Bands of rain and showers moving in from the south west across many areas with temperatures on the rise.

We can see from the expected height above sea level of the freezing level by T72hrs showing how the "warm up" has spread to all areas

Any snow fall by this time would be confined to higher levels in the far north.

 

Edited March 4, 2018 by phil nw.

[knocker]

Keeping in mind last night's anomalies this evening's gfs is not certainly not dissenting. The pattern at T60 is almost a carbon copy with high pressure over NE N, America, a trough in the sout east and a trough in the eastern Atlantic. The twin energy flows and an ideal breeding ground for the formation of depressions portends unsettled weather for the UK with temps generally around the average. This  sort of set up could also produce some very windy spells.

EDIT

I posted this at the same time as Phil's above. Fortunately they don't 'clash'.

Edited March 4, 2018 by knocker

[knocker]

Satellite at 1545 that shows the rain in the south east and showers in the south west.

[knocker]

There is little change with the anomalies this evening and the difference remains the orientation and intensity of the trough in the eastern Atlantic which leads to disagreement on the direction of the upper flow in the vicinity of the UK. This is not unimportant because although both agree on a healthy depression breeding environment in the Atlantic this does alter the positioning  and movement of same and along with the surface temp  For example the EPS might even tend a tad above average. So still looking at an unsettled period with the detail to be sorted.

[knocker]

Today and overnight.

Scotland will be quite chilly with outbreaks of snow, sleet and rain depending on location and these will continue through to tomorrow morning. Further south not unpleasant with broken cloud and plenty of sunshine as the temps creep up but showery rain will move into the south west late in the morning and consolidate and move north during the day  By morning this will have cleared southern England and Wales and thus much drier. The sat. image is for 0400.

Much the same story for Tuesday with Wales and the south remaining dry with sunny spells whilst the north, N. Ireland and Scotland outbreaks of showery snow, sleet and rain will continue, the former restricted  to high ground. Still quite a latitudinal temp variation.

By midweek low pressure continues to be the controlling influence with the upper trough and associated surface lows dominating the Atlantic and points east. Ergo the unsettled weather with outbreaks of showery rain, perhaps thundery, will continue interspersed by sunny intervals and as the temps creep nearer average albeit still cold at night with ice and patchy fog in the north

This scenario continues over Thursday and Friday with low pressure still dominating the eastern Atlantic with the two upstream energy flows coalescing in mid Atlantic. I notice the METO referred to this yesterday as a cyclonic block

Edited March 5, 2018 by knocker

[knocker]

Satellite for 0530 and 0600 surface chart

 

[knocker]

Moderate rain into Cornwall on the 0900 and also coastal NE Scotland where snow is becoming marginal

[chrisbell-nottheweatherman]

6 hours ago, knocker said:

 

This scenario continues over Thursday and Friday with low pressure still dominating the eastern Atlantic with the two upstream energy flows coalescing in mid Atlantic. I notice the METO referred to this yesterday as a cyclonic block

 

Presumably the vortex has remained fairly weak given that most Atlantic depressions would head towards us rather than acting as a cyclonic block?

[knocker]

The 1200 geostationary (Dundee Satellite Receiving Station)

[knocker]

17 minutes ago, chrisbell-nottheweatherman said:

Presumably the vortex has remained fairly weak given that most Atlantic depressions would head towards us rather than acting as a cyclonic block?

Well partly. I'm assuming that the quite intense upper trough in the eastern Atlantic is the 'block' they mean and that depressions still tracking east  phase in with it. Well that's my take on it and perhaps 'block' is a tad misleading.

Edited March 5, 2018 by knocker

[chrisbell-nottheweatherman]

2 minutes ago, knocker said:

Well partly. I'm assuming that the quite intense upper trough in the eastern Atlantic is the 'block' they mean and that depressions still tracking east  phase in with with in with. Well that's my take on it and perhaps 'block' is a tad misleading.

Not a cut-off depression, though, which I'd presumed a blocking cyclone would be - interesting.

