Models, teleconnections and nowcasting

[knocker]

I was down at Portreath this morning and around 1100 a violent rain/hail shower struck and for a fair while the weather was horrific with winds gusting between 50 - 60mph at a guess as it also funnels up the valley. All down to tis occlusion and the midday radiosonde must have gone up in the Cb

Edited February 25, 2020 by knocker

[knocker]

The 06 ecm

[Interitus]

14 minutes ago, knocker said:

with winds gusting between 50 - 50mph at a guess

That's a very specific estimate!

Edited February 25, 2020 by Interitus

[knocker]

2 minutes ago, Interitus said:

That's a very specific estimate!

Ah yes. I'm afraid my decline is gathering pace

 

[knocker]

Rapid cyclogenisis at the end of the week and as the frontal systems from the resulting very deep low rush through, rain and very strong winds This according to the gfs

Edited February 25, 2020 by knocker

[knocker]

It can be readily seen that even at this range there is no agreement on the evolution at the end of the week

Edited February 25, 2020 by knocker

[knocker]

By no stretch of the imagination are the ext anomalies in agreement this evening but they are both still on the same page regarding the re-alignment of the tpv and the the retreat of the atlantic trough. Hopefully this will continue and presage a quieter and.in particular,  a drier period of weather

[knocker]

The North Atlantic 500mb and surface analysis for midnight

The country remains in the unstable north westerly this morning so a continuation of the squally heavy showers of rain/hail and snow, concentrated in western regions, particularly the north west. But as he day wears on these will become less frequent in southern regions and the wind will abate. But by early evening cloud will increase in the south west as the much discussed wave approaches. Temps not that low further south but the wind chill has to be factored in

Through this evening and overnight the rain belt will track east, complicated a tad by an upper warm front preceding the main system, effecting mainly southern regions but spreading north into the Midlands. This could fall as sleet/snow on the higher  along the northern flank.

The rain/sleet and snow will clear through Thursday morning leaving a cold day with showers, mainly in the north west

But as can be seen the upper trough in the Atlantic has become quite complex and further frontal systems track north east to bring rain to many areas on Friday with strengthening winds

Over Friday night through Saturday the whole system deepens rapidly as the jet hits the buffers of the amplifying ridge to the east. So strong winds in the north and a say of sunshine and showers

By Sunday the low is filling over Scotland so another day of sunny interval and showers, perhaps longer periods of rain in Scotland. But now the country is back in the cooler air

 

Edited February 26, 2020 by knocker

[knocker]

According to the gfs it remains unsettled through next week with the  tpv continuing to dominated and the western Atlantic an active baroclinic zone. Not to get too wrapped up with the detail

[knocker]

This mornings fax and the ecm DPs.

[knocker]

The tricky business of pinning down any details next week is immediately apparent when the ecm differs by 20mb with Exeter on the depth of the low on Sunday and scoots another perturbation across the country

In view of that just an overview of next week > unsettled

Edited February 26, 2020 by knocker

[knocker]

Regarding the ext anomalies this morning nothing much to add to last night's comments except perhaps NOAA is also sniffing the coffee

[knocker]

The fax charts for 06 and 12 tomorrow/ I'm not going to attempt to deduce where the precipitation will become snow in this tricky knife edge scenario, way above my pay grade, but according to the latest METO video we are looking Cotswold then east along the M4 northwards to East Anglia.through the morning.And not to forget snow down to low levels in the north of England on the trough tracking south. I will throw in a couple of charts from the 06 ecm

Edited February 26, 2020 by knocker

[knocker]

The fax updates for Saturday

And the main problem being rain in areas that don't need it

[knocker]

Could be some phasing with the trough with snow in the NW

[knocker]

The North Atlantic 500mb wind field and surface analysis for midnight and the 0400 surface chart

The low near the Scilly Isles will move very quickly east this morning as noted by the area of precipitation.Currently, as can be seen, alot of rain around in central and southern areas and this could turn to sleet and snow north of the M4, more particularly over higher ground.There could also be some sleet and snow in the NW of England courtesy of that trough, and a continuation of wintry showers over N. Ireland and western Scotland. Feeling a tad chilly in the wind

The showers will continue in the NW through this evening and overnight but elsewhere will be clear with icy patches developing by morning in the north and east nut cloud will encroach in western regions as further frontal systems are developing at the base of the upper trough in mid Atlantic and tracking north east and rain will arrive in the south west by 0400

The rain will spread north east through Friday effecting most of the UK, NW Scotland has showers and longer periods of rain from a different occlusion, and will be heavy at time and with some snow over the higher ground in the west and maybe a tad lower in the north east. Again feeling quite chilly in the strengthening wind

Over Friday night the complex area of low pressure becomes more organized and deepens rapidly with bands of rain tracking NE across the country in the early hours and through Saturday before becoming showery

By midday Sunday one low centre has drifted across the country into the North Sea with the wrap around occlusion continuing to bring an area of rain. And south of the front it will be quite windy possibly reaching gale force

Monday looking like a sunshine and showers day with more persistent rain in the north

Edited February 27, 2020 by knocker

[knocker]

According to the gfs developments to the west are quite complex at the beginning of next week resulting in further lows swinging across the Channel area over Tuesday and Wednesday. Best left there I feel

Edited February 27, 2020 by knocker

[knocker]

The 0600 chart

 

[knocker]

This morning's updated fax charts for Sa/Sun

And the ecm rainfall over the weekend and quite windy for a time as the low slips east

[knocker]

Although amplification creates a cut off high cell to the north, according to the ecm troughs continue to track across the Atlantic bringing more wet and windy weather next week

 

Edited February 27, 2020 by knocker

[knocker]

The ext anomalies this morning are still indicating a re-alignment of the tpv associated with some amplification of the Atlantic subtropical high and thus a relatively more settled period. Albeit at the moment no agreement on the progress of this with the GEFS being far more bullish

[knocker]

Initially on Saturday the ecm has much of the UK in the warm sector and then the cold front nips through and the winds to the south of tine occlusion increase as the low tracks east

Edited February 27, 2020 by knocker

[knocker]

And further to the above. Exeter has the centre of the low at 949mb by midday Saturday which is very low for one perched over N. Ireland. The precise direction of drift from here over the next 12 hours would seem important as to the strength and positioning of the strongest wind belt

Edited February 27, 2020 by knocker

[knocker]

Once this all clears there is quite a complex energy distribution resulting in another low tracking north east by mid week

[knocker]

The North Atlantic 850mb temp anomaly and surface analysis for midnight

The area of heavy rain, associated with the warm front, will move north east through the day with snow on the higher ground of N. Wales, northern England and southern Scotland and thus by early evening much of England and Wales will be in the warm sector with a wide temp spread. A further band of rain will follow on behind through the afternoon  But whilst this has been going on the low to the west has been deepening rapidly

This band of rain will continue to track north through the evening before the cold front(s) start to track east across the country and the wind starts to pick up

The fronts clear quickly to the east through Saturday morning thus the country back in the colder air, but by midday the low is 949m over N. Ireland and the wind is now very strong along western regions of England and Wales

The low continues to drift north over Saturday night and through Sunday so a very windy night/day, particularly in western and northern regions with showers further south and longer periods of rain over the former

By Monday the low is filling north west of Scotland resulting in another showery day with sunny intervals but more prolonged rain in the north courtesy of the trailing occlusion. But the wind is abating, particularly in the south

And by Tuesday the low is absorbed within the main trough but further troughs have arrived to the south west and more surface frontal systems are tracking north east. Essentially another sunshine and showers day but not as windy

Edited February 28, 2020 by knocker