is this correct or is it outdated now.

Roughly, take the thickness on the 500 hPa chart, and for each 5 mb of pressure above 1000 mb subtract 4 dam of thickness, or for each 5 mb of pressure under 1000 mb add 4 dam of thickness.

E.g. 536 dam on the 500 hPa chart with 1010 mb of pressure corresponds to the magic 528 dam line on the 850 hPa chart.

Is that a possible split in the PV

Way too much variation in the models to make a call for this weekend, let alone next week.

UKMO is a peach for the weekend but not great going forward from day 6 while GFS is the reverse!

All about exactly where and when lows develop along the cold/mild boundary Fri-Sat and then where they track and how strong they become. Usually we have at least a couple of those points nailed down by 4 days range but on this occasion we have nothing sorted out whatsoever. Could be anything from rain as far north as The Midlands to a snow event across the far south with other areas seeing only showers (though probably at least wintry) or dry, bright conditions.

Based on tropical signals, it still looks like the most significant blocking patterns with high latitude components are likely to be right at the end of the season. Typical isn't it? Hopefully we can get trough disruption next week to maintain some nearer-term interest after the Fri-Mon shenanigans.

Nino winters and winters since 1988 re synonymous with a strong +ve NAO, have them both together and there's your answer.

2009-10 was El Niño winter and was the coldest for 31 years and was very -NAO.....

Ian, if you want to bring up the subject of winters in the era post-1988, please find a more appropriate thread for discussion of that subject and leave this thread for the purpose for which it is intended.

Thank you.

http://www.wetterzentrale.de/pics/Rtavn13217.gif

Harsh frost up in Scotland

Interesting pub run!

Eye brow partially raised on the other side of the English Channel too!

Edit: 'Risk' of snow on four out of 5 days next week IMBY according to the 18z GFS Op! 😜

Now then, what's going on here ...

There seems to be a hint of a trend the last few runs of a nascent Scandy high putting up some resistance next week.

Very interesting run

So there we go, Sunday Cold NE airflow 12z and beyond, Are we going to See it again on Monday eh?, the BBC weather at 9:55 p.m. was showing a mostly dry northerly on Monday I bet the UKMO and MetOffice data and charts go against his saying by showing us what it is showing Cold NE flow turning to dry Northerly after Midday Monday.

Will either be getting hit or miss in London some will see some won't- and they will be just sleet showers as it not cold enough with the 6-7 max temperatures they like to show us and we are still less cold it went upto 9 deg c in London maybe 10 today Wednesday Feb. 10th.  Heavy rain for London on Saturday and Sunday nothing wintry at all, max temps should be about 7 deg. Celsius this Weekend for here.

Sunday pm and all of Monday temperature should drop below 7 I hope.🌧💦😀😃.  Now when do 96 and 120hr fax charts update anyone seen it today?.😄.

GEFS has  pretty cold uppers for large majority of ENS persisting out to Thursday 18th.

True, although the Op seems to be by far the coldest on the shorts.

Just a tease.The Greenland HP makes a belated appearance at the end of FI

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=360&code=15&mode=0&carte=0

Massive variance in the models this morning.  ECM will be of interest.  More runs needed as to whether there is a later or early end to the colder spell (or snap).  I'm open minded on this one, ambivalent even.

WI

Agreed, some buckles in the Jet too  - nice to hope that the Scandy high can build and intensify, but given the general pattern of how this Winter has been that's probably a long shot. I suspect when ECM comes out we will end up with something similar to the January cold spell most probably with milder weather rolling in towards the end of next week. At least one of those rare frost things this morning, only seen about 2 or 3 others all winter 

http://www.meteociel.fr/ukmo/fax/fax120s.gif?0

Last nights 120 fax has some fronts dotted about the place , good for usual suspects in this set up

http://www.theweatheroutlook.com/charts/gfs/00_159_preciptype.png?cb

Possibilities for next week

J F F  of course

http://www.theweatheroutlook.com/charts/gfs/00_168_preciptype.png?cb

yep, looks positive 

ECM has moved towards the GFS position of dropping the trough towards the UK rather than the energy going over the top.

Closer to hand and the temperatures this weekend being progged are high given the synoptics; very disappointing for February that these synoptics are not going to deliver very much if anything snow wise.

Also has the 528 isotherm along the M4 corridor on Sunday .GFS ECM and METO have a slight southward shift in LP tracks but giving a better chance of snow from Midlands northward.

( this morning celebrating the first February air frost  in central Winchester)

Longer term nice to see HP appearing to north east but likly to get squeezed away SE-just a question of when.

3rd February 1990: a runner low ran through the Channel, gave a heavy wet snowfall to parts of the south

While I think it's all looking all cold, wet and bleak over the weekend so I won't hold my breath for that, but my back yard may be in a shout with a last minute bit of wintriness if this 850 hpa chart for next Wednesday is to be believed.



But, again, it's all a long way off in forecasting terms, etc, etc, etc, yadda and so forth. Probably end up being all dull and cold given the col-like set up, but it does make a nice change not to see charts showing deep dartboard Atlantic lows sitting over the UK.