[knocker]

The concentrated area of rain cleared here about an hour ago (see 1530 sat. image) leaving a pleasant late afternoon and it will track north through England and Wales this evening and over night whilst outbreaks of rain and snow on the high ground will continue in Scotland. Much of England and Wales will be dry by morning

Edited March 5, 2018 by knocker

[Andy Bown]

Hi Knocker, have we had a small LOW move North this afternoon / evening within the general larger slack LOW? I ask because at around 17.00 low cloud was moving from the ENE while the rain was moving S-N.

[knocker]

43 minutes ago, Andy Bown said:

Hi Knocker, have we had a small LOW move North this afternoon / evening within the general larger slack LOW? I ask because at around 17.00 low cloud was moving from the ENE while the rain was moving S-N.

Not that I know of Andy but a small feature would not necessarily show up on charts that I see  It's possibly you may get a ENE drift within the main low

EDIT

Unless of course this is the small low

Edited March 5, 2018 by knocker

[knocker]

Little change with the anomalies this evening. Upstream a diffuse vortex NW Greenland to NE North America with ridging centrally and the important ridge in the north west Atlantic to the Labrador Sea. So still the two upper flows, one running south east across southern Greenland and the other, stronger one, exiting the eastern seaboard, which coalesce in mid Atlantic. Thus a favourable environment for depressions to track into the UK on the resulting quite strong WSW upper flow. This would portend a period of unsettled weather with possible gales and temps a little below average. The usual caveats vis the det. runs.

Edited March 5, 2018 by knocker

[knocker]

Both the evening fax and ecm take a similar view on deepening the low Friday/Sat

 

[knocker]

The general theme over the next five days (and longer) is unsettled with low pressure dominating.

For most practical purposes today and tonight the UK can be divided into two. Scotland will remain on the cold side with outbreaks of rain, sleet and snow, probably more confined to the north by tonight, whilst the rest will have sunny spells and the odd shower once the cloud and rain has cleared the north, Overnight the showers will die out apart from in the west and more general rain will encroach the south east. Still quite cold in the early morning in many areas.

Wednesday has low pressure covering the country with the center west of the Hebrides with small disturbances in the general circulation thus again sunny spells and rain showers,some heavy, falling as snow on the high ground in Scotland. At this stage probably an idea to keep an eye on the far south west and the energy exiting the eastern seaboard, Temps improving but still a little below average.

The sunny spells showery weather continues through Thursday with snow on the high ground in the north as low pressure continues to be influential with perhaps some longer spells of rain thrown in. Away to the south west a large depression is slowly tracking north east.

By 1200 Friday the UK low is still centred near the Hebrides but a front associated with the low to the south west, that is still moving slowly north east, is already affecting the south of England with rain. The front continues to track north as a small wave forms on it.

Progress of the front/rain, perhaps some snow on the high ground, and quite strong winds north through England and Wales on Saturday is slow as the main, deep low, drifts slowly east to be north west of Coruna by 00 Sunday.

This is of course according to the gfs.

 

 

 

Edited March 6, 2018 by knocker

[knocker]

Satellite for 0520. (courtesy Dundee Satellite Receiving Station)

[knocker]

According to the ecm an interesting temp contrast north and south of the warm front at 1200 Saturday which is orientated Bristol to the Wash. To the south 10-13C and the north 4-6C

[knocker]

Current surface analysis

[johnholmes]

Using my usual anomaly charts and not much different on them from the Sunday outlook I showed, no sign of any real marked warm up. Still the risk of a cold burst behind one of the lows the 500 mb flow may generate from the NW or even N perhaps.

For charts see post in main thread.

Keep up the good work knocker, I suspect more and more folk use your updates for a quick pretty unbiased quick and easy to read outlook.

[chrisbell-nottheweatherman]

2 hours ago, johnholmes said:

 

For charts see post in main thread.

Keep up the good work knocker, I suspect more and more folk use your updates for a quick pretty unbiased quick and easy to read outlook.

I endorse you comments entirely, John - I use Malcolm's thoughts and the outputs he includes to base my understanding of what I'm likely to experience here over the next 48-72 hours.

[knocker]

Brilliant high res. MODIS at 1130. (courtesy Dundee Satellite Receiving Station). Interesting in this neck of the woods after a very fine early morning some very thick Ci encroached, from the Biscay low?, followed by some large Cu and a lengthy moderate rain shower.