Models, teleconnections and nowcasting

[knocker]

According to the gfs over the next three days the tpv extension continues to move east as a new cut off upper low is established over western Europe whilst the high pressure to the west gets a boost as it slips east over the UK. Generally it will be dry, perhaps some showery weather slipping north initially, and becoming quite windy in the south But the main feature probably some extensive ground frost before starting to warm up a tad by Wednesday

Edited May 6, 2020 by knocker

[knocker]

The ecm brings the high pressure quite quickly into play and perhaps not quite so bold with the widespread frosts early next week, albeit still cold mornings/ Not to forget these are air temps not ground

Edited May 6, 2020 by knocker

[knocker]

Nothing enlightening to add to last evening's waffle except perhaps a tad closer agreement which would indicate adry period with temps around average

[knocker]

Midday sat image

[knocker]

Von Karman vortices off the Cape Verde Is.

[knocker]

Arctic Ocean to the Grain Coast

Frontal cloud bands over western UK and Ireland and some Ci over France but widespread over Iberia

http://www.woksat.info/etcace07/ace07-1021-a-apt.html

Edited May 7, 2020 by knocker

[knocker]

Solid cloud from around 5000ft down here courtesy of the trough accompanied by some rain and some medium/high cloud over the Midlands. Frontal rain over Scotland

[johnholmes]

2 hours ago, knocker said:

Solid cloud from around 5000ft down here courtesy of the trough accompanied by some rain and some medium/high cloud over the Midlands. Frontal rain over Scotland

Yes the Watnall/Nottingham ascent is too dry in the bottom few thousand feet for the storms to be released here, shallow Cu outside tops 4-6,000 ft, so far.

[knocker]

I suppose one of the more interesting facts of the gfs and ecm det runs this morning is the quite intense high cell created over the Arctic by the intensifying Russian and Alaskan ridges with sundry tov lobes northern Europe, Canada and the NW Atlantic Downstream the important difference is the role role of the cut off upper low to the south with the ecm indicating the subtropical zones active around this. a much better scenario for the UK, than the gfs which favours a phasing with the tpv lobe. NOAA tending towards the former

 

Edited May 9, 2020 by knocker

[knocker]

The GEFS is actually more in line with the others but as the NH pattern continues to shift east attention switches to the trough in the NW Atlantic and the suppression of amplification of the subtropical zones in the Atlantic and Europe. and there is no agreement on this as yet so a watching brief

Edited May 9, 2020 by knocker

[knocker]

Closer to now the movement of the cold front on Sunday

Edited May 9, 2020 by knocker

[johnholmes]

The 500 mb view from me

Saturday 9 may

Ec-gfs

Show a similar n of west 500 flow into the uk but ec shows much more of +ve heights causing it; they also show similar positions for the troughs either side of this ridging, although shapes of each are not the same; ec shows no E-W orientation which gfs has.

Noaa is not totally dissimilar, it has the western trough elongated out of n America directed ese then a slackish ridge in the uk area with very little in the wat of +ve heights.

Overall they suggest a flow off the atlantic with noaa very slack and about w’ly compared to ec-gfs with a stonger flw thanks to the trough e of the ik really.

Difficult to give a definite surface pattern in the 6-10 day outlook, no raging Atlantic is the one definite from these charts, possibly more ridging than troughing type weather. No heat wave but, once the N’ly into early next week fades away then certainly not a cold outlook.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

 

[mushymanrob]

ok.... if im understanding this right, or somthing close... would this chart for the west mids today at 1800 suggest only a slight CAPE?

and does the rise in temps above 200 hpa account for the cirrostratus?
 

[johnholmes]

44 minutes ago, mushymanrob said:

ok.... if im understanding this right, or somthing close... would this chart for the west mids today at 1800 suggest only a slight CAPE?

and does the rise in temps above 200 hpa account for the cirrostratus?
 

Taking the second question m, no that is the next layer of the atmosphere above the Tropause where temperatures increase with height

It is a pretty soggy ascent above the lowest layers, and using basic meteorology with a Td of 12-14 and a dry bulb of 22-25 C, easily reached in the Midlands the ascent is then unstable to about 35,000 ft, the Troppause. So no doubt the numbers for CAPE etc which the model produces will be high. At least ISOL TS is probable if the ascent is correct. We can chekcthis once the 12 Z soundings are out and assuming also that Watnall/Nottingham do an ascent today, station 03354.

 

If I get cnace I'' take a look later although k may well do that before me.

Hope that helps a bit?

J

[mushymanrob]

5 minutes ago, johnholmes said:

Taking the second question m, no that is the next layer of the atmosphere above the Tropause where temperatures increase with height

It is a pretty soggy ascent above the lowest layers, and using basic meteorology with a Td of 12-14 and a dry bulb of 22-25 C, easily reached in the Midlands the ascent is then unstable to about 35,000 ft, the Troppause. So no doubt the numbers for CAPE etc which the model produces will be high. At least ISOL TS is probable if the ascent is correct. We can chekcthis once the 12 Z soundings are out and assuming also that Watnall/Nottingham do an ascent today, station 03354.

 

If I get cnace I'' take a look later although k may well do that before me.

Hope that helps a bit?

J

yep...thats fine thanks john, ill look into these charts properly when the cold arrives (so stuck inside) , i was just wondering what caused the cirrostratus that i can see..

[knocker]

Sun > Tuesday with the 06 ecm

Currently

 

[knocker]

The cold air already at Lerwick, temp 6.5C, but complicated by the proximity of fronts (700mb?) and very moist in all the tropsphere

 

Edited May 9, 2020 by knocker

[knocker]

In the cold air to the north Widespread open cell convection east of Iceland

[knocker]

The cold front through Nottingham, just, by midday. Note backing upper winds on the Two soundings influenced by the warmer air aloft courtesy of the anticyclone to the west. High cloud likely at Albermarle above the dry zone.

[knocker]

Cold air at Nottingham at midnight in the north easterly wind (surface temp 3.0C) but a large inversion 821mb -8.5C > 708mb -5,5C illustrates the ingress of drier and warmer air above courtesy of the anticyclone to the west and the NE wind backs WNW

Camborne on the other hand is still very close to the cold front

[knocker]

Nice 0600 sat image showing the low over southern France and associated frontal system

[knocker]

Leaving aside the key role of the intense high pressure over the Arctic the next important aspect of the ecm, and the gfs.output is the major trough tracking into the western Atlantic which promotes amplification of the subtropical high, aided and abetted by the cut off low over western Europe and further amplification to the east

Edited May 11, 2020 by knocker

[johnholmes]

1 hour ago, knocker said:

Cold air at Nottingham at midnight in the north easterly wind (surface temp 3.0C) but a large inversion 821mb -8.5C > 708mb -5,5C illustrates the ingress of drier and warmer air above courtesy of the anticyclone to the west and the NE wind backs WNW

Camborne on the other hand is still very close to the cold front

In spite of what the Nottingham ascent shows  a couple of sharp showers here in the past hour and looking NE perhaps further to come

[knocker]

12 minutes ago, johnholmes said:

In spite of what the Nottingham ascent shows  a couple of sharp showers here in the past hour and looking NE perhaps further to come

A Boulmer sounding might have been useful

[knocker]

Following on from the earlier post above and the medium trem GEFS. EPS and NOAA are not adverse to that scenario so settled, dry with temps a tad above average

The ext period is a slightly watered down version of same

Edited May 11, 2020 by knocker