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Paul

Model output discussion - 16th Nov onwards

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h500slp.png

 

h850t850eu.png

 

 

h850t850eu.png

 

North Easterly winds brings cold air back next Thursday.

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ECMWF precipitation for Saturday.

 

 151117_0000_102.png

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The GFS latest run ends on a cold note:

 

h850t850eu.png

 

h850t850eu.png

 

h850t850eu.png

 

I don't think it will happen but it is an idea we are heading atm.

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Colder run than the 0z with a chilly flow maintained throughout. Nothing too spectacular after this weekend, but seasonal. Beyond that, it's proving fruitless looking for trends in the later frames, e.g.

 

T384 on the 0z has a ++++AO:

 

gfsnh-0-384.png?0

 

T384 on the 6z is the, ahem,  polar opposite:

 

gfsnh-0-384.png?6

 

Could happen  :)

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ECMWF precipitation for Saturday.

 

 151117_0000_102.png

Looks good for coastal districts. Is there a chart for 850hpa temps for the same time, not expecting much here at lower levels but I can imagine somewhere like the North York Moors will see some decent snowfall.

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Looks good for coastal districts. Is there a chart for 850hpa temps for the same time, not expecting much here at lower levels but I can imagine somewhere like the North York Moors will see some decent snowfall.

 

Here we go vizzy.

151117_0000_102.png

 

The GFS 6z seem to hold on to a cool/cold Pm flow from the N/W into the run. So certainly more seasonal temps from here-on-in.

post-12319-0-03000300-1447759315_thumb.p

post-12319-0-85342800-1447759324_thumb.p

post-12319-0-20076300-1447759333_thumb.p

Edited by Polar Maritime

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Looks good for coastal districts. Is there a chart for 850hpa temps for the same time, not expecting much here at lower levels but I can imagine somewhere like the North York Moors will see some decent snowfall.

post-15543-0-41934300-1447759535_thumb.p

There ya go.

 

Sorry Polar M. Didn't see you had posted a reply aswell!

Edited by Mark N

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These are good visuals at T72 hrs from the 00z runs.The fax and ECM 850's for Fri 00hrs.

 

post-2026-0-25671100-1447760445_thumb.gipost-2026-0-93360700-1447760473_thumb.pn

 

a snapshot of the impending change to cold from the north.

A real risk of some snow and strong winds for some places as that Arctic airmass comes south.

 

Taken from the 06z GFS

post-2026-0-52673100-1447761034_thumb.pnpost-2026-0-33755500-1447761328_thumb.pn

 

that nasty little low in the N.Sea could bring some real Wintry conditions to the north and east,especially anywhere with elevation.

Strong winds with uppers -7 to -9C-what a change!

 

Currently it looks like a brief but notable cold snap but with those Atlantic heights around next week as the ECM and the GFS06Z run showed,a possible reload from the north is shown,after a brief recovery in temperatures.

 

Autumn seems to be going out on a much colder note than we would have thought a week ago.

 

 

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The ext ecm this morning ends with LP over the Pole with associated troughs Alaska and Greenland/Iceland thus an unsettled zonal westerly tending towards a N/S split over the UK.

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Strong winds with uppers -7 to -9C-what a change!

 

Autumn seems to be going out on a much colder note than we would have thought a week ago.

 

And adding on the Wind-chill Phil it will feel bitter!

 108-290UK.GIF?17-6 96-290UK.GIF?17-6

Edited by Polar Maritime

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Colder run than the 0z with a chilly flow maintained throughout. Nothing too spectacular after this weekend, but seasonal. Beyond that, it's proving fruitless looking for trends in the later frames, e.g.

 

T384 on the 0z has a ++++AO:

 

gfsnh-0-384.png?0

 

T384 on the 6z is the, ahem,  polar opposite:

 

gfsnh-0-384.png?6

 

Could happen  :)

That Siberian high is monstrous. One thing to keep an eye on as we go through the runs. Possible retrogression into Greenland from the poleward side!!

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The ext ecm this morning ends with LP over the Pole with associated troughs Alaska and Greenland/Iceland thus an unsettled zonal westerly tending towards a N/S split over the UK.

Much as Meto monthly forecast. However, just like the upcoming cold northerly blast, these extended have a habit of not picking up on cold bursts.

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Much as Meto monthly forecast. However, just like the upcoming cold northerly blast, these extended have a habit of not picking up on cold bursts.

 

It's not really a habit of not picking up. more that they are not intended to pick up shortwave detail so they should always be read with this in mind.

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And adding on the Wind-chill Phil it will feel bitter!

 108-290UK.GIF?17-6 96-290UK.GIF?17-6

Yes indeed.

A look at the latest  London 2m temp ens

post-2026-0-23179700-1447765275_thumb.gi

 

underlines the cold.These have been solid for days now ,a brief but notable Arctic incursion then a recovery but still on the low side.

Note the ECM op goes cold again later-that next reload from the north shown in the 00z op.run.

The GFS 00z run didn't go with that but the latest 006z run has.

Interesting to see if the 12z's follow on with that.

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It's not really a habit of not picking up. more that they are not intended to pick up shortwave detail so they should always be read with this in mind.

Fair enough but the upcoming weekend cold has been brought about by more than just a shortwave. The main catalyst for the cold spell is the rapid amplification over Newfoundland and then the north atlantic. The extended and also the ECM 32 dayer didn't pick up on these major amplifications.

Yes indeed.

A look at the latest London 2m temp ens

attachicon.gifensemble-tt6-london.gif

underlines the cold.These have been solid for days now ,a brief but notable Arctic incursion then a recovery but still on the low side.

Note the ECM op goes cold again later-that next reload from the north shown in the 00z op.run.

The GFS 00z run didn't go with that but the latest 006z run has.

Interesting to see if the 12z's follow on with that.

Yes, the reload is a trend we need to see increase on the 12z runs. Edited by blizzard81

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The Ecm as perseived.

Seems to by taking

The cleaner evolution for the upcoming cold shot.

Cleaner perhaps with a possible' re_route to a follow up blast shortly afterward.

Intrest will certainly come

With this evenings 12z suite

Compare.....Gfs/Ecm

With 12zte compare ie

GFS/Ecm....

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Much as Meto monthly forecast. However, just like the upcoming cold northerly blast, these extended have a habit of not picking up on cold bursts.

 

I have to disagree with that. The anomaly charts regularly pick up 6-15 days ahead when a marked change of upper air pattern, a wavelength change is going to occur. This with careful use will indicate both bursts of tropical air in summer and cold air outbreaks in winter. They were slower than usual with this current one but did give perhaps 5 days maybe 7 of the upper air changing direction indicating colder weather developing.

see below for NOAA chart issued last Saturday, prior to that ECMWF-GFS had first hinted at this on the Thursday.

 

anomaly chart sat 14 nov for net wx.doc

 

sorry it has copied my whole November anomaly chart file, you will find it for Sat 14 nov if you scroll down

Edited by johnholmes

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WSI euro weathers chart for Saturday morning

 

CUAn_LbW4AIxq6O.png

 

giphy.gif

is this an area of convective showers moving in off the North sea or a front pushing South/West? Cheers

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I have to disagree with that. The anomaly charts regularly pick up 6-15 days ahead when a marked change of upper air pattern, a wavelength change is going to occur. This with careful use will indicate both bursts of tropical air in summer and cold air outbreaks in winter. They were slower than usual with this current one but did give perhaps 5 days maybe 7 of the upper air changing direction indicating colder weather developing.

see below for NOAA chart issued last Saturday, prior to that ECMWF-GFS had first hinted at this on the Thursday.

attachicon.gifanomaly chart sat 14 nov for net wx.doc

sorry it has copied my whole November anomaly chart file, you will find it for Sat 14 nov if you scroll down

Thanks John but I was alluding to the 2 - 3 week extended that knocker was referring to, not to the short/medium term. Edited by blizzard81

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is this an area of convective showers moving in off the North sea or a front pushing South/West? Cheers

 

Not sure sorry

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is this an area of convective showers moving in off the North sea or a front pushing South/West? Cheers

Looks to me like a trough/front sliding down the country, very very similar to 30th January 2003 when East Midlands, East Anglia and even as far as Hampshire and west London got blanketed unexpectedly by snow.

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I see the ECM has another re-load for next week with another northerly.

 

If you look upstream there are big differences between it and the other models,in the state discussions by NCEP we should take note of this:

 

VERY LITTLE CHANGE TO FORECAST GIVEN CONTINUED DISPARITY AMONGST
THE MAJOR MEDIUM RANGE MODELS AT THE 00Z RUN. HANDLING OF
SIGNIFICANT NORTHERN STREAM HIGH AMPLITUDE TROF AND SFC LOW
REDEVELOPMENT OVER THE WEEKEND INTO MONDAY NEXT REMAINS IN
QUESTION.

 

The ECM develops a much deeper low over central Canada at T144hrs and also has another more amplified system ahead of this, these culminate at T168hrs by  phasing and helping to build the ridge to the east by means of WAA.

 

Its quite a complicated set up over the eastern USA and western Atlantic so I'd be cautious about getting too excited about another northerly.

 

A positive in terms of the ECM is in relation to its performance over the last week, both the UKMO and GFS originally were too flat, however we tend to find that the middle ground solution ends up being the way to go.

 

We should have agreement this evening as the differences start as early as T120hrs over the USA and Canada.

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